S3 double-hexagonal bit and preparation method thereof

Abstract

The invention relates to the technical field of preparation of double-hexagonal bits, in particular to a preparation method of an S3 double-hexagonal bit, which comprises the following steps: performing cold drawing treatment on an S3 wire rod subjected to surface treatment through a wire drawing machine to obtain a semi-finished wire rod; the wire is subjected to spheroidizing annealing treatment through a well type annealing furnace, and a granular pearlite structure is obtained; the qualification of annealing treatment is judged according to the uniformity index of the granular pearlite; carrying out acid pickling and phosphating treatment on the wire rod qualified in annealing treatment, and then carrying out hexagonal drawing through a wire drawing machine to obtain a hexagonal wire; shearing, shaping and rod shrinking are conducted on the hexagonal line qualified in drawing through a cold header, and then an S3 double-hexagonal bit is obtained; and judging the qualification of the single S3 double-hexagonal bit according to the comprehensive performance characteristic value, and judging the qualification of the preparation of the S3 double-hexagonal bit according to the qualification ratio of the S3 double-hexagonal bit in sampling inspection. The performance stability and the preparation efficiency of the double-hexagonal bit are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of double hexagonal bits, and particularly to a preparation method of S3 double hexagonal bits. Background Art

[0002] S3 is a medium-carbon alloy tool material with high silicon. The added Si significantly improves the hardness and strength of ferrite and austenite, increases the elastic limit, yield strength and yield ratio of the steel, and improves the fatigue strength. The traditional process of S3 double hexagonal bits is that the hot-rolled wire rods from the steel mill are pickled and drawn into hexagonal wire coils. The wire coils are then cut into sections by a blanking machine and then formed into small-headed hexagons by turning. However, this technical path has large metal losses and low efficiency mainly in the turning and milling processes, and the machining accuracy is greatly affected by tool wear. Therefore, it is necessary to develop a spheroidizing cold heading forming process.

[0003] Chinese Patent Application Publication No.: CN106862475A discloses a cold heading production process for internal hexagonal double-headed stud blanks, which is characterized by including the following steps: blanking; shaping; backward extrusion and stretching; upsetting; backward extrusion and stretching; internal hexagon forming; extrusion of through holes. The present invention centrally uses a variety of technologies such as strong stretching, internal hexagon forming, and extrusion perforation to form a complete processing technology for machining the internal hexagonal double-headed stud on a multi-station cold heading machine.

[0004] However, the following problems exist in the prior art: the lack of intelligent detection and adjustment in the processing process in the prior art leads to poor product quality consistency and low production efficiency. Summary of the Invention

[0005] Therefore, the present invention provides a preparation method of S3 double hexagonal bits to overcome the problems in the prior art that the lack of intelligent detection and adjustment in the processing process leads to unqualified product quality and low production efficiency.

[0006] To achieve the above object, the present invention provides a preparation method of S3 double hexagonal bits, including: Performing cold drawing treatment on the surface-treated S3 wire rods through a wire drawing machine to obtain semi-finished wire rods; Performing spheroidizing annealing treatment on the wire rods through a pit annealing furnace to obtain a granular pearlite structure; Judging the qualification of the annealing treatment according to the uniformity index of the granular pearlite. Based on the condition of unqualified annealing treatment, increasing the annealing holding time, or, when the annealing treatment is judged to be unqualified by obtaining the fracture morphology characteristic values of the wire rods through a torsion test combined with a scanning electron microscope and increasing the annealing temperature according to the fracture morphology characteristic values; Performing pickling and phosphating treatment on the wire rods with qualified annealing treatment and then performing hexagonal drawing through a wire drawing machine to obtain hexagonal wires; Determine the surface defect index through the surface morphology analysis of the hexagonal wire obtained by the metallographic microscope, and determine the qualification of the hexagonal drawing based on the surface defect index. Based on the unqualified conditions, reduce the drawing speed or determine the maximum drawing length according to the surface roughness; The qualified hexagonal wire is sheared, shaped, and necked down by a cold heading machine to obtain an S3 double hexagonal bit; Sample and test the torque bearing capacity and surface quality of the S3 double hexagonal bits and determine the comprehensive performance characteristic value of a single S3 double hexagonal bit; Determine the qualification of a single S3 double hexagonal bit based on the comprehensive performance characteristic value and determine the qualification of the preparation of the S3 double hexagonal bits based on the proportion of qualified S3 double hexagonal bits in the sampling inspection. Based on the unqualified preparation conditions, determine the reason for the unqualified preparation according to the difference between the preset proportion and the proportion, and increase the shaping pressure or reduce the stamping speed.

