A method for controlling the motion accuracy of the rolling mechanism of a seamless steel pipe cold rolling mill

Abstract

The present invention discloses a method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill, including optimizing motion gap parameters and a motion gap control benchmark. The optimized motion gap parameters include online measurement of the actual equivalent motion gap of the cold rolling mill when loaded, unloaded, and in the front and rear positions of its working frame, calculating the wear value of the motion gap and the deviation direction and equivalent of the motion gap on the left and right sides relative to the rolling centerline. The motion gap control benchmark uses the base surface of the cold rolling mill's side panels as a measurement calibration benchmark, and accumulates the actual thickness of the machine base side slides and the frame side slides with the actual gap value to obtain the actual spatial distance between the two sides of the working frame and the base layer of the machine base. The present invention is a technical improvement to the existing method for controlling the motion gap of the rolling mechanism of a two-roller periodic seamless steel tube cold rolling mill.

Description

Technical Field

[0001] The present invention relates to cold rolling production equipment for producing seamless steel pipes in the metallurgical and mechanical industries, and more specifically, to a method for controlling the motion accuracy of the rolling mechanism of a seamless steel pipe cold rolling mill. The method is particularly suitable for controlling the motion accuracy of the rolling mechanism of a two-roll periodic seamless steel pipe cold rolling mill with a product specification of φ15mm or more. Background Art

[0002] Seamless steel pipe is a common metallurgical metal product. Cold rolling technology for seamless steel pipe has become the main method of producing and processing seamless steel pipe due to its high rolling precision, fast speed, large production capacity, high yield rate, and easy production organization and process technology adjustment.

[0003] Cold rolling equipment for seamless steel pipes is categorized into two-roll and multi-roll types based on the number of rolls. The two-roll cyclic cold rolling mill is the most widely used due to its compact structure, high rolling force, and high production capacity. The structure of a two-roll cyclic seamless steel pipe cold rolling mill primarily consists of a rolling mechanism, a feed and rotary mechanism, a transmission mechanism, a mandrel chuck mechanism, a bed support mechanism, a feeding and blanking mechanism, a hydraulic system, a process lubrication system, an electrical automation control system, a pneumatic system, and auxiliary mechanisms. The rolling mechanism performs cold deformation of the seamless steel pipe billet at room temperature using a deformation tool consisting of a plug and a pass.

[0004] Please combine Figure 1 and Figure 2As shown, the rolling mechanism consists of a roll assembly (including an upper roll assembly 1 and a lower roll assembly 2), a base 3, a working frame 4, a transmission rack assembly (including a base left transmission rack 5 and a base left transmission rack 6), and a slide assembly (including a base left slide assembly 7 located within the base left motion gap and a base right slide assembly 8 located within the base right motion gap). The base 3 is placed on a concrete foundation 9, and the working frame 4 is centrally mounted vertically within the base 3 and connected to the transmission mechanism via a horizontal connecting rod. A slide assembly is provided between the working frame 4 and the base 3 to provide support, guidance, and protection. The slide assembly is divided into two parts according to its installation location: a base slide assembly and a frame slide assembly. Furthermore, according to the function of the slide assembly, it is divided into a base upper slide assembly 10, a base side slide assembly 11, and a base slideway 12, as well as a frame upper slide assembly 13, a frame lower slide assembly 14, and a frame side slide assembly 15. The roller device includes two relatively independent roller groups, the upper roller device 1 and the lower roller device 2, which are installed in pairs in the working frame 4. The cylindrical gears at the outer ends of the roller shafts are engaged with the transmission rack devices installed on both sides of the machine base 3; the transmission rack device includes the left side transmission rack 5 and the left side transmission rack 6 of the machine base, which are respectively installed on the steps of the left and right side panels of the machine base 3, and are fixed with special high-strength bolts. The meshing gap between the roller gear and the rack can be adjusted by the axial displacement of the transmission rack device.

[0005] Please combine Figure 3 As shown, for the rolling mechanism of the two-roller periodic seamless steel tube cold rolling mill, the synchronous rotation of the roller device is the main motion, and the horizontal reciprocating motion of the working frame is the secondary motion. Due to the working characteristics of the rolling mechanism, the horizontal reciprocating motion accuracy of the working frame directly affects the operating quality of the entire rolling mechanism, and also determines the rolling accuracy and quality of the seamless steel tube. The motion accuracy of the working frame is the motion gap between the working frame and the machine base. The bottom and both sides of the working frame are in contact with the machine base respectively, forming six operating contact surfaces, and the motion gaps of these six moving contact surfaces determine the horizontal operating accuracy of the entire rolling mechanism. Therefore, the motion gaps of the rolling mechanism of the seamless steel tube cold rolling mill include:

[0006] 1) The left lateral movement gap C1 between the frame side slide on the left side of the working frame and the base side slide on the left side of the base;

[0007] 2) The right side lateral movement gap C2 between the frame side slide on the right side of the working frame and the base side slide on the right side of the base;

[0008] 3) The left upper movement gap S1 between the frame upper slide on the left side of the working frame and the base upper slide on the left side of the base;

[0009] 4) The upper right motion gap S2 between the frame upper slide on the right side of the working frame and the base upper slide on the right side of the base.

[0010] The left and right lateral movement clearances C1 and C2 are composed of the original clearance and wear equivalent between the side slides of the machine base and the working frame; the left and right upper movement clearances S1 and S2 are composed of the original clearance and wear equivalent between the machine base and the upper slide of the working frame, as well as the original clearance and wear equivalent between the machine base and the lower slide of the working frame. Since the working frame is placed as a whole on the machine base slide, there is no gap (original clearance and movement clearance) between the machine base slide and the lower slide of the working frame. The wear of both is fully reflected in the upper movement clearance formed by the upper slide of the working frame and the upper slide of the machine base. The lateral movement clearances C1 and C2 of the rolling mechanism determine the torsion (swing) and lateral horizontal deviation of the working frame during the reciprocating horizontal movement of the machine base. The upper movement clearances S1 and S2 determine the jumping (jitter) and tilt of the working frame during the reciprocating horizontal movement of the machine base. Therefore, effectively controlling the motion gap accuracy of the rolling mechanism is the core element of the precision control of the entire rolling mechanism, and is also the key task of daily equipment operation and maintenance of the seamless steel tube cold rolling mill.

[0011] Due to the long-term operation of the contact surface between the working frame and the base, wear will inevitably occur. Therefore, six sets of slides are installed as replacement parts at the contact points between the working frame and the base. The purpose is to regularly replace the slides to promptly repair the worn movement gap and ensure the operation stability of the working frame in the base. However, in production practice, although the existing rolling mechanism motion accuracy control method can meet the requirements of seamless steel pipe cold rolling deformation processing, it still has certain shortcomings, namely:

[0012] 1) The equivalent of the motion gap parameter is unreasonable: The current motion gap parameter value is set according to the technical parameters provided by the equipment manufacturer, which varies slightly according to different specifications and models. Taking the LG-150H cold rolling mill as an example, the lateral gap C1+C2 is between 1.5 and 2.0 mm, where C1 or C2 is not greater than 0.8 to 1.0 mm; the upper gap S1=S2 is not greater than 1.0 to 1.5 mm. This motion gap parameter is easily affected by factors such as the tilting and sinking of the machine base and online high-flow lubrication. The daily maintenance load is heavy, and the motion gap measurement, calibration, and correction operations are highly technical, and require high qualifications, skills, and experience of the operators.

[0013] 2) The equivalent calculation of the motion gap parameters is inconvenient: At present, the motion gap parameters of the rolling mechanism are measured based on the rolling center line, and the corresponding technical parameters are calculated through the mutual spatial position relationship between the frame and the base. The rolling center line is a virtual straight line, starting from the finished product discharge stand to the billet feeding stand, running through the entire seamless steel pipe cold rolling mill. From the spatial dimension, the rolling center line is both a horizontal and vertical reference, and theoretically should coincide with the axis of the seamless steel pipe being rolled. Therefore, it is theoretically feasible to use the rolling center line as the reference for the running gap of the rolling mechanism, but in production practice, the operation is very inconvenient, time-consuming and labor-intensive, and not worth the effort;

[0014] 3) Different motion clearance wear values: Theoretically, the lateral motion clearances on both sides of the working frame should be equal. However, in production practice, the upper clearance (commonly known as the sky-ground clearance) and the lateral clearance (commonly known as the mountain clearance) on both sides of the working frame are not equal. This is mainly due to the different loads borne during rolling, especially the lateral (mountain) clearances on both sides, which are more affected by the vibration (swing) of the frame. At the same time, the base will tilt slightly due to uneven sinking of the foundation, which will increase the wear equivalent deviation of the working frame in the base. This brings difficulties to the synchronous equal control of motion accuracy.

[0015] 4) There are certain inadaptabilities in the cold rolling deformation processing of high-end seamless steel pipes: In recent years, with the industrial production of high-end seamless steel pipe products such as high-alloy and high-strength products, the requirements for the operating stability of the rolling mechanism of the seamless steel pipe cold rolling mill have become more stringent; Due to the high strength of high-end seamless steel pipes, the rolling mechanism bears a large load during the deformation process, so the motion gap accuracy between the machine base and the working frame is required to be high. If the gap is too large, the working frame is prone to swing and jump, which directly causes damage to the surface of the seamless steel pipe; if the gap is too small, it will cause scratches and stagnation on the contact surface between the working frame and the machine base, resulting in losses due to failure and downtime.

