Hydraulic servo oil cylinder trunnion positioning and repairing method and positioning device

Abstract

The invention provides a hydraulic servo oil cylinder trunnion positioning and repairing method and a positioning device, which are used for carrying out in-situ welding and repairing on a fractured oil cylinder trunnion, and the method comprises the following control conditions: (1) heating an oil cylinder barrel before welding and carrying out heat preservation on the oil cylinder barrel after welding; (2) the tensile strength of the selected welding rod is higher than that of an oil cylinder barrel matrix; and (3) the welding rod is baked and heated before welding.

Description

Technical Field

[0001] This invention relates to the field of coiling machine technology in metallurgical machinery, specifically to a method and device for positioning and repairing the trunnion of a hydraulic servo cylinder. Background Technology

[0002] The hot-rolled coiling process: The strip steel is ejected from the F7 mill, conveyed by the laminar flow roller conveyor, and wound onto the coil by the pinch rollers, the step control of the auxiliary coiling rollers, and the rotation and expansion / contraction of the coil drum, thus establishing coiling tension to achieve strip coiling. The hydraulic cylinder of the auxiliary coiling roller is a key piece of equipment in the coiling machine, and its step control is achieved through the pressure of the auxiliary coiling roller hydraulic system.

[0003] With the increase in the production of hot-rolled high value-added products, especially with the increase in the production of high-strength steel products such as X70-X80 pipeline steel and bridge steel, the impact force of strip steel on the servo hydraulic cylinder of the coiler's auxiliary coiling roll has reached 622kN.

[0004] Due to the special nature of their working environment, servo hydraulic cylinders are subjected to alternating loads such as impact and vibration for extended periods. This can lead to cracking of the weld between the intermediate support trunnion and the cylinder barrel, or even breakage of the trunnion and cylinder body. Once the trunnion of the winding roller cylinder breaks, it causes a shutdown of the winding machine. Replacing the cylinder is difficult, and damaged winding roller cylinders must be scrapped. Purchasing new servo hydraulic cylinders significantly increases spare parts procurement costs and production costs.

[0005] The main technical parameters of the existing servo hydraulic cylinder are as follows: cylinder model and specifications: φ250*160*1046; system working pressure: 210 bar; piston rod extension speed: 200 mm / s; piston rod extension flow rate: 589 dm3 / min; piston rod retraction speed: 200 mm / s; piston rod retraction flow rate: 348 dm3 / min. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a hydraulic servo cylinder trunnion positioning and repair method that can effectively avoid the scrapping of servo hydraulic cylinders due to trunnion breakage, avoid equipment downtime caused by trunnion breakage of hydraulic servo cylinders for auxiliary rollers, and reduce the procurement cost of hydraulic servo cylinder spare parts.

[0007] The technical problem it aims to solve can be addressed through the following technical solutions.

[0008] A method for positioning and repairing a hydraulic servo cylinder trunnion, used for in-situ welding repair of a broken cylinder trunnion, characterized by including the following control conditions:

[0009] (1) Heating the cylinder barrel before welding and heat preservation of the cylinder barrel after welding;

[0010] (2) The tensile strength of the selected welding rod is higher than that of the cylinder barrel body;

[0011] (3) The welding rods are baked and heated before welding.

[0012] Furthermore, in (1), the cylinder barrel of the oil cylinder is heated to 240℃±5℃ before welding.

[0013] Furthermore, in (1), the cylinder barrel is kept warm after welding, and the temperature is controlled at 320-350℃.

[0014] Preferably, the heating and heat preservation in (1) are carried out in an electric furnace.

[0015] Preferably, the welding electrode is a J607RH welding electrode.

[0016] Furthermore, during the welding process, a flame cutting torch is used to heat the welding area between the cylinder trunnion and the cylinder barrel, so that the local temperature is always controlled at 425-430℃.

[0017] Furthermore, in (3), the welding rod is baked at 380-400℃ for 1-2 hours before welding.

[0018] Furthermore, it also includes a step of grinding away the cracks in the cylinder trunnion before welding.

