Rolling of Long-Length Rails with Acceleration

• Published in: Steel in translation 2022-06, Vol.52 (6), p.553-560
• Main Authors: Solov’ev, V. N., Belolipetskaya, E. S.
• Format: Article
• Language: English
• Subjects: Acceleration; Billets; Broadband; Chemistry and Materials Science; Continuous rolling; Height; Hot rolling; Hot rolling mills; Materials Science; Metal sheets; Rails; Strip
• ISSN: 0967-0912; 1935-0988
• DOI: 10.3103/S0967091222060134

A new temperature-velocity mode for rolling long-length rails is considered. Rails less than 50 m long were rolled using linear rolling mills. The production of rails with a longer length requires the use of billets with a greater weight and equipment having a novel design. In the case of modern rail-beam rolling mills, the number of stands is increased and some of the stands are combined into a continuous group. Universal rolling stands began to be used not only as sizing stands. The rails with a length of 100 m are rolled based on large-weight billets using rolling mills with a continuous reversible group of universal stands. A significant billet length leads to the formation of so-called temperature wedge, i.e., to decreasing temperature throughout the rail length while rolling in the last stand of the rolling mill. The calculations have shown that decreasing temperature throughout the rail length can lead to an increase in the height of the rails. A similar problem should be noted in the production of thin sheet metal with the use of a continuous broadband hot rolling mill. The rolling of the rolled metal in the finishing group of stands with acceleration makes it possible to reduce the cooling time of the rear section of the rolled metal and to heat up the metal due to a more intense deformation. The value of acceleration should be chosen in such a way that at the output from the finishing group of stands, the temperature of the strip should be the same throughout the entire strip length. In this paper, it is proposed to perform rolling the rails with the use of acceleration in which the value should provide the same neck temperature throughout the rail length in the last stand of a rolling mill, as well as reduce the height difference along the rolled product length. The same height of the rails throughout the entire rail length should reduce the cost of grinding and accelerate the procedure of rail laying, thereby providing an increase in the consumer demand and in the competitiveness of the product.