[0016] In summary, although the existing technical methods for controlling the motion clearance of the rolling mechanism can meet the rolling technical requirements of the seamless steel tube cold rolling mill, they are prone to deviations in the calibration of the motion clearance. The existing wear equalization correction method cannot completely repair the actual unequal motion clearance equivalents, and is more likely to cause local cumulative deviations, which directly affect the operating accuracy of the working frame. At the same time, since the adjustment of the operating accuracy of the rolling mechanism requires the removal of the working frame, the downtime is long and the maintenance resources are consumed heavily. Therefore, it cannot be implemented as a regular project. Once implemented, it must be corrected and compensated to a motion clearance that meets the technical requirements to create conditions for ensuring the operating accuracy of the rolling mechanism in subsequent production. Summary of the Invention

[0017] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill, which is a technical improvement on the existing method for controlling the motion gap of the rolling mechanism of a two-roll periodic seamless steel tube cold rolling mill.

[0018] To achieve the above object, the present invention adopts the following technical solutions:

[0019] A method for controlling the motion accuracy of a rolling mechanism of a seamless steel tube cold rolling mill, comprising optimizing motion gap parameters and a motion gap control benchmark;

[0020] The optimization of the motion gap parameters includes: online measurement of the actual equivalent of the motion gap of the cold rolling mill under heavy load, no load, and the working frame in the front and rear positions of the machine base, and calculation of the wear value of the motion gap, as well as the deviation direction and equivalent of the motion gap on the left and right sides relative to the rolling center line;

[0021] The motion gap control benchmark includes using the base surface of the two side panels of the cold rolling mill as the measurement calibration benchmark, adding the actual thickness of the base side slide and the frame side slide with the actual gap value to obtain the actual spatial distance between the two sides of the working frame and the base layer of the base.

[0022] Preferably, the method comprises the following steps:

[0023] 1) Preparation for the operation;

[0024] 2) Working frame positioning;

[0025] 3) Online measurement of the motion clearance of the cold rolling mill under heavy load, no load, and its working frame in the front and rear positions of the machine base;

[0026] 4) Calculate the wear equivalent of each moving surface, which is the actual value of the moving clearance;

[0027] 5) Calculation and determination of motion gap parameters.

[0028] Preferably, the step 1) includes safety technology briefing, implementation of on-site safety precautions, registration and posting of maintenance work, and preparation of tooling and equipment.

[0029] Preferably, in step 2), the online detection of the movement gap of the cold rolling mill under heavy load conditions includes the following steps:

[0030] 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device to ensure that the seamless steel pipe is within the full length range of the machine base according to the rolling state;

[0031] 2.2) Measurement of the rear limit position of the working frame: The working frame is positioned at the rear limit position of the machine base. The equipment is powered off, and the operator enters the machine base. The actual gap values of the four moving contact surfaces between the working frame and the machine base are measured using feeler gauges. The actual values of the moving gap parameters C1zh, C2zh, S1zh, and S2zh are recorded, and the operator evacuates the machine base.

[0032] C1zh indicates the left lateral motion gap, C2zh indicates the right lateral motion gap, S1zh indicates the left superior motion gap, and S2zh indicates the right superior motion gap;

[0033] 2.3) Measurement of the front limit position of the working frame: The equipment is powered on, the working frame is positioned at the front limit position of the machine base, the equipment is powered off, the operator enters the machine base, and uses feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base. The actual values of the moving gap parameters C1zq, C2zq, S1zq, and S2zq are recorded, and the operator evacuates the machine base;

[0034] C1zq represents the left lateral movement gap, C2zq represents the right lateral movement gap, S1zq represents the left upper movement gap, and S2zq represents the right upper movement gap.

[0035] Preferably, in step 2.1), the entire length of the stand is such that the end face of the finished pipe after rolling protrudes horizontally from the annular rolling groove of the front limit station of the working stand by no less than 150 mm; or

[0036] The end face of the unrolled tube billet shall protrude horizontally from the annular rolling groove of the rear limit station of the working frame by not less than 350mm.

[0037] Preferably, in step 2), the online detection of the movement gap of the cold rolling mill under no-load working condition includes the following steps:

[0038] 3.1) No-load positioning: Power on the equipment and remove the seamless steel pipe that runs across the inside of the machine base and through the annular hole;

[0039] 3.2) Measurement of the rear limit position of the working frame: The working frame is positioned at the rear limit position of the machine base. The equipment is powered off, and the operator enters the machine base. The actual gap values of the four moving contact surfaces between the working frame and the machine base are measured using feeler gauges. The actual values of the moving gap parameters C1kh, C2kh, S1kh, and S2kh are recorded, and the operator evacuates the machine base.

[0040] C1kh indicates the left lateral motion gap, C2kh indicates the right lateral motion gap, S1kh indicates the left superior motion gap, and S2kh indicates the right superior motion gap;

[0041] 3.3) Measurement of the front limit position of the working frame: The equipment is powered on, the working frame is positioned at the front limit position of the machine base, the equipment is powered off, the operator enters the machine base, and uses feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base. The actual values of the moving gap parameters C1kq, C2kq, S1kq, and S2kq are recorded, and the operator evacuates the machine base;

[0042] C1kq represents the left lateral movement gap, C2kq represents the right lateral movement gap, S1kq represents the left upper movement gap, and S2kq represents the right upper movement gap.

[0043] Preferably, the step 4) further comprises:

[0044] A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition:

[0045] A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the working frame rear limit position) / 2, that is, C1k = (C1kq + C1kh) / 2;

[0046] A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2;

[0047] A3) The wear equivalent of the left upper motion clearance S1k between the left upper slide of the working frame and the left upper slide of the machine base = (the left upper clearance value of the working frame front limit position + the left upper clearance value of the rear limit position of the working frame) / 2, that is, S1k = (S1kq + S1kh) / 2;

[0048] A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2;

[0049] B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions:

[0050] B1) The wear equivalent of the left lateral motion clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the working frame rear limit position) / 2, that is, C1z = (C1zq + C1zh) / 2;

[0051] B2) The wear equivalent of the right lateral clearance C2z between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2z = (C2zq + C2zh) / 2;

[0052] B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1z = (S1zq + S1zh) / 2;

[0053] B4) The wear equivalent of the upper right side movement clearance S2z between the upper right side slide of the working frame and the upper right side slide of the machine base = (the upper right side clearance value of the front limit position of the working frame + the upper right side clearance value of the rear limit position of the working frame) / 2, that is, S2z = (S2zq + S2zh) / 2.

[0054] Preferably, the step 5) further comprises:

[0055] Determination of the horizontal offset of the working frame: the rolling center line deviation Cp = |C1-C2| = |C1z-C1k| - |C2z-C2k|, and based on the heavy load condition, if C1z>C2z, the rolling center line deviates to the right side of the machine base; if C1z<C2z, the rolling center line deviates to the left side of the machine base; if C1z=C2z, there is no deviation of the rolling center line;

[0056] Determination of the longitudinal and horizontal offset of the working frame: Directly determine the tilt direction and equivalent of the working frame, including:

[0057] a) When S1zq>S1zh or S2zq>S2zh, the wear equivalent of the front limit station is greater than that of the rear limit station, and the working frame is tilted forward. The tilt equivalent is the difference between the two.

[0058] b) When S1zq<S1zh or S2zq<S2zh, the wear equivalent of the front limit station is smaller than that of the rear limit station, the working frame is tilted backward, and the tilt equivalent is the difference between the two;

[0059] c) When S1zq = S1zh or S2zq = S2zh, the wear equivalents of the front and rear limit stations are equal, and the working frame does not tilt in the front and rear horizontal directions. The tilt equivalent is the difference between the two.

[0060] d) When S1zq>S2zq or S1zh>S2zh, the wear equivalent of the upper left motion clearance is greater than that of the upper right motion clearance, and the working frame is tilted to the left of the machine base. The tilt equivalent is the difference between the two.

[0061] e) When S1zq < S2zq or S1zh < S2zh, the wear equivalent of the upper left motion clearance is smaller than that of the upper right motion clearance, and the working frame is tilted toward the right side of the machine base. The tilt equivalent is the difference between the two.

[0062] f) When S1zq = S2zq or S1zh = S2zh, the upper motion clearance wear equivalents on the left and right sides are equal, and the working frame does not tilt in the left and right vertical directions. The tilt equivalent is the difference between the two.

[0063] g) When S1zq>S2zq or S1zh<S2zh, S1zq<S2zq or S1zh>S2zh, and S1zq=S2zq or S1zh<S2zh, S1zq=S2zq or S1zh>S2zh, S1zq>S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, then the working frame has an unbalanced disturbance in the front-to-back direction or the left-to-right direction on the machine base;

[0064] Determination factors of the motion clearance of the rolling mechanism: take the base surface of the panels on both sides of the machine base as the measurement calibration reference, add the actual thickness of the machine base side slides and the frame side slides with the actual gap values to obtain the actual space distance between the two sides of the working frame and the machine base base; based on the thickness of the standard components of the working frame and the machine base side slides and the actual space distance values, the difference after subtraction is the actual motion clearance value after replacing the side slides, so as to determine whether the motion clearance value meets the technical requirements.

