The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed.In this investigation,the tribological performance of four base oils with differ...The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed.In this investigation,the tribological performance of four base oils with different chemical structures(paraffinic and naphthenic)and viscosities(2 and 20 cSt),as well as water,was evaluated for the stamping of steel sheets and compared with a non-lubricated contact.Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts.Low-viscosity(LV)naphthenic oil performs very like both high-viscosity(HV)oils.A surprising exception is the LV paraffinic oil,with several-times-higher friction and wear compared to dry contact.This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low,leading to lubricant starvation.In contrast,HV oils provide a sufficiently thick lubricating film,while strong cohesive forces help in the film’s strength,lessening wear,and reducing friction.In thin-film lubrication with LV oils,such as when stamping,it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation,thus ensuring lower friction,less wear,and a longer lifetime of the contact.展开更多
基金supported by the company Hidria Rotomatika d.o.o and Slovenian Research Agency as part of research project No.L2-9244 and research core funding No.P2-0231.
文摘The requirements for green and sustainable manufacturing mean that stamping lubricants must be continuously re-evaluated and re-designed.In this investigation,the tribological performance of four base oils with different chemical structures(paraffinic and naphthenic)and viscosities(2 and 20 cSt),as well as water,was evaluated for the stamping of steel sheets and compared with a non-lubricated contact.Most lubricants reduce the coefficient of friction and maintain a similar wear coefficient for steel sheets as in dry contacts.Low-viscosity(LV)naphthenic oil performs very like both high-viscosity(HV)oils.A surprising exception is the LV paraffinic oil,with several-times-higher friction and wear compared to dry contact.This is due to the excellent wetting-spreading and very low cohesion forces that enable oil to escape from extremely thin-film contacts because the viscosity is so low,leading to lubricant starvation.In contrast,HV oils provide a sufficiently thick lubricating film,while strong cohesive forces help in the film’s strength,lessening wear,and reducing friction.In thin-film lubrication with LV oils,such as when stamping,it is thus extremely important that the lubricant’s wetting behaviour and viscosity are sufficient to provide enough film in the contact and prevent starvation,thus ensuring lower friction,less wear,and a longer lifetime of the contact.
