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A large-diameter s31254 super austenitic stainless steel seamless pipe and its preparation process

A technology for the preparation of austenitic stainless steel, applied in the field of austenitic stainless steel, can solve the problems of reduced pressure resistance, low reliability and service life, and limited corrosion resistance of alloys, and achieve the effect of simple equipment and simple and reliable process

Active Publication Date: 2021-02-05
ZHEJIANG GUOBANG STEEL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 1: S31254 small-diameter cold-rolled seamless pipe greatly limits its scope of use. One can only use small-diameter seamless pipes in harsh corrosive environments, and when large-diameter seamless pipes are required, only It is replaced by welded pipes of the same specification, which severely limits the excellent corrosion resistance of the alloy.
[0006] 2: The use of welded pipe, due to the weld seam, makes the pressure resistance greatly lower than that of the seamless pipe; and the residual stress caused by the forming and welding process can also reduce the pressure bearing capacity of the welded pipe, and seriously affect the quality and service of the welded pipe Reliability; at the same time, the corrosion resistance of the weld is not as good as that of the seamless pipe, and it is prone to fatigue damage
Therefore, welded pipes are much lower than seamless pipes in terms of pressure bearing capacity, reliability and service life.

Method used

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  • A large-diameter s31254 super austenitic stainless steel seamless pipe and its preparation process
  • A large-diameter s31254 super austenitic stainless steel seamless pipe and its preparation process
  • A large-diameter s31254 super austenitic stainless steel seamless pipe and its preparation process

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Effect test

Embodiment 1

[0034] Example 1 Preparation of φ325×17mm S31254 Super Austenitic Stainless Steel Finished Pipe

[0035] The outer diameter of the round tube billet is φ240mm, and the blank tube is φ270×27mm after thermal perforation. First, heat treatment is performed to make the internal structure of the material uniform, the carbide is fully dissolved, and the grain size of the inner and outer walls tends to be uniform; the first time Drawing expansion deformation (1 cold drawing for wall reduction and diameter reduction, 3 consecutive diameter expansion cold drawing), the second drawing and expansion deformation (1 wall reduction and diameter reduction cold drawing, 3 consecutive diameter expansion cold drawing), and then for 3 consecutive times The finished large-diameter S31254 super austenitic stainless steel seamless pipe is obtained by wall-reducing cold drawing and heat treatment in one pass;

[0036] After each cold drawing, the tube blank is heat treated, and after each heat treat...

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Abstract

The present invention provides a large-diameter S31254 super austenitic stainless steel seamless pipe preparation process, the preparation process includes: heat-treating the blank tube and performing three passes of wall-reducing and diameter-reducing cold drawing; the heat treatment method is: After the tube blank is kept warm at 1180°C, it is water-quenched. The holding time is: 1.8-2.1min / mm×the wall thickness of the tube blank. The beneficial effects of the invention are: the controllability of the surface quality of the product is good, the surface is clean and smooth, no cracks are generated inside and outside, the strength and hardness are significantly increased, and the plasticity is good.

Description

technical field [0001] The invention relates to the field of austenitic stainless steel, in particular to a large-diameter S31254 super austenitic stainless steel seamless pipe and a preparation process thereof. Background technique [0002] The material is S31254 (referred to as 254SMo, the national standard is 022Cr20Ni18Mo6CuN) is a super austenitic stainless steel, developed for halide and acid environments, and widely used in harsh working conditions such as high-concentration chloride ion media and seawater. In various industrial occasions in acidic media, especially in acids containing halides, 254SMO is far superior to other stainless steels, and in some cases can be comparable to Hastelloy and titanium. Low carbon content and high molybdenum content make it have good resistance to pitting corrosion and crevice corrosion, excellent resistance to intergranular corrosion, and is a cost-effective stainless steel. widely used. [0003] Due to the particularity of S3125...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21C37/06C21D8/10C21D9/08
CPCB21C37/06C21D8/105C21D9/085C21D2211/001
Inventor 陈深李新略伍素云林日朴
Owner ZHEJIANG GUOBANG STEEL
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