G-TECH 657

Formulated for compatibility with alloy IN-657, these consumables are also well-suited for welding the titanium-bearing wrought version, IN-671. Alloy 657, renowned for its elevated chromium content, exhibits exceptional resistance to hot corrosion (800-950°C). This resistance is particularly effective against fuel ash containing vanadium pentoxide and alkali metal sulfates, emanating from the combustion of low-grade heavy fuel oils. IN-657 castings find extensive applications in oil-fired furnaces and boilers, playing crucial roles in various components like tube sheets, tube hangers, supports, and spacers. These components are vital in diverse settings, including ships, power stations, refineries, and petrochemical plants. The alloy's composition carefully balances chromium, niobium, carbon, and nitrogen to reduce sensitivities to solidification and cold cracking. Maintaining low levels of carbon and nitrogen is crucial, with precautions like minimizing arc length to avoid nitrogen pickup. Preheating is typically necessary, ranging from 150-200°C for 10mm thickness, 200-250°C for most applications, and up to 450°C for the thickest sections. It is imperative to manage interpass temperatures and facilitate a slow cooling process.