[0065] The method provided by this invention for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill features a rational process design, convenient model calculation, no additional investment costs, reduced reliance on skills and experience, ease of on-site implementation, safety, reliability, practicality, and efficiency. This method meets the needs of seamless steel tube cold rolling mills of varying sizes, specifications, and wear equivalence, promoting the improvement of equipment functional precision and ensuring the operational accuracy and efficiency of the entire rolling mechanism. The method is highly versatile and offers valuable reference and application value for improving existing technologies for motion accuracy control of rolling mechanisms in similar two-roller periodic seamless steel tube cold rolling mills.

[0066] It also has the following beneficial effects:

[0067] 1) The process design is reasonable and the process steps are smooth, without increasing related costs. It is safe, reliable, practical and efficient, meeting the cold rolling production needs of high-strength and high-end seamless steel pipes;

[0068] 2) Model measurement is convenient, the calculation model is quick to use, and it saves time and labor, reduces dependence on the skills and experience of operators, and the operation method is replicable, creating good conditions for standardized operations;

[0069] 3) The actual equivalent of the motion clearance under heavy load and no-load conditions, as well as the working frame at the two extreme working positions in front and behind the machine base, is measured online. The wear value of the motion clearance, as well as the deviation direction and equivalent of the motion clearance on the left and right sides relative to the rolling center line, are calculated with small error and high accuracy.

[0070] 4) Optimize the reference surface of the motion gap, use the base surface of the panels on both sides of the seamless steel tube cold rolling mill as the measurement calibration reference, add the actual thickness of the base side slide and the frame side slide with the actual gap value, and obtain the actual space distance between the two sides of the working frame (mountain position) and the base of the base;

[0071] 5) Through online precision measurement and calculation of the rolling mechanism motion clearance, the deviation equivalent between the working frame and the rolling center line, as well as the actual value of the motion clearance between the working frame and the base component, are timely understood. The calculation model is used to determine whether the technical requirements for the rolling mechanism motion accuracy are met.

[0072] 6) By setting standard values and limit values (critical values), determine whether the technical requirements for the rolling mechanism motion accuracy are met, and make a tendency analysis of the rolling mechanism motion accuracy to create conditions for subsequent motion gap correction operations;

[0073] 7) Promote the construction of equipment functional accuracy, ensure the operating accuracy and efficiency of the entire rolling mechanism, and meet the operating gap control technology requirements of the rolling mechanism of seamless steel pipe cold rolling mills of different models, specifications and different wear equivalents;

[0074] 8) It has strong versatility and has certain reference and application value for the improvement of the motion gap precision control technology of the rolling mechanism of similar two-roller periodic seamless steel tube cold rolling mills. It is applicable to all current models and specifications of two-roller periodic seamless steel tube cold rolling mills and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is a structural diagram of the rolling mechanism of a seamless steel pipe cold rolling mill;

[0076] Figure 2 yes Figure 1 Structural diagram of the operating gap of the middle rolling mechanism;

[0077] Figure 3 yes Figure 2 Schematic diagram of the operating clearance of the rolling mechanism;

[0078] Figure 4 It is a process flow chart of the method of the present invention;

[0079] Figure 5 It is a structural diagram of the movement gap of the rolling mechanism under heavy load working condition in the method of the present invention;

[0080] Figure 6 It is a structural schematic diagram of the motion gap of the rolling mechanism in the no-load working condition in the method of the present invention. DETAILED DESCRIPTION

[0081] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0082] Example 1: A steel pipe plant of a certain steel company uses the technology provided by the present invention on the imported SKW-75 and KPW-50 high-speed cold rolling mills on the seamless steel pipe cold rolling production line, as well as the LG-220H, LG-150H, LG-110H, LG-60H, LG-30H and other models of two-roller periodic seamless steel pipe cold rolling mills for cold rolling production and deformation processing of high-alloy austenitic and duplex stainless steel and nickel-based alloy seamless pipes.

[0083] Please combine Figure 4 As shown, the present invention provides a method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill. This method is a technical improvement over the existing method for controlling the motion gap of the rolling mechanism of a two-roll periodic seamless steel tube cold rolling mill. It is characterized by comprising two parts: optimizing the motion gap parameters and the motion gap control benchmark. The method measures the actual equivalent motion gap under load and no-load conditions, as well as the working frame at the front and rear extreme positions of the machine base, and calculates the wear value of the motion gap, as well as the deviation direction and equivalent of the motion gap on the left and right sides relative to the rolling centerline, thereby achieving precise setting of the rolling mechanism motion gap parameters.

[0084] The process includes the following steps: operation preparation, work frame positioning (front and rear limit positions), online measurement of motion clearance under working conditions of each position (heavy load, no load), calculation of wear equivalent of each moving surface (actual value of motion clearance), calculation and determination of motion clearance parameters, etc. That is:

[0085] 1) Operation preparation process includes: safety technology briefing, implementation of on-site safety precautions, registration and communication of maintenance operations, preparation of tooling and equipment, etc.

[0086] 2) Online detection of movement clearance under heavy load conditions of cold rolling mill, such as Figure 5 As shown;

[0087] 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device → ensure that the seamless steel pipe 100 is in the full length range of the machine base 18 according to the rolling state (the end face of the finished pipe after rolling protrudes horizontally from the annular hole rolling groove of the front limit station of the working frame by not less than 150mm, and preferably 200-250mm; or the end face of the unrolled tube protrudes horizontally from the annular hole rolling groove of the rear limit station of the working frame by not less than 350mm, and preferably 350-400mm);

[0088] 2.2) Measurement of the rear limit position of the working frame: Position the working frame 16 at the rear limit position 17 of the machine base (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operators enter the machine base 18 → Use feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame 16 and the machine base 18 (left lateral movement gap C1zh, right lateral movement gap C2zh, left upper movement gap S1zh, right upper movement gap S2zh) → Record the actual values of the movement gap parameters C1zh, C2zh, S1zh, and S2zh → Operators evacuate the machine base 18, as shown in the following example: Figure 5 (a) and (b) in the above;

[0089] 2.3) Measurement of the front limit position of the working frame: Power on the equipment → Position the working frame 16 at the front limit position 19 of the machine base (the ring-shaped rolling groove is at the finishing end of rolling) → Power off the equipment → Operator enters the machine base 18 → Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame 16 and the machine base 18 (left lateral movement gap C1zq, right lateral movement gap C2zq, left upper movement gap S1zq, right upper movement gap S2zq) → Record the actual values of the movement gap parameters C1zq, C2zq, S1zq, and S2zq → Operator evacuates the machine base 18, as shown in the figure. Figure 5 (c) and (d) in the

[0090] 3) Online detection of the movement gap of the cold rolling mill under no-load conditions, such as Figure 6 As shown,

[0091] 3.1) No-load positioning: Power on the equipment → Remove the seamless steel pipe that runs through the inside of the machine base 18 and passes through the annular hole (it is best that the front end of the seamless steel pipe in the machine base 18 does not exceed the inlet end face of the rear limit position 17 of the machine base);

[0092] 3.2) Measurement of the rear limit position of the working frame: Position the working frame 16 at the rear limit position 17 (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operators enter the machine base 18 → Use feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame 16 and the machine base 18 (left lateral movement gap C1kh, right lateral movement gap C2kh, left upper movement gap S1kh, right upper movement gap S2kh) → Record the actual values of the movement gap parameters C1kh, C2kh, S1kh, and S2kh → Operators evacuate the machine base 18, as shown in the following example: Figure 6 (a) and (b) in the above;

[0093] 3.3) Measurement of the front limit position of the working frame: Power on the equipment → Position the working frame 16 at the front limit position 19 (the ring-shaped rolling groove is at the finishing end of the rolling process) → Power off the equipment → Operators enter the machine base 18 → Use feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame 16 and the machine base 18 (left lateral movement gap C1kq, right lateral movement gap C2kq, left upper movement gap S1kq, right upper movement gap S2kq) → Record the actual values of the movement gap parameters C1kq, C2kq, S1kq, and S2kq → Operators evacuate the machine base 18, as shown in the following example: Figure 6 (c) and (d) in the

[0094] 4) Calculate the wear equivalent of each moving surface (actual value of the moving clearance);

[0095] A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition:

[0096] A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the working frame rear limit position) / 2, that is, C1k = (C1kq + C1kh) / 2;

[0097] A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2;

[0098] A3) The wear equivalent of the left upper motion clearance S1k between the left upper slide of the working frame and the left upper slide of the machine base = (the left upper clearance value of the working frame front limit position + the left upper clearance value of the rear limit position of the working frame) / 2, that is, S1k = (S1kq + S1kh) / 2;

[0099] A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the machine base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2.

[0100] B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions:

[0101] B1) The wear equivalent of the left lateral motion clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the working frame rear limit position) / 2, that is, C1z = (C1zq + C1zh) / 2;

[0102] B2) The wear equivalent of the right lateral clearance C2z between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2z = (C2zq + C2zh) / 2;

[0103] B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1z = (S1zq + S1zh) / 2;

[0104] B4) The wear equivalent of the upper right side movement clearance S2z between the upper right side slide of the working frame and the upper right side slide of the machine base = (the upper right side clearance value of the front limit position of the working frame + the upper right side clearance value of the rear limit position of the working frame) / 2, that is, S2z = (S2zq + S2zh) / 2.

