Electric-resistance-welded stainless clad steel pipe or tube

Patent metadata

Field	Value
Publication number	US-10844993-B2
Application number	US-202016830268-A
Country	US
Kind code	B2
Filing date	Mar 26, 2020
Priority date	Jun 30, 2016
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

An electric-resistance-welded stainless clad steel pipe or tube that is excellent in both the fracture property of the weld and the corrosion resistance of the pipe or tube inner surface as electric resistance welded without additional welding treatment such as weld overlaying after electric resistance welding is provided. An electric-resistance-welded stainless clad steel pipe or tube comprises: an outer layer of carbon steel or low-alloy steel; and an inner layer of austenitic stainless steel having a predetermined chemical composition, wherein a flatness value h/D in a 90° flattening test in accordance with JIS G 3445 is less than 0.3, and a pipe or tube inner surface has no crack in a sulfuric acid-copper sulfate corrosion test in accordance with ASTM A262-10, Practice E, where h is a flattening crack height (mm), and D is a pipe or tube outer diameter (mm).

First claim

The invention claimed is:

1. An electric-resistance-welded stainless clad steel pipe or tube, comprising:
an outer layer of carbon steel or low-alloy steel; and
an inner layer of austenitic stainless steel having a chemical composition containing, in mass %, C: 0.1% or less, Si: 1.5% or less, Mn: 2.5% or less, Ni: 7.0% to 35.0%, Cr: 16.0% to 35.0%, Mo: 0.1% to 10.0%, and the balance being Fe and inevitable impurities,
wherein a welded seam part exits in the electric-resistance-welded stainless clad steel pipe or tube, and
wherein a flatness value h/D in a 90° flattening test in accordance with JIS G 3445 is less than 0.3, and an inner surface of the electric-resistance-welded stainless clad steel pipe or tube has no crack in a sulfuric acid-copper sulfate corrosion test in accordance with ASTM A262-10, Practice E, where h is a flattening crack height in mm, and D is an outer diameter of the electric-resistance-welded stainless clad steel pipe or tube in mm.

2. The electric-resistance-welded stainless clad steel pipe or tube according to claim 1 ,
wherein the chemical composition further contains at least one of (i) N: 2.0% or less, (ii) Cu: 3.0% or less, (iii) at least one of Ti, Nb, V, and Zr: 0.01% to 0.5% in total, (iv) at least one of Ca, Mg, B, and REM: 0.1% or less each, and (v) Al: 0.2% or less.

Assignees

• Jfe Steel Corp

Inventors

• Ide Shinsuke
• Matsumoto Atsushi
• Hashimoto Yuji
• Okabe Takatoshi

Classifications

• B21C37/08 Primary

  Making tubes with welded or soldered seams {(with helically arranged seams B21C37/122)} · CPC title

• C22C38/18

  containing chromium · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• F16L9/16

  wound from sheets or strips, with or without reinforcement · CPC title

• C22C38/001

  containing N · CPC title