Effect of beam offset on the characteristics of copper/304stainless steel electron beam welding

• Published in: Vacuum Vol. 128; pp. 205 - 212
• Main Authors: Guo, Shun, Zhou, Qi, Kong, Jian, Peng, Yong, Xiang, Yan, Luo, TianYuan, Wang, KeHong, Zhu, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2016
• Subjects: 304stainless steel; AUSTENITIC STAINLESS STEELS; Beam offset; Copper; Copper (T2); Dissimilar metal welding; Electron beam welding; Fracture mechanics; FUSION WELDING; Heat affected zone; JOINTS; Microscopic characteristics; Offsets; STAINLESS STEELS; STEELS; Strength; Structural steels; TENSILE STRENGTH; Welded joints; WELDING; Beam offset; Copper (T2); Electron beam welding; Dissimilar metal welding; Microscopic characteristics; 304stainless steel
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2016.03.034

Copper (T2) and 304stainless steel were joined by EBW with different beam offset. Full-strength joint as well as the offset joints of sufficient strength can be obtained. The highest tensile strength reaches 250Mpa, which is almost equal to the strength of copper. By analyzing phase structure and distribution of weld zone, bonding interface of fusion zone, width and grain size of heat affected zone, diffusion behavior of Fe/Cr, cooling rate and fracture behavior, the effect of beam offset on the joint strength was detailed studied. The results show that beam offset is flexible and allowed to be in the range of −0.2 mm to 1 mm. Under the condition of small beam offset, the performance of the joint is nice because of narrow HAZ and weld zone of few defects. But for large offset which leads to low joint performance on copper side or steel side, the main reasons respectively are deterioration of HAZ, FZ and low metallurgical bonding of root interface. Toughness fracture was proved by dimples for fusion welding, but brittle fracture occurred for re-melt deposit welding of large offset. •Connection of T2 copper and 304stainless steel can be well realized by EBW with reasonably parameters and offset.•Beam offset is flexible and allowed to be in the range of −0.2 mm to 1 mm.•Detailed investigation of microstructures and mechanical properties.•HAZ, FZ and root connection interface of joint are the weakness.