EFFECT OF COLD FORMING ON TENSILE AND COMPRESSIVE PROPERTIES OF HY-80 STEEL PLATES.

Because the cold forming of submarine-hull plates can significantly alter their mechanical properties, a study was made to determine the effect of cold deformation on the mechanical properties of 2-12-in. thick plates of HY-80 steel cold-formed to small radii and consequently to large surface strains. The present report describes the effects of cold deformation and subsequent stress relieving or aging on the standard tensile and compressive properties of HY-80 steel. The results indicated that simple generalizations on the effect of cold forming on mechanical properties cannot be made because the effects depend upon the method of deformation plane strain or uniaxial tension, the type of deformation tension or compression, the type of test tension or compression, the specimen orientation longitudinal or transverse, and the specific mechanical property under consideration. For plane-strain deformation, the largest changes in properties were observed for the longitudinal 0.2 offset yield strengths, which increased about 30 ksi for cold deformation of about 10 percent when the cold deformation and testing were of the same type. A similar size decrease in yield strengths was observed when the cold deformation and testing were of the opposite type. Author