Papers by Keyword: Pass Schedule

Abstract: A fast optimization approach is demonstrated for design optimization of the multi-pass wire drawing process with the multi-objective genetic algorithm, and with the aims at minimizing both power consumption and temperature, via optimizing the process parameters involving pass number, pass schedule, die angle, bearing length and loops on capstan etc. A jump fitness function and a penalty fitness function are proposed for the survival of good designs and killing the bad designs which temperature, die wear factor, delta factor, or ratio of drawing stress to yield stress exceed the limits during optimization. The numerical examples show that the optimizer with the penalty fitness function, when its parameter n ranges from 1 to 2, presents the best performance in finding the minimum power consumption with a limit in temperature. Compared with a reference design, a significant reduction in the total power consumption about 300W, with the well control in temperature, delta factor and die life, has been achieved by the optimization. The penalty fitness function presents the better performance in the reduction of the iteration generations and computational cost to the jump fitness function.

Abstract: In this paper, pass schedule calculation method for single-stand reversing cold rolling mill is introduced. Newton－Rapshon method is used to solve non-linear equations composed of each pass loads according to equal power rolling strategy. After the thickness of each pass is calculated, rolling parameters of each pass is obtained by modification. Based on the method pass schedule calculation procedure is developed. The practical application shows that calculation result of program is close to the actual data, and the speed and stability of the procedure can meet the requirement of on-line process control, so it is suitable for the single-stand reversible cold rolling mill.

Abstract: Although forming of porous metal is demanded for industrial applications, the deformation characteristics have not been investigated sufficiently. In this study, lotus-type porous copper is processed by multi-pass cold rolling. At the early stage of rolling, the elongation of the porous copper in the rolling direction is small, and the porosity decreases almost linearly with the total reduction in thickness. It is found that pass schedule with small rolls and with small reduction per pass is effective to suppress pore closure. Hardness of the porous copper increases almost linearly with total reduction. If the effective total reduction is considered, the hardness change is similar to that of a nonporous copper.

Abstract: High speed multi pass wet wire drawing has become very common for production of high carbon steel cord because of the increase in customer demand and production rates in real industrial fields. Although the wet wire drawing is preformed at a high speed usually above 1000 m/min, greater speed is required to improve productivity. However, in the high carbon steel wire drawing, the wire temperature rises greatly as the drawing speed increase. The excessive temperature rise makes the wire more brittle and finally leads to wire breaks. In this study, the variations in wire temperature during wet wire drawing process were investigated. A multi pass wet wire drawing process with 21 passes, which was used to produce steel cord, was redesigned by considering the increase in temperature. Through a wet wire drawing experiment, it was possible to increase the maximum final speed from 1000 m/min to 2000 m/min.