The rolling process for rings with island bosses on outer surface

Abstract

Most research objects of ring rolling process are axisymmetric ring forgings. With the increasing requirements for energy efficiencies and material savings in the industry, the demand for the type of non-axisymmetric rings is becoming increasingly urgent. In response to this demand, the research proposed a new rolling process by adding a constraint die set in conventional ring rolling machine for the Rings with Island Bosses on Outer Surface. This process includes two stages: 1) the diameter growth stage, ring blank is first rolled between die and mandrel until the outer surface of ring contact around at the inner surface of die; 2) the boss growth stage, the material is gradually extruded into the holes on the inner surface of die. Finite element simulation and physical experiments were carried out to confirm that the proposed rolling process was practicable on conventional rolling machine. By design of experiment of this process, folding and shrinkage defects were studied to determine the range of rolling process parameters. The factors, such as shape, area and fillet radius of boss, ring wall thickness and friction, which affect height of boss in boss growth stage, were investigated. The proposed rolling process is practicable for the Rings with Island Bosses on Outer Surface.