On the Investigation of the Change of Modulus of Elasticity of Steel due to Quenching

Abstract

The change of modulus of elasticity of quenched steel compared with that of annealed steel was measured by the vibration method which can easily measure it with small test pieces suitable for perfect hardening. The test pieces used in this investigation were armco iron, carbon steels with carbon content of 0.1, 0.2, 0.4, 0.6, 0.9 and 1.3% chrome steel, chrome-molybdenum steel, and leaded free cutting steel. The dimension of the test pieces of carbon steels were 5 mm in diameter and 100 mm in length, and that of special were 8 mm in diameter and 120 mm in length. The test pieces were quenched in oil or water at 800∼930° and tempered at 100°, 200°, 300°, 400° and 550°. The modulus of elasticity decreases several per cent by quenching and gradually recovers by tempering up to the value of annealed state. The rate of decreasing in the carbon steels by quenching decreases according as the increase of carbon content and it takes the maximum value 3.5% at 0.6%C and when the carbon content further increases it falls to 3%. The rate of decreasing of modulus of elasticity is 6∼6.5% at chrome steel, 3.3% at chrome-molybdenum steel and 4.5% at leaded free cutting steel.