Effect of carbon and of cold plastic deformation following quenching on the properties of steel

Abstract

1. Cold deformation after quenching increases the strength characteristics of carbon and carbon-free steels. 2. The increase of the degree of plastic deformation up to 9.8% in steels in the nonequilibrium state leads to a considerable change in the mechanical properties. Further increase of the degree of deformation does not lead to any significant further changes. 3. In the case of deformation of carbon steels (with the exception of 38Kh2) the increase of the strength characteristics is accompanied (up to a certain degree of plastic deformation) by an increase of ductility. 4. When the steels are treated by quenching + tempering + deformation, the ductility is higher than after quenching + deformation. 5. The increase of strength after cold deformation increases with the carbon concentration, and the yield strength as well as the proportionality limit increases much more than the ultimate strength. 6. Cold deformation after quenching decreases the physical widening of x-ray fringes in the case of carbon steels and increases the width of the fringes of carbon-free steels. The change in the width of the friges is due to the decomposition of martensite and also to the cold working during deformation. 7. The increase of the strength characteristics as the result of deformation of steel after quenching is apparently due to additional accumulations of defects and to the precipitation of small carbide particles from the supersaturated solid solution.