Study On The Effect Of Friction And Wear Properties Of Hot Formed High Strength Steel On Die Steel

H13 is the most common die steel used in automobile industry at present.The service life of die is very important for automobile enterprises to reduce costs and win competition.At present the main materials used of body are relatively mature hot stamping of boron steel,at the same time,the third generation of high strength steel for automobile has broad application prospect because of its excellent performance.after a long-term exploration of its organization adjustment,at present,the research on its forming properties has been carried out step by step.In the actual process of hot stamping molding,it is of great practical value to explore the influence of high-strength steel's high-temperature friction and wear properties on the die steel life.In this paper,HT-1000 high-temperature friction and wear testing machine is used to conduct high-temperature friction and wear tests on H13 die steel and different high-strength steel,The high-temperature friction and wear properties of different high-strength steels and H13 die steels were compared by analyzing the change rule of high-temperature friction coefficient of different materials and H13 die steels with different test temperatures over time and the change rule of average friction coefficient with test temperature.By observing the white light interference point cloud mathematical model and local wear morphology mathematical model of confocal microscopy system of die steel,the wear mechanism at different temperatures was analyzed,and the wear rate was calculated and analyzed.The following conclusions:(1)Analyzed the first 8 min friction coefficient variation law with time,with the increase of test temperature,coefficient of friction values by sharp fluctuations in the runningin stage has a tendency to shorten the period of time to the stable wear stage,combining with the calculation results of wear rate and its change with temperature curve analysis,this is because in the higher test temperatures,the wear is more intense,the friction pair surface grinding faster to relatively smooth state,thus entered into a state of stable wear much earlier.(2)Analysis of the average friction coefficient with the temperature change rule,in the test temperature overlap region,namely between 550 ? ~ 800 ?,the three kinds of material and H13 die steel high temperature friction coefficient difference is not big,the hightemperature friction coefficient between the three materials and H13 die steel decreased with the increase of temperature.Medium manganese steel's optimum forming temperature is 550 ?,two kinds of boron steel's optimum forming temperature is 800 ?,near the optimum forming temperature range,namely the medium manganese steel at 500 ? ~ 600 ?,two kinds of boron steel at 700 ? ~ 900 ?,Compared with the high temperature friction coefficient of H13 die steel,the high temperature friction coefficient of medium manganese steel is relatively high,but its value is stable around 0.7,and the difference is not more than 0.04.It can be speculated that the wear mechanism is consistent within this temperature range,and the wear is relatively stable.And two kinds of boron steel from the initial molding temperature 900 ? to the end of the forming temperature 700 ?,The friction coefficient of high temperature is generally low,but its variation range is large,so it is speculated that there may be a change in the form of wear within this temperature range,that is,abrasive wear mainly gradually to adhesive wear as the dominant.(3)On the whole,medium manganese steel has the lowest wear rate to H13 die steel,followed by boron steel with aluminum silicon coated,and boron steel without coating has the highest wear rate to H13 die steel,and correspondingly,medium manganese steel has the highest die life when forming;Meanwhile,on the whole,the wear rate of the three materials on H13 die steel increases with the increase of forming temperature.Manganese steel test curve there was a sharp point at 600 ?,analysis reason that is the main wear form under the forming temperature shift,abrasive wear and adhesive wear are both severe in this temperature lead to the total wear rate is higher.As the test temperature increases,the surface hardness and shear limit of the material decrease,resulting in a gradual increase in the wear rate,and at the same time,the friction resistance decreases gradually because the surface of the material is more easily damaged.