[0019] Furthermore, the welding employs a narrow-channel welding method with a short arc, and welding stress is relieved by tapping the weld seam during the welding process.

[0020] Another technical problem to be solved by the present invention is to provide a positioning device for implementing the aforementioned hydraulic servo cylinder trunnion positioning and repair method, the device comprising:

[0021] A vertical connecting plate (1) is provided. One end of the horizontally placed cylinder barrel (4) abuts against the connecting plate (1) and is connected and fixed to the connecting plate. A frame structure is provided around the cylinder barrel (4). The frame structure is surrounded by two positioning plates (2) that are opposite each other in the vertical direction and two fixing plates (3) that are opposite each other in the left and right direction. The positioning plates (2) and fixing plates (3) are fastened together by several fastening screws (8).

[0022] On the upper and lower sides of the cylinder barrel (4), there are several set screws (7) on the two positioning plates (2) positioned on the upper and lower sides. The front end of the set screw (7) abuts against the outer end of the cylinder barrel (4) and is used to limit and fix the cylinder barrel (4) in the upper and lower positions.

[0023] On the left and right sides of the cylinder barrel (4), there are corresponding cylinder trunnions (5). The outer end of each cylinder trunnion (5) is inserted and fixed in the positioning hole (10) opened on the inner end of the corresponding side fixing plate (3) for limiting and fixing. The inner end of the cylinder trunnion (5) is directly opposite the positioning base (11) provided on the cylinder body of the cylinder barrel (4). The positioning base (11) is used to frame the welding position of the cylinder trunnion (5). The corresponding side fixing plate (3) and the cylinder trunnion (5) are fastened together by several connecting screws (9).

[0024] It also includes a set of positioning screws (6), one end of which is fixed to the connecting plate (1), and the threaded section of the other end is threadedly connected to the corresponding fixing plate (3). The thread feed depth of the threaded section relative to the position of the fixing plate is adjustable.

[0025] The hydraulic servo cylinder trunnion positioning and repair method and positioning device using the above technical solution have the following characteristics and beneficial effects:

[0026] 1) The hydraulic servo cylinder trunnion positioning and repair method is based on the actual working conditions of the auxiliary roll cylinder on site. After the auxiliary roll cylinder trunnion is broken, it is welded and repaired. The welding strength of the auxiliary roll cylinder body and the intermediate trunnion is improved by improving the welding performance.

[0027] 2) The hydraulic servo cylinder trunnion positioning and repair method is adopted to restore the servo hydraulic cylinder of the auxiliary roll to its original technical performance and ensure normal use. This not only greatly reduces the cost of spare parts procurement, but also reduces spare parts consumption.

[0028] 3) The hydraulic servo cylinder trunnion positioning and repair method was adopted to repair the servo hydraulic cylinder used on the machine. After three years of use, it is still in normal working condition. This not only reduces equipment failure caused by trunnion breakage of the auxiliary roll cylinder, but also reduces the spare parts cost of servo hydraulic cylinder by 1.1 million.

[0029] 4) In view of the special nature of the servo hydraulic cylinder trunnion repair method, through the analysis of servo hydraulic cylinders and field operating conditions, a special tooling positioning device for servo hydraulic cylinder trunnion repair is designed to ensure the installation accuracy of servo hydraulic cylinder trunnion after repair, avoid the servo hydraulic cylinder being scrapped due to trunnion breakage, restore the normal function of the repaired servo hydraulic cylinder, and reduce the spare parts procurement cost of servo hydraulic cylinders. Attached Figure Description

[0030] Figure 1 This is a three-dimensional structural diagram of the positioning device of the present invention;

[0031] Figure 2 This is an exploded view of the positioning device of the present invention;

[0032] Figure 3 This is a side view of the positioning device of the present invention;

[0033] In the diagram: 1. Connecting plate; 2. Positioning plate; 3. Fixing plate; 4. Cylinder barrel; 5. Cylinder trunnion; 6. Positioning screw; 7. Set bolt; 8. Fastening bolt; 9. Connecting screw; 10. Positioning hole; 11. Positioning base. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific examples.

