A method for analyzing steel plate stamping problems

Abstract

The present invention discloses a method for analyzing steel plate stamping problems, which is characterized in that a mold is assembled, a steel plate is placed in and stamping is started. When stamping cracking / wrinkling / deformation / necking / hair pulling problems are found, seven steel plates are used to complete the problem identification work at the stamping production site. The method is not only simple and easy to operate, but also solves the problem of steel plate problem identification that has plagued stamping plants for many years. It also provides a systematic strategy for rapid response of steel plants, greatly improving the work efficiency of both parties.

Description

Technical Field

[0001] The present invention relates to a steel plate stamping problem analysis method (a steel plate stamping applicability factor identification method). Background Art

[0002] Steel mills and stamping plants frequently encounter various stamping problems. However, determining the root cause—the mold, the press, or the steel plate—and determining whether the problem lies with the surface, performance range, performance distribution, or thickness tolerance—often consumes considerable effort on both sides' technical staff. These issues are the most common and often cause the most confusion. In practice, these issues rely entirely on the technicians' experience, with no easy and reliable method for rapid identification.

[0003] This method summarizes a large amount of experience in solving physical stamping and mold problems accumulated by front-line tracking. By fully refining and abstracting the problem-solving ideas and principles, it optimizes and simplifies the on-site testing method, and can complete the steel plate stamping process identification task without limiting the professional level of tracking personnel. Summary of the Invention

[0004] The purpose of this invention is to provide a steel plate stamping problem analysis method suitable for process control and optimization of steel plate manufacturers and automobile stamping factories, and to realize a strategic and systematic method for analyzing the causes of problems that occur during the steel plate stamping process.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for analyzing steel plate stamping problems. The method involves assembling a mold, placing a steel plate in the mold, and starting stamping. If stamping cracking, wrinkling, deformation, necking, or fuzzing is found:

[0007] 1) Prepare 7 steel plates from the same batch

[0008] The macroscopic characteristic values ​​of the seven steel plates were measured and counted to ensure that there was no unreasonable fluctuation in the selected sheet materials; one sheet was placed in the stamping die under completely unchanged working conditions, and the characteristics of each area of ​​the part were observed after stamping as a benchmark;

[0009] 2) Take a steel plate, apply colorant to both the upper and lower surfaces of the steel plate and stamp it. Observe the color printing coverage of the upper and lower molds. If there is a corresponding relationship between the uncovered area and the problem area of ​​the part, or if the uncovered area and the problem area do not overlap but are larger in area, it means that the mold manufacturing condition is poor and needs to be re-developed. At the same time, carry out the following work;

[0010] 3) Take a steel plate, wipe off the oil film on the surface of the steel plate, and then stamp it again under the same working conditions. Compare it with the reference part. If the problem areas related to stamping and expansion worsen while the wrinkling and deformation problems are alleviated, it indicates that the surface lubrication condition is the main influencing factor, and one or more of the following aspects should be improved: "surface roughness / lubrication effect of oil / oil quantity / dynamic friction coefficient". If there is no obvious change, the above factors are not the main factors.

[0011] 4) Take a steel plate and apply a layer of smooth transparent tape to the wide area of ​​the die corresponding to the area with the smaller plate thickness measured previously. Place the plate into the die and press it into shape under the same working conditions. If the stamping problem is alleviated and does not transfer, it indicates that the plate shape is the main influencing factor.

[0012] 5) Take 2 steel plates, close the empty mold and use a feeler gauge to measure the gap size between the mold blank holder and the upper mold. Then open the mold and place gaskets of the same thickness on the 4 directions of the blank holder, 0.1mm once and 0.5mm once, to ensure that the same height is added on all sides. Other factors remain unchanged. Stamp twice to obtain part observation and compare with the benchmark. If there is no obvious change with 0.1mm / 0.5mm gaskets, it is not related to "steel plate thickness, mold blank holder gap, and lubrication friction"; if the change at 0.1mm is ideal and the change at 0.5mm is too large, it means that it is related to "steel plate thickness, mold blank holder gap, and lubrication friction". You can choose one or more to optimize. If the change of 0.1mm is small and the change of 0.5mm is ideal, you can change the above factors at the same time.

