Ti和Nb对18Cr-2Mo铁素体不锈钢韧脆转变温度的影响

通过真空冶炼、锻造、热轧和退火试验制备出18Cr-2Mo铁素体不锈钢，结合其冲击试验和透射电子显微镜、扫描电子显微镜及电子背散射衍射等分析结果探讨了Ti和Nb微合金化对其韧脆转变温度的影响.结果表明：在C和N含量较低的条件下，添加微量元素Ti和Nb可以显著降低18Cr 2Mo铁素体不锈钢的韧脆转变温度（降低约40 °C），并改变热轧后的织构类型而形成(001)和(111)复合织构；通过合适的退火工艺处理，可进一步提高其冲击韧性；在热轧过程中，产生细小弥散的Ti（N, C）和Nb（C, N）相是复合织构形成的主要原因.

Influence of Ti and Nb Microalloying on the Ductile to Brittle Transition Temperature of 18Cr-2Mo Ferritic Stainless Steel

18Cr-2Mo ferritic stainless steel was fabricated by vacuum melting, forging, hot rolling and annealing. The effects of titanium (Ti) and niobium (Nb) on the ductile to brittle transition temperature (DBTT) of 18Cr-2Mo ferritic stainless steel were investigated by means of impact experiments and microscopy analysis, including transmission electron microscope (TEM), scanning electron microscope and electron back scatter diffraction (EBSD). The results indicate that the addition of Ti and Nb markedly lowers the DBTT (about 40 °C) under the condition of lower C and N content. The Ti and Nb microalloying results in the variation of texture type, namely, coexistence of (001) and (111) textures, in stead of (101) texture in 18Cr-2Mo without the addition of Ti and Nb elements, which are important factors to the decrease of DBTT. Further decrease of DBTT could be obtained by appropriate annealing processing. Fine TiN and NbC precipitated during hot rolling are the main reasons for the formation of the complex textures.