This WPS addresses heavy structural welding using the FCAW-G (dual-shield flux core) process on 1" A572 Gr 50 plate. The procedure covers both CJP groove welds and large fillet welds in multiple positions — making it versatile for shop and field use on industrial projects. The 150°F preheat is specified per AWS D1.1 Table 3.3 for Gr 50 steel over 3/4" thick. IronKit generated this for a bridge and industrial steel fabricator who needed a single procedure covering both their shop (1G/2F) and field (3G/4F) operations. The dual-shield process was specified because the 75/25 shielding gas provides better out-of-position performance than self-shielded FCAW.
Frequently Asked Questions
What is dual-shield FCAW?
FCAW-G (gas-shielded flux core) uses a flux-core wire plus an external shielding gas (typically 75/25 Ar/CO2). It combines the high deposition rate of flux core with the cleaner arc and better out-of-position performance of gas shielding. It is preferred over self-shielded FCAW for code work.
Why 150°F preheat instead of 300°F?
AWS D1.1 Table 3.3 bases preheat on the combination of steel group and thickness. A572 Gr 50 at 1" requires 150°F minimum. The 300°F preheat applies to thicknesses above 1-1/2" or when the carbon equivalent exceeds certain limits.
Can I use this WPS for 4G overhead groove?
No. This procedure qualifies groove welds in 1G, 2G, and 3G only. Overhead groove (4G) requires separate qualification. However, fillet welds are qualified in all four positions including 4F overhead.