Purpose

The purpose of this paper is to demonstrate the effect of δ-ferrite on the susceptibility to hydrogen embrittlement of type 304 stainless steel in hydrogen gas environment.

Design/methodology/approach

The mechanical properties of as-received and solution-treated specimens were investigated by the test of tensile and fatigue crack growth (FCG) in 5 MPa argon and hydrogen.

Findings

The presence of δ-ferrite reduced the relative elongation and the relative reduction area (H₂/Ar) of 304 stainless steel, indicating that δ-ferrite increased the susceptibility of hydrogen embrittlement in 304 stainless steel. Moreover, δ-ferrite promoted the fatigue crack initiation and propagation at the interface between δ-ferrite and austenite. The FCG tests were used to investigate the effect of δ-ferrite on the FCG rate in hydrogen gas environment, and it was found that δ-ferrite accelerated the FCG rate, which was attributed to rapid diffusion and accumulation of hydrogen around the fatigue crack tip through δ-ferrite in high-pressure hydrogen gas environment.

Originality/value

The dependence of the susceptibility to hydrogen embrittlement on δ-ferrite was first investigated in type 304 steel in hydrogen environment with high pressures, which provided the basis for the design and development of a high strength, hydrogen embrittle-resistant austenitic stainless steel.

中文翻译：

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δ-铁素体对高压氢气氛下304奥氏体不锈钢氢脆敏感性的影响

目的

本文旨在论证δ-铁素体对304不锈钢在氢气环境中氢脆敏感性的影响。

设计/方法/方法

通过在 5 MPa 氩气和氢气中进行拉伸和疲劳裂纹扩展 (FCG) 测试，研究了原样和固溶处理试样的机械性能。

发现

δ-铁素体的存在降低了304不锈钢的相对伸长率和相对还原面积(H ₂ /Ar)，表明δ-铁素体增加了304不锈钢的氢脆敏感性。此外，δ-铁素体促进了δ-铁素体和奥氏体界面处疲劳裂纹的萌生和扩展。通过FCG测试研究了δ-铁素体在氢气环境下对FCG速率的影响，发现δ-铁素体加速了FCG速率，这是由于氢在疲劳裂纹尖端周围的快速扩散和积累通过δ-高压氢气环境中的铁氧体。

原创性/价值

氢脆敏感性对δ-铁素体的依赖性首先在高压氢环境中的304钢中进行研究，为高强度、抗氢脆奥氏体不锈钢的设计和开发提供了基础。