Effects of Cooling Paths on Through-Thickness Microstructure and Mechanical Properties of Heavy Gauge X80 Pipeline Steel  

作　　者：Xu-Dong Li Cheng-Ning Li Guo Yuan Guo-Dong Wang 

机构地区：[1]State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2017年第5期483-492,共10页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51234002);the Fundamental Research Funds for the Central Universities(N130407001)

摘　　要：The effects of various cooling paths on uniformity of through-thickness microstructure and mechanical properties of X80 pipeline steel of 22.0 mm in thickness were studied. The finite difference method was employed to calculate the temperature field during cooling. It was confirmed by the experimental result and temperature field calculation that the optimizing process was achieved by the ultra-fast cooling with medium cooling capacity（cooling rate of ＊23 K/s）followed by ultimate cooling capacity（cooling rate of ＊50 K/s）. After optimization, the experimental steel displayed much uniform microstructure and the deviation of through-thickness hardness was controlled within 20 HV. In addition,the yield strength, tensile strength and elongation of the experimental steel were 621, 728 MPa and 21.5%, respectively,meeting the requirements of the API standard for X80 pipeline steels.The effects of various cooling paths on uniformity of through-thickness microstructure and mechanical properties of X80 pipeline steel of 22.0 mm in thickness were studied. The finite difference method was employed to calculate the temperature field during cooling. It was confirmed by the experimental result and temperature field calculation that the optimizing process was achieved by the ultra-fast cooling with medium cooling capacity（cooling rate of ＊23 K/s）followed by ultimate cooling capacity（cooling rate of ＊50 K/s）. After optimization, the experimental steel displayed much uniform microstructure and the deviation of through-thickness hardness was controlled within 20 HV. In addition,the yield strength, tensile strength and elongation of the experimental steel were 621, 728 MPa and 21.5%, respectively,meeting the requirements of the API standard for X80 pipeline steels.

关 键 词：X80 pipeline steel Ultra-fast cooling Cooling path Finite difference method Microstructure Mechanical properties 

分 类 号：TG142.1[一般工业技术—材料科学与工程]