Volume-surface hardening of freight bogie springs from steels with reduced and controlled hardenability

Some scientific, engineering, and process aspects of heat hardening of rolling stock screw springs from steels with reduced (55PP) and controlled (55RP) hardenability by the method of volume-surface hardening are considered. The efficiency of the new process from the standpoint of saving of resources due to decrease in the content of alloying elements in the metal and increase in the relaxation resistance and in the endurance limit of the springs hardened by the volume-surface method is demonstrated. Results of laboratory and field tests are analyzed. The main components of a spring production line are described.