Hi-Tech Engineering srl (Turin, Italy):

Motetti M., Eng., Techn. Manager, e-mail: hi-forni@hitecheng.com

Large-diameter rings and their increasing market are affected by this enemy: 2 million € for each millimeter of lost steel during the operation that is necessary because of the unusual deformation of the rings. The survey of all means of control of the deformation is the imperative duty for the survival of this product category. This article explains the causes of the deformation and the technical and financial impact of this phenomenon. Its main scope is to illustrate the major differences and plant engineering techniques aimed to reduce these “wastes” due to deformations. The heat treatment process, most of all handling and quenching operations, produces important deformations that should be predicted. The anticipation of these phenomena allows keeping the piece inside the interval of the preset dimensional tolerances for the important technological and economic reasons described in the preliminary remarks. The causes of the deformations may be a lot: the ability to go back to them, to prevent them and to limit their development, represents today’s real challenge of the main producers. Moreover, the predictability represents an arm that brings to the resolution of this serious industrial handicap, through the design and the use of plant engineering techniques suitable to face an enemy that may remain invisible till after the heat treatment. In conclusion, this article’s aim has been to outline this topic and partially show the set of problems together with the possible solution systems of a natural defect, partially overcoming thanks to the latest technologies and to dedicated metallurgical technical precautions.