| Electron beam surface modeling has developed speedily within the past 20 years.The use of various surface modeling morphologies in a variety of areas will significantly raise the friction coefficient of the work surface,improve the hardness and wear resistance of the material surface,and expand the area to speed up temperature reduction,among other things.304 stainless-steel is wide used thanks to its smart corrosion resistance,massive thermal linear growth constant and non-magnetic state in primary solid solution state.Based on the finite element volume method,the simulation model of the single-channel modeling of the electron beam underneath the focused beam was established.The Fluent software system was accustomed simulate the single-channel modeling process of the 304stainless-steel electron beam underneath the beam,and the temperature field and flow field within the monophonic modeling method were obtained.and therefore the amendment law of action crystallization.The forming mechanism of single-pass molding was analyzed;and therefore the effects of different process parameters(beam power,beam speed)on the flow of molten pool,surface modeling size and solidification and crystallization process were mentioned.The influence of various process parameters on the shape size,the macroscopic morphology of the molten pool and therefore the microstructure verifies the rationality of the simulation model.The results show that the surface tension,Marangoni shear stress and recoil pressure play a very important role within the flow of the molten metal pool,and therefore the shape size is affected by the flow behavior within the molten pool.Within the power range of600W～1200W,with the rise of the lower beam power,the volume of the molten pool increases,the molten pool’s tailing grows,the molten pool’s breadth grows,and the penetration depth deepens,the result of every driving force is enhanced,and also the surface of the molten pool is the largest.The flow velocity became quicker,that led to a linear increase within the peak height and dimension of the surface modeling;When the lower beam power was 1200 W,the modeling was the biggest,with a height of 205 μm and a width of 2764 μm.In the moving speed range of 10mm/s～15mm/s,with the rise of the beam source moving speed,the volume of the molten pool decreases,the surface trailing becomes longer,the impact of every driving force is slightly weakened,and therefore the maximum surface of the molten pool becomes slightly slower;With the rise of the beam source moving speed,the melting width W of the melting region decreases,the penetration depth H has no obvious modification,and therefore the peak width of the surface modeling decreases and therefore the height has no important modification.once the moving speed is 15mm/s,the form is that the smallest,with a height of 251 μm and a width of 2090 μm.The single-channel modeling can be used to improve the heat transfer performance,and the surface area improvement rate will increase with the rise of the lower beam power and the speed of the beam source,reaching 2.84% at 1500 W and 15mm/s.The microstructure is principally composed of austenite mixed with ferrite.The G/R decreases nonlinearly and therefore the GR value increases nonlinearly with the decreasing width and depth of the modeling crosswise,however at the modeling surface,the G/R increases and therefore the GR decreases.The crystal morphology of the microstructure from the small hole area to the surface layer is:equiaxed crystals→columnar dendrites→ cellular dendrites;And from the edge to the center:columnar dendrites →fine dendrites.the rise of the lower beam power and also the speed of the beam source has no obvious impact on the crystallization tendency.The distribution law of microhardness within the modeling area: modeling center > modeling edge > modeling surface,and also the increase of lower beam power and beam source speed has very little impact on the microhardness of the joint.when the ability is 1500 W and the speed is 15mm/s,the hardness is 0.65 times,0.72 times and 0.89 times that of the base metal,and the hardness is principally affected by the grain size.The surface modeling area’s friction and wear test findings demonstrate that increasing lower beam power increases the friction coefficient and wear scar volume inside the modeling region,and once the facility is 1500 W,it’s the same as the substrate;the rise of the beam source speed increases the friction coefficient and wear scar volume.the volume impact isn’t significant. |
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