[0105] 5) Calculation and determination of motion clearance parameters (wear equivalent);

[0106] 5.1) The determination of the offset (deviation) in the horizontal direction (roller centerline direction) of the working frame is the offset between the horizontal centerline of the working frame and the rolling centerline. The spatial distance is calculated through the lateral movement gap between the working frame and the machine base. That is, under the heavy-load condition of the rolling mechanism, the seamless steel pipe is constrained by the inlet and outlet chucks and other components, and the deviation relative to the rolling centerline is extremely small, which can be identified as the rolling centerline in the actual state. When the rolling mechanism is in the no-load condition, due to the lack of the centering constraint of the seamless steel pipe and the roller ring hole rolling groove, the working frame is in a free state in the horizontal direction. At this time, the absolute value of the difference between the lateral movement gap value between the working frame and the machine base and the measured gap value under the heavy-load condition can be identified as the deviation equivalent (offset) between the centerline of the working frame and the actual rolling centerline, and the direction of the offset is directly determined according to the lateral movement gap values on the left and right sides. That is, the rolling centerline deviation is the absolute value of the difference between the lateral movement gap C1 on the left side of the rolling mechanism and the lateral movement gap C2 on the right side, that is:

[0107] The rolling center line deviation Cp = |C1-C2| = |C1z-C1k| - |C2z-C2k|, and is based on the heavy load condition. If C1z>C2z, the rolling center line deviates to the right side of the machine base; if C1z<C2z, the rolling center line deviates to the left side of the machine base; if C1z=C2z, there is no deviation of the rolling center line.

[0108] 5.2) The vertical offset (deviation) of the working frame in the longitudinal horizontal direction (rolling centerline direction) is determined by the offset between the horizontal centerline of the working frame and the rolling centerline. Since the working frame is placed on the slide at the bottom of the machine base, there is no movement gap between the lower slide of the working frame and the machine base slide. The upper movement gaps S1 and S2 between the upper slide of the machine base and the upper slide of the working frame are the vertical deviations of the working frame relative to the rolling centerline. The inclination direction and equivalent of the working frame can be directly determined based on the actual values of the upper movement gaps S1zq and S1zh, S2zq and S2zh under heavy load conditions. That is:

[0109] a) When S1zq>S1zh or S2zq>S2zh, the wear equivalent of the front limit station is greater than that of the rear limit station, and the working frame is tilted forward (in the direction of seamless steel pipe rolling output), and the tilt equivalent is the difference between the two.

[0110] b) When S1zq<S1zh or S2zq<S2zh, the wear equivalent of the front limit station is smaller than that of the rear limit station, and the working frame is tilted toward the rear (input direction of seamless steel pipe rolling), and the tilt equivalent is the difference between the two.

[0111] c) When S1zq=S1zh or S2zq=S2zh, the wear equivalent of the front limit station is equal to that of the rear limit station, and the working frame does not tilt in the front and rear horizontal directions. The tilt equivalent is the difference between the two.

[0112] d) When S1zq>S2zq or S1zh>S2zh, the wear equivalent of the upper left motion clearance is greater than that of the upper right motion clearance, and the working frame is tilted toward the left side of the machine base. The tilt equivalent is the difference between the two.

[0113] e) When S1zq<S2zq or S1zh<S2zh, the wear equivalent of the upper left motion clearance is smaller than the upper right motion clearance, and the working frame is tilted toward the right side of the machine base. The tilt equivalent is the difference between the two.

[0114] f) When S1zq=S2zq or S1zh=S2zh, the upper motion clearance wear equivalents on the left and right sides are equal, and the working frame does not tilt in the left and right vertical directions. The tilt equivalent is the difference between the two.

[0115] g) When S1zq>S2zq or S1zh<S2zh, S1zq<S2zq or S1zh>S2zh, and S1zq=S2zq or S1zh<S2zh, S1zq=S2zq or S1zh>S2zh, S1zq>S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, etc., the working frame will have unbalanced disturbance in the front-to-back direction or left-to-right direction on the machine base, which is more destructive than tilting in a single direction and is more inconvenient to deal with on site.

[0116] 5.3) Determination factors of rolling mechanism movement clearance;

[0117] Using the base surface of the machine base's side panels as the measurement and calibration benchmark, the actual thickness of the machine base side slides and the actual clearance values of the frame side slides are added together to obtain the actual spatial distance between the two sides of the working frame (mountain position) and the machine base base. The difference between the thickness of the standard components of the working frame and the machine base side slides and the actual spatial distance values is the actual motion clearance value after replacing the side slides, which can be used to determine whether the motion clearance value meets the technical requirements. Specifically, the standard value of the rolling mechanism motion clearance is set within a certain range. For the LG-150H cold rolling mill as an example, under heavy load conditions, the lateral clearance C1z + C2z = 1.2 to 1.5 mm, with C1z or C2z no greater than 0.6 to 0.75 mm; the upper clearance S1 = S2 and no greater than 0.8 to 1.0 mm. If the actual motion clearance value after measurement and calculation exceeds the standard value range, offline correction should be considered until the motion clearance value meets the technical requirements.

[0118] Because the repair work for the rolling mechanism's motion clearance involves both offline correction by dismantling the working frame and online correction of the stand, the work is labor-intensive and time-consuming, with long downtimes. Therefore, a limit of +20% of the standard value (critical value) is used. When the measured motion clearance value is between the standard value and the limit value, rolling production can be maintained and preparations for offline correction work are made. When the measured motion clearance value exceeds the limit value, production must be stopped and the rolling mechanism's motion clearance must be inspected and maintained. Taking the LG-150H cold rolling mill as an example, the standard value for lateral clearance is C1+C2 = 1.2 to 1.5 mm, with C1 or C2 no greater than 0.6 to 0.75 mm. The upper clearance S1 = S2 is no greater than 0.8 to 1.0 mm. The limit value (critical value) is C1+C2=(1.2~1.5mm)×1.2=1.45~1.8mm, and C1 or C2 is not greater than (0.6~0.75)×1.2=0.7~0.9mm; the upper gap S1=S2 and is not greater than (0.8~1.0)×1.2=1.0~1.2mm.

[0119] According to the above-mentioned process steps, the on-site use of the method for controlling the motion accuracy of the rolling mechanism of the seamless steel pipe cold rolling mill provided by the present invention is completed, creating conditions for timely determination of the motion gap state of the rolling mechanism, and ensuring the motion accuracy and operation stability of the rolling mechanism during the cold rolling deformation processing of the seamless steel pipe.

[0120] Example 2, taking the LG-220H two-roller periodic seamless steel pipe cold rolling mill with a rolled product specification of φ114~219mm as an example, the rolling mechanism motion gap precision control technology is implemented on site. The standard value of the upper motion gap of the rolling mechanism is S1=S2=1.0~1.2mm, the standard value of the lateral motion gap is C=1.5~1.8mm, and the motion gaps C1 and C2 on any side should not be greater than 0.75~1.0mm. The steps included in this operation process are: operation preparation, working frame positioning (front and rear limit stations), online measurement of the motion gap under the working conditions of each station (heavy load, no-load), calculation of the wear equivalent of each moving surface (actual value of the motion gap), calculation and judgment of the motion gap parameters, etc. That is:

[0121] 1) Operation preparation procedures include: safety technical explanation, implementation of on-site safety precautions, registration and posting of maintenance operations, preparation of tooling and equipment, etc.

[0122] 2) Online detection of movement clearance of cold rolling mill under heavy load conditions;

[0123] 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device → ensure that the seamless steel pipe is in the full length range of the machine base according to the rolling state (the end face of the finished pipe after rolling protrudes horizontally from the annular hole rolling groove of the front limit station of the working frame by not less than 150mm, and preferably 200-250mm; or the end face of the unrolled tube protrudes horizontally from the annular hole rolling groove of the rear limit station of the working frame by not less than 350mm, and preferably 350-400mm);

[0124] 2.2) Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position of the machine base (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operator enters the machine base → Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zh, right lateral movement gap C2zh, left upper movement gap S1zh, right upper movement gap S2zh) → Record the movement gap parameters C1zh = 1.2mm, C2zh = 1.5mm, S1zh = 1.2mm, S2zh = 1.4mm → Operator evacuates the machine base;

[0125] 2.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position of the machine base (the ring-shaped rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zq, right lateral movement gap C2zq, left upper movement gap S1zq, right upper movement gap S2zq) → record the movement gap parameters C1zq = 1.4mm, C2zq = 1.6mm, S1zq = 1.2mm, S2zq = 1.3mm → the operator evacuates the machine base.

[0126] 3) Online detection of movement clearance of cold rolling mill under no-load condition;

[0127] 3.1) No-load positioning: Power on the equipment → Remove the seamless steel pipe that runs across the inside of the machine base and through the annular hole (inside the machine base (it is best if the front end of the seamless steel pipe does not exceed the inlet end face of the rear limit position of the machine base);

[0128] 3.2) Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operator enters the machine base → Use a feeler gauge to measure the actual clearance values of the four moving contact surfaces between the working frame and the machine base (left lateral movement clearance C1kh, right lateral movement clearance C2kh, left upper movement clearance S1kh, right upper movement clearance S2kh) → Record the movement clearance parameters C1kh = 1.2mm, C2kh = 1.3mm, S1kh = 1.2mm, S2kh = 1.4mm → Operator evacuates the machine base;

[0129] 3.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position (the annular rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1kq, right lateral movement gap C2kq, left upper movement gap S1kq, right upper movement gap S2kq) → record the movement gap parameters C1kq = 1.3mm, C2kq = 1.4mm, S1kq = 1.2mm, S2kq = 1.3mm → the operator evacuates the machine base.

