Conclusions
For the development of a new spread formula for computer control of rod rolling process, the spread characteristics of hot rolling of mild steel rods in the Square-Oval, Round-Oval, Square-Diamond, and Diamond-Diamond passes were experimentally investigated. The conclusions are summarized as follows:
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(1)
The profile of side free surface differs for the four types of passes: in the Square-Oval pass, it is assumed to be a straight line; in the Round-Oval pass, it is approximated by two special circular arcs; in the Square-Diamond pass, the angle of side surface is similar before and after rolling; in the Diamond-Diamond pass, its angle after rolling is slightly smaller than before rolling. The maximum projected width of contact (W 1) and the cross sectional area after rolling (F 1) can be precisely calculated.
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(2)
A new spread formula has been proposed as follows:\(\frac{{\Delta B}}{{B_0 }} = \alpha \cdot \frac{{Ldm}}{{B_0 + 0.5 \cdot H_0 }} \cdot \frac{{F_H }}{{F_0 }}\) This formula is very simple and has only one coefficient α but can predict the spread for every type of pass with practical high accuracy. The common value of α for all four passes is 0.83.
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Originally published in Japanese in Tetsu-to-Hanane, Vol. 67 (1981), No. 5. Translated and published by permission of Iron and Steel Institute of Japan.
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Shinokura, T., Takai, K. A new method for calculating spread in rod rolling. J. Applied Metalworking 2, 94–99 (1982). https://doi.org/10.1007/BF02834206
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DOI: https://doi.org/10.1007/BF02834206