材料期刊网

目的 获得45钢表面重熔Ni60粉末的最佳重熔工艺,以期提高涂层的耐磨性能.方法 在Ni60合金粉末中加入A型、B型两种胶,滴入适量酒精,制作Ni60预制涂层;采用预粘接法+炉内重熔二步法工艺,在45钢表面重熔镍基合金涂层,通过金相组织实验、显微硬度实验,分别研究重熔温度对所得试样基体至涂层组织形貌和显微硬度的影响,讨论温度对所获试样基体至涂层组织与耐磨性的影响.结果 重熔温度达到1000℃、1100℃时,基体与涂层形成机械咬合的组织形态;1200℃时,基体与涂层形成机械咬合与冶金结合相结合的组织形态,涂层中硬化相数量增多,大小、分布均匀,缺陷最少.1100℃重熔所得涂层的平均显微硬度最高,达到496 HV;1200℃重熔所得试样分界线处的平均显微硬度最好,达到389.7HV,且该温度下所得试样的硬度曲线分布最有规律.结论 45钢基体表面重熔Ni60合金粉末,重熔温度为1200℃时,可有效改善涂层与基体的结合方式,获得机械结合与冶金结合的组织形态;此温度下,涂层组织均匀、细密,试样硬度分布有规律、波动不大,耐磨性最好.

Objective To acquire the best re-melting process of Ni60 on the surface of 45 steel, and improve the wear resistance of the coating. Methods Prefabricated Ni60 coating was produced by adding two kinds of glue, type A and type B, into Ni60 alloy powder, and dripping a right amount of alcohol. This experiment adopted the two-step re-melting process of pre-cementation and re-melting in stove to prepare the nickel-base alloy coating on 45 steel surfaces, studied the impacts of re-melting temperature on the morphology and micro-hardness of the substrate and the coating structure of the samples, and discussed the impact of temperature on the micro-structure and wear resistance of the substrate and the coating structure of the sample. Results Mechanical interlocking were formed between the substrate and the coating at 1000 ℃ or 1100 ℃, while mechanical interlocking and metallurgical bond were formed between the substrate and the coating when the re-melting temperature was 1200 ℃. The number of coating hardening phase increased, the size and distribution of which were even, with minimal amount of defects. Seen from a hardness distribution curve, the quality was the best. Based on the data, the average hardness of the re-melting coating prepared at 1100 ℃ was the highest, reaching 496HV, while the average micro-hardness at the dividing line of the sample obtained by re-melting at 1200 ℃was the best, reaching 389. 7HV, and the hardness distribution curve of the sample was the most regular. Conclusion Re-melting Ni60 alloy powder on 45 steel surface at 1200 ℃ could effectively improve the binding mode of the substrate and the coating, and gain access to machinery in conjunction with metallurgical bonding of structure morphology. At this temperature, the coating was homogeneous and fine, with regular and relatively stable distribution of the sample hardness as well as the best wear resistance.