高合金含量对激光熔覆高速钢涂层组织与性能的影响

    Effects of High Alloying Content on Microstructure and Properties of Laser Cladded High-speed Steel Coating

    • 摘要: 在M2牌号W6Mo5Cr4V2高速钢成分基础上增加钨、钼、钴含量至5 at%,通过CO2横流式激光成套加工设备在Q235钢基体表面进行激光熔覆。对试样在500℃进行摩擦磨损实验。结果表明:两涂层凝固组织均为板条马氏体基体、残余奥氏体和细小的共晶碳化物M2C。提高M2成分中钨钼钴含量可增加涂层中碳化物硬质相的析出量,且激光快速凝固动力学条件能有效抑制涂层中一次碳化物的长大和粗化,最大回火硬度从M2涂层的813 HV0.5提高至872 HV0.5。高钨钼钴含量涂层的摩擦系数相比于M2涂层减少约18%,磨损失重降低约23%。激光快速凝固方法制备高速钢涂层可适量提高钨钼钴成分含量以获得更高的涂层硬度和热磨损性。

       

      Abstract: 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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