[0007] Furthermore, determine the qualification of the annealing treatment according to the uniformity index of the granular pearlite. Among them, if the uniformity index is less than the first preset uniformity index, it is determined that the annealing treatment is qualified, and the wire rod is subjected to pickling and phosphating treatment; If the uniformity index is greater than or equal to the first preset uniformity index and less than the second preset uniformity index, it is determined that the annealing treatment is unqualified, and the qualification of the annealing treatment is determined again according to the fracture morphology characteristic value; If the uniformity index is greater than or equal to the second preset uniformity index, it is determined that the annealing treatment is unqualified, and the annealing holding time is increased according to the difference between the uniformity index and the second preset uniformity index.

[0008] Furthermore, the uniformity index is jointly determined by the size uniformity and distribution uniformity of the granular pearlite.

[0009] Furthermore, based on the condition that the fracture morphology characteristic value is less than the preset morphology characteristic value, it is determined again that the annealing treatment is unqualified, and the annealing temperature is increased according to the difference between the preset morphology characteristic value and the fracture morphology characteristic value; Based on the condition that the fracture morphology characteristic value is greater than or equal to the preset morphology characteristic value, it is determined again that the annealing treatment is qualified, and the wire rod is subjected to pickling and phosphating treatment.

[0010] Furthermore, the fracture morphology characteristic value is jointly determined by the fracture shrinkage rate and the fracture roughness.

[0011] Furthermore, determine the qualification of the hexagonal drawing according to the surface defect index. Among them, if the surface defect index is less than the first preset surface defect index, it is determined that the hexagonal drawing is qualified, and the hexagonal wire is cold headed to obtain an S3 double hexagonal bit; If the surface defect index is greater than or equal to the first preset surface defect index and less than the second preset surface defect index, it is determined that the hexagonal drawing is unqualified, and the drawing speed is reduced according to the difference between the second preset surface defect index and the surface defect index; If the surface defect index is greater than or equal to the second preset surface defect index, it is determined that the hexagonal drawing is unqualified, and the maximum drawing length is reduced according to the surface roughness of the hexagonal wire.

[0012] Furthermore, based on the condition that the comprehensive performance characteristic value is less than the preset comprehensive performance characteristic value, it is determined that a single S3 double hexagonal bit is unqualified, and the unqualified S3 double hexagonal bit is marked; based on the condition that the comprehensive performance characteristic value is greater than or equal to the preset comprehensive performance characteristic value, it is determined that a single S3 double hexagonal bit is qualified, and the qualification of the remaining S3 double hexagonal bits is continuously detected and determined.

[0013] Furthermore, the qualification of the preparation of the S3 double hexagonal bits is determined according to the proportion of qualified S3 double hexagonal bits in the sampling inspection. Among them, if the proportion is less than the preset proportion, it is determined that the preparation of the S3 double hexagonal bits is unqualified, and the reason for the unqualified preparation is determined according to the difference between the preset proportion and the proportion; If the proportion is greater than or equal to the preset proportion, it is determined that the preparation of the S3 double hexagonal bits is qualified, and the preparation is completed according to the current preparation parameters.

[0014] Furthermore, the reason for the unqualified preparation is determined according to the proportion difference. Among them, if the proportion difference is less than the preset proportion difference, it is determined that the reason for the unqualified preparation is that the sizing pressure in the cold heading process does not meet the standard, and the sizing pressure is increased according to the across-flat tolerance value of the unqualified S3 double hexagonal bit; If the proportion difference is greater than or equal to the preset proportion difference, it is determined that the reason for the unqualified preparation is that the stamping speed in the cold heading process does not meet the standard, and the stamping speed is reduced according to the deformation rate of the unqualified S3 double hexagonal bit; The proportion difference is the difference between the preset proportion and the proportion.

