储罐用610 MPa大热输入高强钢焊接接头性能及组织研究

摘要

The properties and microstructure of welded joint for 610 MPa high strength steel in oil tank were studied. The results show that it is feasible to manufacture large oil tank with the 610 MPa high strength steel because of good properties of welded joint such as tensile strength, cold bending property and low temperature impact property. The microstructure of in coarse grained heat-affected zone ( CGHAZ) are mostly lath bainite, granular bainite and a few M-A island, and the microstructure of CGHAZ is slightly bigger than that of base metal. There are many TiN particle in test steel, which can refine heat-affected zone grain by preventing the growth of primitive austenite, preventing M-A island and proeutectoid ferrite from the generation by promoting the phase transformation of ferrite as nucleus.%研究了储罐用610 MPa级大热输入高强度钢板采用气电立焊和埋弧横焊焊接对接接头的组织及性能.结果表明,焊接对接接头的拉伸强度、低温冲击和冷弯性能优良,性能指标富余量大,淬硬倾向小,钢板完全可以应用于10万立方米及以上大型石油储罐的建造.储罐用610 MPa级大热输入高强度钢板焊接热影响粗晶区组织比母材组织有所粗化,以板条贝氏体和粒状贝氏体为主,基体和晶界存在少量形状较为圆滑的M-A岛.钢板中存在大量的TiN粒子有效钉扎奥氏体晶界和促进铁素体晶内形核,抑制了焊接热影响区组织粗化和先共析铁素体、粗大M-A岛的形成,是保证610 MPa大热输入高强钢焊接性能的关键.