Reasearch Of 14Cr11MoV Martensitic Heat-resistant Stainless Steel Applying Plasma Harden Treatment

14Cr11Mo V(old brand: 1Cr11 Mo V) martensitic heat-resistant stainless steel has good corrosion resistance, excellent mechanical properties and high creep resistance,etc, because of these advantages, it?s widely used in turbine blades, valve rod, tail shaft and other occasions, but like other stainless steel, it has some shortcomings, such as low hardness, low wear resistance, etc, this severely reduces the life of martensitic stainless steel and limits its application in industry. Plasma harden treatment could improve surface hardness and wear resistance of stainless steel, but now it has few of reports on 14Cr11 Mo V plasma harden treatment in domestic and aboard, so it makes sense to study14Cr11 Mo V applying plasma harden treatment.In this paper, we study 14Cr11 Mo V martensitic heat-resistant stainless steel applying plasma nitriding, carburizing, nitrocarburizing harden treatment, using spectral composition analyzer, metallurgical microscope, micro-hardness tester, XRD diffraction and other equipment analyze properties and structure of layer, it includes layer thickness, surface hardness, surface brittleness, hardness gradient and phase structure, etc. Through the study, the main conclusions are as follows:(1) Plasma nitriding penetrate rate is the fastest in the three kinds of harden treatment, above 610?, plasma nitrocarburizing penetrate rate is faster than carburizing, below 610?, plasma nitrocarburizing penetrate rate is slower than carburizing; for surface hardness, plasma nitriding surface hardness relatively high at the same temperature, carburizing surface hardness is relatively stable, nitrocarburizingsurface hardness is relatively fluctuation with temperature changing, it is more high than nitriding at the 530?,but it deceases rapidly, it is the lowest hardness below570 ?.(2) Layer thickness gradually increasing with the temperature and time increasing,but the growth rate is gradually slowing down; there is no crack in the layer when hardening treat 14Cr11 Mo V applying plasma carburizing and nitrocarburizing, but when applying plasma nitriding, if the layer don?t have crackle, the temperature should above 630?, and the heating process can?t pass nitrogen gas; for hardness gradient,plasma nitriding is the steepest, nitrocarburizing hardness gradient is relatively alleviate, carburizing hardness gradient is steep at the beginning,then it becomes relatively alleviate.(3) The surface brittleness only 1 and 1-2 grade under all process, so brittleness is qualified; by XRD diffraction analysis, nitrided layer is composed of ?, Fe3 N, Fe4 N and Cr N, carburized layer is composed of ?, Fe3 C and Cr23C6, nitrocarburized layer is composed of ?, Fe3 N, Fe4 N, Fe3 C, Cr N, Cr23C6; the precipitation of Cr decrease corrosion resistance, the precipitation of carbides and nitrides r decrease surface hardness.