[0015] The present invention also provides an S3 double hexagonal bit, and the ratio of the across-flat lengths of the two end faces of the S3 double hexagonal bit is 3:4.

[0016] Compared with the prior art, the beneficial effects of the present invention are that the present invention significantly improves the product quality and production efficiency by optimizing the process flow. Through the processes of cold drawing, annealing, pickling, hexagonal drawing and cold heading, the problem of material waste in traditional turning and milling processing is avoided. Also, through the optimized heat treatment and forming processes, the bit has a more uniform organizational structure and higher dimensional accuracy, while improving the production efficiency.

[0017] Furthermore, the present invention introduces a uniformity index to determine the qualification of annealing treatment. When the annealing treatment is determined to be unqualified, the qualification of the annealing treatment is re-determined based on the fracture morphology characteristic values, or the annealing holding time is increased. The uniformity index is jointly determined by the size uniformity and distribution uniformity of the particles, improving the accuracy of the determination. At the same time, through intelligent grading determination and precise parameter adjustment, the problems of lagging quality control and rough adjustment in traditional annealing processes are effectively solved, realizing the refined management of the spheroidizing annealing process of S3 steel balls.

[0018] Furthermore, the present invention determines the qualification of hexagonal drawing based on the surface defect index. Based on the unqualified conditions, the drawing speed or the maximum drawing length is reduced, and through the real-time regulation of the drawing process, a better quality wire rod basis is provided for the subsequent cold heading process.

[0019] Furthermore, the present invention determines the qualification of the preparation of S3 double hexagonal socket heads based on the proportion of qualified S3 double hexagonal socket heads in the sampling inspection. Based on the unqualified conditions, the reasons for the unqualified preparation are determined and the cold heading parameters are adjusted. By promptly giving a process adjustment plan, the preparation efficiency is improved, and at the same time, the product quality is guaranteed.

[0020] Furthermore, the present invention selects S3 wire rod as the raw material, improving the elastic limit, yield strength and fatigue strength of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flowchart of the preparation method of the S3 double hexagonal socket head according to an embodiment of the present invention; Figure 2 is a flowchart of determining the qualification of annealing treatment according to an embodiment of the present invention; Figure 3 is a flowchart of determining the qualification of the preparation of the S3 double hexagonal socket head according to an embodiment of the present invention; Figure 4 is a flowchart of determining the reasons for the unqualified preparation of the S3 double hexagonal socket head according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0024] It should be noted that the data in this embodiment are all obtained through comprehensive analysis and evaluation of the historical detection data in the three months before this detection by the present invention and the corresponding historical detection results. Those skilled in the art can understand that the determination method of the above single parameter by the present invention can be to select the value with the highest proportion according to the data distribution as the preset standard parameter, use weighted summation to take the obtained value as the preset standard parameter, substitute each historical data into a specific formula and take the value obtained by using this formula as the preset standard parameter, or other selection methods, as long as it satisfies that the present invention can clearly define different specific situations in the single-item determination process through the obtained values.

[0025] Please refer to Figures 1 to 4 as shown, which are respectively the flowchart of the preparation method of the S3 double hexagon bit in the embodiment of the present invention; the flowchart of determining the qualification of the annealing treatment in the embodiment of the present invention; the flowchart of determining the qualification of the preparation of the S3 double hexagon bit in the embodiment of the present invention; the flowchart of determining the reason for the unqualified preparation of the S3 double hexagon bit in the embodiment of the present invention.