[0130] 4) Calculate the wear equivalent of each moving surface (actual value of the moving clearance);

[0131] A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition:

[0132] A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the rear limit position of the working frame) / 2, that is, C1k = (C1kq + C1kh) / 2 = (1.3 + 1.2) / 2 = 1.25 mm;

[0133] A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2 = (1.4 + 1.3) / 2 = 1.35 mm;

[0134] A3) Wear equivalent of the left upper motion clearance S1k between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1k = (S1kq + S1kh) / 2 = (1.2 + 1.2) / 2 = 1.2 mm;

[0135] A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the machine base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2 = (1.3 + 1.4) / 2 = 1.35 mm.

[0136] B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions:

[0137] B1) The wear equivalent of the left lateral motion clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the rear limit position of the working frame) / 2, that is, C1z = (C1zq + C1zh) / 2 = (1.4 + 1.2) / 2 = 1.3 mm;

[0138] B2) Wear equivalent of the right lateral clearance C2z between the right side slide of the working frame and the right side slide of the machine base = (right lateral clearance value of the working frame front limit position + right lateral clearance value of the working frame rear limit position) / 2, that is, C2z = (C2zq + C2zh) / 2 = (1.6 + 1.5) / 2 = 1.55 mm;

[0139] B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the working frame and the left upper slide of the base = (the left upper clearance value of the working frame front limit position + the left upper clearance value of the rear limit position of the working frame) / 2, that is, S1z = (S1zq + S1zh) / 2 = (1.2 + 1.2) / 2 = 1.2 mm;

[0140] B4) The wear equivalent of the upper right side movement clearance S2z between the upper right side slide of the working frame and the upper right side slide of the machine base = (the upper right side clearance value of the front limit position of the working frame + the upper right side clearance value of the rear limit position of the working frame) / 2, that is, S2z = (S2zq + S2zh) / 2 = (1.3 + 1.4) / 2 = 1.35 mm.

[0141] 5) Calculation and determination of motion clearance parameters (wear equivalent);

[0142] 5.1) Determination of the offset (deviation) of the horizontal direction (roller centerline direction) of the working frame is the offset between the horizontal centerline of the working frame and the rolling centerline. The spatial distance is calculated through the lateral movement gap between the working frame and the machine base. The absolute value of the difference between the lateral movement gap value between the working frame and the machine base and the measured gap value under heavy load conditions can be used to determine the deviation equivalent (offset) between the centerline of the working frame and the actual rolling centerline. The direction of the offset can be directly determined based on the lateral movement gap values on the left and right sides. That is, the rolling centerline deviation is the absolute value of the difference between the lateral movement gap C1 on the left side of the rolling mechanism and the lateral movement gap C2 on the right side, that is: rolling centerline deviation Cp = |C1z-C1k||-|C2z-C2k||=|1.3-1.25||-|1.55-1.35||=0.15mm;

[0143] Based on the heavy load condition, if C1z = 1.3mm, C2z = 1.55mm, that is, C1z < C2z, it means that the rolling center line deviates to the left side of the stand, and the deviation (deviation) equivalent value = 0.15mm;

[0144] 5.2) The vertical offset (deviation) of the working frame in the longitudinal horizontal direction (rolling centerline direction) is determined by the offset between the horizontal centerline of the working frame and the rolling centerline. The upper movement clearances S1 and S2 between the upper slide of the machine base and the upper slide of the working frame are the vertical deviations of the working frame relative to the rolling centerline. The tilt direction and equivalent of the working frame can be directly determined based on the actual values of the upper movement clearances S1zq = 1.2mm, S1zh = 1.2mm, S2zq = 1.3mm, and S2zh = 1.4mm under heavy load conditions. That is:

[0145] S1zq=S1zh=1.2mm, indicating that there is no tilt in the front and rear of the left side of the working frame;

[0146] S2zq = 1.3 mm < S2zh = 1.4 mm, indicating that the right side of the working frame is tilted backward (in the direction of seamless steel pipe rolling input), and the tilt equivalent = S2zh - S2zq = 1.4 mm - 1.3 mm = 0.1 mm;

[0147] S1zq=1.2mm<S2zq=1.3mm, S1zh=1.2mm<S2zh=1.4mm, indicating that the working frame is tilted as a whole toward the right side of the machine base, and the tilt equivalent=[(S2zq-S1zq)+(S2zh-S1zh)] / 2=[(1.3-1.2)+(1.4-1.2)] / 2=0.15mm.

[0148] 5.3) Determination factors of rolling mechanism movement clearance;

[0149] Taking the base surfaces of the panels on both sides of the machine base as the measurement and calibration benchmark, the standard values of the movement clearance of the LG-220H cold rolling mill are: the standard value of the upper movement clearance is S1=S2=1.0~1.2mm, the standard value of the lateral movement clearance is C=1.5~1.8mm, and the movement clearance C1 and C2 on any side should not be greater than 0.75~1.0mm, with +20% of the standard value as the limit value (critical value). That is, under heavy load conditions, the standard value of the upper movement clearance of the rolling mechanism is S1z=S2z=1.0~1.2mm, the standard value of the lateral movement clearance is C1z+C2z=1.5~1.8mm, and C1z or C2z is not greater than 0.75~1.0mm; the limit value (critical value) lateral movement clearance C1z+C2z=(1.5~1.8)×1.2=1.8~2.2mm, and C1z or C2z is not greater than (0.75~1.0)×1.2mm=0.9~1.2mm; the upper movement clearance S1z=S2z=(1.0~1.2)×1.2=1.2~1.45mm;

[0150] The measured motion clearance wear equivalents are C1z=1.3mm, C2z=1.55mm, S1z=1.2mm, and S2z=1.35mm.

[0151] 1) Lateral clearance = C1z + C2z = 1.3 + 1.55 = 2.85 mm, exceeding the limit of 1.8 to 2.2 mm. C1z = 1.3 mm and C2z = 1.55 mm are both outside the limit of 0.9 to 1.2 mm.

[0152] 2) The upper movement clearance S1z=1.2mm, S2z=1.35mm, which is between the standard value and the limit value.

[0153] The upper movement clearance of the moving part of the rolling mechanism of the LG-220H cold rolling mill is between the standard value and the limit value (critical value), and the equipment can still be maintained in operation. However, the lateral movement clearance exceeds the range of the standard value and the limit value (critical value), which does not meet the technical requirements for the movement accuracy of the rolling mechanism. Therefore, it is determined that the machine should be shut down and the relevant movement clearance should be corrected to meet the technical requirements for the movement accuracy of the rolling mechanism of the seamless steel pipe cold rolling mill.

[0154] Example 3, taking the LG-150H two-roller periodic seamless steel pipe cold rolling mill with a rolled product specification of φ70~159mm as an example, the rolling mechanism motion gap precision control technology is implemented on site. The standard value of the upper motion gap of the rolling mechanism is S1=S2=0.8~1.0mm, the standard value of the lateral motion gap is C=1.2~1.5mm, and the motion gaps C1 and C2 on any side should not be greater than 0.6~0.75mm. The steps included in this operation process are: operation preparation, working frame positioning (front and rear limit stations), online measurement of the motion gap under the working conditions of each station (heavy load, no load), calculation of the wear equivalent of each moving surface (actual value of the motion gap), calculation and judgment of the motion gap parameters, etc. That is:

[0155] 1) Operation preparation process includes: safety technology briefing, implementation of on-site safety precautions, registration and communication of maintenance operations, preparation of tooling and equipment, etc.

[0156] 2) Online detection of movement clearance of cold rolling mill under heavy load conditions;

[0157] 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device → ensure that the seamless steel pipe is in the full length range of the machine base according to the rolling state (the end face of the finished pipe after rolling protrudes horizontally from the annular hole rolling groove of the front limit station of the working frame by not less than 150mm, and preferably 200-250mm; or the end face of the unrolled tube protrudes horizontally from the annular hole rolling groove of the rear limit station of the working frame by not less than 350mm, and preferably 350-400mm);

[0158] 2.2) Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position of the machine base (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operator enters the machine base → Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zh, right lateral movement gap C2zh, left upper movement gap S1zh, right upper movement gap S2zh) → Record the movement gap parameters C1zh = 1.2mm, C2zh = 1.1mm, S1zh = 1.1mm, S2zh = 1.0mm → Operator evacuates the machine base;

[0159] 2.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position of the machine base (the ring-shaped rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zq, right lateral movement gap C2zq, left upper movement gap S1zq, right upper movement gap S2zq) → record the movement gap parameters C1zq = 1.1mm, C2zq = 1.0mm, S1zq = 1.2mm, S2zq = 1.2mm → the operator evacuates the machine base.

[0160] 3) Online detection of movement clearance of cold rolling mill under no-load condition;

[0161] 3.1) No-load positioning: Power on the equipment → Remove the seamless steel pipe that runs across the inside of the machine base and through the annular hole (inside the machine base (it is best if the front end of the seamless steel pipe does not exceed the inlet end face of the rear limit position of the machine base);

[0162] 3.2) Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operator enters the machine base → Use a feeler gauge to measure the actual clearance values of the four moving contact surfaces between the working frame and the machine base (left lateral movement clearance C1kh, right lateral movement clearance C2kh, left upper movement clearance S1kh, right upper movement clearance S2kh) → Record the movement clearance parameters C1kh = 1.3mm, C2kh = 1.0mm, S1kh = 1.1mm, S2kh = 1.0mm → Operator evacuates the machine base;

[0163] 3.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position (the ring-shaped rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1kq, right lateral movement gap C2kq, left upper movement gap S1kq, right upper movement gap S2kq) → record the movement gap parameters C1kq = 1.2mm, C2kq = 1.1mm, S1kq = 1.2mm, S2kq = 1.2mm → the operator evacuates the machine base.

