Powder Nitrocarburizing at Low Temperatures

摘要

A low temperature powder nitrocarburizing technology was developed by applying appropriate direct current field (DCF) between the treated sample and the powder agents, which overcomes the shortage of energy consuming and low-efficiency in the conventional powder nitrocarburizing process. The cross-sectional microstructures and the depth of the bright layers were investigated, and the micro-hardness distribution along the depth of the layer was measured. The results showed that DCF could produce the temperature gradient between the sample and the powder agents, and thus increase the concentration of the active nitrogen and carbon-containing species and accelerate their diffusion rate. With the effect of DCF, the depth of bright layer was increased 2～5 times for 45 steel when the furnace temperature was the same as that in conventional process for test temperatures of 300℃～500℃, and the micro- hardness distribution of the diffusion layer was improved for 20 CrMnMo.