Friction And Wear Behaviors Of Different Friction Pairs Of45Steel And TC4in Magnetic Field

Reducing friction and wear is always the common pursuit of engineers andtechnicians. With the continuous development of magnetic technology, more and moreelectric and electromagnetic comments needs to run in the magnetic field, it’snecessary to study the dry friction characteristics of metal materials.Based on the ferromagnetic material45steel and paramagnetic material TC4titanium alloy as the main object, the influence of magnetic field intensity, load andsliding speed on the dry friction of magnetic pair45steel/45steel, TC4/TC4,45steelpin/TC4ring, TC4pin/45steel ring were investigated on improved MPV-1500pin/ringtribometer under magnetic field in this paper. By using Scanning Electron Microscope(SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and otherinstruments, the worn surface and internal microstructure were analyzed. The mainresearch works in this paper are as follows:The tribological properties of these friction pairs have been investigated underdifferent magnetic field intensity, load and sliding velocity. The results show that: afterapplying the magnetic field, for the pair of ferromagnetic materials, both the wear rateand the friction coefficient decreased, which shows that the magnetic field can improvethe abrasive resistance of ferromagnetic materials; for paramagnetic pairs orparamagnetic/magnetic pairs, both the wear rate and the friction coefficient increasedslightly, this indicates that the magnetic field can exacerbate the wear of friction pairswith paramagnetic materials.By microscopic analysis the worn surface of the pin specimens, it’s found that theworn surface of ferromagnetic materials have absorbed more wear debris, whichinsolated the direct contact of friction surface and reduced the friction and wear, whilethe paramagnetic materials didn’t. Besides, the obviously increasing of the oxygencontent of the worn surface and the wear debris of45steel shows that the magneticfield could also promote the oxidation of ferromagnetic materials, thus the proportion of oxidative wear was increased while the adhesion wear was decreased, which meansthe friction and wear of ferromagnetic materials was modified; for paramagneticmaterials, the oxidation is not obvious with the magnetic field, the abrasive wear andthe adhesion wear were still the main mechanisms.By observing the subsurface microstructure of ferromagnetic pairs, the motion ofthe internal dislocation defect increased in the magnetized45steel. The increase ofdislocation density improved the strength and the abrasive resistance of materialsindirectly.The influence of magnetic field on different magnetic properties materials frictionpairs was studied in this paper, compared with other friction pairs, the frictioncoefficient and wear rate variation tendency of45steel pairs under the condition ofmagnetic is the largest, meaning that the magnetic field improved the wear resistanceof45steel significantly; for the paramagnetic materials, the increase of the friction andwear is not obvious.