A sensor was designed, manufactured, calibrated and tested with the objective of measuring the stresses in the roll gap during cold rolling of aluminum billets. The sensor geometry is a circular diaphragm, continuous with the roll surface, supported by a square post. The post was instrumented with metal foil strain gauges to measure normal and bending stresses. The sensor was embedded in the face of an 8-inch diameter roll in a two-high experimental rolling mill, instrumented to measure the driving torque to the instrumented roll and the roll separating force. Nominal reductions of 17.5% to 32.9% were performed to correlate sensor response with nominal reduction. The performance of the sensor as a normal-force-distribution measuring tool was satisfactory with the exception of spatial resolution problems. The performance of the sensor as a shear-force measuring tool was unsatisfactory. The bending stress signal from the sensor in the direction of rolling was found to be highly sensitive to the gradient and offset of the normal force. Two compensation procedures to subtract the effect of the normal force's gradient and offset from the rolling bending signal were performed but were unsuccessful in extracting consistent shear force data. The size of the sensor relative to the roll gap was considered to be a central reason for the sensitivity to offset and gradient effects. Recommendations for future designs are presented.
展开▼
