(1. 武汉钢铁(集团)公司技术中心, 武汉 430080;
2. 武汉科技大学材料系, 武汉 430081)
摘 要: 简要叙述了新研制的大线能量焊接低焊接裂纹敏感性调质高强度钢的特点。 研制的新钢种属低碳低合金高强钢, 集高强度(σs≥490MPa、 σb≥610MPa)、 高韧性(-20℃时横向Akv≥47J)、 优异的焊接性能(厚度≤50mm钢板焊前不需预热或稍加预热而不产生冷裂纹)于一体,并能承受大线能量(≥50kJ/cm)焊接。 研究了模拟焊接热影响粗晶区(CGHAZ)的微观组织结构特征及其与力学性能的关系。结果表明: CGHAZ中复合夹杂物可促进针状铁素体的形成,针状铁素体的数量与输入线能量有关并显著影响CGHAZ的力学性能。
关键字: HSLA钢; 低焊接裂纹敏感性; 大线能量焊接; 焊接热影响粗晶区;微观组织; 针状铁素体
(1. NETC of Wuhan Iron and Steel(Group) Corporation,
Wuhan 430080, China;
2. Department of Material, Wuhan University of Science and Technology, Wuhan 430081, China)
Abstract:The feature of new developed HSLA steels for large heat input welding with low susceptivity to weld cracking was presented. The steels designated as WDL610D2, which gather high strength(σs≥490MPa, σb≥610MPa), high impact toughness(at -20℃, Akv≥47J) and excellent weldability(the weld crack may be not formed without preheat or preheat with a little heat input for the steel plate with a thickness of less than 50mm), can be welded with large heat input(≥50kJ/cm). The microstructure nature of CGHAZ, which is a function as mechanical properties, was investigated. The complex inclusions in CGHAZ promote the acicular ferrite formation, which is associated with heat input and affects the mechanical properties of CGHAZ.
Key words: HSLA steel; low susceptivity to weld cracking; large heat input welding; coarse grain heat affected zone; microstructure; acicular ferrite