High-strength stainless steel pipe

Patent metadata

Field	Value
Publication number	US-9803257-B2
Application number	US-200913263124-A
Country	US
Kind code	B2
Filing date	May 7, 2009
Priority date	May 7, 2009
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A stainless steel material having compositions which contain on the basis of percent by mass, C from 0.04 to 0.12%, Ni from 0 (including a case of no addition) to 5.0%, Cr from 12.0 to 17.0%, N from 0.0 to 0.10%, Si from 0.2 to 2.0%, Mn at 2.0% or less, Cu from 0.0 to 2.0%, P at 0.06% or less, S at 0.006% or less, with residue being Fe and unavoidable impurities. Further, a parent phase has any one of a single phase structure of ferrite phase or martensite phase and a diploid phase structure of ferrite phase and martensite phase. An end of the base material is melt-welded as a joint to form a pipe. The parent phase is provided with carbide uniformly separated at grain boundaries and within grains, with a dissolved amount of C being 0.03% by mass or less.

First claim

The invention claimed is:

1. A high-strength stainless steel pipe, wherein, as a base material, a stainless steel material which contains on the basis of percent by mass, C from 0.04 to 0.12%, Ni from 0 to 5.0%, Cr from 12.0 to 17.0%, N at 0.022% or less, Si from 0.2 to 2.0%, Mn at 2.0% or less, Cu from 0 to 2.0%, P at 0.06% or less, S at 0.006% or less, with residue being Fe and unavoidable impurities, and in which a parent phase is constituted with any one of a single phase structure of ferrite phase, and a diploid phase structure of ferrite phase and martensite phase, in which carbide is uniformly separated at grain boundaries and within grains, and which is 0.03% or less in a dissolved amount of C, is used,
the high-strength stainless steel pipe includes a joint in which a molten structure resulting from melt-welded is formed, and
the parent phase and the joint after heat treatment are those in which separated carbide is dissolved, and are a diploid phase structure including martensite phase and 10% or more and 25% or less by volume of ferrite phase.

Assignees

• Isozaki Seiichi
• Hideshima Yasutoshi
• Fujimoto Hiroshi
• Suzuki Satoshi
• Nisshin Steel Co Ltd

Inventors

• Isozaki Seiichi
• Hideshima Yasutoshi
• Fujimoto Hiroshi
• Suzuki Satoshi

Classifications

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• C22C38/42

  with copper · CPC title

• C22C38/02

  containing silicon · CPC title

• C21D6/002

  containing Cr (C21D6/004 takes precedence) · CPC title

• C21D6/008

  containing Si · CPC title