A methodology for roll pass optimization for multi-pass shape rolling

Abstract

Improper roll pass designs can lead to either underfill, which results in the formation of hairline cracks on the surface of the finished bars, or overfill, which results in roll overloading and the formation of fins. Therefore, to reduce downtime and improve yields, it becomes important to design an acceptable roll pass in reasonable time. This paper presents a methodology for roll pass optimization (improvement of pass design). This methodology uses three-dimensional finite element simulation along with empirical procedures to arrive at an iterative scheme for reducing the number of passes and improving metal flow in the passes. This methodology is applied to improving an existing seven pass square-to-round sequence resulting in reduced number of passes, and improved reduction in area and distributions of effective strains in the rolled product.