[0026] The preparation method of the S3 double hexagon bit in the embodiment of the present invention includes: Step S1, cold-drawing the surface-treated S3 wire rod through a wire drawing machine to obtain a semi-finished wire rod; Step S2, subjecting the wire rod to spheroidizing annealing treatment through a pit annealing furnace to obtain a granular pearlite structure; Step S3, determining the qualification of the annealing treatment according to the uniformity index of the granular pearlite. Based on the unqualified conditions of the annealing treatment, increase the annealing holding time, or obtain the fracture morphology characteristic value of the wire rod through a torsion test combined with a scanning electron microscope and increase the annealing temperature when the annealing treatment is determined to be unqualified according to the fracture morphology characteristic value; Step S4, pickling and phosphating the wire rod with qualified annealing treatment and then performing hexagonal drawing through a wire drawing machine to obtain a hexagonal wire; Step S5, determining the surface defect index through the surface morphology analysis of the hexagonal wire obtained by a metallurgical microscope and determining the qualification of the hexagonal drawing according to the surface defect index. Based on the unqualified conditions, reduce the drawing speed or determine the maximum drawing length according to the surface roughness; Step S6, subjecting the qualified hexagonal wire through a cold heading machine to shearing, shaping, and necking down to obtain an S3 double hexagon bit; Step S7, sampling and detecting the torque bearing capacity and surface quality of the S3 double hexagon bit and determining the comprehensive performance characteristic value of a single S3 double hexagon bit; Step S8: Determine the qualification of a single S3 double hexagon bit according to the comprehensive performance characteristic value, and determine the qualification of the preparation of S3 double hexagon bits according to the proportion of qualified S3 double hexagon bits in the sampling inspection. Based on the condition of unqualified preparation, determine the reason for unqualified preparation according to the difference between the preset proportion and the proportion, and increase the shaping pressure or reduce the stamping speed.

[0027] Specifically, the surface treatment of the S3 wire rod includes rust removal, pickling, water washing, phosphating, and saponification treatment. Through the surface treatment of the S3 wire rod, the scale on the surface of the wire rod is removed and a phosphate lubricating layer is formed, making it suitable for drawing treatment.

[0028] In the embodiment of the present invention, the initial annealing temperature of the spheroidizing annealing treatment is set at 760 °C, and the initial holding time is set at 8 hours. However, the above values are not limited thereto, and those skilled in the art can adjust these values according to actual needs.

[0029] Specifically, the processing process of step S6 includes: feeding the drawn hexagonal wire into a cold heading machine. The cold heading machine first shears the fed wire, performs the first shaping of the cut end face in the second process, then flips in the third process to shape the other shearing surface, performs necking in the fourth process, first necking into a round shape, and performs translation at the fifth station and then neck the round bar into a small hexagon to obtain the final S3 double hexagon bit product.

[0030] Specifically, determine the qualification of the annealing treatment according to the uniformity index of granular pearlite. Among them, if the uniformity index is less than the first preset uniformity index of 0.75, it is determined that the annealing treatment is qualified, and the wire is subjected to pickling and phosphating treatment; If the uniformity index is greater than or equal to the first preset uniformity index and less than the second preset uniformity index of 0.90, it is determined that the annealing treatment is unqualified, and the qualification of the annealing treatment is re-determined according to the fracture morphology characteristic value; If the uniformity index is greater than or equal to the second preset uniformity index, it is determined that the annealing treatment is unqualified, and the annealing holding time is increased according to the difference between the uniformity index and the second preset uniformity index.

[0031] In the embodiment of the present invention, the value of the first preset uniformity index is 0.75, and the value of the second preset uniformity index is 0.90. However, the above values are not limited thereto, and those skilled in the art can adjust these values according to actual needs.

[0032] Specifically, the uniformity index is jointly determined by the size uniformity and distribution uniformity of granular pearlite, and is calculated by the following formula: In the formula, is the uniformity index, is the size uniformity weight coefficient, set = 0.55, is the dimensional uniformity, is the distribution uniformity weight coefficient, and is set = 0.42, is the distribution uniformity.

[0033] Specifically, the uniformity index of granular pearlite is obtained by combining a metallographic microscope with an image processing algorithm. Five points are randomly selected on the wire rod to take metallographic images, and then the dimensional uniformity and distribution uniformity of the granular pearlite in each image are determined through the image processing algorithm. Then, the uniformity index obtained from each image is averaged to obtain the uniformity index of granular pearlite. Among them, the dimensional uniformity represents the degree of discreteness of the pearlite particle area and is used to quantify the size consistency of the carbide particles in the pearlite; the distribution uniformity is used to evaluate the spatial distribution uniformity of the pearlite particles in the matrix and avoid local aggregation or sparseness.

