Ring forgings using ring processing is the use of ring machine (also known as ring mill, ring mill, hole expansion machine) to make the ring parts produce continuous local plastic deformation, and then achieve wall thickness reduction, diameter expansion, cross-sectional profile forming plastic processing process. The stress strain and deformation flow during pressure expansion are the same as about core shaft opening.
It is characterized by: the tool is rotating, deformation is continuous, that is, the ring blank rolling. When the pressure is expanded, the amount of pressure is generally small, so it has the characteristics of surface deformation.
The ring is a continuous local plastic formation process, is the cross-combination of rolling technology and machinery manufacturing technology, compared with the traditional free forging process, die forging process, etc., has significant technical and economic characteristics.
Ring forgings are mainly enlarged by horse bar during free forging. The stress strain of the horse bar expansion hole is approximately long, and the long shaft pull length is different, it is the ring forging blank along the circular direction of the pull length, is local loading, the overall force.
The metal in the deformation zone flows in the direction of tangent and width when the horse bar is enlarged. When the horse bar is enlarged, the metal of the deformation area mainly flows along the tangent, and the internal and outer diameters are increased.
The forgings that widen holes on the horse bar are generally thinner, so the metal cut to the outer deformation area is far from the direction of the resistance width, and the contact surface of the horse bar and the ring forging is curved, which is conducive to the metal flowing along the tangent.
Therefore, the change of forging size when the horse bar widens is the wall thickness reduction, the inner and outer diameter is enlarged, and the width (height) direction is slightly increased. Therefore, in small batches, small ring parts, the selection of horse bar on the widening hole is more suitable for forging ring.