EFFECT OF ROLL MATERIALS ON LUBRICITY IN COLD-ROLLING

The effect of rolls made of various tool steels on the lubrication cha racteristics are examined by rolling annealed low carbon steels by mea ns of the simulation testing machine developed by one of the authors. The lubricity is evaluated by measuring the coefficient of friction fo r each test and the antiseizure property of rolls is evaluated by the observation of surfaces of rolled workpieces and rolls which are rolle d under various conditions of rolling speed and reduction in thickness . The experimental results on the anti-seizure property are discussed based on the calculation of temperature at the interface between roll and workpiece and based on the: observation of appearance of friction pick up on surface of rolls. The conclusion obtained are as follows. ( 1)The difference of coefficient of friction among roil materials is sm all. (2)Anti-seizure property depends on the carbide content of roll m aterial and it can be quantitatively evaluated by the calculated inter facial temperature. (3)Carbides on roll surface are effective for fric tion pick up.