[0034] Specifically, the annealing holding time is increased according to the difference between the uniformity index and the second preset uniformity index. Among them, if the difference in the uniformity index is less than the first preset difference in the uniformity index of 0.05, the annealing holding time is increased to the corresponding value using the first time adjustment coefficient of 1.05; if the difference in the uniformity index is greater than or equal to the first preset difference in the uniformity index and less than the second preset difference in the uniformity index of 0.12, the annealing holding time is increased to the corresponding value using the second time adjustment coefficient of 1.13; if the difference in the uniformity index is greater than or equal to the second preset difference in the uniformity index, the annealing holding time is increased to the corresponding value using the third time adjustment coefficient of 1.25; The difference in the uniformity index is the difference between the uniformity index and the second preset uniformity index.

[0035] In the embodiment of the present invention, the value of the first preset difference in the uniformity index is 0.05, and the value of the second preset difference in the uniformity index is 0.12. However, the above values are not limited to this, and those skilled in the art can adjust this value according to actual needs.

[0036] Specifically, in the step S3, a torsion experiment is carried out by a microcomputer-controlled torsion testing machine. The torsion speed is set to 3 r / min. Through the torsion test, not only the maximum torque and shear modulus of the wire rod can be obtained, but also the morphology of the wire rod fracture can be obtained. Then, the fracture morphology characteristic value is obtained by observing the fracture morphology with a scanning electron microscope.

[0037] Specifically, based on the condition that the fracture morphology characteristic value is less than the preset morphology characteristic value of 0.7, it is determined that the annealing treatment is unqualified for the second time, and the annealing temperature is increased according to the difference between the preset morphology characteristic value and the fracture morphology characteristic value; Based on the condition that the fracture morphology characteristic value is greater than or equal to the preset morphology characteristic value, the annealing treatment is determined to be qualified for the second time, and the wire rod is subjected to pickling and phosphating treatment.

[0038] Specifically, the fracture morphology characteristic value is jointly determined by the fracture shrinkage rate and the fracture roughness, and is calculated by the following formula. , in the formula, is the fracture morphology characteristic value. is the shrinkage rate weight coefficient, set = 0.52. is the shrinkage rate threshold, set = 10%. is the fracture shrinkage rate. is the roughness weight coefficient, set = 0.45. is the roughness threshold, set = 15 μm. is the fracture roughness.

[0039] Specifically, the fracture shrinkage rate and the fracture roughness are obtained through image analysis software, such as ImageJ, MATLAB, etc., and are not specifically limited.

[0040] Specifically, the annealing temperature is positively correlated with the difference in fracture morphology. Among them, the difference in fracture morphology is the difference between the preset morphology characteristic value and the fracture morphology characteristic value. In this embodiment, the adjustment range of the annealing temperature is 760 °C to 780 °C.

[0041] Specifically, the qualification of the hexagonal drawing is determined according to the surface defect index. Among them, if the surface defect index is less than the first preset surface defect index of 3%, it is determined that the hexagonal drawing is qualified, and the hexagonal wire is cold-headed to obtain an S3 double hexagonal bit. If the surface defect index is greater than or equal to the first preset surface defect index and less than the second preset surface defect index of 5%, it is determined that the hexagonal drawing is unqualified, and the drawing speed is reduced according to the difference between the second preset surface defect index and the surface defect index. If the surface defect index is greater than or equal to the second preset surface defect index, it is determined that the hexagonal drawing is unqualified, and the maximum drawing length is reduced according to the surface roughness of the hexagonal wire.

[0042] In the embodiment of the present invention, the value of the first preset surface defect index is 3%, and the value of the second preset surface defect index is 5%. However, the above values are not limited thereto, and those skilled in the art can adjust this value according to actual needs.

