Finite element modelling of chain-die forming for ultra-high strength steel

• Main Authors: Majji, Raju, Xiang, Yang, Ding, Scott, Yang, Chunhui
• Format: Conference Proceeding
• Language: English
• Subjects: Automobiles; Chains; Cold rolling; Computer simulation; Deformation effects; Design analysis; Design optimization; Die forming; Dies; Finite element method; Fuel consumption; High strength steel; High strength steels; Mathematical models; Measuring instruments; Metal forming; Metal sheets; Passenger safety; Residual stress; Roll forming; Springback; Weight reduction
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5008088

There has been a high demand for weight reduction in automotive vehicles while maintaining passenger safety. A potential steel material to achieve this is Ultra High Strength Steel (UHSS). As a high strength material, it is difficult to be formed with desired profiles using traditional sheet metal forming processes such as Cold Roll Forming. To overcome this problem, a potentially alternative solution is Chain-die Forming (CDF), recently developed. The basic principal of the CDF is to fully combine roll forming and bending processes. The main advantage of this process is the elongated deformation length that significantly increases effective roll radius. This study focuses on identifying issues with the CDF by using CAD modelling, Motion Analysis and Finite Element Analysis (FEA) to devise solutions and construct a more reliable process in an optimal design sense. Some attempts on finite element modelling and simulation of the CDF were conducted using relatively simple models in literature and the research was still not sufficient enough for optimal design of a typical CDF for UHSS. Therefore two numerical models of Chain-die Forming process are developed in this study, including a) one having a set of rolls similar to roll forming but with a large radius, i.e., 20 meters; and b) the other one with dies and punch segments similar to a typical CDF machine. As a case study, to form a 60° channel with single pass was conducted using these two devised models for a comparison. The obtained numerical results clearly show the CDF could generate less residual stress, low strain and small springback of a single pass for the 60° UHSS channel. The design analysis procedure proposed in this study could greatly help the mechanical designers to devise a cost-effective and reliable CDF process for forming UHSS.