Introduction and Validation of Chromium-Free Consumables for Welding Stainless Steels. Version 2.

摘要

Fusion welding of stainless steels results in the formation of Cr (VI) in the welding fume. The Cr (VI) is a carcinogen and is considered a significant health hazard for the welding personnel. In 2006, OSHA reduced the Permissible Exposure Limit (PEL) for Cr (VI) in welding fume from 52 to 5 micrograms per cubic meter 8-hour time weighted average. This regulatory change has imposed stringent requirements for reduction of Cr (VI) exposure during welding of stainless steel that necessitate considerable expense for ventilation systems and/or personal protective equipment. The objective of this project was to demonstrate and validate two new chromium (Cr)-free welding consumables for application at the Department of Defense (DOD). These consumables have been developed as a replacement for the conventional consumables used to weld austenitic stainless steel and provide almost a 100-fold reduction of the carcinogenic hexavalent chromium in the welding fume of stainless steel. Welds of both Cr-free consumables met the performance objectives of 70,000 pounds per square inch tensile strength and successfully passed the bend test. During the Field Demonstration, some of the ENiCuRu welds contained lack of fusion defects and did not pass the X-ray test. Lack of fusion, lack of penetration, and undercut defects were found in welds made with the ERNiCuRu electrode.