Effect of Cr3C2 Grain Size on the Microstructure and Wear Performance of Fe-based Alloy Plasma Transferred Arc Surfacing; [Cr3C2粒径对等离子堆焊铁基合金层组织与耐磨性能的影响]

초록

Plasma surfacing with Fe50 and composite plasma surfacing with 40% (mass fraction) micron and nano Cr3C2 (Fe50+40% micro/nano Cr3C2) were prepared by plasma surfacing on low carbon steel surface. Effect of Cr3C2 with different dia-meter on microstructure and wear properties of Fe50 alloy plasma surfacing were comparatively studied. The phase composition of the plasma surfacing was analyzed by X-ray diffractometry (XRD), the microstructure and micro-area composition observed by scanning electron microscopy (SEM) and energy depressive spectroscopy (EDS), the hardness distribution tested by microhardness tester, and the wear performance investigated respectively by a sliding wear tester and impact wear tester. The results indicate that the microstructure of Fe50 plasma surfacing is mainly composed of columnar crystal α-Fe and its network eutectic α-Fe+Cr23C6. The solidification mode of Fe+40% micro/nano Cr3C2 plasma surfacing is hypereutectic, which is composed of a large number of pre-eutectic carbides and fine and uniform dendrites and eutectic structures among them, with additional phases such as γ-Fe, Cr7C3 and unmel-ted Cr3C2; however, the Fe+40% nano-Cr3C2 coating precipitates more than the pre-eutectic carbide of Fe+40% micron Cr3C2 coating, which is, furthermore finer, and denser. Compared with Fe50 plasma surfacing coating, the microhardness, sliding wear performance and impact wear performance of Fe+40% micron Cr3C2 coating were increased by 21%, 1.5 times and 0.8 times, respectively; whereas the performances of Fe+40% nano Cr3C2 coating were increased by 34.1%, 2.4 times and 1.7 times respectively, whose furrow, spalling and plastic deformation were significantly reduced, while the wear resistance notably improved. © 2018, Materials Review Magazine. All right reserved.

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