Rolling contact and adhesive wear of bainitic and pearlitic steels in low load regime

Serious problems have been observed in railroad systems as a consequence of uncontrolled wear, which is considered a key factor regarding performance losses and maintenance costs. One alternative to face the demanding requirements of the newest systems is the development of materials with more resistant and durable microstructures. In order to study the behavior of AISI 15B30 (bainitic) and AISI 1070 (pearlitic) steels, a disc-on-disc tribometer was used to test them under properly controlled load and relative slip conditions. The steels were conveniently heat treated to obtain hardness values similar to those of actual wheels and rails in commercial railroad systems, i.e. 320 HV for the wheels and 370 HV for the rails, and only pairs of discs made of the same material were tested each time. The results indicated that the average wear rates were similar for all the pairs and slip ratios tested. Under pure rolling, both AISI 1070 and AISI 15B30 showed larger deformed subsurface layers and more significant work hardening when compared to rolling–sliding conditions, which was related to the magnitude of stresses beneath surface for each condition.

Research highlights▶ Mass losses were similar for bainitic and pearlitic microstructures. ▶ Work hardening effects were more significant in bainitic microstructure. ▶ Pearlitic microstructure was influenced by the occurrence of ratchetting. ▶ Bainitic microstructure was influenced by adhesive wear in the tests with creepage.