Papers by Author: Pei Jie Yan

Abstract: Roll forming is a 3D deformation complex process. Stiffness of stands and strength of shafts are the preconditions for the production of precision products. However, the existing roll forming equipment cannot meet the requirements of the production for high strength steel or ultra high strength steel. In order to solve the forming problem of high strength steel or ultra high strength steel, it needs to redesign a set of roll forming equipment. The redesign of roll forming equipment not only makes the production cycle too long, but also results in a high cost. So it is not suitable for the production of forming products. In this paper, based on the existing roll forming equipment a new method of roll forming operation is proposed to optimize the production of U shaped products. The influences of the new method on the roll forming products such as mechanical properties, microstructures and surface qualities, have also been discussed, Based on the new warm roll forming operation, numerical simulation has also been carried out. The simulation result of geometry is in good agreement with experimental result.

Abstract: In recent years, the number of automobiles has been steadily increasing, which has significantly impacted on the society and human life, and led to many social problems such as fuel crisis, environment pollution. Therefore, lightweight designing becomes a focused issue. Lightweight materials application, optimized structure design and advanced manufacturing process are the main ways to achieve the lightweight. However, low plasticity and ductility of high strength steel constrain the application of high strength steel. In this paper, the basic principle of roll forming for automotive parts is investigated, and it is innovatively applied in the hot roll forming process of the ultra high strength steel.

Abstract: In this paper, the extrusion process of bimetallic tubes is discussed, and the extrusion pressure is calculated based on the method of energy conservation, according to the three categories of metal flow that may occur during the process. A number of parameters, geometry of bimetallic tube, mechanical properties of material components and friction conditions, are highlighted in this analytical method. Compared with the data of TP304l/20G bimetallic tubes which were extruded at 1100-1200 °C, the calculated results show a good agreement with the industrial results, with the error less than 10 %. It also proves that the friction between the two layers play an important role in the process.