The Determination of Residual Stresses in Hardened, Ground Steel

Abstract

The residual surface stresses induced by grinding a hardened SAE 4340 steel have been investigated by means of x-ray diffraction and by optical interferometric methods. The depth of penetration of the residual stresses increases as the severity of grinding is increased. The higher the hardness level of the steel, the greater is the absolute value of the residual stress. The magnitude of the residual stresses varies from 100,000 psi in tension to 135,000 psi in compression depending on the hardness level of the steel and the severity of grinding. Light grinding produces residual compressive stresses while heavy grinding produces tensile stresses.