| Wind tunnel is an indispensable experimental platform for aircraft wings,engine research and development and is the symbol of national aviation industry development level.It not only plays an important role in the research and development of aviation and aerospace engineering,but also has been widely used in transportation,housing construction,wind energy utilization and environmental protection with the development of industrial aerodynamics.Large axial compressor is the key equipment of continuous wind tunnel.Axial compressor main shaft in the case of high load high speed,prone to surface wear,so the appropriate surface of the spindle to strengthen the development of axial compressor is of great significance.Submerged arc welding technology,high efficiency,no arc dust pollution,good working conditions,especially for large parts of the surface to strengthen the work.W-Mo high-speed steel alloy because of its excellent wear resistance,and good red hardness at high temperatures,the enterprises are widely used in the surface of the various parts of the strengthening,but because of the alloy in the cooling process of thermal stress comparison high,easy to crack,so the need to take appropriate heat treatment process to eliminate thermal stress,to prevent cracking.At the same time after welding heat treatment can also make the hardening layer secondary hardening.In this paper,the method of submerged arc welding is used to study the effect of YD565-S on the surface of 304 stainless steel substrate with thickness of 20 mm.(SEM),X-ray diffraction(XRD),ring-block friction,wear tester and microhardness tester were studied by optical microscope(OM),equipped with an energy dispersive spectrometer,scanning electron microscopy(SEM-EDS).Welding parameters and different heat treatment on the structure of the surfacing layer,microhardness,wear resistance of the impact.The results are as follows:(1)The optimum parameters of welding with submerged arc welding machine were determined by welding the cladding layer on the surface of 304 austenitic stainless steel.The welding voltage was 30 V,the welding current was 300 A,the welding speed was 22m/h.Through the observation of the organization and the detection of mechanical properties,the optimal post-weld heat treatment process was established: tempering at 550℃,holding time is 1 hour.(2)Carbide surfacing layer is mainly composed of retained austenite,martensite,intergranular lamellar primary carbides and dispersed secondary carbides,welds in the surfacing layer of carbide is mainly M2 C type carbide(M is mainly W,Mo element),a small amount of MC carbide precipitation,the matrix is mainly martensite and retained austenite,after 550℃ tempering insulation 1h,MC carbide increased,the organization by the residual austrian transformation of martensite to tempered martensite.In the 600℃ temperature tempering insulation 1h,found a small amount of M6 C carbide.(3)The wear resistance of the surfacing layer was tested and found that it is mainly adhesive wear and abrasive wear,not the heat treatment of the surfacing layer wear the most serious,after tempering heat treatment,the wear is more minor.The hardness of the surfacing layer was the lowest,the tempering was carried out at 550℃,the hardness of the surfacing layer reached the peak,the tempering was carried out at the temperature of 600℃,the hardness will drop significantly. |
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