Study on the Micro Laser Welding Parameter of Ultrathin Stainless Steel Sheet
CHEN Yu-hua1,2, KE Li-ming1, XU Shi-long2, XING Li2
1. National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang, 330063, China; 2. School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang, 330063, China
Abstract：Butt welding of 0.2mm thick 321 stainless steel sheet was realized using micro impulse laser.The processing parameters were optimized by orthogonal experimental and influence of processing parameter on the morphology and microstructure of welded joint was studied.The results show that the optimized processing parameters that can get the maximum stretching resistance are:pulse power percentage is 15,pulse frequency is 5 Hz and pulse width is 2.1ms.With the optimized processing parameters,the stretching resistance of the welded joint can achieve 95% of base metal.Burn through in welded seam is easy to occur when laser pulse energy is too big and nonpenetration occurs when pulse width is too small.Both burn through and nonpenetration can lead to the decrease of stretching resistance.The microstructures of welded joint that has best stretching resistance are composed of equiax crystals in weld center and fine columnar crystals in weld edge.