Development of Chromium-Free Welding Consumables for Stainless Steels

摘要

Stainless steel components are often joined by welding when fabricated into structures. Fusion welding of these steels results in the formation of carcinogenic Cr(VI) in the weld fumes as a result of the Cr content of the commonly used filler metals. This is a significant health hazard for the welders and necessitates protective gear or expensive ventilation systems to meet the stringent Permissible Exposure Limit for chromate set by OSHA. This project developed a Cr-free consumable for welding 304 austenitic stainless steel that provides mechanical properties and corrosion resistance comparable to the commonly used Cr-bearing consumables. A weld wire of composition Ni-7.5Cu-1Ru-0.5Ti worked well in gas metal arc and gas tungsten arc welding operations. For shielded metal arc welding, coated electrodes with cores wires of composition Ni-7.5Cu-4Ti-1Ru performed well. The performance characteristics of these welds were excellent, including mechanical properties and corrosion resistance. Essentially no Cr was detected in the weld fume.