Orthogonal test was performed to determine the
laser phase-transformation hardening process suitable for a rotary joint made
of 35CrMo alloy,which was aiming at increasing the
wear-resistance of the rotary joint.Thus the optimized processing parameters were established,while the effect of
laser phase-transformation hardening on the hardness and wear-resistance of the rotary joint was examined.As the results,the optimized processing parameters including laser power,laser spot size(diameter),and scanning speed were determined to be 1 500 W,3.5 mm,and 20 mm/s,respectively,at which a satisfactory surface-modification was realized.Namely,the surface hardness of the 35CrMo alloy rotary joint after laser phase-transformation hardening was as much as 786 HV- 1 N ,which was higher by 30% than that of the same rotary joint after carburization hardening.At the same time,the wear-resistance of the 35CrMo rotary joint was doubled after laser phase-transformation hardening,and the residual stress was dominated by compressive one,which could well accommodate the working conditions of the rotary joint.