王演铭 王锋 李智华

摘要： 采用明弧自保焊在Q235钢板表面堆焊了金属陶瓷相耐磨层，测定了耐磨层的成分、金相组织、硬度和耐磨性，并和常规焊丝堆焊耐磨层进行了对比。结果表明，金属陶瓷相堆焊耐磨层成分中Cr和C的含量更高，质量分数分别为29.8%和5.8%;堆焊耐磨层中含有强碳化物形成元素，析出的碳化物尺度更加细小;金属陶瓷相呈纤维状分布，垂直于工作面，体积分数高于常规焊丝堆焊耐磨层，达到64.7%;金属陶瓷相堆焊耐磨层的平均硬度为64.7 HRC，高于常规焊丝堆焊耐磨层;金属陶瓷相堆焊耐磨层的耐磨性高于常规焊丝堆焊耐磨层，其磨损失重量仅为常规焊丝堆焊耐磨层的38%。采用金属陶瓷相堆焊耐磨层的磨煤机磨碗衬板及辊套的检修时间可延长1.5～2.0倍。

关键词： 金属陶瓷; 磨碗衬板和辊套; 成分; 金相组织; 耐磨性

中图分类号： TG 455

Abstract： The surface of Q235 steel plate was overlaid with cermet wear-resistant layer by open arc self-shielded welding. The composition， microstructures， hardness and wear resistance of the hardfaced layer were analyzed， compared with those of the conventional hadfacing wire. The results showed that the contents（mass fraction） of Cr and C of cermet phase in hardfaced layer were higher， which were 29.8% and 5.8% respectively. The cermet hardfaced layer contained strong carbide forming elements， and the precipitated carbides were finer. Cermet phase was distributed in fiber shape， perpendicular to the working surface. Volume fraction of the cermet phase was 64.7%， higher than that of conventional hardfacing wire. The average hardness of cermet hardfaced layer was 64.7 HRC， higher than that of conventional hardfacing wire. Wear resistance of cermet phase hardfaced layer was higher than that of conventional hardfacing wire， and its wear loss was only 38% of that of conventional hardfacing wire. Maintenance cycle of grinding bowl liner and roller sleeve of coal mill with cermet phase hardfaced wear-resistant layer could be prolonged by 1.5～2.0 times， and remarkable economic benefits were obtained.

Key words：  cermet; grinding bowl liner; grinding roller sleeve; composition; microstructures; wear resistance

0 前言

中速磨煤機碾磨件的使用寿命是影响燃煤电厂机组负荷及综合运行成本的重要因素。如何提高碾磨件，尤其是磨碗衬板、磨辊套的使用寿命，减少检修次数，是各个燃煤电厂急需解决的问题。

建国后，中国没有中速磨煤机的设计生产基础，引进消化吸收成了国内生产中速磨煤机的必经之路。1985年中国从美国引进了全套的RP系列碗式磨煤机制造技术，又从德国引进了MPS系列磨煤机技术，1989年从美国引进了HP系列磨煤机的生产技术[1]。中国目前所生产的磨煤机几乎都是这些磨煤机的翻版或改进型，寿光电厂使用的MW31B/L-Dyn型中速磨煤机就是原上海重型机器厂引进的HP系列磨煤机的改进型号。……