热处理对20钢韧脆转变温度的影响

针对煤炭行业常用的20钢冻结管的作业环境,参考低温用管的有关标准,对热轧态及不同正火状态下的20钢冻结管的拉伸性能和低温冲击韧性进行检验分析,并采用Origin软件拟合20钢的韧脆转变温度曲线.分析结果表明：经过860℃、880℃、910℃正火后,20钢的韧脆转变温度下降到-30～-20℃;正火态的组织晶粒度比热轧态的粗大,但正火后20钢的低温冲击性能大幅度提高.

Effect by Heat Treatment on DBTT of 20 Steel

Addressing the operation conditions for the 20 steel freezing pipes as used for coal mining industry, and using applicable standard for cryogenic pipes for reference, the tensile property and low temperature impact toughness of the as-hot rolled pipes and pipes as normalized variably are tested and analyzed, and the Origin software is used to fit the DBTT（ductile brittleness transformation temperature）curve. Result of the analysis reveals that after being normalized at 860 ℃, 880 ℃ and 910 ℃, the DBTT of the 20 steel drops to -30--20 ℃, and the grain size of the normalized structure is more coarse than that of the as-hot rolled structure, whereas the post-normalization low temperature impact property of the steel is remarkably increased.