Melted Characteristics Effects of Shielding Gas on Laser Deep Penetration Welding

Abstract:

Adopting coaxial and side blown protective gas to control plasma, many experiments of CO₂ laser deep penetration welding on the stainless steel are finished. Considering the protective gas effect of melten characteristics on laser welding,the experiments choose the gas species and composition to promote the collision and energy exchange of gas and plasma; The laminar flow state is holded by controlling the gas runoff, the angle and direction, increaseing the gas stiffness to prevent plasma punctured, and the plasma energy exchange range is close on the surface of the workpiece so that the energy of laser beam is less absorbed by plasma than the workpiece.The experiments indicate that shielding gas suppression are adverse factors on plasma to use alone Ar, He and N₂. Adopting He-Ar-N₂ and the ratio of 7:4:l as a protective gas when gas flow rate is about 30L/min, the deep and wide ratio is large,the deep penetration welding seam surfaces obtained are smooth,the defects aren't obvious;the protective effect is poor if the gas flow is too large or too small.

• Periodical: Key Engineering Materials (Volume 620)
• Pages: 116-121
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.620.116
• Online since: August 2014
• Authors: Qiang Wu*, Lan Ying Xu, Yong Mao
• Keywords: Laser Welding, Melted Characteristics, Stainless Steel

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