Procedure WPS-1401-ASME-2 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for gas tungsten arc welding of 28 Mo-5Fe, 15.5 Cr-16Mo-3.5W and Low C-16 Mo-16 Cr-5.5Fe (P-44), in thickness range 0.035 to 0.432 in.; filler metals are respectively ERNiMo-1, ERNiCrMo-5 and NiCrMo-4 (F-44); shielding gas is argon.