一种高氮钢的高温力学性能和组织演变规律

Mechanical properties and microstructure evolution of a high nitrogen steel at elevated temperature

6Cr21Mn10MoVNbN合金是重型发动机用高氮钢。采用Gleeble1 500热模拟、金相分析、扫描电镜、XRD和理论分析相结合的方法研究了该合金的高温变形特性。微观结构分析表明,变形温度和应变速率对该合金微观组织的演变有很大的影响。合金在850,950,1 050℃经历相同的变形量后,合金晶粒尺寸相差不大。但当温度升至1 150℃,变形后合金晶粒尺寸迅速增大,此类变化主要是由于温度升高使合金中铬的碳化物快速溶解和转化所致。

The alloy of 6Cr21Mn10MoVNbN is a high nitrogen steel for heavy-duty engine. Combining theoretical analysis with Gleeble1500 thermal simulation, metallurgical structure examination, SEM and XRD, the high temperature deformation behavior of the alloy was investigated. Microstructure analysis shows that deformation temperature and strain speed have a great impact on the alloy＇s microstructural evolvement. After going through the same deformation at 850 ℃, 950 ℃ and 1 050 ℃, the grain sizes differ little. Yet when the temperature goes up to the 1 150 ℃, the post-information size increases fast, which can be explained by the fast dissolution and change of Cr-carbide in the alloy caused by the rise of temperature.