800MPa级低合金高强钢板的组织优化  

Microstructure optimization of 800 MPa grade high strength low alloy(HSLA) steel plate

作　　者：杨建勋[1] 

机构地区：[1]莱芜钢铁集团有限公司技术中心,山东莱芜271104

出　　处：《金属热处理》2012年第12期14-19,共6页Heat Treatment of Metals

摘　　要：测试了不同成分和工艺生产的800 MPa级低合金高强钢板的力学性能,借助光学金相显微镜、扫描电镜及透射电镜对其组织进行了分析。结果表明,800 MPa级低碳非调质钢,具有较低的淬硬倾向,可实现免预热焊接,该钢轧后冷速>12℃/s时,形成以针状铁素体和板条贝氏体为主的微观组织,钢板冲击韧性大幅度提高,且裂纹敏感性值更低,焊接后也表现出更强的抗裂性能。而800 MPa级中碳调质钢具有一定淬硬倾向,焊接时必须预热否则接头部位易出现裂纹,母材组织主要为回火马氏体,焊接接头组织为少量回火马氏体、大量未溶解碳化物及一定量准多边形铁素体,对塑性变形抗力很小。Mechanical properties of 800 MPa grade HSLA steel plate were tested, and microtructure of the steel was analyzed by optical metallograghic microscope, SEM and TEM. The results show that 800 MPa grade low-carbon non-quenched and tempered steel has lower tendency of being hardened, the non-preheating welding can be realized on it. After roiling, when the cooling rate is 〉 12 ℃/s, the mainly microstrcture of the steel consists of acicular ferrite and lath bainite which lead to impact toughness increased significantly and crack sensitivity lower, it also shows a stronger crack resistance after welding. But 800 MPa grade medium-carbon quenched and tempered steel with some hardened tendency, must be preheated in course of welding, otherwise the joints prone to cracks. The mainly microstructure of matrix is tempered martensite, and microstructure of welded joint consists of a small amount of tempered martensite, a large number of undissolved carbides and a certain amount of quasi-polygonal ferrite, with smaller plastic deformation resistance.

关 键 词：低合金高强钢 力学性能 组织优化 

分 类 号：TG142.1[一般工业技术—材料科学与工程]