Papers in JOURNAL OF THE JAPAN SOCIETY FOR TECHNOLOGY OF PLASTICITY
(Vol.39 No.447 April 1998)
Characterization of Wire Rolling and Wire Roll Drawing
Using 2-Roll, 3-Roll and 4-Roll Mills
Kunimasa ONO and Jun YANAGIMOTO
(Received on June 9, 1997)
Three-dimensional deformation features of workpieces in wire rolling and wire roll drawing using 2-, 3- and 4-roll mills have been clarified using a general purpose FEM simulator for rolling processes named gCORMILL Systemh. Various deformation characteristics of wires such as true reduction in area, elongation, width spread, average equivalent strain, roll separating force, drawing stress and rolling torque have been successfully simulated. These characteristics are formulated by means of consistent numerical case studies. Rolling using a 3-roll mill or 4-roll mill results in better elongation, width spread and ovality with a relatively smaller roll separating force than that obtained using a 2-roll mill. The maximum reduction in area in 3-roll rolling/roll drawing is much more than that obtained using a 2-roll mill or a 4-roll mill. The general deformation characteristics resulting from roll drawing are quite similar to those resulting from rolling, but those resulting from roll drawing have smaller width spread and ovality than those resulting from rolling.
Key words : numerical simulation, FEM, wire rolling, wire roll drawing, 2-roll mill, 3-roll mill, 4-roll mill
Influence of Die-Wire Contact Length Ratio
on Chevron Crack and Optimum Drawing Condition in Wire Drawing
Akikazu NAKAGIRI, Katsuhiko MATSUKAWA, Shin-ichi WATANABE and Yasuhide SASAGAWA
(Received on September 24, 1997)
The internal stress during wire drawing and the residual stress after wire drawing have been analyzed by the elastoplastic finite-element method (FEM). The die-wire contact length ratio l/d0 (the contact length/the diameter before drawing) affects the stress, temperature and residual stress distributions during wire drawing. The mean stress, which influences chevron cracks due to internal stress of the central part, was found to be maximum at the contact length ratio of 0.1, and simultaneously, the surface residual stress was also maximum. In addition, the mean stress which influenced the optimum drawing condition, due to internal stress of the central part, was found to be at a minimum value of 0 at the contact length ratio of 0.55, and at the same time, the surface residual stress was less than one-half its value at the contact length ratio of 0.1.
Key words : wire drawing, internal stress, residual stress, die angle, reduction in area, elastoplastic FEM