Novel technique for producing seamless steel pipe

Abstract

A new process for producing a seamless steel pipe comprises the following processing steps: firstly, producing a hollow pipe blank, at one end of which an annular cup bottom is arranged, through centrifugal casting; secondly, mechanically processing the inner surface and the outer surface of the hollow pipe blank; thirdly, heating the processed hollow pipe blank; fourthly, performing pipe jacking mill processing to the heated hollow pipe blank, and obtaining pipe fittings meeting the requirements of the wall thickness, the diameter and the length; and fifthly, after bar loosening and bar releasing, performing end cropping and finishing operation to the pipe fittings after the pipe jacking mill processing, and obtaining qualified finished product pipe materials. The invention can produce a high-quality stainless steel and special steel pipe difficult to process, and overcomes the defects in the prior art, so as to form an energy-saving, high-quality and economic new process with the short procedure for producing the seamless steel pipe compared with the traditional method.

Description

technical field [0001] The invention relates to the manufacturing technology of seamless steel pipes, in particular to the manufacturing technology of large-caliber medium-thick wall seamless steel pipes. Background technique [0002] Large-diameter seamless steel pipes, especially large-diameter medium-thick-wall seamless steel pipes with a diameter greater than 500 mm and a diameter-to-wall ratio of less than 25, are widely used in important occasions in many industrial fields. Such as: the main steam pipeline used for thermal power generation and the loop pipeline of nuclear power, as well as high-pressure gas cylinders for CNG trailers and gas stations, cylinders of various high-pressure containers, etc. Because of the wide range of uses of large-diameter thick-walled seamless steel pipes, the requirements for their mechanical properties and physical and chemical properties are different, so the selection of their materials and processing methods are also different. For...

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Problems solved by technology

Compared with the above three methods, although this method can produce special steel pipes containing elements such as Cr, Ni, Mo, N, etc., this method still needs an expensive cold drawing machine, and requires multiple cycles of cold drawing, and each After the second cold drawing, solid solution treatment, pickling treatment and lubrication treatment are also carried out

There are also defects such as high equipment cost and many processing procedures, and for the production of large-diameter and medium-thick-wall seamless steel pipes, this method is difficult to adopt

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