Micro-alloy Axle Steel Microstructure And Properties

Axle which quality directly affects the safety of railway transport is the train of the key components. therefore,the axle steel must is very good in both strength and toughness.In order to make the strength of steel axle than the typical high-LZ50 steel with not reduce the plastic and ductile, the paper proposed the microalloyed of the alex.The summary introduced the production status of the axle in china and the development of the materials for axle steel in domestic and foreign.And investigated the affect of alloying elements and the alloying principle of V,Cr.Basised the design theory of micro-alloy steel, the paper designed chemical composition for the new axle steel. With existing test equipment of Panzhihua Iron and Steel Institute,it analysised structure, mechanical properties and corrosion resistance to axle steel.The results show that the mechanical properties of micro-alloy axle steel is controlled mainly by the C content in the steel. But V and Cr also improved well the mechanical properties of axle steel. When the carbon content is about 0.41%,the 57.1%～58.3% of V would separate out'in the form of V(C,N). The precipitation strengthening of V is fully reflected increaseing the strength of axle steel. When the-content of V increase 0.01%,the yield strength increased 17 Mpa and tensile strength 11MPa. Compared with LZ50 steel on mechanical properties,it is found that increaseing the content of V and Cr can get strength which lost as reduced the carbon content. In short, the the new axle steel is passable.The grain size level of axle steel can be more than 8.0 as V alloying,which also affects the content,morphology and spacing of pearlite., As V reacts with the C, when the content of V increases, the pearlite is increased,the shape of cementite appeared wave and the spacing of pearlite became thiner.After salt spray tested for 72h,the corrosion rate of the micro-alloy axle steel is lower than LZ50 steel,but little difference.