Modeling of on-line measurement for rolling the rings with blank size errors in vertical hot ring rolling process

The size errors of the ring blanks have a considerable effect on the vertical hot ring rolling process and the ring products’ dimensional precision. In this paper, the geometric relationship between the ring’s outer diameter and the measuring roll’s displacement is studied, and then, the influence of the blank size errors on this geometric relationship is analyzed. Subsequently, a modeling method of the measurement model for vertical hot ring rolling process is proposed, that is, the ring’s outer diameter can be measured indirectly through the relations of the ring’s outer diameter with respect to the measuring roll’s displacement and the ring blank’s outer diameter. Using this modeling method, the on-line measurement model of a certain type of vertical hot ring rolling mill was established, and the verification experiments were also conducted. The experiments showed that this on-line measurement model could calculate the ring’s outer diameter precisely, and the absolute errors of the formed rings were less than ±1.5 mm. The research results of this paper have general significance for the on-line measurement and process control of vertical hot ring rolling process.