| As the speed and load of train increase,the wear of wheel and rail continues to increase.By using the top of rail friction modifier,the friction coefficient between the wheel and the rail is controlled within an appropriate range,which plays a role in alleviating wheel and rail wear,reducing noise,and improving driving safety.Due to the many performance indicators of friction modifier,it is difficult to take into account multiple properties when optimizing the formula.As a result,the existing friction modifiers have problems such as poor mechanical properties,excessive friction coefficient,and large amounts of wear.In this research,an innovative method of mathematical formula is built to optimize the formula,which can achieve the effect of considering multiple performance indicators,thereby preparing the top of rail friction modifier with excellent comprehensive performance.1.The effects of four kinds of phenolic resins on the mechanical,friction and wear properties of friction modifier were studied,and the thermal properties of the four resins were tested.By analyzing and comparing the comprehensive performance of different resins,6816 phenolic resin was determined as the adhesive of friction modifier.2.When using 6816 phenolic resin as the adhesive,the effects of titanium dioxide,potassium feldspar,garnet,zircon sand,alumina and silicon carbide on the mechanical,friction and wear properties of friction modifier were studied.By analyzing and comparing the comprehensive performance of the above materials,zircon sand was determined as the friction enhancing agent of friction modifier.3.When using 6816 phenolic resin as the adhesive and zircon sand as the friction enhancing agent,the effects of carbon fiber content and the ratio of carbon fiber to aramid fiber on the mechanical,friction and wear properties of the friction modifier were explored.The results show that it has a great reinforcement effect when the content of carbon fiber is 4 wt%～6 wt%.When carbon fiber and aramid fiber are used as the composite fiber,the reinforcement effect is better than the same amount of single fiber.The friction modifier has excellent comprehensive performance when the ratio of carbon fiber to aramid fiber is 3:1.4.Uniform design was used to explore the effects of the contents of 6816 phenolic resin,zircon sand and carbon fiber/aramid fiber on the mechanical,friction and wear,noise reduction properties of friction modifier.The data processing system was used to establish a regression equation between the content of each component and performance of the friction modifier,and the formula was optimized by MATLAB.The results show that when the content of 6816 phenolic resin is 18.2 wt%,the content of zircon sand is 14.8 wt%,the content of carbon fiber is 5.25 wt%,and the content of aramid fiber is 1.75 wt%,the friction modifier has excellent comprehensive performance.The results of performance test show that: the shore hardness is 72,the compressive strength is 26.76 MPa,the flexural strength is 25.42 MPa,the friction coefficient is 0.336,the amount of wear is 13.32 mg,and the noise of friction is reduced by 8.1 d B.5.Orthogonal design was used to explore the effects of molding temperature,pressure and time on the mechanical properties,friction and wear properties,noise reduction properties of the friction modifier.The results show that the comprehensive performance of the friction modifier is excellent when the molding temperature is160°C,the molding pressure is 6 MPa,and the molding time is 2 h.The results of performance test show that: the shore hardness is 77,the compressive strength is 28.46 MPa,the flexural strength is 26.58 MPa,the friction coefficient is 0.346,the amount of wear is 12.26 mg,and the noise of friction is reduced by 9.6 d B.The result of super wide depth of field test shows the friction modifier forms a solid friction control film with an average thickness of 4.9 μm on the surface of the steel disk. |
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