120t转炉流程管线钢X70的生产实践

Practice of X70 Pipe Line Steel Production by 120 t Converter Flow Sheet

X70管线钢(%:0.02～0.05C、0.145～0.25Si、≤0.015P、≤0.002S、1.70～1.80Mn、0.085～0.15Nb、0.2～0.3Ni、0.015～0.040Al、0.01～0.03Ti)用铁水预处理-120 t转炉-RH-LF-(200～250)mm×(900～1 800)mm连铸工艺冶炼。通过金属锰替代低碳锰铁和部分硅锰合金,减少RH处理后钢水增碳,控制LF精炼时钢水增C量≤0.01%,预处理铁水[S]≤0.002%,LF精炼渣碱度控制在1.5左右,使LF初始[C]为0.03%,初始[S]为0.001 5%,终点[C]为0.04%,终点[S]为0.000 8%,满足了使用要求。

The X70 pipeline steel （%： 0.02-0.05C, 0.145 - 0. 25 Si , ≤〈0.015P,≤0.002S, 1.70-1.80Mn, O. 085- 0. 15Nb, 0.2 - O. 3Ni, O. 015 -0. 040Al, 0. 01 -0. 03Ti） is produced by hot metal pretreatment - 120 t converter - RH - LF - （200 -250）mm × （900 - 1 800）mm slab eoneasting process. With metal manganese to replace low- carbon fen＇o-manganese and partial silieo-manganese to decrease carbon pickup amount in liquid after RH treatment, con- trolling LF liquid carbon pickup amount ≤0. 01% , controlling pretreated hot metal [ S ] ≤0. 002% and basieity of LF refi- ning slag being about 1.5, the LF initial [C] and IS] are respectively 0. 03% and 0.001 5%, and the LF end [C] and IS] are respectively 0. 04% and 0. 000 8% , to meet the requirement of service.