FORM:Round@ square@ and flat wire.APPLICATION:Primarily for helical springs used at elevated temperatures.Direct precipitation hardening as in 6.3.1 after coiling@ produces optimum stress and low relaxation?at service temperatures up to 700 F (370 C).Fully heat treated as in 6.3.2 after coiling@ produces optimum resistance to relaxation combined with fairly fine and uniform grain size at service temperatures of 1000 - 1300 F (540 - 705 C).