Analysis on CCT(Continuous Cooling Transformation)Curve of 345 MPa Grade Fire-resistant Steel
The characteristics of continuous cooling transformation of fire-resistant test steel are analyzed as well as its microstructure at different cooling rates within 1～100℃/s are observed through drawing the continuous cooling transfor-mation(CCT)curve of 345 MPa grade fire-resistant test steel.The results showed that there were ferritic and perlitic transformations of test steel when cooling rate was 1℃/s;there were ferritic and bainite transformations of test steel when cooling rate was 8～20℃/s,pearlite completely disappeared,grain size was reduced and proportion of bainite structure was increased;microstructure transformation of test steel was mainly bainite transformation,proportion of ferritic transfor-mation was very low and grain size was further reduced when cooling rate was 50～100℃/s;ferrite disappeared complete-ly,all the microstructure was changed to bainite and was with obvious tendency of lath when cooling rate was increased to 100℃/s.The analysis of CCT curve and microstructure for fire-resistant test steel provides theoretical basis for formula-ting cooling processes in the production process of 345 MPa grade fire-resistant test steel.
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万方数据
