Unique Solidification Cracking Mechanism in Ultra-Low Interstitial Iron and Iron Alloy Weld Metal

超低间隙铁及铁合金焊缝金属独特的凝固裂纹机制

• 批准号: 9972052
• 负责人: Jack Devletian
• 金额: --
• 依托单位: Oregon Graduate Institute of Science & Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9972052&HistoricalAwards=false
• 关键词: Unique; Solidification; Cracking; Mechanism; Ultra

Devletian9772052The objective of this proposal is to determine, characterize and model a new mechanism for solidification cracking observed in high purity iron-base alloys. These alloys were thought to be immune to solidification cracking and their surprisingly poor cracking resistance defies current theory. In this project ultra-low carbon iron alloys that contain systematic additions of Ni, Mn, Mo, Nb, Ti, B, and O are examined to determine their susceptibility to solidification cracking and the mechanism of cracking when it occurs. The research plan combines modeling with experimental studies, including varestraint testing to measure the solidification cracking tendencies of the alloys and characterization of fracture surfaces by Auger spectroscopy. Differential thermal analysis (DTA) establishes the length of the mushy zone in the selected alloys and the Gleeble and DTA determine the expansion/contraction effects of solid state phase transformations on weld shrinkage stresses.%%%It is important that "clean" iron-based alloys be resistant to solidification cracking since they represent the current trend in selection of high strength, high toughness structural alloys for applications in ships, bridges and buildings.***

Devletian 9772052该提案的目的是确定、表征和建模高纯度铁基合金中观察到的凝固裂纹的新机制。这些合金被认为是免疫凝固裂纹和他们令人惊讶的差抗裂性违背了目前的理论。在这个项目中，超低碳铁合金，含有系统添加Ni，Mn，Mo，Nb，Ti，B，和O进行了检查，以确定其敏感性凝固裂纹和裂纹发生时的机制。该研究计划将建模与实验研究相结合，包括可变约束测试，以测量合金的凝固开裂趋势和俄歇光谱表征断裂表面。差热分析（DTA）确定所选合金中糊状区的长度，Gleeble和DTA确定固态相变对焊接收缩应力的膨胀/收缩效应。重要的是，“清洁”铁基合金要能抵抗凝固裂纹，因为它们代表了目前选择高强度、高韧性结构合金用于船舶、桥梁和建筑的趋势。