Influence of tempering on the mechanical properties and the fine structure of quenched and deformed steels

Conclusions

• 1. Hardening of quenched and deformed carbon-free steels is a means of increasing the degree of imperfection of the crystal structure of quenched steels as the result of plastic deformation. This can be proved by the widening of the (220) lines with increasing hardening and the narrowing of these lines with increasing softening resulting from tempering at temperatures above 300°C.

• 2. There are two reasons for the hardening of quenched and deformed steels: the first is a more intense precipitation of the carbide phase as the result of deformation, which is confirmed by the narrowing of the (220) line when the tempering temperature is below 250°C. The second is the plastic deformation of the metal matrix of the quenched steel, which is confirmed by the widening of the x-ray lines relative to deformed steel as compared to those for quenched but undeformed steel tempered above 250°C. The strength of the deformed steel turned out to be higher at all the tempering temperatures investigated.