熔覆电流对Fe-Cr-B-C合金涂层组织与耐磨性的影响

Effect of cladding current on microstructure and wear resistance of Fe-Cr-B-C alloy layer

为了研究熔覆电流的变化对Fe-Cr-B-C熔覆合金层组织及性能的影响,采用等离子熔覆技术在不同的熔覆电流下(75、85和95 A)在Q235钢板表面制备了Fe-Cr-B-C合金熔覆层,采用X射线衍射仪(XRD)、电子背散射衍射(EBSD)技术、维氏硬度计和扫描电镜(SEM)对熔覆层的物相、硬度和微观组织进行表征,并采用摩擦磨损试验机对熔覆层的摩擦磨损性能进行研究。结果表明:Fe-Cr-B-C熔覆层的物相主要为马氏体,同时有大量的Fe_(3)C、Cr_(23)C_(6)、Fe_(2)B、Cr_(2)B、Fe^(2)C、Fe_(7)C_(3)硬质相及少量的氧化物在基体内呈网状分布。随着熔覆电流的升高,熔覆层的稀释率增加,硬质相的含量逐渐降低。熔覆层硬度随着电流增大呈现先增大后减小的趋势,电流为85 A时熔覆层硬度最高。随着电流的升高,熔覆层的耐磨性先升高后下降,当熔覆电流为85 A时,熔覆层的磨损量仅为Q235基体的7%,表明Fe-Cr-B-C熔覆层能显著提高Q235钢板基体的耐磨性能。Fe-Cr-B-C熔覆层的磨损机制是粘着磨损、磨粒显微切削、显微断裂共同主导。

In order to study the influence of the change of cladding current on microstructure and properties of Fe-Cr-B-C cladding alloy layer,the plasma cladding technology was used to prepare Fe-Cr-B-C alloy cladding layer on the surface of Q235 steel plate under different cladding current(75,85 and 95 A).The phase,hardness and microstructure of the cladding layer were characterized by means of X-ray diffractometer(XRD),electron back scattering diffraction(EBSD)technique,Vickers hardness tester and scanning electron microscopy(SEM),and the friction and wear properties of the cladding layer were studied using a friction and wear tester.The results show that the phase of the Fe-Cr-B-C cladding layer is mainly martensite,and a large number of Fe_(3)C,Cr_(23)C_(6),Fe_(2)B,Cr_(2)B,Fe_(2)C,Fe_(7)C_(3) hard phases and a small amount of oxides,which are distributed in the matrix in a network form.With the increase of cladding current,the dilution ratio of the cladding layer increases and the content of hard phase decreases.The hardness of the cladding layer first increases and then decreases with the increase of current,and reaches the highest when the current is 85 A.With the increase of current,the wear resistance of the cladding layer first increases and then decreases.When the cladding current is 85 A,the wear volume loss of the cladding layer is about 7%of that of the Q235 substrate,indicating that the Fe-Cr-B-C cladding layer can significantly improve the wear resistance of the Q235 steel substrate.The wear mechanism of the Fe-Cr-B-C cladding layer is dominated by adhesive wear,abrasive micro cutting and micro fracture.