Microstructure and mechanical property of austenitic steel Cr18Ni3Mn11Cu3NbN
1.School of Material Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.Institute for Structural Materials, Central Iron and Steel Research Institute, Beijing 100081, China)
摘要 为研究超临界火电用奥氏体不锈钢Cr18Ni3Mn11Cu3NbN的显微组织和性能,分析了Cr18Ni3Mn11Cu3NbN的金相组织和断口形貌,检测了室温拉伸性能和高温短时拉伸性能．金相组织分析表明,在奥氏体基体中呈弥散分布着NbN化合物,并有少量呈簇状析出,还存在少量高温铁素体和纯Nb相．断口分析表明,室温拉伸断口有明显缩颈,断面形貌呈等轴韧窝状,是韧性断裂．Cr18Ni3Mn11Cu3NbN的室温力学性能满足ASME Code Case 2328-1标准,其中拉伸强度远大于规定值;高温短时拉伸强度大于Super304H奥氏体不锈钢的实测值,但延伸率有一定的差距,主要原因是少量高温铁素体的存在．
Abstract：In order to study the microstructure and mechanical property of a newly developed austenitic stainless steel Cr18Ni3Mn11Cu3NbN, the metallographic microstructure and fracture morphology were analysed, and the shorttime tensile properties at roomtemperarure and elevatedtemperature were also detected. The metallographic analysis showed that NbN compounds were distributed in austenitic matrix, thereinto a few of them were precipitated as cluster. At the same time, a small amount of elevatedtemperature ferrite and pure Nb phases were also presented. The fracture analysis showed that equiaxed dimples were at the fracture surface, indicating the existence of toughness fracture. In addition, the roomtemperature mechanical properties of the steel could meet the standard ASME Code Case 2328-1, thereinto, its tensile strength was much larger than the standard value, the hightemperature tensile strength was greater than that of the Super304H steel, but the elongation was less because of the existence of a small amount of elevatedtemperature ferrite.
2010, Vol. 31 