[0035] This invention provides a method and device for positioning and repairing the trunnion of a hydraulic servo cylinder, as detailed below:

[0036] 1) Based on the actual dimensions of the cylinder barrel and trunnion of the servo hydraulic cylinder for the auxiliary winding roll, a special tooling for welding the servo hydraulic cylinder trunnion (i.e., the positioning device mentioned in this invention) is designed. Its purpose is to ensure that the cylinder trunnion is welded in the original position of the cylinder barrel, and at the same time, the positioning dimension between the cylinder barrel and the trunnion remains unchanged after welding, thus playing a positioning role.

[0037] 2) Grind off the cracks in the cylinder trunnion. Use an angle grinder to grind off about 20 mm deep until it is smooth.

[0038] 3) The steel sleeve is shortened by 10 mm from the original size and installed into the shaft, with a 5 mm welding distance at both ends. The heat-release fitting allowance is 1 / 1000 (the sleeve material is 35CrMo).

[0039] 4) Before welding, the hydraulic cylinder barrel is heated in an electric furnace to 240℃±5℃. This is mainly to ensure that the high temperature and trunnion stress of the servo hydraulic cylinder at the moment of welding cause plastic deformation and internal cracks between the materials, achieving the bonding strength of the welded material and the body material in the molten pool. Secondly, after the trunnion is welded, the cylinder barrel will not experience creep after cooling. After the welding work is completed, the servo hydraulic cylinder barrel is placed in the electric furnace for heat preservation, with the temperature controlled at 320~350℃, to ensure that the welded material does not crack and the cylinder barrel does not deform after the servo hydraulic cylinder barrel and trunnion are welded.

[0040] 5) During the heating process of the hydraulic servo cylinder barrel in the electric furnace, the inner diameter of the cylinder barrel is deformed, and the surface finish of the inner diameter of the cylinder barrel is roughened. After the trunnion welding is completed, the inner diameter of the cylinder barrel is inspected and repaired according to the requirements specified in the drawings to ensure that the inner diameter accuracy, surface finish, coaxiality and other parameters are controlled within the range required by the drawings.

[0041] 6) The cylinder trunnion material is 35CrMo, a high-strength heat-resistant alloy steel. Therefore, the welding electrode grade selected is: CHE607RH (J607RH)GBE6015-G AWS E9015-G. This is because the tensile strength of the J607RH welding electrode can reach 610–690 MPa (60–70 kg), while the tensile strength of the 35CrMo trunnion material can reach 450–500 MPa. This means the welding electrode's tensile strength is higher than that of the cylinder body, allowing for easier fusion of the welding material with the base material. This ensures both welding strength and performance.

[0042] 7) The welding electrode CHE607RH is made of 690MPa grade crack-free steel. It uses superhydrogen sodium high-toughness welding electrode, which has good notched impact toughness and crack resistance. It employs DC backlash welding and can be used for all-position welding. To ensure that the inner wall of the cylinder does not deform and the weld does not produce porosity during the welding process, a flame cutting torch is used to heat the trunnion and cylinder area, keeping the local temperature consistently between 425-430℃ (preferably 427℃).

[0043] 8) Welding requirements for servo hydraulic cylinder trunnions:

[0044] a) Before welding, the welding rods must be baked at 380-400℃ for 1-2 hours and used immediately after baking. Heating the welding rods during welding is mainly to ensure that the plastic expansion of the material does not occur during welding, that the molten pool is firmly bonded during welding, and that the molten iron and the cylinder body material are better integrated together, so that their crystal structure remains consistent.

[0045] b) Before welding, the welding area must be cleaned of oil, rust, water and other impurities.

[0046] c) Use short-arc operation and narrow-channel welding methods.

[0047] d) During welding, the weld seam is frequently tapped to relieve welding stress.

[0048] e) The weld seam is about 2 mm higher than the shaft head, with machining allowance.