[0043] Specifically, the surface defect index is the ratio of the defect area within the hexagonal line acquisition area to the acquisition area. The calculation method is to randomly select 5 points on the surface of the hexagonal line, take surface images through a metallurgical microscope, obtain the defect area through image analysis software, calculate the surface defect index of a single image, and then take the average value of the surface defect indices of these 5 points to obtain the surface defect index of the hexagonal line. Among them, defects include surface cracks, scratches, pits, etc., and no specific limitations are imposed.

[0044] Specifically, in step S7, the sampling ratio is 5%. The surface quality is characterized by the surface defect value. The process of jointly determining the comprehensive performance characteristic value by the torque bearing capacity and the surface defect value of the S3 double hexagonal bit is as follows: Take the square root of the ratio of the torque bearing capacity to the torque bearing capacity threshold and multiply it by the first weight coefficient to obtain the torque bearing capacity evaluation value, where the torque bearing capacity threshold is set to 15 and the first weight coefficient is set to 0.6; Take the square root of the ratio of the surface defect value to the surface defect threshold and multiply it by the second weight coefficient to obtain the surface defect evaluation value, where the surface defect threshold is set to 5% and the second weight coefficient is set to 0.4; Add the torque bearing capacity evaluation value and the surface defect evaluation value to obtain the comprehensive performance characteristic value.

[0045] Specifically, the surface defect value is the ratio of the defect area of the S3 double hexagonal bit to the overall area, which is obtained through image analysis and calculation by collecting images of the S3 double hexagonal bit from multiple perspectives.

[0046] Specifically, based on the condition that the comprehensive performance characteristic value is less than the preset comprehensive performance characteristic value of 0.92, it is determined that a single S3 double hexagonal bit is unqualified, and the unqualified S3 double hexagonal bits are marked; Based on the condition that the comprehensive performance characteristic value is greater than or equal to the preset comprehensive performance characteristic value, it is determined that a single S3 double hexagonal bit is qualified, and the qualification of the remaining S3 double hexagonal bits is continuously detected and determined.

[0047] In the embodiment of the present invention, the preset comprehensive performance characteristic value is taken as 0.92, but the above value is not limited thereto, and those skilled in the art can adjust this value according to actual needs.

[0048] Specifically, the qualification of the S3 double hexagonal bit preparation is determined according to the proportion of qualified S3 double hexagonal bits in the sampling inspection. Among them, if the proportion is less than the preset proportion of 95%, it is determined that the S3 double hexagonal bit preparation is unqualified, and the reason for the unqualified preparation is determined according to the difference between the preset proportion and the proportion; If the proportion is greater than or equal to the preset proportion, it is determined that the S3 double hexagonal bit preparation is qualified, and the preparation is completed according to the current preparation parameters.

[0049] Specifically, the reason for the unqualified preparation is determined according to the ratio difference. Among them, if the ratio difference is less than the preset ratio difference of 2%, it is determined that the reason for the unqualified preparation is that the sizing pressure during the cold heading process does not meet the standard, and the sizing pressure is increased according to the opposite side tolerance value of the unqualified S3 double hexagon bit; If the ratio difference is greater than or equal to the preset ratio difference, it is determined that the reason for the unqualified preparation is that the stamping speed during the cold heading process does not meet the standard, and the stamping speed is reduced according to the deformation rate of the unqualified S3 double hexagon bit; The ratio difference is the difference between the preset ratio and the ratio.

[0050] In the embodiment of the present invention, the preset ratio is taken as 95%, and the preset ratio difference is taken as 2%. However, the above values are not limited to this, and those skilled in the art can adjust this value according to actual needs.

[0051] Specifically, the sizing pressure is increased according to the opposite side tolerance value of the unqualified S3 double hexagon bit. Among them, if the opposite side tolerance value is less than the first preset tolerance value of 0.08 mm, the sizing pressure is increased to the corresponding value using the first pressure adjustment coefficient of 1.1; If the opposite side tolerance value is greater than or equal to the first preset tolerance value and less than the second preset tolerance value of 0.15 mm, the sizing pressure is increased to the corresponding value using the second pressure adjustment coefficient of 1.3; If the opposite side tolerance value is greater than or equal to the second preset tolerance value, the sizing pressure is increased to the corresponding value using the third pressure adjustment coefficient of 1.5.

