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柴油机球铁曲轴经气体软氮化处理后,表面形成一层高硬度的软氮化层,提高了耐磨性;同时表面渗层体积胀大产生一定的压应力,且高度瀰散分布在次层(扩散层)中的微细氮化物和原固溶于铁素体中,而在交变应力作用下沿某些晶面析出的超显微氮化物,阻碍了位错的移动,从而较大地提高了曲轴的疲劳强度。目前,我国295型柴油机曲轴经气体软氮化处理后,断轴率已由1.5％下降到0.05％,一次大修期达到了五千小时,提前达到了一机部机械工业基础件攻关一九八○年的指标,并已用井式炉投入批量生产,取代了现行的轴颈
After nitrocarburizing the diesel nodular crankshaft by gas, the surface forms a layer of high hardness nitrocarburized layer to improve the abrasion resistance. At the same time, the volume of the surface permeable layer expands to generate a certain compressive stress and is highly dispersed in the sub-layer (Diffusion layer) of fine nitrides and the original solid solution in the ferrite, and under the alternating stress along certain crystal plane precipitation of super-minitrides, disrupt dislocation movement, which greatly increased Crankshaft fatigue strength. At present, China’s 295 diesel engine crankshaft after gas nitrocarburizing treatment, the broken shaft rate has dropped from 1.5% to 0.05%, an overhaul of up to 5,000 hours, ahead of a machine to reach the basic piece of machinery to tackle key 189 ○ years of indicators, and has been put into use pit furnace mass production, replacing the existing journal