Effects Of Ce On The Microstructure And Properties Of 202 Stainless Steel

200 series stainless steel is a kind of austenitic stainless steel using Mn and N instead of part of Ni, 202 stainless steel is representative one of them, widely used in consumer products. Trace RE-Ce is added to the steel to study effects of rare earth on microstructure and properties of 202 stainless steel, which is important to the social and economic sustainable development.In this dissertation, effects of RE-Ce on microstructures and properties of 202 stainless steel that are systematically studied through metallographic, electrochemical measurement, SEM, EDS and mechanical performance testing, etc. Through different RE-Ce content of 202 stainless steel in 5% H₂SO₄ solution and 3.5% NaCl solution for different period of electrochemical corrosion experiments and the room temperature tensile test, the results are as follows:Adding RE-Ce can restrain the growth of grain which can refine grain size, and with increase of the rare earth content in steel, the refining effect more visible. Grain boundary is purified and the shape of inclusions is changed after RE-Ce is added to 202 stainless steel, at the same time the size and quantity of inclusions are effective controlled. But when there is too much RE-Ce in steel, it will produce a large number of rare earth inclusions, which reduces the corrosion resistance and mechanical properties of 202 stainless steel.With increase of the rare earth content in steel, the corrosion resistance of 202 stainless steel improves gradually. But when the rare earth content is more than 0.016% in steel, the corrosion resistance of 202 stainless steel slightly decrease. 202 stainless steel with RE-Ce element of 0.016 % in mass fraction has the best corrosion resistance.The strength and ductility of 202 stainless steel are obviously improved, due to the addition of proper amount of RE-Ce can effectively refine grain size,modify inclusions and purify grain boundary. 202 stainless steel with RE-Ce element of 0.016% in mass fraction has the best comprehensive mechanical properties.