Technical Paper
Gas Metal Arc Welding of Coated Advanced High Strength Steel (AHSS) - Developments for Improved Weld Quality
2007-04-16
2007-01-1360
Gas Metal Arc Welding (GMAW) is commonly used in the automotive industry for joining heavier gauge mild and High Strength Low Alloy (HSLA) uncoated steels, where it is recognized for its versatility and speed. The only constraints typically encountered relate to fatigue performance of the joint as a result of poor design or manufacturing fit-up. Advanced High Strength Steels (AHSS), now being considered for more and more applications, however, do not offer the same ease of welding and process control is significantly more critical. They differ from mild steels in chemical composition and thermal processing, resulting in a different microstructure; designed with a richer metallurgy to have higher strength at equivalent thickness. As a result, the sensitivity to heat input is greater and the process window in which acceptable welds can be achieved is narrower.