The Effect of Age-Hardening on the Rigidity Modulus and the Internal Friction in 17-7PH Stainless-Steel Wire

The change of the rigidity modulus, the electrical resistivity, the hardness and the internal friction following age-hardening were studied with 17-7PH stainless-steel wire containing 1.24%Al.The measurement were made on specimen of 0.65 mm diameter, using a torsion pendulum, a potentiometer and a micro-Vicker’s hardness tester. The results obtained were as follows: (1) The hardness of 17-7PH stainless-steel wire increased remarkably by aging at 400∼500°, but only slightly by aging at 100∼200°. (2) The electrical resistivity decreased in three temperature ranges of aging, namely, 150∼200°, 300∼450° and 500∼600°. (3) The rigidity modulus increased in the aging temperature range of 100∼250° and 400∼500°, but decreased by aging above 550°. (4) The internal friction of 17-7PH steel wire decreased remarkably by aging at 100∼300°, but increased again by aging at 550∼650°.