[0164] 4) Calculate the wear equivalent of each moving surface (actual value of the moving clearance);

[0165] A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition:

[0166] A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the rear limit position of the working frame) / 2, that is, C1k = (C1kq + C1kh) / 2 = (1.2 + 1.3) / 2 = 1.25 mm;

[0167] A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2 = (1.1 + 1.0) / 2 = 1.05 mm;

[0168] A3) Wear equivalent of the left upper motion clearance S1k between the left upper slide of the work frame and the left upper slide of the machine base = (the left upper clearance value of the work frame front limit position + the left upper clearance value of the rear limit position) / 2, that is, S1k = (S1kq + S1kh) / 2 = (1.2 + 1.1) / 2 = 1.15 mm;

[0169] A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the machine base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2 = (1.2 + 1.0) / 2 = 1.1 mm.

[0170] B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions:

[0171] B1) Wear equivalent of the left lateral clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (left lateral clearance value of the working frame front limit position + left lateral clearance value of the working frame rear limit position) / 2, that is, C1z = (C1zq + C1zh) / 2 = (1.1 + 1.2) / 2 = 1.15 mm;

[0172] B2) Wear equivalent of the right lateral clearance C2z between the right side slide of the working frame and the right side slide of the machine base = (right lateral clearance value of the working frame front limit position + right lateral clearance value of the working frame rear limit position) / 2, that is, C2z = (C2zq + C2zh) / 2 = (1.0 + 1.1) / 2 = 1.05 mm;

[0173] B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1z = (S1zq + S1zh) / 2 = (1.2 + 1.1) / 2 = 1.15 mm;

[0174] B4) The wear equivalent of the upper right side movement clearance S2z between the upper right side slide of the working frame and the upper right side slide of the machine base = (the upper right side clearance value of the front limit position of the working frame + the upper right side clearance value of the rear limit position of the working frame) / 2, that is, S2z = (S2zq + S2zh) / 2 = (1.2 + 1.0) / 2 = 1.1 mm.

[0175] 5) Calculation and determination of motion clearance parameters (wear equivalent);

[0176] 5.1) Determination of the offset (deviation) of the work stand in the horizontal direction (toward the roll centerline) is the offset between the horizontal centerline of the work stand and the rolling centerline. The spatial distance is calculated using the lateral clearance between the work stand and the base. The absolute value of the difference between the lateral clearance between the work stand and the base and the measured clearance under heavy load conditions is used to determine the equivalent deviation (offset) between the work stand centerline and the actual rolling centerline. The direction of the offset is directly determined based on the lateral clearance values on the left and right sides. The rolling centerline deviation is the absolute value of the difference between the lateral clearance C1 on the left side of the rolling mechanism and the lateral clearance C2 on the right side, i.e., rolling centerline deviation Cp = |C1z-C1k|-|C2z-C2k|=|1.15-1.25|-|1.05-1.05|=0.1mm.

[0177] Based on the heavy load condition, if C1z = 1.15mm, C2z = 1.05mm, that is, C1z>C2z, it means that the rolling center line deviates to the right side of the stand, and the deviation (deviation) equivalent value = 0.1mm;

[0178] 5.2) The vertical offset (deviation) of the working frame in the longitudinal horizontal direction (rolling centerline direction) is determined by the offset between the horizontal centerline of the working frame and the rolling centerline. The upper movement clearances S1 and S2 between the upper slide of the machine base and the upper slide of the working frame are the vertical deviations of the working frame relative to the rolling centerline. The tilt direction and equivalent of the working frame can be directly determined based on the actual values of the upper movement clearances S1zq = 1.2mm, S2zq = 1.2mm, S1zh = 1.1mm, and S2zh = 1.0mm under heavy load conditions. That is:

[0179] S1zq=1.2mm>S1zh=1.1mm, indicating that the left side of the working frame is tilted forward (in the direction of seamless steel pipe rolling output), and the tilt equivalent=S1zq-S1zh=1.2mm-1.1mm=0.1mm.

[0180] S2zq=1.2mm>S2zh=1.0mm, indicating that the right side of the working frame is tilted forward (in the direction of seamless steel pipe rolling output), and the tilt equivalent=S2zq-S2zh=1.2mm-1.0mm=0.2mm.

[0181] S1zq = S2zq = 1.2 mm, S1zh = 1.1 mm > S2zh = 1.0 mm, indicating that the front side of the working frame is not tilted, but the rear side is partially tilted to the left. The entire working frame is partially tilted to the left and rear, and the tilt equivalent = [(S2zq - S1zq) + (S2zh - S1zh)] / 2 = [(1.2 - 1.2) + (1.0 - 1.1)] / 2 = 0.05 mm.

[0182] 5.3) Determination factors of rolling mechanism movement clearance;

[0183] Taking the base surfaces of the panels on both sides of the machine base as the measurement and calibration benchmark, the standard values of the movement clearance of the LG-150H cold rolling mill are: the standard value of the upper movement clearance is S1=S2=0.8~1.0mm, the standard value of the lateral movement clearance is C=1.2~1.5mm, and the movement clearance C1 and C2 on any side should not be greater than 0.6~0.75mm, with +20% of the standard value as the limit value (critical value). That is: the standard value of the upper movement clearance of the rolling mechanism under heavy load conditions is S1z=S2z=0.8~1.0mm, the standard value of the lateral movement clearance is C1z+C2z=1.2~1.5mm, and C1z or C2z is not greater than 0.6~0.75mm; the limited value (critical value) lateral movement clearance C1z+C2z=(1.2~1.5)×1.2=1.45~1.8mm, and C1z or C2z is not greater than (0.6~0.75)×1.2mm=0.7~0.9mm; the upper movement clearance S1z=S2z=(0.8~1.0)×1.2=1.0~1.2mm.

[0184] The measured motion clearance wear equivalents are C1z=1.15mm, C2z=1.05mm, S1z=1.15mm, and S2z=1.1mm.

[0185] 1) Lateral clearance = C1z + C2z = 1.15 + 1.05 = 2.2 mm, exceeding the limit of 1.45 to 1.8 mm. C1z = 1.15 mm and C2z = 1.05 mm both exceed the limit of 0.7 to 0.9 mm.

[0186] 2) The upper movement clearance S1z=1.15mm, S2z=1.1mm, which is between the standard value and the limit value.

[0187] The upper movement clearance of the moving part of the rolling mechanism of the LG-150H cold rolling mill is between the standard value and the limit value (critical value), and the equipment can still maintain operation, but the lateral movement clearance exceeds the range of the standard value and the limit value (critical value), which does not meet the technical requirements of the rolling mechanism movement accuracy. Therefore, it is determined that the machine should be shut down and the relevant movement clearance should be corrected to meet the technical requirements of the rolling mechanism movement accuracy of the seamless steel pipe cold rolling mill.

[0188] Example 4, taking the LG-60H two-roller periodic seamless steel pipe cold rolling mill with a rolled product specification of φ25~60mm as an example, the rolling mechanism motion gap precision control technology is implemented on site. The standard value of the upper motion gap of the rolling mechanism is S1=S2=0.5~0.7mm, the standard value of the lateral motion gap is C=0.8~1.0mm, and the motion gaps C1 and C2 on any side should not be greater than 0.4~0.5mm. The steps included in this operation process are: operation preparation, working frame positioning (front and rear limit stations), online measurement of the motion gap under the working conditions of each station (heavy load, no load), calculation of the wear equivalent of each moving surface (actual value of the motion gap), calculation and judgment of the motion gap parameters, etc. That is:

[0189] 1) Operation preparation process includes: safety technology briefing, implementation of on-site safety precautions, registration and communication of maintenance operations, preparation of tooling and equipment, etc.

[0190] 2) Online detection of movement clearance of cold rolling mill under heavy load conditions;

[0191] 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device → ensure that the seamless steel pipe is in the full length range of the machine base according to the rolling state (the end face of the finished pipe after rolling protrudes horizontally from the annular hole rolling groove of the front limit station of the working frame by not less than 150mm, and preferably 200-250mm; or the end face of the unrolled tube protrudes horizontally from the annular hole rolling groove of the rear limit station of the working frame by not less than 350mm, and preferably 350-400mm);

[0192] 2.2) Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position of the machine base (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operator enters the machine base → Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zh, right lateral movement gap C2zh, left upper movement gap S1zh, right upper movement gap S2zh) → Record the movement gap parameters C1zh = 0.9 mm, C2zh = 0.6 mm, S1zh = 0.8 mm, S2zh = 0.9 mm → Operator evacuates the machine base;

[0193] 2.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position of the machine base (the ring-shaped rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1zq, right lateral movement gap C2zq, left upper movement gap S1zq, right upper movement gap S2zq) → record the movement gap parameters C1zq = 1.0 mm, C2zq = 0.5 mm, S1zq = 0.7 mm, S2zq = 0.7 mm → the operator evacuates the machine base.

