Extrusion and Wall Reduction Method for Large Diameter Pipe

Abstract

The invention relates to a squeezing-drawing method for wall thickness reduction of a heavy caliber tubular product and belongs to the field of plastic processing. According to the method, a squeezing force and a drawing force are exerted on a tube blank at the same time so as to improve the short-core mark single-gate thickness reduction rate by more than one time of the short-core mark single-gate thickness reduction rate when only the drawing force is exerted on the tube blank, that is, the thickness reduction rate is improved from less than or equal to 20% to less than or equal to 45%; if induction heating is adopted, the deformation resistance of a material can be lowered greatly and high-efficient wall thickness reduction operation for a high-strength thick-walled seamless steel pipe with a heavy caliber can be realized. The method can be used for producing heavy caliber tubular products of different specifications, wherein the outer diameters range from 325 mm to 1,200 mm, the wall thicknesses are less than or equal to 40 mm, and the lengths are less than or equal to 12,500 mm, so that the method can be applied to the production of pipes used for a super (super) critical electric power unit and tubular products made of copper, aluminum and magnesium; a high-pressure boiler pipe produced according to the method meets the requirements of standards such as ASMESA335, EN10216-2 and GB5310, so as to effectively solve the efficient wall thickness reduction problems of the multi-specification small-batch heavy caliber tubular products, improve the wall thickness reduction efficiency of the tubular products greatly, comprehensively improve the utilization rates of materials and reduce the production cost.

Description

technical field [0001] The invention relates to a large-caliber pipe extrusion wall reduction method, which belongs to the field of plastic processing. Background technique [0002] High-alloy steel, copper, aluminum, magnesium alloy and other pipes need to be produced by extrusion technology, and the extrusion force and yield of the pipe are closely related to the wall thickness of the pipe. For example: using a steel ingot with a riser as raw material to extrude a P91 steel pipe of Φ550×60×7500, the extrusion force is 30,000 tons, and the material utilization rate is 60%, while the extrusion force of a Φ550×30×7500 steel pipe is 33,000 tons , The material utilization rate is 48%; the extrusion force of the Φ550×30×12500 steel pipe is 39,000 tons, and the material utilization rate is 50%. If the thick-walled tube blanks of a certain specification can be processed into relatively thin tubes through wall reduction, it will be of great significance for expanding the productio...

AI Technical Summary

Problems solved by technology

Although the cold drawing process is divided into long plug drawing, short plug drawing, no plug drawing and expansion drawing, etc., the efficiency of wall reduction is low.

In recent years, the thermal tube expansion technology, which has emerged in recent years, can play a certain role in reducing the wall while expanding the diameter. However, this process is limited by the stress state during the deformation process, and its products cannot be applied to important load-bearing components.

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