Limits to making L-shape ring profiles without ring growth

A novel ring rolling process is proposed to flexibly produce shaped rings without circumferential growth, potentially saving material and energy as well reducing upstream downstream processing requirements. In this paper, six constraint rolls are used constrain growth enable L-shape profiles be developed through axial flow, via a compressive hoop stress. Process limits were studied in 22 experiments on lead set of axisymmetric thermally coupled simulations high value engineering material, Inconel 718. Profile depths 75 % the original wall thickness achieved range operating conditions, savings up 60 demonstrated over rectilinear rolling. There was no evidence cracking or void formation, unlike processes where under-deformed regions stretched circumferentially vulnerable cracking. several cases non-circular shape developed, limiting achievable profile depth especially for small thicknesses, large reductions per pass, heights. The roll forces when ‘collapse’ occurs an upper bound predicted by plastic hinge model. thermal showed that all except 4 reheats would required keep within safe temperature bounds, thus suggesting optimum reduction pass avoid both excessive cooling collapse.