MICROSTRUCTURE DEVELOPMENT DURING ROUGHING AND INTERMEDIATE COOLING OF THICK HTP LINEPIPE STEELS
The microstructural development during roughing and early finishing of thick,high Nb-Ti steels containing high and low Mn contents has been investigated for conventional cold charging(CCR)and quasi compact strip production(CSP)conditions.Multi-pass rolling simulations were performed,followed by interrupted accelerated cooling,to study the “ascoiled” ferrite/pearlite microstructure.Local heterogeneous regions,LHR,were often found after CSP simulations,but not after CCR where the microstructure was generally uniform.Coarse,local heterogeneous regions can be prevented in HTP steels though complete recrystallization of the as-cast austenite during and after roughing by i)applying sufficient strain at roughing temperatures above the TiNb(C,N)precipitation region,ii)slow intermediate cooling and iii)using high Mn contents to suppress precipitation.For thick HTP skelp,the initiation of dynamic recrystallization is of little use in avoiding LHR due to limited strain available for completing the necklacing process.
Nb Mn recrystallization roughing austenite intermediate cooling CSP
Kevin Banks Rorisang Maubane
IMMRI,Dept. Material Science and Metallurgical Eng. University of Pretoria South Africa
国内会议
杭州
英文
783-789
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）