Effect of scanning speed during PTA remelting treatment on the microstructure and wear resistance of nodular cast iron
来源期刊：International Journal of Minerals Metallurgy and Materials2014年第4期
论文作者：Hua-tang Cao Xuan-pu Dong Qi-wen Huang Zhang Pan Jian-jun Li Zi-tian Fan
文章页码：363 - 370
摘 要：The surface of nodular cast iron（NCI） with a ferrite substrate was rapidly remelted and solidified by plasma transferred arc（PTA） to induce a chilled structure with high hardness and favorable wear resistance. The effect of scanning speed on the microstructure, microhardness distribution, and wear properties of PTA-remelted specimens was systematically investigated. Microstructural characterization indicated that the PTA remelting treatment could dissolve most graphite nodules and that the crystallized primary austenite dendrites were transformed into cementite, martensite, an interdendritic network of ledeburite eutectic, and certain residual austenite during rapid solidification. The dimensions of the remelted zone and its dendrites increase with decreased scanning speed. The microhardness of the remelted zone varied in the range of 650 HV0.2 to 820 HV0.2, which is approximately 2.3–3.1 times higher than the hardness of the substrate. The wear resistance of NCI was also significantly improved after the PTA remelting treatment.
Hua-tang Cao，Xuan-pu Dong，Qi-wen Huang，Zhang Pan，Jian-jun Li，Zi-tian Fan
State Key Laboratory of Materials Processing and Die & Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology
摘 要：The surface of nodular cast iron（NCI） with a ferrite substrate was rapidly remelted and solidified by plasma transferred arc（PTA） to induce a chilled structure with high hardness and favorable wear resistance. The effect of scanning speed on the microstructure, microhardness distribution, and wear properties of PTA-remelted specimens was systematically investigated. Microstructural characterization indicated that the PTA remelting treatment could dissolve most graphite nodules and that the crystallized primary austenite dendrites were transformed into cementite, martensite, an interdendritic network of ledeburite eutectic, and certain residual austenite during rapid solidification. The dimensions of the remelted zone and its dendrites increase with decreased scanning speed. The microhardness of the remelted zone varied in the range of 650 HV0.2 to 820 HV0.2, which is approximately 2.3–3.1 times higher than the hardness of the substrate. The wear resistance of NCI was also significantly improved after the PTA remelting treatment.
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