LASER-SURFACE ALLOYING OF A LOW-ALLOY STEEL WITH COBALT

Features of laser surface alloying on a 0.21C-1.46Cr-3.52Ni-0.80W stee l with cobalt powder are studied. Experimental results show that laser surface cobaltizing is possible and that the cobalt content of the su rface alloy may achieve 3.10 wt.%-5.63 wt.%. The maximum cobalt conten t attained is 9.96 wt.%. After alloying with cobalt, the performance o f the surface at elevated temperature is clearly improved. The hardnes s at 700 degrees C is 880 MPa, while the fatigue performance in the pr esence of thermal cycles is improved by 160%, when compared with the s urface of the untreated steel.