Increase in ironing limit of stainless steel cups with lubricants containing ceramic particles

The seizure resistance in the ironing process of stainless steel cups was improved with lubricants containing Al2O3 particles, and the ironing limit of the cups was increased. The effects of suspending different concentrations of Al2O3 particles in paraffin based oils on increasing the ironing limit of SUS430 cylindrical cups before seizure were investigated using a lapped tungsten carbide die. By containing c = 2vol% of Al2O3 particles having nominal diameter d between 0.02 to 4 micrometres in an oil with a kinematic viscosity of 500 mm2/s, the ironing limit of the cup was 8% under a punch speed of 100 mm2/s. The limit was similar to the limit using a commercial low-viscosity oil with chlorine additive. The kinematic viscosity of the base oil was reduced. In d = 0.2 μm and c = 0.5vol%, the limit of the oil more than kinematic viscosity of 180 mm2/s was similar to the limit by the commercial oil. In d = 4 μm and c = 1vol%, the limit of the oil having more than kinematic viscosity of 100 mm2/s was effective. It was found that the seizure resistance in the ironing process was improved by the proper ironing conditions with lubricants containing particles.