打壳锤头等离子堆焊镍基涂层组织和性能

Structure and Properties of Nickel-based Surfacing on Crust Breaker Deposited by Plasma Arc Welding

采用等离子堆焊技术在打壳锤头基体Q235钢表面进行堆焊,堆焊材料选用分别含有50%WC、40%WC和30%WC+Ti C的复合镍基粉末。借助金相显微镜、扫描电子显微镜、显微硬度仪、摩擦磨损试验仪等仪器对所得各堆焊层的显微组织、化学成分、显微硬度、耐磨性和耐蚀性进行分析。试验结果表明,三种合金堆焊层显微组织均为γ-Ni固溶体和弥散分布的不同形态的硬质化合物相,如WC,(Ti,V)C等。三种合金堆焊层与基体界面处冶金结合良好,堆焊层稀释率低,且与基体Q235钢相比,耐电解腐蚀性显著提高。含有30%WC+Ti C的镍基合金堆焊层与含有50%WC和40%WC的镍基合金堆焊层相比,具有更高的耐磨性和抗热腐蚀性。因而含有30%WC+Ti C的镍基合金堆焊层综合性能最优,能够大幅度延长打壳锤头使用寿命,具有广泛的应用前景。

Nickel-based alloy coatings are deposited on the surface of crust breaker made of Q235 steel through plasma arc welding with the nickel-based powders containing 50% WC, 40% WC and 30% WC＋TiC, respectively. And the microstructure, chemical composition, micro-hardness, abrasive resistance and corrosion resistance are examined on the samples investigated by using optical microscope（OM）, scanning electron microscope（SEM）, Vickers hardness tester and friction and wear testing machine. The microstructures of the coatings are γ-Ni solid solution and hard dispersed compound particles, such as WC, （Ti, V） C, etc. The coatings with low dilution rate possess a better metallurgical bonding with the matrix metal, and better electrolytic corrosion resistance compared with the Q235 matrix. The Nickel-based alloy coating containing 30%WC＋TiC has the highest wear resistance and hot corrosion resistance in comparison with the coatings containing 50%WC and 40%WC. Therefore, the Nickel-based alloy coating layer containing 30%WC＋TiC has the optimum comprehensive properties and extensive application prospect.