To improve the hardness and wear resistance of mild steel, A-100 ultra-high-strength steel cladding coatings were prepared on the surface of mild steel by laser cladding. In this study, the effects of laser cladding process parameters on the forming quality, phase composition, microstructure, microhardness and wear resistance of the A-100 ultra-high-strength steel cladding coatings were researched. The results show that the main phase of the coating is martensite and a small amount of austenite. The microstructures of the upper part of the cladding coatings are mainly equiaxed grains, while those of the lower part are mainly columnar grains. With an increase in laser specific energy, the microstructures of the cladding coatings become coarse. When the laser specific energy is 70.8 J/mm², the microhardness of the cladding coating is the highest, and the maximum average microhardness of the cladding coatings is 548.3 HV. When the laser specific energy is low, the wear of the cladding coatings is mainly pitting, while when the laser specific energy is high, the wear type of the cladding coatings is mainly adhesive wear. Moreover, the microhardness and wear resistance of the cladding coatings are reduced if the laser specific energy is too high.

Among many methods to enhance the crack resistance of laser cladding coatings, adjusting the composition of laser cladding material is the most simple, feasible, and effective method. To improve the plastic toughness and crack resistance of A100 laser cladding coating, Ni and Ti powders of an equal molar ratio were added to A100 powder as laser cladding powder. Laser cladding technology prepared A100-(Ni-Ti) coatings without crack defects. The cladding coatings’ phase composition and microstructure were analyzed using XRD and SEM, respectively. A ring-block friction and wear tester tested the wear resistance of the A100-(Ni-Ti) cladding coatings. A100-(Ni-Ti) cladding coatings mainly contain martensite and austenite. The elements Ni and Ti are distributed primarily in the austenitic phase region. The results show that adding Ni and Ti elements can reduce the microhardness of A100 cladding coatings. The average microhardness of the A100-0%(Ni-Ti) cladding coating is 532.50 HV, and the average microhardness of the A100-10%(Ni-Ti) cladding coating is 430.99 HV, while the average microhardness of the A100-30%(Ni-Ti) cladding coating is only 307.49 HV. The wear surface of the A100-10%(Ni-Ti) cladding mainly shows pits and a small amount of adhesive wear. The A100-20%(Ni-Ti) and A100-30%(Ni-Ti) cladding coatings show severe adhesive wear. The A100-10%(Ni-Ti) cladding with high microhardness and good run-in performance exhibits the best wear resistance.