Regularities of changes in physical and mechanical and corrosion properties of heat-strengthened reinforcing 35GS steel

The effect of heat treatment on the change in the physical and mechanical and corrosion properties of reinforcing 35GS steel is considered. It is established that the use of triple heat treatment (intercritical hardening from temperatures of 900/700 °C or 800/700 °C, followed by tempering at temperatures of 300 or 400 °C, respectively, hardening from 900 °C with double tempering (from 400 °C (oven heating) and 500 °C (electro-thermal hardening)), significantly reduce the sensitivity of reinforcing 35GS steel to hydrogen cracking. During intercritical hardening of 35GS steel with obtaining properties corresponding to the At600 class during the first hardening from 900 °C, the second hardening from 700 °C and tempering up to 300 °C resistance in an environment causing hydrogen cracking at stress intensity factor of 0.6 increases by 10 times (19.5 hours versus 2 hours) and during the first hardening from 800 °C, the second hardening 700 °C and tempering up to 400 °C resistance increases by 20 times (40.5 hours versus 2 hours). It is shown that under conditions of intense hydrogenation, to reduce the sensitivity of steel to hydrogen cracking, it is more preferable to use volume rather than surface tempering.