Seamless steel tube perforation forming method

Abstract

The invention provides a seamless steel tube perforation forming method. The seamless steel tube perforation forming method comprises the procedures of round billet heating, descaling, thermal centering, perforation, rolling, diameter expanding, leveling, sizing and the like, and comprises the following steps that a tube blank is deformed by adopting an inner containing arc-shaped surface of an annular spinning roller to generate an axial component speed, a traction force and a counter friction force which are beneficial to the flowing of a metal material; and therefore, the deformation resistance and the stress on a dangerous section are reduced, and the defects of pipe bending, longitudinal cracks, obvious ripples on the surface and the like can be reduced. Compared with two-roller skewrolling perforation, a guide plate or a guide disc is not needed, and the outer surface of a hollow billet is not prone to being scratched. The multiple annular spinning rollers are adopted for spinning through the inner arc faces of the annular spinning rollers, the good supporting and balanced friction feeding amount can be achieved, the rolling hole pattern can be controlled by adjusting the number, the inner diameter, the inclination angle and the like of the annular spinning rollers, the proper "Mann effect" is kept for different types of materials, punching forming is facilitated, operation is easy, adjustment is flexible, and the equipment cost is low.

Description

technical field [0001] The invention belongs to the field of forming seamless steel pipes, and in particular relates to a forming method for perforating seamless steel pipes by adopting an annular rotary rolling method. Background technique [0002] The production methods of seamless steel pipes are roughly divided into cross rolling method (Mannesmann method) and extrusion method. The skew rolling method is to first perforate the tube blank with skew rolls, and then extend it with a rolling mill. This method has a fast production speed, but has high requirements on the machinability of the tube blank, and is mainly suitable for the production of carbon steel and low alloy steel pipes. The extrusion method is to use a piercer to perforate the tube billet or steel ingot, and then use an extruder to extrude it into a steel pipe. This method is less efficient than the skew rolling method and is suitable for the production of high-strength alloy steel pipes. In the production ...

AI Technical Summary

Problems solved by technology

The barrel roll piercer also has the following disadvantages: (1) The perforation forms a "Mann effect"

(2) Looking at the two rolls from the horizontal plane, the axes of the two rolls are basically arranged in parallel (rolling angle is 0), the longitudinal component of the deformation of the rolled piece is small, the lateral deformation of the metal and the torsional deformation of the section are serious, and these additional unevenness Deformation (also known as cross-rolling excess deformation) will cause quality problems on the outer surface of the capillary, such as buckling, surface tearing, etc.

[0007] However, whether it is a barrel-shaped cross-rolling piercer or a tapered cross-rolling piercer, there are still problems that the amount of deformation is limited and the quality of the capillary after piercing is not high. The thickness quality level is not high, the cross-section wall thickness is uneven, and the longitudinal wall thickness difference is also obvious; the quality of the capillary after perforation is poor, there are cracks or scratches on the outer surface, and there are serious spirals on the inner surface; the inner surface of the capillary is prone to infolding or internal cracking ;The head and tail of the capillary are easy to crack or take off the skin, which directly leads to unsmooth production

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