The Research Of Nitriding Process By Deep-Layer QPQ Technology

Deep-layer QPQ technology is a composite technology which is composed by nitridingand oxidation process, nitriding process is core technology, and it is improved by ordinaryQPQ technology. Duo to Deep-layer QPQ technology can improve the abrasion resistance,corrosion resistance and fatigue resistance better, it has extensive application. Therefore thestudy of nitriding technology on deep-layer QPQ technology will improve the nitriding process,and the quality of nitrided layer, and make far-reaching significance in manufacturing industry.This paper will make research on influence of nitriding process for formation of nitridedlayer on workpiece, so we use deep-layer QPQ technology on45steel,35CrMo steel and316Lstainless steel by different nitriding process. Then we test the thickness and hardness ofnitrided layer, and its elements. What’s more, observing the features and microstructure ofnitrided layer by using optical microscope, SEM and X-ray diffractometer.Through the experiment, we obtain the influence of variation of layer formation andthickness for different materials by different nitriding process of deep-layer QPQ technology.Found the nitriding process in two temperature section will have a certain role in promoting theimprovement of nitrided layer quality, at the same time the nitriding process in two temperaturesection will improve the surface hardness of workpiece and the hardness of nitrided layer, butnot for phase composition of nitrided layer. However it will have the impact on the content ofnitrogen element in nitrided layer, which affects the content of each phase. At last, we obtainthe optimization nitriding process parameter of deep-layer QPQ technology:480℃nitriding1hour for first nitriding section, and630℃nitriding1hour for second nitriding section.