Deep hole extrusion forming process of medium-carbon low-alloy structural steel

Abstract

The invention belongs to the formation field of metal materials and relates to a deep hole extrusion forming process of medium-carbon low-alloy structural steel. When a punch head extrudes downwards, the upper end of a blank keeps still, the lower end of the blank is extruded downwards along the barrel wall of a die, one or more punch heads are adopted to extrude according to the forming requirement of a deep hole, and the sizes of the punch head, the die and the initial blank and the relation among the punch head, the die and the initial blank meet the following forming conditions: the diameter of the punch head is d, and the initial length L1 of the blank is (1.5-6) d; the initial diameter of the blank is same as the inner diameter of the upper part of the die, and the size range of the initial diameter of the blank is greater than d+10 millimeters and less than 2d; a single-side gap between the punch head and the inner diameter of the upper part of the die is greater than 5 millimeters; an annular gap is arranged between the caliber D2 of a next-stage stair on the inner wall of the die and the punch head, and the single-side width of the annular gap is greater than 1 millimeter and less than 0.4d; the annular area of the next-stage stair on the inner wall of the die is 39% greater than the sectional area of the punch head; and the head of the punch head is in a 15-degree conical surface shape, the most front end of the head of the punch head is a circular-arc surface, and the length of the head of the punch head is (0.8-1) d. The invention can obtain better strength than tempering heat treatment and flexible comprehensive mechanical properties.

Description

technical field [0001] The invention belongs to the field of metal material forming technology, and relates to a deep-hole extrusion forming technology of medium-carbon low-alloy structural steel. Background technique [0002] Medium-carbon low-alloy structural steels include: 40Cr, 42CrMo, 40MnB, 40CrMnMo, 35CrMo, 35CrMnSi, 40CrV, etc. At present, the extrusion forming methods of hollow parts of this kind of material mainly include back extrusion, such as figure 1 shown; positive extrusion, such as figure 2 Shown; Composite extrusion of positive and negative extrusion at the same time. Due to the high deformation resistance of the metal of this kind of material, limited by the strength and structure of the mold, the temperature of the extruded metal billet is higher than 800 ° C, which belongs to hot extrusion. Moreover, the surface quality of the inner hole of the hollow part is poor, and the extrusion The improvement of the metal structure and its mechanical propertie...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to provide a deep-hole extrusion forming process for medium-carbon low-alloy structural steel that reduces the deformation resistance of the metal during the extrusion process and reduces the eccentric force of the metal deformation resistance on the punch. Forming hollow parts with a ratio of hole depth to hole diameter greater than 5, to solve the problem of extrusion forming of slender hollow rods

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