Surface Nanocrystalline Treatment And Low Temperature Gas Nitriding Of Steels

Lots of performance of metal materials ties up with their grain size, and refining grain is deemed to a kind of effective approach being used to ameliorate the combination property of metal materials all the while. At attended time, destabilization of metal materials more begins with the surface, so the surface nanocrystalline treatment which induces forming nanostructure on the surface of metals can obviously improve the surface and combination property of materials. There is not obvious interface between the layer of nanostructures and the matrix, thus the nanostructures layer don't separate and appear breadcrust because of the change of external condition.High volume fraction interface begins to form on the surface by surface nanocrystalline treatment, supplying ideal entryway for the diffuseness of chemical elements, and can markedly lower the temperature and time of chemical treatment and enhance infiltration concentration and deepness. The surface nanocrystalline treatment affords powerful supply for developing new surface treatment process.In this paper, we systematically study the surface nanocrystalline treatment process and low temperature nitriding process of steels. The task mainly includes three parts:First, we utilize alternating current to treat iron and 45 steel in electrolyte at different parameter for forming nanostructure on the sample surface, characterize the sample by multiform test methods and discuss the mechanics of forming nanostructures. Secondly, the samples are nitridized respectively at 300℃ 400 ℃ 460℃ and characterized by multiform test methods, then we bring forward the principium of low temperature nitriding. Lastly, we study the frictional wear character of nitriding samples using friction wear testing machine WWM-1. As a result, the friction factors of the samples after nitriding fall down and the wear extent decrease comparing with that of original samples. It is obvious that the low temperature nitriding process improve the abrasion-resistance of metal materials.