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本文研究了室温形变对15~#钢离子氮化和氰化后组织和性能的影响,结果表明,予形变显著提高钢表面的碳、氮浓度,而且使晶粒和碳氮化物细化。予形变对沿不同方向上渗层深度的影响,可能和“位错通道”的组态有关,既可能使渗层增厚(沿与“位错通道”一致的方向)也可能使渗层变浅(与位错通道相交叉的方向)。应用正电子湮灭谱仪测定了氰化过程中晶体缺陷密度的变化规律,结果表明,由于碳氮原子的渗入不仅可以迅速将位错固定,而且还可能使位错密度不断增加。这就使得形变产生的缺陷对高温化学热处理的促进作用得以贯穿于处理过程的始终,并取得明显的实际应用效果。自行车另件的实际应用结果表明,可使轴挡的接触疲劳寿命提高0.5～1倍;产品合格率可由12.5％提高到87.5％。本文还对室温形变对间隙原子扩散的机理进行了探讨,并提出了一些新的见解。
The effects of room temperature deformation on the microstructure and properties of 15 # steel after nitriding and cyanidation were studied. The results showed that pre-deformation significantly increased the carbon and nitrogen concentrations on the steel surface and refined the grains and carbonitrides. The effect of pre-deformation on the depth of the layers along different directions may be related to the configuration of the “Dislocation Channel”, which may not only make the diffusion layer thicker (along the same direction as the “dislocation channel” Shallow (the direction crossing the dislocation channel). Positron annihilation spectroscopy was used to determine the variation of crystal defect density during cyanidation. The results show that not only the dislocation can be rapidly fixed due to infiltration of carbon and nitrogen atoms, but also the dislocation density may increase continuously. This makes the deformation of the defects caused by high-temperature chemical heat treatment to promote the role throughout the process from beginning to end, and achieved significant practical application results. The practical application results of bicycle parts show that the contact fatigue life of shaft block can be increased by 0.5 ~ 1 times; the passing rate of products can be increased from 12.5% to 87.5%. The mechanism of space atom diffusion at room temperature is also discussed. Some new ideas are also proposed.