A novel approach to regulate energy allocation and melt flow in narrow gap laser welding with electromagnetic assisted wire wobbling

• Published in: Journal of materials processing technology Vol. 289; p. 116909
• Main Authors: Li, Junzhao, Liu, Yibo, Kang, Kexin, Sun, Qi, Jin, Peng, Liu, Yue, Cai, Chunwei, Sun, Qingjie
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-03-2021; Elsevier BV
• Subjects: Austenitic stainless steels; Crystal growth; Electromagnetic assisted wire wobbling; Forced convection; Grain refinement; Grooves; High temperature; Laser beam welding; Laser welding; Lasers; Melt flow; Melting; Metallurgy; Microhardness; Morphology; Narrow gap welding; Sidewall wetting; Weld metal; Wetting; Wire; Electromagnetic assisted wire wobbling; Narrow gap welding; Sidewall wetting; Melt flow; Laser welding
• ISSN: 0924-0136; 1873-4774
• DOI: 10.1016/j.jmatprotec.2020.116909

[Display omitted]
•Electromagnetic assisted wire wobbling is proposed to regulate melt flow.•Electromagnetic swing wire can enlarge melt pool and improve sidewall wetting.•Lack of fusion defect is solved and concave surface morphology is obtained.•Uniform temperature, element distribution and grain refinement are achieved.
A novel, new approach of electromagnetic assisted wire wobbling to regulate energy allocation, melt flow and metallurgical structure is introduced in laser narrow gap welding of 316 L stainless steel. The formation of melt pool, weld surface morphologies and microstructure features in conventional laser welding, laser wobble welding and electromagnetic assisted wire wobble welding were compared. The results reveal that the forced convection generated by electromagnetic swing wire could broaden the melt pool size and compulsively push high-temperature weld metal towards groove sidewall. The wetting of liquid weld metal on groove sidewall was improved and concave weld morphology was obtained, thereby avoiding incomplete fusion of sidewall and favoring the filling of next weld bead. The temperature and element distribution in weld zone would be more uniform by the periodically and drastically forced convection, which helped to inhibit the growth of columnar crystals and promote the uniform distribution of elements. The average microhardness value in weld zone was uniform with the using of electromagnetic swing wire. Moreover, mechanisms of enhanced sidewall wetting and grain refinement were discussed in electromagnetic assisted wire wobble laser welding.