[0013] 6) Take two steel plates, cut off part of the plate on both sides of one horizontally so that the plate width direction is smaller than the blank holder, and cut off part of the plate on both sides of the longitudinally so that the plate width direction is smaller than the blank holder. Punch them separately and compare them with the benchmark sample. If punching the plate with both horizontal and longitudinal cuts significantly improves the punching problem, it means that the mechanical properties of the steel need to be improved; if there is a significant improvement in the horizontal or longitudinal direction but there is no significant improvement in the other direction of cutting, it means that the anisotropy needs to be optimized; if there is no improvement in both horizontal and longitudinal cuts, the performance is not the main influencing factor, and the reasons obtained from other tests should be considered.

[0014] Furthermore, the macroscopic characteristic values ​​include: surface roughness, dynamic friction coefficient, oil film thickness, sheet thickness tolerance, and plate convexity.

[0015] Furthermore, in the above 2), the steel plate contains an initial oil film.

[0016] Furthermore, in the above 3), the oil film on the surface of the steel plate is wiped off by using dust-free paper dipped in petroleum ether.

[0017] Furthermore, it is suitable for process control and optimization of steel plate manufacturers and automobile stamping factories.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] The method of the present invention uses only 7 steel plates and can complete the problem identification work at the stamping production site. It is not only simple and easy to operate, but also solves the problem of steel plate problem identification that the stamping plant has been troubled by for many years. It also provides a systematic strategy for the steel plant to respond quickly, greatly improving the work efficiency of both parties. DETAILED DESCRIPTION

[0020] A method for analyzing steel plate stamping problems: assemble the mold, put the steel plate in and start stamping. If you find problems such as stamping cracking / wrinkling / deformation / necking / hair pulling:

[0021] 1) Prepare seven steel plates from the same batch. Measure and compile macroscopic characteristics of these seven plates, including surface roughness, dynamic friction coefficient, oil film thickness, sheet thickness tolerance, and profile convexity, to ensure that the selected plates exhibit no unreasonable fluctuations. While maintaining the same working conditions, including the stamping die, insert one plate. After stamping, observe the characteristics of each region of the part as a benchmark.

[0022] 2) Take a steel plate, apply colorant to the upper and lower surfaces of the steel plate (including the initial oil film) and stamp it. Observe the color printing coverage area of ​​the upper and lower molds. If there is a corresponding relationship between the uncovered area and the problem area of ​​the part, or if the uncovered area does not overlap with the problem area but the area is larger, it means that the mold manufacturing condition is poor and needs to be re-developed. At the same time, carry out the following work.

[0023] 3) Take a steel plate and wipe off the oil film on the surface with a dust-free paper dipped in petroleum ether. After stamping again with other working conditions unchanged, compare it with the benchmark part. If the problem areas related to stamping and expansion (strain, necking, cracking, etc.) worsen while the problem areas such as wrinkling and deformation are alleviated, it means that the surface lubrication condition is the main influencing factor, and one or more of the aspects of "surface roughness / oil lubrication effect / oil amount / dynamic friction coefficient" should be improved. If there is no obvious change, the above factors are not the main factors.

[0024] 4) Take a steel plate and stick a layer of smooth transparent tape on the wide area of ​​the die corresponding to the area with smaller plate thickness measured previously. Put the plate into the stamping process without changing other working conditions. If the stamping problem is alleviated and there is no transfer compared with the benchmark, it means that the plate shape is the main influencing factor.

[0025] 5) Take 2 steel plates, close the empty mold and use a feeler gauge to measure the gap size between the mold blank holder and the upper mold. Then open the mold and place gaskets of the same thickness in the four directions of the blank holder (0.1mm once, 0.5mm once) to ensure that the same height is added on all sides. Other factors remain unchanged. Stamp twice to obtain part observation and compare with the benchmark. If there is no obvious change with 0.1mm / 0.5mm gaskets, it is not related to "steel plate thickness, mold blank holder gap, and lubrication friction"; if the change at 0.1mm is ideal and the change at 0.5mm is too large, it means that it is related to "steel plate thickness, mold blank holder gap, and lubrication friction". You can choose one or more of them for optimization. If the change of 0.1mm is small and the change of 0.5mm is ideal, you need to change the above factors at the same time.

