External mould assembly for cold-drawing pipes

Abstract

The invention relates to an external mould assembly for cold-drawing pipes, comprising a mould seat, the middle part of the mould seat is provided with an axial external mould containing cavity, the front of the external mould containing cavity is the exit of the mould seat; wherein the external moulding containing cavity is internally provided with a front mould and a rear mould, aperture of a rear mould sizing region is larger than the aperture of a front mould sizing region, and a rear mould transition angle of a rear mould transition region is greater than the a front mould transition angle of a front mould transition region. The invention adopts double external mould structure to carry out steel tube empty sinking operation, not only dimensional change of inner hole and wall thickness of target steel tube can be controlled by the external mould, but also the phenomenon that the diameter of the original pipe is sharply reduced can be eliminated, the problem that the target pipe is easy to crack and has high flexibility when in cold-drawing pipe process reinforcement is effectively solved, and the invention has the advantage that structure improvement is simple while mould cost is not increased.

Description

【Technical field】 [0001] The invention belongs to an outer mold assembly for cold-drawn pipes. 【Background technique】 [0002] At present, if you want to obtain seamless steel pipes with smaller size and better quality, you must use cold rolling, cold drawing or a combination of both. Cold drawing refers to drawing the material at room temperature in order to achieve a certain shape and certain mechanical properties. Cold drawing is usually carried out on a 0.5-100T single-chain or double-chain cold drawing machine. Its products Compared with thermoformed products, it has the advantages of high dimensional accuracy and good surface finish. The empty drawing process is one of the production methods of cold drawn steel pipes. In the operation, only the outer mold assembly is needed instead of the inner mold and mandrel assembly. The outer mold assembly includes the mold base and the outer mold. The through hole is used to receive the outer mold. The working area inside the o...

AI Technical Summary

Problems solved by technology

[0003] The external mold components used in the existing hollow drawing process have the following problems: 1. The inner hole and wall thickness of the original pipe can only be allowed to increase or decrease naturally, and it is difficult to control the dimensional changes of the original pipe inner hole and wall thickness through the outer mold

2. The working transition area of ​​the entire outer mold assembly is short, and the original pipe material has a phenomenon of sharp reduction in diameter. If the cold-drawn pipe material process is strengthened, the target pipe material is prone to cracking, large bending, etc., which will affect the quality of the target pipe material and the scrap rate high

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