Steel plate with excellent hydrogen-induced cracking resistance and toughness, and line pipe steel tube

A hydrogen-induced crack resistance and toughness technology, which is applied in the field of steel pipes for line pipes, can solve the problems that it is difficult to ensure high toughness of the surface layer at the same time, and achieve the effect of excellent hydrogen-induced crack resistance and toughness

Inactive Publication Date: 2015-11-25
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

According to this method, although HIC resistance can be ensured, it is considered that fine HIC is likely to occur in the surface layer of the steel sheet where the hydrogen concentration is particularly high, as will be described later, and it is also difficult to ensure high toughness in the surface layer.

Method used

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  • Steel plate with excellent hydrogen-induced cracking resistance and toughness, and line pipe steel tube
  • Steel plate with excellent hydrogen-induced cracking resistance and toughness, and line pipe steel tube
  • Steel plate with excellent hydrogen-induced cracking resistance and toughness, and line pipe steel tube

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Effect test

Embodiment Construction

[0033] The inventors of the present invention have made intensive studies in order to solve the above-mentioned problems. First, the inventors of the present invention conducted the HIC test (NACE test) specified in NACE (National Association of Corrosion and Engineer) TM0284 using each steel plate in order to re-examine the cause of HIC occurrence in the surface layer of the steel plate under the most severe condition in a sulfur-containing environment. . In this NACE test, a test piece, that is, a steel plate, is immersed in a mixed aqueous solution of pH 2.7 of 5% NaCl solution saturated with 1 atm of hydrogen sulfide gas and 0.5% acetic acid for 96 hours, and then the occurrence of HIC is evaluated.

[0034] Next, the present inventors implemented a pendulum impact test in compliance with ASTMA370 on the surface portion of the steel plate after the HIC test. As a result, even when no cracks are observed in the NACE test under the prescribed "microscopic observation with a...

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Abstract

Provided is a steel plate which has excellent resistance against hydrogen-induced cracking and excellent toughness and which sufficiently suppresses minute HIC on the order of several μm's especially in the steel plate surface layer portion, which will be in a harsh environment with a high hydrogen concentration. This steel plate with excellent hydrogen-induced cracking resistance and toughness is characterized by comprising prescribed elements with the remainder being iron and unavoidable impurities, wherein the ratio (Ca/S) of Ca content to S content is 2.0 or greater, and the ratio (Cmax/Cave) of the greatest Ca concentration (Cmax) in the region from the surface to 5mm deep in the thickness direction to the average Ca concentration (Cave) of said region is 1.20 or less.

Description

technical field [0001] The present invention relates to a steel plate excellent in hydrogen cracking resistance and toughness suitable for line pipes for natural gas and crude oil transportation, pressure vessels, storage tanks, etc., and a steel pipe for line pipes obtained by using the steel plate excellent in hydrogen cracking resistance and toughness . Background technique [0002] With the development of inferior resources such as crude oil and gas containing hydrogen sulfide, the pipeline pipes, pressure vessels and storage tanks used for their transportation, refining and storage need to have so-called sulfur-resistant properties such as hydrogen-induced cracking resistance and stress corrosion cracking resistance. sex. It is known that hydrogen-induced cracking (Hydrogen-Induced Cracking, hereinafter referred to as "HIC") is accompanied by the corrosion reaction caused by the above-mentioned hydrogen sulfide, etc., and hydrogen invades into the interior of the steel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C22C38/06C22C38/58
CPCC22C38/00C21D8/0226C21D8/0263C21D9/46C22C38/001C22C38/002C22C38/005C22C38/02C22C38/04C22C38/06C22C38/08C22C38/12C22C38/14C22C38/16C22C38/18C22C38/26C22C38/28C22C38/42C22C38/44C22C38/48C22C38/50C22C38/54
Inventor 田代喜一郎加藤拓佐藤进佑川野晴弥三宅孝司
Owner KOBE STEEL LTD
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