| As load-carrying component, oil-film bearing is widely used in metallurgy,aerospace, mining and other large equipment. Babbitt alloy in bushing is theeasiest damage part in oil-film bearing. Babbitt alloy has good wear-resistance,and it belongs to low melting point alloy. The obvious creep phenomenon isproduced in the working process of alloy, which will produce negative effectthat cannot be ignored for the working performance of oil-film bearing. Themethod and specific content of study were determined based on metal creeptheory. Creep characteristics and creep life of Babbitt alloy SnSb11Cu6ofoil-film bearing were systematically researched, and the main research contentsare as follows:Firstly, creep test standards at home and abroad were contrastively analyzed.Creep test equipment of SnSb11Cu6was designed, which satisfied therequirement of creep test standard. The specific operation procedures were putforward. Test method of SnSb11Cu6creep was studied, which confirmed thatthe arrival time of steady-state creep stage was shorten by increasing the heatingtime, heat preservation time and loading rate, decreasing the initial force. Thetest period was reduced by73%. At the same time, the test results showed thatobvious creep phenomenon of SnSb11Cu6will happen under the workingconditions of oil-film bearing. Creep mechanic performances of SnSb11Cu6were acquired; stress had the greatest influence on the creep strain andsteady-state creep rate of alloy; temperature had the greatest influence on theduration of decelerating creep stage of alloy.Secondly, based on creep test data, the accuracies of four kinds of creepmodels were contrastively analyzed. SnSb11Cu6creep model based on McVettyand Dorn formula used to calculate SnSb11Cu6creep had the highest accuracy.The relative error of steady-state creep stage was only1.64%. At the same time, two kinds of steady-state creep constitutive equations based on Dom theory andconstant speed theory were respectively established by using creep test data. Thetest results showed that the steady-state creep constitutive equation based onDom formula had higher accuracy, and its relative error was only1.52%.And then, the relations of creep, mechanical performances and microstructurewere analyzed by creep test, tensile test, hardness experiment andmetallographic experiment. Test results showed that the strength, plasticity andelastic deformation resistance of SnSb11Cu6were obviously reduced by creep.What is more, the creep mechanism of SnSb11Cu6was obtained, whichindicated that the creep deformation of SnSb11Cu6was the result of long-timealternative reactions of strain-hardening and recrystallization reply. Thecalculation formula of change of alloy hardness with the temperature wasacquired by hardness experiment of SnSb11Cu6. The critical temperature ofSnSb11Cu6creep was determined to be within50~60℃. The analysis methodof Babbitt creep based on ANSYS was put forward, and creep of test specimenwas calculated by ANSYS. Accuracies of three typical implicit creep modelswere contrastively analyzed, and model11(time-hardening implicit creep model)describing creep property of Babbitt had the highest accuracy; the relative errorof steady-state creep stage was only2.6%. The calculated results of ANSYS andSnSb11Cu6creep model were contrastively analyzed, and SnSb11Cu6creepmodel had higher accuracy.Finally, creep life calculation model of SnSb11Cu6of oil-film bearing basedon its steady-state creep constitutive equation was established. According to themeasurements of resistivity and hardness of alloy after creep, the evaluationmodel of creep life of SnSb11Cu6based on the resistivity was established, andone method measuring resistivity of alloy to evaluate the service life of bearingwas put forward. In addition, the software about creep life prediction of Babbittalloy of oil-film bearing based on the creep life calculation model was compiled, which provided some technical support for prolonging the service life of oil-filmbearing. |
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