On the applicability of hardening mechanisms to low-carbon and low-alloy steels

On the basis of experimental studies, the approximate contribution of various hardening mechanisms to the yield point of low-carbon and low-alloy steels is estimated. It has been established that for hot-rolled steels (St.3sp and St5ps), solid-solution and grain-boundary hardening (54.0% and 29.0, %) make the greatest contribution to the yield point. The predominant strengthening mechanism of low-alloy steel 10HNDP is solid solution, a high proportion of which in this steel is explained by the resistance to moving dislocations from the side of dissolved atoms of Ni, Cu, P, and Cr in α-Fe. In low-alloy steel 16G2AF, along with these hardening components, the role of precipitation hardening is noticeable (20.0%). It is shown that thermomechanical treatment of steel grade St.5ps leads to an increase in the value of dislocation hardening up to 27.0% due to an increase in the density of dislocations and the retention of most of the dislocations in the rolled stock during accelerated cooling of hot-deformed austenite. It is noted that solid solution hardening with alloying with cheap alloying elements (Mn, Si), as well as dislocation and dispersion hardening through the use of thermomechanical treatment in combination with the addition of carbide and nitride-forming elements V (C, N).