中厚板T型接头双机器人焊接组织与力学性能

Microstructure and mechanical properties of medium-thick-plate T-joint prepared by dual-robot welding

针对Q345中厚板高强钢构成的T型接头横角焊接位置在焊接过程中位置准确性差与根部难熔透的问题,提出一种双机器人双面双弧全熔透不清根MAG焊接方法.焊后对焊缝进行显微组织分析和接头力学性能测试.结果表明:打底焊前焊道过热区为板条状马氏体和下贝氏体组织,正火区为铁素体和珠光体组织;打底焊前弧焊道组织为板条状马氏体、针状铁素体和少量下贝氏体;打底焊后弧焊道组织为针状铁素体和先共析铁素体;填充焊道组织主要为针状铁素体.焊缝平均硬度为220 HV,高于母材平均硬度,-20℃条件下冲击吸收功高于27 J,符合标准要求,可实现自动化生产.

Aiming at the problems of poor position accuracy and difficult penetration at the root of transverse angle position of welded T-joint comprised of Q345 medium-thick-plate high-strength steel,a double-sided double-arc full-penetration MAG welding method without back-chipping by dual-robot was proposed.After welding,the microstructures of weld seam and the mechanical properties of weld joint were analyzed and tested,respectively.The results show that the overheated area of weld bead before backing welding is composed of lamellar martensite and lower bainite;the normalized area is composed of ferrite and pearlite;the microstructures of arc weld bead before backing welding consist of lamellar martensite,acicular ferrite and a small amount of lower bainite;the microstructure of arc weld bead after backing welding is composed of acicular ferrite and proeutectoid ferrite;the microstructure of filler weld bead is mainly acicular ferrite.The average hardness of weld is 220 HV,which is higher than that of base metal;the impact absorption energy under-20℃is higher than 27 J to meet the standard requirements for automatic production.