Effect of rare-earths carburizing on friction behavior of GCr15 steel laser melting layer

In order to improve the surface strength and wear-resistance property of GCr15 steel applied widely in the fields of aerospace and civil use, the laser melting treatments (LMT) on RE (rare-earths) carburizing layer of GCr15 steel were carried out and the effects of the complex treatments of RE carburizing and LRT on friction coefficient and wear extent were investigated. The experimental results showed that the friction coefficient of RE carburizing laser melting layer was steadily decreased, and the wear weight-loss was 14% (mass fraction) compared to unmodified GCr15 steel. The wear weight loss of GCr15 steel is apparently decreased by RE carburizing laser melting modification with the increase of friction slide distance and loading weight. The type of abrasion in the RE carburizing layer was plow-groove, while scratch abrasion was the dominant abrasion type in the RE carburizing-LRT layers. The functions of RE carburizing on the LRT include the refining of the grain sizes, the micro-alloying, the purifying and the improvement of the densification of the microstructure.