[0052] In the embodiment of the present invention, the initial sizing pressure is set to 200 MPa, the first preset tolerance value is taken as 0.08 mm, and the second preset tolerance value is taken as 0.15 mm. However, the above values are not limited to this, and those skilled in the art can adjust this value according to actual needs.

[0053] Specifically, the opposite side tolerance value of the unqualified S3 double hexagon bit is measured by an on-line laser measuring instrument.

[0054] Specifically, the stamping speed is reduced according to the deformation rate of the unqualified S3 double hexagon bit. Among them, if the deformation rate is less than the first preset deformation rate of 1.5%, the stamping speed is reduced to the corresponding value using the first speed adjustment coefficient of 0.92; If the deformation rate is greater than or equal to the first preset deformation rate and less than the second preset deformation rate of 3.0%, the stamping speed is reduced to the corresponding value using the second speed adjustment coefficient of 0.83; If the deformation rate is greater than or equal to the second preset deformation rate, the stamping speed is reduced to the corresponding value using the third speed adjustment coefficient of 0.75.

[0055] In the embodiment of the present invention, the initial stamping speed is set to 70 mm / s, the value of the first preset deformation rate is 1.5%, and the value of the second preset deformation rate is 3.0%. However, the above values are not limited thereto, and those skilled in the art can adjust the values according to actual needs.

[0056] Specifically, the deformation rate of the unqualified S3 double hexagon bit is measured by a laser scanner.

[0057] In the S3 double hexagon bit of the embodiment of the present invention, the ratio of the opposite side lengths of the two end faces of the S3 double hexagon bit is 3:4, and the length is not specifically limited.

[0058] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0059] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an S3 double hexagonal screwdriver bit, characterized in that: include: The surface treated S3 wire rod is cold drawn through a wire drawing machine to obtain a semi-finished wire rod; The wire is subjected to spheroidizing annealing treatment in a pit-type annealing furnace to obtain a granular pearlite structure; The eligibility of the annealing treatment is determined according to the uniformity index of the granular pearlite. Based on the condition that the annealing treatment is unqualified, the annealing holding time is increased, or the annealing temperature is increased when the annealing treatment is unqualified by obtaining the fracture morphology characteristic value of the wire through a torsion test combined with a scanning electron microscope and the fracture morphology characteristic value is used to secondarily determine that the annealing treatment is unqualified; The qualified wire material after annealing is pickled and phosphated, and then hexagonally drawn by a wire drawing machine to obtain a hexagonal wire; Obtain the surface morphology of the hexagonal wire through a metallographic microscope to analyze and determine the surface defect index and determine the eligibility of the hexagonal drawing based on the surface defect index, reduce the drawing speed based on the unqualified condition or determine the maximum drawing length based on the surface roughness; The qualified hexagonal wire is sheared, shaped and reduced by a cold heading machine to obtain an S3 double hexagonal bit; Sampling test of torque carrying capacity and surface quality of S3 double hexagonal screwdriver bits and determination of comprehensive performance characteristic values ​​of single S3 double hexagonal screwdriver bits; The qualification of a single S3 double hexagonal screwdriver bit is determined according to the comprehensive performance characteristic value, and the qualification of the preparation of S3 double hexagonal screwdriver bits is determined according to the proportion of qualified S3 double hexagonal screwdriver bits in the random inspection. Based on the conditions for unqualified preparation, the cause of unqualified preparation is determined according to the difference between the preset proportion and the proportion, and the shaping pressure is increased or the stamping speed is reduced.

2. The method for preparing the S3 double hexagonal screwdriver bit according to claim 1, characterized in that: The eligibility of the annealing treatment is determined according to the uniformity index of the granular pearlite, wherein if the uniformity index is less than a first preset uniformity index, the annealing treatment is determined to be qualified, and the wire is subjected to pickling and phosphating treatment; If the uniformity index is greater than or equal to the first preset uniformity index and less than the second preset uniformity index, the annealing treatment is judged to be unqualified, and the eligibility of the annealing treatment is secondarily judged according to the fracture morphology characteristic value; If the uniformity index is greater than or equal to the second preset uniformity index, the annealing process is determined to be unqualified, and the annealing holding time is increased according to the difference between the uniformity index and the second preset uniformity index.