[0049] f) Machin the shaft head according to the drawing requirements, leaving an R3 radius at the root.

[0050] g) The shaft head weld must be inspected for defects and a defect inspection report must be attached.

[0051] h) Repair of each screw hole, 16 M30 screws for the cylinder head, and 4 M16 screws for the shaft head.

[0052] The positioning device used as a special tooling for welding trunnions of servo hydraulic cylinders in this invention will be further described below.

[0053] Reference Figures 1 to 3This is a specialized tooling for welding operations, comprising a vertical connecting plate 1. One end of a horizontally placed hydraulic cylinder 4 rests against the connecting plate 1 and is fixed to the connecting plate 1 with screws to stabilize the end of the hydraulic cylinder 4. A frame structure is provided on the outside of the hydraulic cylinder 4, consisting of two vertically opposed positioning plates 2 and two horizontally opposed fixing plates 3, which are fastened together by multiple fastening screws 8. On the upper and lower sides, the front ends of several set bolts 7 positioned on the positioning plates 2 abut against the outer end of the cylinder body of the hydraulic cylinder 4, used to limit and fix the hydraulic cylinder 4 in its vertical and horizontal positions. On the left and right sides, the outer end of the cylinder trunnion 5 is inserted and fixed to the positioning hole 10 opened on the inner end of the corresponding side fixing plate 3 for limiting and fixing. The inner end of the cylinder trunnion 5 is fixed to the cylinder body of the cylinder barrel 4 through the positioning base 11. The positioning base 11 is a platform machined on the outer side of the cylinder barrel to frame or determine the welding position of the cylinder trunnion 5. The fixing plate 3 and the cylinder trunnion 5 are further fastened together by the connecting screw 9 to maintain the stability and alignment of the cylinder trunnion 5 relative to the cylinder barrel 4. The axial position of the cylinder trunnion 5 relative to the cylinder barrel 4 is controlled by the depth of the positioning screw 6 screwed into the fixing plate 3. That is, one end of the positioning screw 6 is fixed to the connecting plate 1, and the control of the screwing depth of the threaded end of the other end relative to the fixing plate 3 controls the distance between the fixing plate 3 and the connecting plate 1. Due to the positioning hole 10 on the fixing plate 3 locking the cylinder trunnion 5, the axial position of the cylinder trunnion 5 relative to the cylinder barrel 4 is further controlled. The cylinder barrel 4 is parallel to the surfaces of the fixed plate 3 and the positioning plate 2, but perpendicular to the surface of the connecting plate 1.

[0054] After the above-mentioned tooling completes the positioning of the cylinder trunnion and cylinder barrel, the aforementioned repair method is used for welding repair.

[0055] In one embodiment of the present invention, by adopting the above-mentioned hydraulic servo cylinder trunnion positioning and repair technology, the hydraulic servo cylinder used on the machine has been in normal working condition for three years.

[0056] The hydraulic servo cylinder trunnion positioning and repair technology used has enabled the originally scrapped auxiliary roll hydraulic servo cylinder to be restored to normal use. This not only reduces equipment failures caused by trunnion breakage of the auxiliary roll cylinder, but also reduces the cost of servo hydraulic cylinder spare parts by 1.1 million.

[0057] The method and apparatus of the present invention have the following characteristics:

[0058] 1) In view of the special nature of servo hydraulic cylinder trunnion repair technology, through analysis of servo hydraulic cylinders and field operating conditions, a special tooling for servo hydraulic cylinder trunnion repair has been designed and provided. This ensures the installation accuracy of the servo hydraulic cylinder trunnion after repair, avoids the servo hydraulic cylinder from being scrapped due to trunnion breakage, restores the normal function of the repaired servo hydraulic cylinder, and reduces the spare parts procurement cost of servo hydraulic cylinders.

[0059] 2) Based on the actual usage of the servo hydraulic cylinder of the auxiliary winding roll, the trunnion of the auxiliary winding roll cylinder was repaired by welding. The welding performance was improved to enhance the welding strength of the cylinder body and the intermediate trunnion of the auxiliary winding roll cylinder, while ensuring that the original dimensions of the trunnion and cylinder body of the servo hydraulic cylinder remained unchanged after repair.

