Below is a list of Seamless Rolled Rings manufacturers from St. Johns, Michigan. Seamless rolled rings are forgings formed from a single "donut"-shaped block of metal by the application of horizontal and vertical pressure. Seamless ring-rolling is a unique type of metal forging that produces seamless metal rings with great tensile strength and structural integrity. Seamless rings may be forged into a wide range of dimensions, from small bearing housings to wind turbine slewing rings.