Max Temp: 650°F (350°C). HBWAK Series gages are constructed of self-temperature compensated K alloy wire, and bonded to a Hastelloy® X shim. Standard gages are compensated for mild steel (6ppm/°F). K alloy is a highly corrosion resistant alloy with superior properties. Many of our customers utilize K-Alloy gages for nuclear and fossil fuel applications as well as renewable energy projects, where harsh environments cause corrosion.