ABSTRACT High-silicon cast steels and proper heat treatment cycles were designed in order to obtain carbide-free bainitic microstructures. The design process allowed to obtain the desired microstructures after heat treatment cycles compatible with industrial practices and using low amounts of inexpensive alloying elements. The different chemical compositions and austempering temperatures tested resulted in ultra-high-strength steels showing remarkably total elongations. The obtained tensile properties satisfy the minimum requirements specified for AHSS in ASTM A1088 standard, and also the requirements for high-strength cast steels stated in ASTM A148. Moreover, many microstructures developed in this work reach the tensile performance of the very expensive maraging steels.

中文翻译：

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超高强度无碳化物贝氏体铸钢的开发

摘要 为了获得无碳化物的贝氏体显微组织，设计了高硅铸钢和适当的热处理循环。设计过程允许在符合工业实践的热处理循环后获得所需的微观结构，并使用少量廉价的合金元素。测试的不同化学成分和奥氏体回火温度导致超高强度钢显示出显着的总伸长率。所获得的拉伸性能满足ASTM A1088标准中对AHSS规定的最低要求，以及ASTM A148中规定的对高强度铸钢的要求。此外，在这项工作中开发的许多微观结构达到了非常昂贵的马氏体时效钢的拉伸性能。