Examination of a Composite Ring Rolling Process with Different Wall Thicknesses to Produce a Ring of 1.7225 and 1.4462 in FEM and Experiment

The ring rolling process offers the possibility of producing seamless rings. For certain applications, it would be advantageous for cost reasons to produce rings with different materials at the area of the inner and outer circumference. Composite ring rolling, the combination of ring rolling and roll bonding, enables the production of such rings. In this study, a composite ring made of stainless steel (inside) and quenched and tempered steel (outside) is investigated to reduce the proportion of expensive stainless steel in the overall component. The ratio of wall thicknesses of the rings s_OR (outer ring)/s_IR (inner ring) was varied in simulations. The simulation shows permanent contact between ring sections for a wall thickness ratio of s_OR/s_IR > 3, which is a pre-condition for a successful bonding. When these ratios are applied, a given absolute reduction leads to higher relative wall thickness reductions of the inner ring, since the given absolute reduction meets a smaller wall thickness of the inner ring at the roll gap entrance. The higher relative reductions of the inner ring then lead to a faster diameter growth of the inner ring during rolling. According to the simulation, the most promising wall thickness ratio was then investigated in the experiment. In addition, the effect of axial rolling was reproduced in the simulation and investigated in the experiment. The results show that a successful composite ring rolling process is supported by a high wall thickness ratio in combination with a low or without an axial reduction.