Outer die of square special-shaped steel pipe equilateral line core die

Abstract

The invention discloses an outer die of a square special-shaped steel pipe equilateral line core die. The related parameters of the inlet section of the outer die can be quantified. The outer die comprises a bushing and a die core disposed in the bushing. A draw hole penetrating the die core is formed in the die core. The draw hole comprises an inlet section and a sizing section. The sizing section comprises four straight edges and four corner arc-shaped faces with the curvature radius being R1, and the distance between every two opposite flat and straight faces is L. The inlet section comprises four guide-in slopes and four inlet corner cambered faces, the curvature radius of the outer edge of each inlet corner cambered face is R2, R2 is 1.5-.2.5 times of R1, the distance between the outer edges of every two opposite guide-in slopes is L1, the formula of L1 is showed in the description and claims, and in the formula, 1.15< / =k1< / =1.25, 1< / =k2< / =1.6, and 0.5< / =k3< / =0.8. The outer die is used for drawing circular pipe blanks into square steel pipes.

Description

technical field [0001] The invention relates to a forming and drawing die in the technical field of metal plastic processing, in particular to a forming and drawing die for drawing a round steel pipe into a square special-shaped steel pipe. Background technique [0002] The drawing die is an important tooling part in the production of cold-drawn steel pipes, and has been widely used in the production process of steel pipe diameter reduction and / or deformation. The steel pipe is cold drawn and formed by using a drawing die, which has the characteristics of high material utilization rate, low energy consumption, excellent product performance, high production efficiency and low cost. Among the drawing dies, according to the different cross-sectional shapes of the drawn pipes, they can be divided into oval drawing dies and special-shaped drawing dies. ); Among them, the special-shaped drawing die is divided into empty drawing die (referred to as empty drawing die) and lining co...

AI Technical Summary

Problems solved by technology

[0003] As we all know, if the opening size of the outer mold and the length of the entrance section are set unreasonably, the contact area between the steel pipe and the mold will change accordingly, and the longitudinal and lateral flow of the metal will be unbalanced, which will lead to The quality of the square tube is poor, and the main surface has defects such as poor straightness (with varying degrees of curvature), uneven wall thickness, uneven fillet, unstable size, and uneven surface, and even more so during the drawing process. Steel pipe breakage and cracking

[0004] At present, there is no uniform design standard for the outer mold of the special-shaped steel pipe lining mandrel. The opening size and length of the entrance section are set based on experience. For each type of square pipe, when designing the outer mold, It takes repeated tests, improvements, and retests to get an ideal outer mold, which not only prolongs the processing cycle of the outer mold, but also increases the production cost

Images