[0194] 3) Online detection of movement clearance of cold rolling mill under no-load condition;

[0195] 3.1) No-load positioning: Power on the equipment → Remove the seamless steel pipe that runs across the inside of the machine base and through the annular hole (inside the machine base (it is best if the front end of the seamless steel pipe does not exceed the inlet end face of the rear limit position of the machine base);

[0196] 3.2 Measurement of the rear limit position of the working frame: Position the working frame at the rear limit position (the annular rolling groove is at the starting end of rolling) → Power off the equipment → Operators enter the machine base → Use feeler gauges to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1kh, right lateral movement gap C2kh, left upper movement gap S1kh, right upper movement gap S2kh) → Record the movement gap parameters C1kh = 0.9mm, C2kh = 0.8mm, S1kh = 0.8mm, S2kh = 0.8mm → Operators evacuate the machine base;

[0197] 3.3) Measurement of the front limit position of the working frame: power on the equipment → position the working frame at the front limit position (the ring-shaped rolling groove is at the finishing end of rolling) → power off the equipment → the operator enters the machine base → use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base (left lateral movement gap C1kq, right lateral movement gap C2kq, left upper movement gap S1kq, right upper movement gap S2kq) → record the movement gap parameters C1kq = 0.9 mm, C2kq = 0.9 mm, S1kq = 0.7 mm, S2kq = 0.7 mm → the operator evacuates the machine base.

[0198] 4) Calculate the wear equivalent of each moving surface (actual value of the moving clearance);

[0199] A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition:

[0200] A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the rear limit position of the working frame) / 2, that is, C1k = (C1kq + C1kh) / 2 = (0.9 + 0.9) / 2 = 0.9 mm;

[0201] A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2 = (0.9 + 0.8) / 2 = 0.85 mm;

[0202] A3) Wear equivalent of the left upper motion clearance S1k between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1k = (S1kq + S1kh) / 2 = (0.7 + 0.8) / 2 = 0.75 mm;

[0203] A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the machine base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2 = (0.7 + 0.8) / 2 = 0.75 mm.

[0204] B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions:

[0205] B1) The wear equivalent of the left lateral motion clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the rear limit position of the working frame) / 2, that is, C1z = (C1zq + C1zh) / 2 = (1.0 + 0.9) / 2 = 0.95 mm;

[0206] B2) Wear equivalent of the right lateral clearance C2z between the right side slide of the working frame and the right side slide of the machine base = (right lateral clearance value of the working frame front limit position + right lateral clearance value of the working frame rear limit position) / 2, that is, C2z = (C2zq + C2zh) / 2 = (0.5 + 0.6) / 2 = 0.55 mm;

[0207] B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the working frame and the left upper slide of the base = (left upper clearance value of the working frame front limit position + left upper clearance value of the working frame rear limit position) / 2, that is, S1z = (S1zq + S1zh) / 2 = (0.7 + 0.8) / 2 = 0.75 mm;

[0208] B4) The wear equivalent of the upper right side movement clearance S2z between the upper right side slide of the working frame and the upper right side slide of the machine base = (the upper right side clearance value of the front limit position of the working frame + the upper right side clearance value of the rear limit position of the working frame) / 2, that is, S2z = (S2zq + S2zh) / 2 = (0.7 + 0.9) / 2 = 0.8 mm.

[0209] 5) Calculation and determination of motion clearance parameters (wear equivalent);

[0210] 5.1) Determination of the offset (deviation) in the horizontal direction (toward the roll centerline) of the work stand refers to the offset between the horizontal centerline of the work stand and the rolling centerline. The spatial distance is calculated using the lateral clearance between the work stand and the base. The absolute value of the difference between the lateral clearance between the work stand and the base and the measured clearance under heavy load conditions is used to determine the equivalent deviation (offset) between the work stand centerline and the actual rolling centerline. The direction of the offset is directly determined based on the lateral clearance values on the left and right sides. The rolling centerline deviation is the absolute value of the difference between the lateral clearance C1 on the left side of the rolling mechanism and the lateral clearance C2 on the right side. That is, the rolling centerline deviation Cp = |C1z-C1k|-|C2z-C2k|=|0.95-0.9|-|0.55-0.85|=0.25mm.

[0211] Based on the heavy load condition, if C1z=0.95mm, C2z=0.55mm, that is, C1z>C2z, it means that the rolling center line deviates to the right side of the machine base, and the deviation (deviation) equivalent value=0.4mm.

[0212] 5.2) The vertical offset (deviation) of the working frame in the longitudinal horizontal direction (rolling centerline direction) is determined by the offset between the horizontal centerline of the working frame and the rolling centerline. The upper movement clearances S1 and S2 between the upper slide of the machine base and the upper slide of the working frame are the vertical deviations of the working frame relative to the rolling centerline. The inclination direction and equivalent of the working frame can be directly determined based on the actual values of the upper movement clearances S1zq = 0.7mm, S2zq = 0.7mm, S1zh = 0.8mm, and S2zh = 0.9mm under heavy load conditions. That is:

[0213] S1zq=0.7mm<S1zh=0.8mm, indicating that the left side of the working frame is tilted backward (in the direction of seamless steel pipe rolling input), and the tilt equivalent=S1zh-S1zq=0.8mm-0.7mm=0.1mm.

[0214] S2zq=0.7mm<S2zh=0.9mm, indicating that the right side of the working frame is tilted backward (in the direction of seamless steel pipe rolling input), and the tilt equivalent=S2zh-S2zq=0.9mm-0.7mm=0.2mm.

[0215] S1zq=S2zq=0.7mm, S1zh=0.8mm<S2zh=0.9mm, indicating that the front side of the working frame is not tilted, and the rear side is partially tilted to the right. The entire working frame is partially tilted toward the right rear, and the tilt equivalent=[(S2zq-S1zq)+(S2zh-S1zh)] / 2=[(0.7-0.7)+(0.9-0.8)] / 2=0.1mm.

[0216] 5.3) Determination factors of rolling mechanism movement clearance;

[0217] Taking the base surfaces of the panels on both sides of the machine base as the measurement and calibration benchmark, the standard values of the movement clearance of the LG-60H cold rolling mill are: the standard value of the upper movement clearance is S1=S2=0.5~0.7mm, the standard value of the lateral movement clearance is C=0.8~1.0mm, and the movement clearance C1 and C2 on any side should not be greater than 0.4~0.5mm, with +20% of the standard value as the limit value (critical value). That is: the standard value of the upper movement clearance of the rolling mechanism under heavy load conditions is S1z=S2z=0.5~0.7mm, the standard value of the lateral movement clearance is C1z+C2z=0.8~1.0mm, and C1z or C2z is not greater than 0.4~0.5mm; the limited value (critical value) lateral movement clearance C1z+C2z=(0.8~1.0)×1.2=1.0~1.2mm, and C1z or C2z is not greater than (0.4~0.5)×1.2mm=0.5~0.6mm; the upper movement clearance S1z=S2z=(0.5~0.7)×1.2=0.6~0.85mm.

[0218] The measured motion clearance wear equivalents are C1z=0.95mm, C2z=0.55mm, S1z=0.75mm, and S2z=0.8mm.

[0219] 1) Lateral clearance = C1z + C2z = 0.95 + 0.55 = 1.5 mm, which exceeds the limit value by 1.0 to 1.28 mm. C1z = 0.95 mm exceeds the limit value by 0.5 to 0.6 mm, while C2z = 0.55 mm is within the range between the standard value and the limit value.

[0220] 2) The upper movement clearance S1z = 0.75 mm, S2z = 0.8 mm, which is between the standard value and the limit value.

[0221] The upper movement clearance of the moving part of the rolling mechanism of the LG-60H cold rolling mill is between the standard value and the limit value (critical value), and the equipment can still be maintained in operation. However, the lateral movement clearance exceeds the range of the standard value and the limit value (critical value), which does not meet the technical requirements for the movement accuracy of the rolling mechanism. Therefore, it is determined that the machine should be shut down and the relevant movement clearance should be corrected to meet the technical requirements for the movement accuracy of the rolling mechanism of the seamless steel pipe cold rolling mill.

[0222] In summary, the present invention provides a method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill. The method has a reasonable process design, convenient model calculation, no need to increase related investment expenditure, is easy to implement on site, reduces reliance on personnel skills and experience, is safe, reliable, practical and efficient, and meets the technical requirements for operating clearance control of the rolling mechanism of seamless steel tube cold rolling mills of different models, specifications and wear equivalents. It promotes the construction of equipment functional accuracy, ensures the operating accuracy and efficiency of the entire rolling mechanism, and can create economic benefits of more than 800,000 yuan per year. The actual equivalent of the motion clearance is measured online under heavy and no-load conditions, as well as in the two extreme working positions of the working frame in front and rear of the machine base. The wear value of the motion clearance is calculated, as well as the deviation direction and equivalent of the motion clearance on the left and right sides relative to the rolling center line, thereby achieving precise setting of the rolling mechanism motion clearance parameters with small error and high accuracy. The base surface of the panel on both sides of the seamless steel tube cold rolling mill machine base is used as the measurement and calibration reference. The actual thickness of the machine base side slide and the frame side slide are accumulated with the actual gap value to obtain the actual spatial distance between the two sides of the working frame and the machine base base. By measuring and calculating the rolling mechanism's kinematic clearance online, the equivalent deviation between the work stand and the rolling centerline, as well as the actual value of the kinematic clearance between the work stand and the base, is determined. This allows for a determination of whether the kinematic accuracy requirements for the rolling mechanism are met, and allows for a trend analysis of the kinematic accuracy, paving the way for subsequent kinematic clearance corrections. This highly versatile approach offers valuable insights and applications for improving the kinematic accuracy control technology for similar two-roller periodic seamless steel tube cold rolling mills.

