Method to solve the heat treatment quenching deformation of stamping die

Control of quenching deformation of stamping die parts. Quenching deformation of stamping die parts is a common phenomenon in stamping die heat treatment, and it is almost inevitable. If reasonable measures can be taken to control the quenching deformation within the allowable range, it is possible to avoid the generation of heat treatment waste. Methods to control heat treatment deformation: First, the cause of deformation: the selection of parts is unreasonable. Solution: Use steel correctly. For parts with large differences in cross-sections and complex shapes, alloy tool steels should be used as much as possible. Second, the reason for the deformation: the part design process is unreasonable. Solution: ①Under the premise of meeting the requirements of use, the parts should be as symmetrical as possible to avoid the difference in thickness and sharp corners. The thickness junction should be smoothly transitioned. ② For parts with complex shapes, it is advisable to appropriately increase process holes or design a combined structure. ③The hardness requirements should be reasonable. Third, the cause of deformation: the forging process is unreasonable. Solution: Reasonably control the forging temperature and forging process, and pay attention to the directionality of the material. After forging, it should be annealed. Fourth, the cause of deformation: the heating process is not strictly controlled. Solution: Reasonably select and control the heating temperature, the lower limit of the quenching temperature is generally selected, and it is best to preheat first when heating. For parts that are large in size and only require surface hardness, rapid heating can be used. Fifth, the cause of deformation: the cooling method and coolant are unreasonable. Solution: ①For easily deformable parts, pre-cooling technology should be used, but the pre-cooling time should not be too long. ②Austempering or graded quenching shall be adopted for alloy steel parts. ③Using two-liquid or three-liquid quenching method. For small parts, nitrate salt and then oil for quenching; for large parts or parts with low surface roughness requirements, oil first and then nitrate salt for cooling. ④ Cold treatment process can be used for high alloy steel. Sixth, the cause of deformation: the tempering process is incorrect. Solution: ① After the workpiece is taken out of the coolant, it should not stay in the air, and immediately transferred to the tempering furnace for tempering. ② Choose the tempering temperature reasonably, not too high or too low, sometimes the method of multiple tempering can be used. ③Using convex and concave mold limited shape quenching and sleeve tempering process. That is, the concave mold is first quenched without tempering, and then the convex mold is quenched, removed from the coolant, and stuffed into the concave mold. After isothermally cooling to room temperature, it is combined and tempered together. Seven, the cause of deformation: the heat treatment operation is incorrect. Solution: ①Before quenching, reasonable protective measures such as iron wrapping, iron wire binding, and concrete blockage should be carried out on the stress concentration parts of the parts. ②For easily deformable trough-shaped workpieces, screws can be used to fix the same. ③ Correctly master the heat treatment process operation. 8. The cause of deformation: the influence of machining stress. Solution: Correctly handle the relationship between heat treatment and mechanical processing, and arrange processing procedures reasonably. Generally, before the final forming of the stamping die, stress relief treatment should be carried out, and then the size should be trimmed, and then quenched. With the emergence of EDM machine tools, wire cutting machine tools, CNC machine tools, and forming grinders, the original manual mold making process has been broken, that is, the accuracy of stamping die parts is no longer troubled by heat treatment deformation. This is because the stamping die parts are first roughed and heat-treated and hardened and then finished with these special equipment, so that even if the parts are deformed after quenching, they will not be affected much, and in some respects It can be corrected and compensated. Previous post: Methods and precautions for processing different materials with a hand saw