Form:This specification covers a corrosion and heat resistant nickel alloy in the form of round@ square@ and flat wire 0.625?in. (15.50 mm) and under in nominal diameter or thickness.Application:Primarily for helical springs for use?at elevated temperatures.Direct precipitation hardening as in 3.3.2@ after coiling@ produces optimum stress and low relaxation up to 700??(370??.Solution?and precipitation heat treatment?as in 3.3.3@ after coiling produces optimum resistance to relaxation combined with fairly fine and uniform grain size for use in service at 1000?? 1300??(540?? 705??.?