八钢X60管线钢冶炼实践

Production Practice of X60 Pipeline Steel in Bayi Steel

文章介绍了八钢公司采用铁水脱硫预处理、复吹转炉、LF精炼、板坯连铸工艺开发X60管线钢的过程。在成分设计上应用了Nb、V、Ti微合金化,采用低碳含量,提高产品的韧性和延性,同时具有良好的焊接性能。将Nb、V、Ti微合金化与热机械轧制工艺(TMCP)相结合,充分应用管线钢的晶粒细化、固溶强化、析出强化和相变强化等机制,提高管线钢的强度和韧性。采用微钛处理技术,改善管线钢焊接热影响区的韧性。生产控制上采用纯净钢冶炼工艺和连铸的保护浇铸工艺,降低钢中的氮含量、非金属夹杂和硫含量,并对钢水中的Al2O3夹杂进行钙处理,提高管线钢热轧卷板的断裂韧性。采用该工艺生产的X60管线钢成品[S]≤0.0050%,[N]≤0.0055%,钢中的A、B、C、D各类夹杂物能控制到1.5级以下。钢材的抗拉强度控制在550～670 MPa,屈服强度控制在475～545 MPa,屈强比控制在0.82～0.90,断后伸长率控制在35%～43.5%,-20℃夏比V型横向冲击功AkV88～112 J,各项力学性能完全满足国内外标准和用户技术条件要求,已形成批量供货能力。

Development course of X60 pipeline steel in Bayi steel with hot metal pretreatment and combined blowing converter,LF refining,the Slab continuous casting is introduced.Nb,V,Ti microalloy and low carbon technique is adopted in composition design to enhance toughness,elongation rate and excellent weld ability.Grain refining,solid dis-solve strengthen,precipitation strengthen and phase strengthen etc,mechanisms are applied and combined with Nb,V,Ti fine grain and TMCP.Micro titanium improve toughness and strengthen in the HZA.Low N,Non-metallic inclusion and S and Ca treatment on Al2O3inclusion realized by pure steel smelt and protection cast technique to enhance the rup-ture toughness.[S] and [N] are below0.0050% and 0.0055% respectively in X60 pipeline steel produced by this craft,besides,A,B,C and D kinds of inclusions are controlled below1.5 grade.The tensile strength Rm,Yield strength ReL,ReL / Rm,elongation rate and the Charpy V type notch transversal impact test carry out at-20℃ is controlled between 550～670MPa,475～545MPa,0.82～0.90,35%～43.5% and AkV88～112J,respectively,each mechanical properties ab-solutely satisfy domestic and overseas standard and gain the capability of offering production.