[0223] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for controlling the motion accuracy of a rolling mechanism of a seamless steel tube cold rolling mill, characterized in that: Including optimizing motion gap parameters and motion gap control benchmarks; The optimization of the motion gap parameters includes: online measurement of the actual equivalent of the motion gap of the cold rolling mill under heavy load, no load, and the working frame in the front and rear positions of the machine base, and calculation of the wear value of the motion gap, as well as the deviation direction and equivalent of the motion gap on the left and right sides relative to the rolling center line; The motion gap control benchmark includes taking the base surface of the two side panels of the cold rolling mill stand as the measurement calibration benchmark, accumulating the actual thickness of the stand side slide and the frame side slide with the actual gap value, and obtaining the actual space distance between the two sides of the working frame and the base of the stand. The method comprises the following steps: 1) Preparation for the job; 2) Working frame positioning; 3) Online measurement of the motion clearance of the cold rolling mill under heavy load, no load, and its working frame in the front and rear positions of the machine base; 4) Calculate the wear equivalent of each moving surface, which is the actual value of the moving clearance; 5) Calculation and determination of motion gap parameters, Step 1) includes safety technology briefing, implementation of on-site safety precautions, registration and communication of maintenance work, and preparation of tooling and equipment. Step 4) further includes: B. Calculation of wear equivalent of the clearance between the seat and the working frame under heavy load conditions: B1) The wear equivalent of the left lateral clearance C1z between the left side slide of the working frame and the left side slide of the machine base = (C1zq + C1zh) / 2, where C1zq is the left lateral clearance value at the front limit position of the working frame, and C1zh is the left lateral clearance value at the rear limit position of the working frame; B2) The wear equivalent of the right side lateral movement gap C2z between the right side slide of the working frame and the right side slide of the machine base = (C2zq + C2zh) / 2, where C2zq is the right side lateral gap value at the front limit position of the working frame, and C2zh is the right side lateral gap value at the rear limit position of the working frame; B3) Wear equivalent of the left upper motion clearance S1z between the left upper slide of the work frame and the left upper slide of the machine base = (S1zq + S1zh) / 2, where S1zq is the left upper clearance value of the work frame at the front limit position, and S1zh is the left upper clearance value of the rear limit position; B4) Wear equivalent of the upper right side clearance S2z between the upper right side slide of the work frame and the upper right side slide of the machine base = (S2zq + S2zh) / 2, where S2zq is the upper right side clearance value of the work frame at the front limit position, and S2z is the upper right side clearance value of the work frame at the rear limit position; Step 5) further includes: Determination of the longitudinal and horizontal offset of the working frame: Directly determine the tilt direction and equivalent of the working frame, including: a) When S1zq>S1zh or S2zq>S2zh, the wear equivalent of the front limit station is greater than that of the rear limit station, and the working frame is tilted forward. The tilt equivalent is the difference between the two. b) When S1zq<S1zh or S2zq<S2zh, the wear equivalent of the front limit station is smaller than that of the rear limit station, and the working frame is tilted backward. The tilt equivalent is the difference between the two. c) When S1zq=S1zh or S2zq=S2zh, the wear equivalent of the front limit station is equal to that of the rear limit station, and the working frame does not tilt in the front and rear horizontal directions. The tilt equivalent is the difference between the two. d) When S1zq>S2zq or S1zh>S2zh, the wear equivalent of the upper left motion clearance is greater than that of the upper right motion clearance, and the working frame is tilted toward the left side of the machine base. The tilt equivalent is the difference between the two. e) When S1zq < S2zq or S1zh < S2zh, the wear equivalent of the upper left motion clearance is smaller than that of the upper right motion clearance, and the working frame is tilted toward the right side of the machine base. The tilt equivalent is the difference between the two. f) When S1zq=S2zq or S1zh=S2zh, the upper motion clearance wear equivalents on the left and right sides are equal, and the working frame does not tilt in the left and right vertical directions. The tilt equivalent is the difference between the two. g) When S1zq>S2zq or S1zh<S2zh, S1zq<S2zq or S1zh>S2zh, and S1zq=S2zq or S1zh<S2zh, S1zq=S2zq or S1zh>S2zh, S1zq>S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, S1zq<S2zq or S1zh=S2zh, there is an unbalanced disturbance in the front-to-back direction or left-to-right direction of the working frame on the base.

2. The method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill according to claim 1, characterized in that: In step 2), the online detection of the movement gap of the cold rolling mill under heavy load conditions includes the following steps: 2.1) Tube positioning: When the equipment is powered on, turn off the machine base spray device to ensure that the seamless steel pipe is within the full length range of the machine base according to the rolling state; 2.2) Measurement of the rear limit position of the working frame: The working frame is positioned at the rear limit position of the machine base. The equipment is powered off, and the operator enters the machine base. Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base. The actual values of the moving gap parameters C1zh, C2zh, S1zh, and S2zh are recorded. The operator then evacuates the machine base. C1zh indicates the left lateral motion gap, C2zh indicates the right lateral motion gap, S1zh indicates the left superior motion gap, and S2zh indicates the right superior motion gap; 2.3) Measurement of the front limit position of the working frame: Power on the equipment, position the working frame at the front limit position of the machine base, power off the equipment, and have the operator enter the machine base. Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base, and record the actual values of the moving gap parameters C1zq, C2zq, S1zq, and S2zq. The operator then evacuates the machine base. C1zq represents the left lateral movement gap, C2zq represents the right lateral movement gap, S1zq represents the left upper movement gap, and S2zq represents the right upper movement gap.

3. The method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill according to claim 2, characterized in that: In the step 2.1), the full length of the stand is such that the end face of the finished pipe after rolling protrudes horizontally from the annular rolling groove of the front limit station of the working stand by not less than 150 mm; or The end face of the unrolled tube billet shall protrude horizontally from the annular rolling groove of the rear limit station of the working frame by not less than 350mm.

4. The method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill according to claim 1, characterized in that: In step 2), the online detection of the movement gap of the cold rolling mill under no-load working conditions includes the following steps: 3.1) No-load positioning: Power on the equipment and remove the seamless steel pipe that runs across the inside of the machine base and through the annular hole; 3.2) Measurement of the rear limit position of the working frame: The working frame is positioned at the rear limit position of the machine base. The equipment is powered off, and the operator enters the machine base. Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base. The actual values of the moving gap parameters C1kh, C2kh, S1kh, and S2kh are recorded. The operator then evacuates the machine base. C1kh indicates the left lateral motion gap, C2kh indicates the right lateral motion gap, S1kh indicates the left superior motion gap, and S2kh indicates the right superior motion gap; 3.3) Measurement of the front limit position of the working frame: Power on the equipment, position the working frame at the front limit position of the machine base, power off the equipment, and have the operator enter the machine base. Use a feeler gauge to measure the actual gap values of the four moving contact surfaces between the working frame and the machine base, and record the actual values of the moving gap parameters C1kq, C2kq, S1kq, and S2kq. The operator then evacuates the machine base. C1kq represents the left lateral movement gap, C2kq represents the right lateral movement gap, S1kq represents the left upper movement gap, and S2kq represents the right upper movement gap.

5. The method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill according to claim 2 or 4, characterized in that: The step 4) further includes: A. Calculation of wear equivalent of the clearance between the seat and the working frame in the no-load condition: A1) The wear equivalent of the left lateral motion clearance C1k between the left side slide of the working frame and the left side slide of the machine base = (the left lateral clearance value of the working frame front limit position + the left lateral clearance value of the working frame rear limit position) / 2, that is, C1k = (C1kq + C1kh) / 2; A2) The wear equivalent of the right lateral clearance C2k between the right side slide of the working frame and the right side slide of the machine base = (the right lateral clearance value of the working frame front limit position + the right lateral clearance value of the working frame rear limit position) / 2, that is, C2k = (C2kq + C2kh) / 2; A3) The wear equivalent of the left upper motion clearance S1k between the left upper slide of the working frame and the left upper slide of the machine base = (the left upper clearance value of the working frame front limit position + the left upper clearance value of the rear limit position of the working frame) / 2, that is, S1k=(S1kq+S1kh) / 2; A4) The wear equivalent of the upper right motion clearance S2k between the upper right slide of the working frame and the upper right slide of the machine base = (the upper right clearance value of the working frame front limit position + the upper right clearance value of the working frame rear limit position) / 2, that is, S2k = (S2kq + S2kh) / 2.

6. The method for controlling the motion accuracy of the rolling mechanism of a seamless steel tube cold rolling mill according to claim 5, characterized in that: The step 5) further includes: Determination of the horizontal offset of the working frame: the rolling center line deviation Cp = |C1-C2| = |C1z-C1k| - |C2z-C2k|, and based on the heavy load condition, if C1z>C2z, the rolling center line deviates to the right side of the machine base; if C1z<C2z, the rolling center line deviates to the left side of the machine base; if C1z=C2z, there is no deviation of the rolling center line; Determination factors of the motion clearance of the rolling mechanism: take the base surface of the panels on both sides of the machine base as the measurement calibration reference, add the actual thickness of the machine base side slides and the frame side slides with the actual gap values to obtain the actual space distance between the two sides of the working frame and the machine base base; based on the thickness of the standard components of the working frame and the machine base side slides and the actual space distance values, the difference after subtraction is the actual motion clearance value after replacing the side slides, so as to determine whether the motion clearance value meets the technical requirements.

Images