AHSS: Development of High Strength, High Toughness Bainitic Steel

AHSS：高强度、高韧性贝氏体钢的开发

• 批准号: 0727004
• 负责人: Susil Putatunda
• 金额: $ 3万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727004&HistoricalAwards=false
• 关键词: AHSS; Development; Strength; Toughness; Bainitic

The primary focus of this research proposal is on creation of high strength, high toughness bainitic steel with extremely fine scale microstructure consisting of bainitic ferrite and austenite. This will be achieved by applying a novel two step austempering process in a high carbon high silicon steel. The basic approach is to create extremely fine grain microstructure consisting of two ductile phases (ferrite andaustenite) by a detailed phase transformation study. This extremely fine scale microstructure will result in simultaneous high yield strength, fatigue strength and fracture toughness. Currently such combination of properties is not available in any structural steel.Intellectual MeritThe intellectual merit of this proposal lies in the fact that it will establish whether a two step austempering process will lead to large super cooling and carbon partitioning, and this leading to extremely fine scale bainitic ferrite and carbon stabilized austenite. Moreover, it will validate whether such a microstructure will impart the desired combination of mechanical properties i.e. simultaneous high yield strength, fatigue strength, fracture toughness and impact strength. This study will also generate significant knowledge base in bainitic transformations in steel.Broad ImpactIf the project is successful, the broad impact of the project will be significant in materials processing and manufacturing industries since it will pioneer a totally new and novel material processing technique for steel and ductile cast irons. This will lead to high-reliability, low cost engineering materials with greater durability. Furthermore, it will generate a new class of structural materials with unique combination of properties (simultaneous high yield strength, fatigue strength, fracture toughness and impact strength). This novel steel will make the structural components lighter, more energy efficient and consequently improve fuel economy and reduce pollution. The austempering process is a more energy efficient heat treatment process since no post heat treatment after quenching is required. Therefore, this process will lead to significant energy savings.

本研究计划的主要重点是创造具有由贝氏体铁素体和奥氏体组成的极细尺度显微组织的高强度、高韧性贝氏体钢。这将通过在高碳高硅钢中应用新颖的两步等温淬火工艺来实现。基本的方法是通过详细的相变研究来创建由两个延性相（铁素体和奥氏体）组成的极细晶粒显微组织。这种极细的微观结构将同时产生高的屈服强度、疲劳强度和断裂韧性。目前，这种性能的组合在任何结构钢中都是不可用的。智力优点这个建议的智力优点在于，它将确定两步等温淬火过程是否会导致大的过冷和碳分配，这将导致极细尺度的贝氏体铁素体和碳稳定奥氏体。此外，它将验证这种微结构是否将赋予机械性能的期望组合，即同时高屈服强度、疲劳强度、断裂韧性和冲击强度。这项研究也将产生重要的知识基础，在钢中的贝氏体转变。广泛的影响如果该项目是成功的，该项目的广泛影响将是重大的材料加工和制造业，因为它将开创一个全新的和新颖的材料加工技术的钢和球墨铸铁。这将导致高可靠性，低成本的工程材料具有更大的耐用性。此外，它还将产生一类具有独特性能组合（同时具有高屈服强度、疲劳强度、断裂韧性和冲击强度）的新型结构材料。这种新型钢材将使结构部件更轻，更节能，从而提高燃油经济性并减少污染。等温淬火工艺是一种更节能的热处理工艺，因为淬火后不需要后热处理。因此，该过程将导致显著的能源节约。