BIMETAL FOR MAKING COINS AND METHOD OF FABRICATING IT Russian patent published in 1997 - IPC

FIELD: group of inventions is asserted in range of plastic metal working, namely, for production of bimetallic strips and coin fabrication. SUBSTANCE: coat material is in the form of two bands of copper-nickel alloy containing 4-26% of nickel. Total thickness of both copper-nickel bands in cladding layers consists 14-40% of steel base thickness. Summed deformation degree of pack including steel band and two copper-nickel bands at process of cladding and cold rolling to endless bimetallic strip is selected in range 3.5-5. Temperature of roller piece at output of deformation zone at cladding is sustained 165-265 C. Mixture of mineral oil (20-32%) and kerosene (the balance) is used as lubricant at cladding process. Said lubricant has kinematic viscosity at 100 C no less than 10 and acid number not more than 0.003. Rolled belt is cooled to temperature lower than 60 C; annealing is performed at temperature of metal 650-700 C for 620-660 min at subsequent cooling in furnace to 140 C and lower. Group of inventions provides set of factors with sufficiently high efficiency to realize new manufacturing process of fabricating coins of bimetal. EFFECT: enhanced efficiency. 2 cl