Research On Material Composition Optimization Of Coupler

Automatic coupler casting material that Qiqihar railway rolling stockcompany export to Mongolia is ZG25MnCrNiMo. This component containsprecious metal elements, such as Cr, Ni, Mo. With the development of our countyeconomy, the price of precious metal materials is rising, it leads to higher cost onsteel than before. The components need to be optimized to reduce the cost as wellas guarantee the performance of stabilization.Based on the ZG25MnCrNiMo, chemical constituents are determined bycontrast test. Plasticity, toughness, fracture surface of low-temperature andmetallographic structure are analyzed by tensile testing machine, impact testingmachine, brinell hardness tester, metallographic microscope and SEM. Thecoupler composition is optimized after test steel microstructure and properties ofdifferent Ni, Mo, RE, C and Cr content.The result shows that: whether containing the Ni element or not, all themechanical property of samples satisfy mechanical property index of couliematerial. It indicates that the Ni element can be cancelled. When adding0.1%-0.2%Mo element, samples’ properties can meet the requirements of the materialon the mechanical properties of the coupler. Addition of RE element can improvethe morphology of inclusions in molten steel and can significantly improve themechanical properties of samples. When the C content exceeds0.26%, all themechanical property of samples Satisfy mechanical property index of couliematerial. When the Cr element is added, without adding Ni and Mo elements, theperformance of the specimens is difficult to meet the index requirements ofcoupler on mechanical properties of materials. Only the Cr content of0.7%samples just can satisfy the mechanical properties of the material requirements ofcoupler. Under the condition of this experiment, the optimum composition rangeof elements can be determined: C:0.26%-0.31%; Cr:0.40%-0.60%; Mo:0.10%- 0.20%.Through repeated test in the laboratory, the results show that: In the absenceof RE modification conditions, All components of the samples are upper, Themechanical properties of specimens meet mechanical performance index ofcoupler material. new chemical composition: C:0.26%-0.30; Si:0.30%-0.50%;Mn:1.10%-1.40%; Cr:0.40%-0.60%; Mo:0.15%-0.25%.