[0026] 6) Take two steel plates, cut off part of the plate on both sides of one horizontally so that the width direction of the plate is smaller than the blank holder, and cut off part of the plate on both sides of the other vertically so that the width direction of the plate is smaller than the blank holder. Punch them separately and compare them with the benchmark sample. If punching the plate with horizontal and vertical cuts significantly improves the punching problem, it means that the mechanical properties of the steel need to be improved (while the yield strength remains unchanged, the tensile strength and elongation are improved); if there is a significant improvement in the horizontal or vertical direction but there is no significant improvement in the other direction of cutting, it means that the anisotropy needs to be optimized; if there is no improvement in both horizontal and vertical cutting, the performance is not the main influencing factor, and the reasons obtained from other tests should be considered.

[0027] The method of the present invention uses only 7 steel plates and can complete the problem identification work at the stamping production site. It is not only simple and easy to operate, but also solves the problem of steel plate problem identification that the stamping plant has been troubled by for many years. It also provides a systematic strategy for the steel plant to respond quickly, greatly improving the work efficiency of both parties.

[0028] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for analyzing steel plate stamping problems, characterized in that: Assemble the mold, put the steel plate in and start stamping. If you find problems such as stamping cracking / wrinkling / deformation / necking / straining: 1) Prepare 7 steel plates from the same batch The macroscopic characteristic values ​​of the seven steel plates were measured and counted to ensure that there was no unreasonable fluctuation in the selected sheet materials; one sheet was placed in the stamping die under completely unchanged working conditions, and the characteristics of each area of ​​the part were observed after stamping as a benchmark; 2) Take a steel plate, apply colorant to both the upper and lower surfaces of the steel plate and stamp it. Observe the color printing coverage of the upper and lower molds. If there is a corresponding relationship between the uncovered area and the problem area of ​​the part, or if the uncovered area and the problem area do not overlap but are larger in area, it means that the mold manufacturing condition is poor and needs to be re-developed. At the same time, carry out the following work; 3) Take a steel plate, wipe off the oil film on the surface, and then re-stamp under the same working conditions. Compare it with the reference part. If the strain, necking, and cracking areas worsen while the wrinkling and deformation areas improve, it indicates that the surface lubrication condition is the main influencing factor. You need to improve one or more of the following aspects: surface roughness, oil lubrication effect, oil quantity, and dynamic friction coefficient. If there is no significant change, the above factors are not the main factors. 4) Take a steel plate and apply a layer of smooth transparent tape to the wide area of ​​the die corresponding to the area with smaller plate thickness measured previously. Place the plate into the die and press it into shape while keeping other working conditions unchanged. If the stamping problem is alleviated and not transferred, it indicates that the plate shape is the main influencing factor. 5) Take two steel plates, close the empty mold, and use a feeler gauge to measure the gap between the mold blank holder and the upper mold. Then, open the mold and place shims of the same thickness on the four directions of the blank holder, 0.1mm and 0.5mm respectively, to ensure that the height is increased by the same amount on all sides. Other factors remain unchanged. Stamp twice to obtain the part observation and compare it with the benchmark. If there is no obvious change with 0.1mm / 0.5mm shims, it is not related to "steel plate thickness, mold blank holder gap, and lubrication friction"; if the change at 0.1mm is ideal and the change at 0.5mm is too large, it indicates that it is related to "steel plate thickness, mold blank holder gap, and lubrication friction". Select one or more of them for optimization. If the change at 0.1mm is small and the change at 0.5mm is ideal, all the above factors need to be changed at the same time. 6) Take two steel plates, cut off part of the plate on both sides of one horizontally so that the plate width direction is smaller than the blank holder, and cut off part of the plate on both sides of the other vertically so that the plate width direction is smaller than the blank holder. Punch them separately and compare them with the benchmark sample. If punching the plate with both horizontal and vertical cuts significantly improves the punching problem, it means that the mechanical properties of the steel need to be improved; if there is a significant improvement in the horizontal or vertical direction but there is no significant improvement in cutting the plate in the other direction, it means that the anisotropy needs to be optimized; if there is no improvement in both horizontal and vertical cuts, the performance is not the main influencing factor, and the reasons obtained from other tests should be considered.

2. The steel plate stamping problem analysis method according to claim 1, characterized in that: The macroscopic characteristic values ​​include: surface roughness, dynamic friction coefficient, oil film thickness, sheet thickness tolerance, and plate convexity.

3. The steel plate stamping problem analysis method according to claim 1, characterized in that: In the above 2), the steel plate contains an initial oil film.

4. The steel plate stamping problem analysis method according to claim 1, characterized in that: In the above 3), the oil film on the surface of the steel plate is wiped off with a dust-free paper dipped in petroleum ether.