Effect of Heat Treatment on Microstructures and Properties of 550MPa Grade Offshore Platform Steel Z084
FH550 offshore platform steels containing 0.5-0.8% Nickel was treated by TMCP-lamellarizing-tempering (TMCP-L-T) and controlled rolling-ultra fast cooling-tempering (CR-UFC-T) processes,respectively,their microstructures and properties were also examined.This investigation was aimed at demonstrating the effect of heat treatment processes on microstructures and properties of high strength and high toughness offshore platform steel,especially the improvement of toughness of thick plates.The results indicated that tempered bainite was the main microstructure,with the proceeding of tempering processes,coalescence of martensite packets and increasing of volume fraction of polygonal ferrite (PF) could be noticed,static recovery of some dislocations could also be observed,and large quantity of (Nb,Ti)C precipitates rich Nb,20 to 40 nm in diameter,were founded in matrix.The extremely fine alloyed carbides with dispersive distribution can strengthen experimental steels.On the contract,CR-UFC-T had a shorter technologic process than TMCP-L-T,but the yield strength was improved from 555MPa to 627MPa while the -60℃ impact toughness was at upper 90J level,much more than 55J with standard.
offshore platform steel ultra fast cooling tempering precipitates impact toughness
ZHOU Yan-lei CHEN Jun XU Yang DI Guobiao LIU Zhenyu WANG Guodong
State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110004,China Shougang Research Institute of Technology,Beijing 100041,China
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-5
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）