Does anyone has any technical information about GTA-welding 1.25Cr-0.5Mo and 2.5Cr-1Mo without the use of backing gas. I'm specially interested in any material degradation (if any) and / or welding problems.
I have welded these materials for years with an open butt TIG root pass. These welds were performed in boiler applications and never failed in 26+ years of service.