3. The method for preparing the S3 double hexagonal screwdriver bit according to claim 2, characterized in that: The uniformity index is determined by the uniformity of the size and the uniformity of the distribution of the pearlite particles.

4. The method for preparing the S3 double hexagonal screwdriver bit according to claim 2, characterized in that: Based on the condition that the fracture morphology characteristic value is less than the preset morphology characteristic value, the annealing treatment is secondarily determined to be unqualified, and the annealing temperature is increased according to the difference between the preset morphology characteristic value and the fracture morphology characteristic value; Based on the condition that the fracture morphology characteristic value is greater than or equal to the preset morphology characteristic value, it is determined that the annealing treatment is qualified for the second time, and the wire is subjected to pickling and phosphating treatment.

5. The method for preparing the S3 double hexagonal screwdriver bit according to claim 4, characterized in that: The fracture morphology characteristic value is determined by the fracture shrinkage rate and the fracture roughness.

6. The method for preparing the S3 double hexagonal screwdriver bit according to claim 1, characterized in that: The eligibility of the hexagonal drawing is determined according to the surface defect index, wherein if the surface defect index is less than the first preset surface defect index, the hexagonal drawing is determined to be qualified, and the hexagonal wire is cold-forged to obtain an S3 double hexagonal bit; If the surface defect index is greater than or equal to the first preset surface defect index and less than the second preset surface defect index, the hexagonal drawing is determined to be unqualified, and the drawing speed is reduced according to the difference between the second preset surface defect index and the surface defect index; If the surface defect index is greater than or equal to the second preset surface defect index, the hexagonal drawing is determined to be unqualified, and the maximum drawing length is reduced according to the surface roughness of the hexagonal wire.

7. The method for preparing the S3 double hexagonal screwdriver bit according to claim 1, characterized in that: Based on the condition that the comprehensive performance characteristic value is less than the preset comprehensive performance characteristic value, a single S3 double hexagonal screwdriver bit is judged as unqualified, and the unqualified S3 double hexagonal screwdriver bit is marked; Based on the condition that the comprehensive performance characteristic value is greater than or equal to the preset comprehensive performance characteristic value, the single S3 double hexagonal screwdriver bit is judged to be qualified, and the qualification of the remaining S3 double hexagonal screwdriver bits is continued to be tested and determined.

8. The method for preparing the S3 double hexagonal screwdriver bit according to claim 1, characterized in that: The qualification of the preparation of the S3 double hexagonal screwdriver bits is determined according to the proportion of qualified S3 double hexagonal screwdriver bits in the random inspection, wherein if the proportion is less than the preset proportion, the preparation of the S3 double hexagonal screwdriver bits is determined to be unqualified, and the reason for the unqualified preparation is determined according to the difference between the preset proportion and the proportion; If the proportion is greater than or equal to the preset proportion, it is determined that the S3 double hexagonal screwdriver bit is qualified, and the preparation is completed according to the current preparation parameters.

9. The method for preparing the S3 double hexagonal screwdriver bit according to claim 8, characterized in that: Determine the reason for the unqualified preparation according to the proportion difference, wherein, if the proportion difference is less than the preset proportion difference, determine that the reason for the unqualified preparation is that the shaping pressure during the cold heading process does not meet the standard, and increase the shaping pressure according to the opposite side tolerance value of the unqualified S3 double hexagonal screwdriver bit; If the proportion difference is greater than or equal to the preset proportion difference, it is determined that the reason for the unqualified preparation is that the stamping speed during the cold heading process does not meet the standard, and the stamping speed is reduced according to the deformation rate of the unqualified S3 double hexagonal screwdriver bit; The proportion difference is the difference between the preset proportion and the proportion.

10. An S3 double hexagonal screwdriver bit obtained according to the preparation method according to any one of claims 1 to 9, characterized in that: The ratio of the lengths of opposite sides of the two end faces of the S3 double hexagonal screwdriver bit is 3:4.

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