A review on straightening of bars and application of probabilistic approach on Moment-curvature relationship

Abstract

Bar straightening is a significant process in the value stream of bar manufacturing processes. Any improvement in the process has a substantial impact on quality and productivity as a whole. This paper presents the outline of the fundamentals of the straightening process from a material science perspective and discusses the state of art in terms of process analysis and development. It has been inferred that the major aspect of the process is to understand the moment-curvature relationship in bars subjected to re-rolling. The process is governed by several parameters such as bar speed, the angle between osculating plane and loading plane, bar size or radius of bar, applied reverse bending moment, initial and final curvature, etc. It has also been observed that the research in this domain has seldom applied a statistical approach to enhance process capability. A brief account of the potential use of statistical process control has been presented. Use of statistics shall enable a better understanding of various process parameters. This, in turn, will help in deciding whether the process is in control and therein to assist in deciding the acceptance or rejection of lot.