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| Influence of Ti and Nb Microalloying on the Ductile to Brittle Transition Temperature of 18Cr-2Mo Ferritic Stainless Steel |
| LIN Shu1,2，JIANG Laizhu2，ZHANG Ke1，ZHANG Zhixia2，RONG Yonghua1 |
| (1.School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China;2.Shanghai Baosteel Research Institute, Shanghai 201900, China) |
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Abstract 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 backscatter 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.
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Received: 15 September 2009
Published: 31 May 2010
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