AHSS: Development of a High Strength, High Toughness Ausferritic Steel

AHSS：高强度、高韧性奥铁素体钢的开发

• 批准号: 0854962
• 负责人: Susil Putatunda
• 金额: $ 30.35万
• 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: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2013-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0854962&HistoricalAwards=false
• 关键词: AHSS; Development; Strength; Toughness; Ausferritic

The objective of this research award is to advance fundamental understanding of the synthesis of a high strength, high toughness bainitic steel with extremely fine scale microstructure consisting of ferrite and carbon stabilized austenite. This novel steel will be synthesized using the concept of austempered ductile cast iron technology and by applying a novel concept of adiabatic deformation together with a two-step austempering process in a medium carbon low alloy steel with high silicon content. This novel process will result in extremely fine bainitic ferrite and carbon stabilized austenite which will in turn provide simultaneous high yield strength, fracture toughness, impact strength and fatigue strength. Currently such combination of unique properties can not be obtained in conventional low alloy steels.If successful, the results of this research will pioneer a novel technology for creation of a series of Ausferritic Steels with excellent combination of mechanical properties. It will establish whether a combination of adiabatic deformation and two-step austempering will lead to large super cooling and carbon partitioning, and thus lead to an 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. The creation of Ausferritic steel will be totally new and a novel concept. The concept of Ausferritic steel will make a valuable contribution to the theory of phase transformation in ferrous alloys. In addition to this, we have also developed a thermodynamic model and the assumptions made in derivation of this thermodynamic model will also be examined. Thus this proposed research will advance the state of knowledge in the ferrous physical metallurgy as well as basic thermodynamics and kinetics of phase transformation. This novel steel will make the structural components lighter, more energy efficient and consequently improve fuel economy and reduce pollution. This novel process will also lead to a near net shape production technology for steels. 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.

该研究奖的目的是促进对合成具有极细尺度组织的高强度、高韧性贝氏体钢的基本了解，该组织由铁素体和碳稳定奥氏体组成。这种新型钢将采用等温淬火球墨铸铁技术，并在高硅中碳低合金钢中应用绝热变形的新概念和两步等温淬火工艺来合成。这一新工艺将产生极细小的贝氏体铁素体和碳稳定奥氏体，从而同时提供高屈服强度、断裂韧性、冲击强度和疲劳强度。目前，常规低合金钢无法获得这样的独特性能组合。如果研究成功，本研究成果将为开发一系列具有优异机械性能组合的奥氏体钢开辟新的技术途径。它将确定绝热变形和两步等温处理相结合是否会导致较大的过冷和碳的分配，从而导致极细小的贝氏体铁素体和碳稳定奥氏体。此外，它还将验证这种微观结构是否会提供所需的机械性能组合，即同时具有高屈服强度、疲劳强度、断裂韧性和冲击强度。奥铁素体钢的制造将是一个全新的概念。奥氏体钢的概念将对铁合金相变理论作出有价值的贡献。此外，我们还建立了一个热力学模型，并对推导该热力学模型时所作的假设进行了检验。因此，这项研究将促进对黑色金属物理冶金的认识，以及相变的基本热力学和动力学。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和减少污染。这一新工艺还将导致钢材的近净成形生产技术。等温淬火工艺是一种更节能的热处理工艺，因为不需要淬火后的后热处理。因此，这一过程将带来显著的能源节约。