590 MPa级高强钢双面双弧立焊焊缝组织性能

为研究590 MPa级高强钢双面双弧工艺得到的焊接接头组织与性能的关系,采用钨极氩弧焊(TIG)与熔化极气体保护焊(MAG)方法获得成型良好的焊接接头,经过拉伸、冲击、弯曲试验及光学显微镜、扫描电镜、EBSD分析,对590 MPa级高强钢双面双弧立焊打底焊与盖面焊焊接接头的组织及性能进行了研究.结果表明:打底焊缝组织主要为贝氏体,盖面焊缝组织以贝氏体与针状铁素体为主;打底焊缝经历过一次热循环后组织得到一定程度的细化;打底焊缝硬度值与盖面焊缝相近,盖面焊缝热影响区最高硬度值高于打底焊缝热影响区最高硬度;2 mm坡口间隙性能较5 mm坡口间隙有较大提高,2 mm坡口间隙断口以韧窝断裂为主,5 mm坡口间隙断口以解理断裂为主.

Weld structure and mechanical properties of 590 MPa high strength steel thin slab in vertical position double-sided arc welding

To establish the relationship between microstructures and mechanical properties of 590 MPa high strength steel through double-sided arc welding, the welded joints were obtained by TIG and MAG.The properties, including tensile, strength, toughness, and flexural strength, were measured. The microstructures were observed by optical microscopy, scanning electron microscopy and electron backscattered diffraction. In this paper, the microstructure and properties of welded joint of the 590 MPa high strength steel double-sided arc vertical welding of back welding and cosmetic welding are studied. The results show that the backing weld bead mainly consists of bainite while the cosmetic welding bead mainly consists of acicular ferrite and bainite. Meanwhile, microstructure of the cosmetic welding bead become finer after one thermal cycle. The hardness of backing weld bead is close to that of the cosmetic welding bead. The highest hardness value of heat affected zone in the cosmetic weld bead is higher than that of the backing weld bead. The performance of the 2 mm groove gap is better than that of 5 mm one. Dimple fracture dominates the 2 mm groove gap whereas cleavage fracture dominates the 5 mm groove gap upon loading. .