Improved cold drawing mould of seamless steel pipe and cold drawing process thereof

Abstract

The invention discloses an improved cold drawing mould of a seamless steel pipe and a cold drawing process thereof. The improved cold drawing mould comprises a cold drawing inner mould and a cold drawing outer mould, wherein a drawhole is formed on the cold drawing outer mould; the cold drawing inner mould is sequentially divided into a guide section, a conical wall-reduction section and a cylindrical uniform-wall section along the steel pipe drawing direction; and the entire structural strength of the cold drawing mould is improved. By adopting the cold drawing mould provided by the invention to draw a GCr15 bearing steel seamless steel pipe, the extension coefficient mu[sigma] of single-pass drawing of the pipe blank can be increased; and as the extension coefficient of single-pass drawing is increased, the drawing passes for drawing the seamless steel pipe of the same specification are reduced, the drawing yield is increased, the production period is shortened, and the production cost is lowered.

Description

technical field [0001] The invention belongs to the field of metal drawing forming dies and drawing forming processes thereof, and in particular relates to an improvement of a seamless steel pipe cold drawing die and a cold drawing process thereof. Background technique [0002] Such as figure 1 As shown, the cold drawing die used in the cold drawing process of the traditional high-carbon chromium bearing steel seamless steel pipe includes a cylindrical inner die 02 and a tapered outer die 01, the outer wall of the cylindrical inner die 02 and the tapered outer die 01 The deformation section formed between the inner walls is used to reduce the wall and diameter of the steel pipe. During the cold drawing process of the steel pipe, the cylindrical inner mold needs to use a stretch rod to fix the working position and keep it in the deformation section. . The disadvantage of drawing high-carbon chromium bearing steel seamless steel pipes with existing cylindrical inner molds is...

AI Technical Summary

Problems solved by technology

The disadvantage of drawing high-carbon chromium bearing steel seamless steel pipes with existing cylindrical inner dies is that: due to the high deformation resistance of high-carbon chromium bearing steel pipes in the cold drawing deformation process, when drawing with ordinary cylindrical inner dies, If the drawing elongation is slightly greater than μ∑1.30, fracture will occur. Practice has proved that the steel pipe has a hig

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