摘要
采用一种新型复合焊接工艺——电阻塞焊对1.5 mm等厚TRIP980高强钢/SPCC低碳钢板进行焊接,利用正交试验优化其焊接参数,随后增加焊前预热,分析对比无预热和焊前预热两种条件下较优焊接参数时接头的力学性能及组织、硬度特点.结果表明,各焊接参数对接头的拉剪载荷影响程度由大到小依次为焊接电流、填充物直径、焊接时间及电极力;在电极头端面直径为8 mm的条件下,填充物直径为5.5 mm时的接头力学性能优于其它直径;相同焊接参数时,焊前预热塞焊接头的拉剪载荷比无预热提高7%以上;两种条件下较优焊接参数时,焊前预热塞焊接头的熔核偏移量小于无预热,熔核和熔合区的硬度比无预热时有所下降,熔合区脆硬马氏体组织比无预热少;焊前预热塞焊接头断口为韧性断裂,无预热塞焊接头断口为脆性断裂;其主要机理是,预热减小了熔核区金属过热倾向,使熔核扩展均匀,熔合区脆硬组织减少,有利于接头强度的提高.
A new type of hybrid welding-resistance plug welding was used for welding of dissimilar steels between 1.5mm thick TRIP980 high strength steel and SPCC low carbon steel sheets. The orthogonal test was conducted to optimize the welding parameters. Then preheating before welding was carried out. The mechanical properties of the joints and the microstructure and hardness in different regions were compared under the same welding parameters with and without preheating before welding.The results show that the effect of welding parameters on the shear tensile load of the joint decreased in the order of is welding current,filler diameter,welding time and electrode pressure.When the end diameter electrode was 8mm and the filler diameter was 5.5 mm,the mechanical properties of the joints were better than those with other diameters. Under the same welding parameters,the tensile shear strength of the joints with preheating was improved 7% more than that without preheating before welding. With optimum welding parameters,weld nugget was larger with preheating than without preheating,the nugget offset was smaller with preheating,and the fusion zone with brittle martensite was also smaller. The fracture of joint with preheating was ductile,but that without preheating was brittle. The hardness of weld nugget and fusion zone with preheating decreased. The main mechanism is that preheating reduced the overheating tendency of the nugget zone in the plug weld,made the expansion in weld nugget uniform,and reduced the brittle and hard structure in the fusion zone,which was beneficial to improve the joint strength.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2017年第7期109-114,共6页
Transactions of The China Welding Institution
关键词
高强钢
异种钢
电阻塞焊
high strength steel
dissimilar steel plate
resistance plug welding