Effects of High Alloying Content on Microstructure and Properties of Laser Cladded High-speed Steel Coating
The each elemental content of W,Mo and Co was improved to 5 at%on the basis of M2 HSS component(W6Mo5Cr4V2)and the coating was cladded on a Q235 steel substrate by a 5 kW continuous-wave CO2 laser system.The results show that the solidified microstructure is mainly composed of lath martensite,retained austenite and fine eutectic M2C carbide in the proposed HSS coating,which is similar with the M2 HSS coating.The high additive content of W,Mo and Co can improve the precipitation content of hard carbide in the proposed HSS coating without the obvious growth and coarsening of primary carbide,and hence,the maximum tempering hardness increases from 810 HV0.5 to 875 HV0.5.In comparison with the hot wear testing results in the M2 coating at 500℃,the friction coefficient and weight loss in the proposed HSS coating decreases by 18%and 23%,respectively.The hardness and hot wear resistance in the laser cladded HSS coating can be obtained by improving the additive content of W,Mo and Co alloying elements.
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