Influence of Shielding Gas on Fume Size Morphology and Particle Composition for Gas Metal Arc Welding

Abstract

Shielding gas is an important parameter in Gas Metal Arc Welding (GMAW). Nevertheless, the influence of shielding gas on particle composition and size distribution of welding aerosols is not clearly understood. Increasing the O₂ or CO₂ content of Ar-based shielding gases resulted in an increase in the average particle size. For binary and ternary Ar, CO₂, O₂ mixtures, increasing CO₂ had a greater impact than raising O₂ on particle size. Variations in Ar–He–CO₂ mixtures had the least influence. For 100% CO₂, the particle size distribution was altered significantly due to the change of the weld transfer mode to globular and particle size coarsened with increasing arc voltage. Shielding gas composition had no observable influence on particle composition and only a slight variation of composition with particle size was observed. Particles were identified as (Fe,Mn)₃O₄ with trace additions of Si.