钒对18Cr-2Mo铁素体不锈钢性能的影响

 利用Thermo-Calc热力学软件、扫描电子显微镜、X射线衍射仪及透射电镜等分析方法，研究了不同钒含量对单铌稳定18Cr-2Mo铁素体不锈钢微观组织、力学性能和点腐蚀性能的影响规律。结果表明：添加钒后的析出相主要是NbC和VN，弥散分布于晶内和晶界，其中NbC的尺寸为100~250nm；随着钒含量的增加，试验钢的晶粒尺寸及屈服强度变化不明显，而冲击韧性及点腐蚀性能逐步得到改善和提高，当wV=0.36%时，钢的韧脆?湮露扔稍嫉?10℃下降至-30℃，点腐蚀电位由0.38V提高至0.42V。

Effect of Vanadium on Properties of 18Cr-2Mo Ferritic Stainless Steel

Thermo-Calc software, scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to investigate the effect of vanadium (V) on the microstructure, mechanical properties and pitting corrosion resistance of 18Cr-2Mo ferritic stainless steel stabilized by niobium (Nb). The results show that the precipitates are mainly composed of NbC and VN which are dispersed in the intragranular and grain boundary, and the size of most of NbC particles is in the range from 100 to 250nm. The grain size and yield strength of materials nearly keep the same with different V addition amount under the condition of ultra-low C and N content, while the impact toughness and pitting resistance are improved gradually with the increasing of V. With the addition of 0.36%V (mass fraction), the ductile to brittle transition temperature (DBTT) of the steel is decreased from -10 to -30℃, and the pitting potential (Ep) is improved from 0.38 to 0.42V.