Effect of chemical composition and heat treatment on hydrogen embrittlement susceptibilities of 4340M Martensitic and Bainitic steels

化学成分和热处理对4340M马氏体和贝氏体钢氢脆敏感性的影响

• 批准号: 543696-2019
• 负责人: Song, Jun
• 金额: $ 5.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=719884
• 关键词: Effect; chemical; composition; heat; treatment; Effect; chemical; composition; heat; treatment

High strength materials are often used for their high specific strength in limited space. Among those, low alloy steels exhibit a combination of high strength, ease of production and manufacturability, making them an economical and worthwhile choice for many structural components (e.g., landing gear, fasteners and actuators) in aerospace and manufacturing industries. Despite the various beneficial properties offered, one common problem low alloy steel suffers is hydrogen embrittlement (HE), i.e., the material experiences deterioration in mechanical properties and subsequent premature and delayed brittle fracture, in the presence of hydrogen that is often introduced during the plating process. In combating HE, it is necessary to have accurate material-specific knowledge of hydrogen trapping and HE susceptibility so that appropriate measures (e.g., baking to remove hydrogen and determination of in-service loading levels) can be taken. AISI 4340 steel has been the prevailing landing gear material used in aerospace applications. Recently, AISI 300M (4340M) low alloy steel and Bainitic steel were developed as alternative materials due to the improved strength, superior fracture toughness and impact strength. Their mechanical properties can be further tuned by additional thermal/mechanical treatments. However, hydrogen trapping characteristics and HE susceptibility of those materials remain unknown. This project aims to address such knowledge deficit by conducting a detailed study to identify key microstructural metrics responsible for hydrogen trapping and establish threshold curves for 4340M and Bainitic steel. Further, a microstructure-informed numerical model will be developed to enable generic numerical analysis of hydrogen trapping and HE susceptibility for low alloy steel, and atomistic simulations will be performed to gain fundamental understanding of the role of alloy carbides in HE of low alloy steel. Outcomes from this project will provide the industrial partners better and quantitative knowledge of the effect of microstructure on hydrogen trapping and HE susceptibility of low alloy steel, and subsequently help them take informed and reliable decisions in practices towards HE prevention.

高强度材料通常用于有限的空间中的高特异性。其中，低合金钢表现出高强度，易于生产和制造性的结合，使它们成为航空和制造业中许多结构性组件（例如起落架，紧固件和执行器）的经济和有价值的选择。尽管提供了各种有益的特性，但一个常见的问题低合金钢遭受的是氢含糖（HE），即机械性能中的材料经历恶化以及随后在平板过程中通常引入的氢气中的氢气中的过早和延迟的脆性裂缝。在打击HE时，有必要对氢捕获的精确材料特异性知识，并具有易感性，以便可以采取适当的措施（例如，烘烤以去除氢和确定服务中的负载水平）。 AISI 4340钢是航空航天应用中使用的主要起落架材料。最近，由于强度提高，优势断裂韧性和冲击强度，AISI 300m（4340m）的低合金钢和贝纳特钢被开发为替代材料。它们的机械性能可以通过其他热/机械处理来进一步调节。但是，氢捕获特性和对这些材料的敏感性仍然未知。 该项目旨在通过进行详细的研究来确定负责氢气捕获的关键微观结构指标，并建立4340m和贝纳尼特钢的阈值曲线，以解决此类知识不足。 此外，将开发一个微观结构的数值模型，以实现氢诱捕的一般数值分析，并且他对低合金钢的敏感性，并将进行原子模拟，以获得对合金碳化物在低合金钢中的作用的基本了解。该项目的成果将为工业伙伴提供更好的定量知识，了解微观结构对氢气捕获的影响，并且他对低合金钢的敏感性，随后帮助他们在预防他的预防方面做出明智而可靠的决定。