[0060] 3) By adopting this hydraulic servo cylinder trunnion positioning and repair technology, the hydraulic servo cylinders used on the machine can be repaired and have a service life of up to three years. They are still in normal working condition, avoiding equipment downtime caused by trunnion breakage of the hydraulic servo cylinders for the auxiliary rollers, while reducing the procurement cost of hydraulic servo cylinder spare parts.

[0061] 4) The hydraulic servo cylinder trunnion positioning and repair technology adopted is fully applicable to the repair of similar servo hydraulic cylinder trunnions. It not only improves the service life of the servo hydraulic cylinder, but also reduces equipment maintenance costs and ensures the continuous and stable operation of the coiler auxiliary roll servo hydraulic cylinder. It can be promoted in the hot rolling field and other similar fields. The application prospects of this technology are broad and it can be actively promoted in relevant enterprises.

Claims

1. A method for positioning and repairing a hydraulic servo cylinder trunnion, used for in-situ welding repair of a broken cylinder trunnion, characterized in that... Including the following control conditions: (1) Heating the cylinder barrel before welding and heat preservation of the cylinder barrel after welding; (2) The tensile strength of the selected welding rod is higher than that of the cylinder barrel body; (3) The welding rods are baked and heated before welding.

2. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, (1) Before welding, the cylinder barrel of the oil cylinder is heated to 240℃±5℃.

3. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, (1) After welding, the cylinder barrel of the oil cylinder is kept warm, and the temperature is controlled at 320-350℃.

4. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, (1) The heating and heat preservation are carried out in an electric furnace.

5. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, The welding electrode is J607RH welding electrode.

6. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, During the welding process, a flame cutting torch is used to heat the welding area between the cylinder trunnion and the cylinder barrel, so that the local temperature is always controlled at 425-430℃.

7. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, (3) Before welding, the welding rod is baked at 380-400℃ for 1-2 hours.

8. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, It also includes the step of grinding away the cracks in the cylinder trunnion before welding.

9. The hydraulic servo cylinder trunnion positioning and repair method according to claim 1, characterized in that, Welding employs a narrow-channel welding method with short arc operation, and welding stress is relieved by tapping the weld seam during the welding process.

10. A positioning device for implementing the hydraulic servo cylinder trunnion positioning and repair method according to any one of claims 1-9, characterized in that, include: A vertical connecting plate (1) is provided. One end of the horizontally placed cylinder barrel (4) abuts against the connecting plate (1) and is connected and fixed to the connecting plate. A frame structure is provided around the cylinder barrel (4). The frame structure is surrounded by two positioning plates (2) that are opposite each other in the vertical direction and two fixing plates (3) that are opposite each other in the left and right direction. The positioning plates (2) and fixing plates (3) are fastened together by several fastening screws (8). On the upper and lower sides of the cylinder barrel (4), there are several set screws (7) on the positioning plates (2) positioned on the upper and lower sides. The front end of the set screw (7) abuts against the outer end of the cylinder barrel (4) and is used to limit and fix the cylinder barrel (4) in the upper and lower positions. On the left and right sides of the cylinder barrel (4), there are corresponding cylinder trunnions (5). The outer end of each cylinder trunnion (5) is inserted and fixed in the positioning hole (10) opened on the inner end of the corresponding side fixing plate (3) for limiting and fixing. The inner end of the cylinder trunnion (5) is directly opposite the positioning base (11) provided on the cylinder body of the cylinder barrel (4). The positioning base (11) is used to frame the welding position of the cylinder trunnion (5). The corresponding side fixing plate (3) and the cylinder trunnion (5) are fastened together by several connecting screws (9). It also includes a set of positioning screws (6), one end of which is fixed to the connecting plate (1), and the threaded section of the other end is threadedly connected to the corresponding fixing plate (3). The thread feed depth of the threaded section relative to the position of the fixing plate is adjustable.

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