Tempering microstructure and mechanical properties of pipeline steel X80
The tempering microstructure and mechanical properties of X80 steel used for heating-bent pipe were analyzed. The results show that the microstructure of X80 steel tempered at 550 ℃ and 600 ℃ is bainitic ferrite (BF)+granular bainite (GB), and partial ferrite laths in BF merge and broaden. The interior sub-lath boundary of some GB begins to disappear due to merging, the M/a constituent (a mixture of martensite plus retained austenite) in GB is orbicular. At the two tempering temperatures the tested X80 steel shows a certain degree of tempering stability. After being tempered at 650 ℃, the microstructure of X80 steel is GB+quasi-polygonal ferrite(QF), and the original Bf laths have merged to form smaller GB crystal grains. The reason is that the steel shows better match of strength and toughness. After being tempered at 700 ℃, the microstructure of X80 steel is composed mainly of QF, which can improve the plasticity but decline severely the yield strength of X80, and the M/A constituent assembles and grows up at the grain boundary of QF, resulting in excellent lower lowtemperature toughness of X80.
X80 steel microstructure tempering temperature mechanical property
NIU Jing QI Li-hua LIU Ying-lai MA Lei FENG Yao-rong ZHANG Jian-xun
Xian Tubular Goods Research Center of China National Petroleum Corporation, Xian 710065,China Scho Xian Tubular Goods Research Center of China National Petroleum Corporation, Xian 710065,China School of Materials Science and Engineering, Xian Jiaotong University, Xian 710049,China
国际会议
2009 Frontier Symposium of China Postductors on Materrials Science(2009年中国博士后材料科学前言论坛)
长沙
英文
573-578
2009-11-22（万方平台首次上网日期，不代表论文的发表时间）