控轧控冷对钢板质量的影响
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摘要
针对微合金化的低合金高强度结构钢Q390B的性能特点,设计了4种控轧控冷方案,研究了第二相析出的时机和形态,以及对钢板表面质量的影响。结果表明:采用CR+ACC轧制工艺,二次开轧温度≤860℃,终轧温度780～830℃,终冷温度610～650℃,并开启后段强冷模式,生产的板材综合力学性能最佳。同时认为P、S、O等杂质元素的富集及其夹杂物是造成钢板表面裂纹的首要原因,通过控制出钢温度、保护浇注等措施,钢板表面裂纹率由0.31%降至0.17%。
According to the properties of microalloyed low alloy high strength structural steel Q390 B, four schemes of controlled rolling and cooling were designed. The timing and morphology of the second phase precipitation and its effect on the surface quality of the steel plate were studied. The results show that the comprehensive mechanical properties of the sheet are the best by adopting CR+ACC rolling process, controlling starting temperature of the second rolling≤860 ℃, finishing rolling temperature 780～830 ℃, and finishing cooling temperature 610～650 ℃, and opening the strong cooling mode in back section. At the same time, it is considered that the enrichment of impurity elements such as P, S, O and their inclusions are the primary cause of plate surface crack. By controlling tapping temperature and protecting pouring, the surface crack rate of steel plate decreases from 0.31% to 0.17%.
According to the properties of microalloyed low alloy high strength structural steel Q390 B, four schemes of controlled rolling and cooling were designed. The timing and morphology of the second phase precipitation and its effect on the surface quality of the steel plate were studied. The results show that the comprehensive mechanical properties of the sheet are the best by adopting CR+ACC rolling process, controlling starting temperature of the second rolling≤860 ℃, finishing rolling temperature 780～830 ℃, and finishing cooling temperature 610～650 ℃, and opening the strong cooling mode in back section. At the same time, it is considered that the enrichment of impurity elements such as P, S, O and their inclusions are the primary cause of plate surface crack. By controlling tapping temperature and protecting pouring, the surface crack rate of steel plate decreases from 0.31% to 0.17%.
引文
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[2]郭仁辉,韩毅,邓想涛.新一代TMCP条件下钛微合金化Q460钢种开发[J].河北冶金,2018,(11):17～20.
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[7]王大宝.中厚板微裂纹成因分析[J].炼钢,2000,(2):15～17.
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[9]孙胜英.中厚板表面裂纹的金相分析[J].河北冶金,2010,(2):48.
[10]常愕,于学斌,袁己百.连铸过程中钢液二次氧化的研究[J].连铸,2003,(1):8.
[2]郭仁辉,韩毅,邓想涛.新一代TMCP条件下钛微合金化Q460钢种开发[J].河北冶金,2018,(11):17～20.
[3]胡达新,王家军,杨志刚,等.Mn-B系贝氏体钢冷却曲线及组织观察 [J]汽车技术,1995(1):27～30.
[4]徐伟.42CrMo 钢控轧工艺试验[J].河北冶金,2017,(10):48～50.
[5]Cota A B,Modenesi P J,BarbosaR,Santos D B,Determination of CCT diagrams by thermal analysis of an HSLA bainitic steel submitted to thermomechanical treatment[J].ScriptaMateialsTrnasactions JIM,1991,32(8):715～728.
[6]Suzuki K,MiyagawaS,Saito Yet a1.Effect of microalloyednitride forming elements on preeipitation of earbonitrideandhigh temperature ductinuously cast low carbon Nbcontainingsteel stab[J].1SIJ International,35(1995),(1):34.
[7]王大宝.中厚板微裂纹成因分析[J].炼钢,2000,(2):15～17.
[8]吴巍.含铌、钛船板钢中板微裂纹研究[J].钢铁,2002,(37):41.
[9]孙胜英.中厚板表面裂纹的金相分析[J].河北冶金,2010,(2):48.
[10]常愕,于学斌,袁己百.连铸过程中钢液二次氧化的研究[J].连铸,2003,(1):8.