Die structure for hot upset forging of stainless steel bolt

Abstract

The invention belongs to the technical field of dies, and particularly relates to a die structure for hot upset forging of a stainless steel bolt. The die structure comprises a female die and a male die, wherein the male die comprises a first die shell, a first die core and a first cavity, the first die core is placed in the first die shell, the first cavity is formed in the first die core, the female die comprises a second die shell, a second die core and a second cavity, the second die core is placed in the second die shell, the second cavity is formed in the second die core, and a containing space for the bolt is jointly formed by the first cavity and the second cavity. According to the die structure, compared with the prior art, the female die and the male die are arranged to be of a split structure with parts replaceable, and thus replacement can be performed more conveniently and fast; if some part in a die is damaged, the die does not need to be scrapped as a whole, only the damaged part needs to be replaced, and therefore die cost is greatly reduced, and the service life of the whole die is prolonged.

Description

technical field [0001] The invention belongs to the technical field of dies, and in particular relates to a die structure for hot upset forging of stainless steel bolts. Background technique [0002] Due to the particularity of the stainless steel material, when using the cold heading method to form a part with a relatively large head upsetting ratio (such as a stainless steel T-shaped bolt), the head is easily hardened by cold work due to severe deformation, resulting in the next step of cold deformation of the blank. Even if the billet is re-annealed and then cold-formed, it is easy to explode the mold, because annealing will definitely change the crystal structure of the material. If the annealing time is too long and too thorough, it will cause the crystal of the entire billet to refine and the billet will become soft, seriously affecting The mechanical properties of the rod portion (need to form the thread) with appropriate hardness and strength are required, resulting ...

AI Technical Summary

Problems solved by technology

[0002] Due to the particularity of the stainless steel material, when using the cold heading method to form a part with a relatively large head upsetting ratio (such as a stainless steel T-shaped bolt), the head is easily hardened by cold work due to severe deformation, resulting in the next step of cold deformation of the blank. Even if the billet is re-annealed and then cold-formed, it is easy to explode the mold, because annealing will definitely change the crystal structure of the material. If the annealing time is too long and too thorough, it will cause the crystal of the entire billet to refine and the billet will become soft, seriously affecting The mechanical properties of the rod portion (need to form the thread) with appropriate hardness and strength are required, resulting in a decrease in the performance of the product; and if the annealing time is used to ensure the strength of the billet rod portion, the cold work hardening of the head of the billet cannot be completely eliminated. , it is easy to cause frequent mold explosion during cold forming

[0003] Therefore, the stainless steel bolts with large upsetting ratio (such as stainless steel T-bolts) currently produced and sold in the industry and the market generally adopt cold heading forming plus turning process or cold heading forming heating upsetting forming process, because the turning process is in the product Part of the material is removed from the surface to achieve the purpose of forming. The fiber structure of the metal will be destroyed during the processing, which will seriously affect the appearance and mechanical properties of the product. At the same time, the production efficiency is low and the processing cost is very high. It is not suitable for mass production.

[0004] At present, the hot forging die material adopts the mold structure of full hot work steel or hot forging tungsten steel outer covering hot work steel, which generally has the disadvantages of easy chipping, cracking or straining of the die, and the service life is not ideal, resulting in production costs. Higher, and once a certain part of it is damaged, the entire mold needs to be replaced; therefore, in order to improve the performance of the product and reduce the production cost, it is urgent to develop a mold structure for hot upset forging of stainless steel bolts

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