We have a 17/7 PH rather complex structure of 0.050" 1.5" diameter tubes that is being welded together with 17/7 filler. To get the full strength after weld we plan on solution treating at 1900 Deg F, and then Austenitize at 1400 Deg F and then Harden at 1050 Deg F (TH1050). The structure is 15 ft long, so we will be heat treating in air and want to inhibit heat treat scale growth. Our research found a product ATP 641 for coating stainless steel that we are considering. Does anyone have any experience with this product or can anyone suggest another product. The following is a link to the ATP 631.