Rolling and Metal forming | |
Название | Development and improvement of modes of rolling of asymmetric rail profiles on the modern universal rolling mill |
Автор | A. A. Umanskiy, V. V. Dorofeev, A. V. Golovatenko, A. V. Dobryanskiy |
Информация об авторе | Siberian State Industrial University (Novokuznetsk, Russia): A. A. Umanskiy, Cand. Eng., Ass. Prof., Chair of Iron and Steel Metallurgy, Director of the Center of collective usage “Material science”, e-mail: umanskii@bk.ru
EVRAZ United West Siberian Iron and Steel Works (Novokuznetsk, Russia): |
Реферат | The existing tendency to the constant increase of speed of movement of railway trains causes increase of requirements to quality of the railway transfers which are the fastest – knowing element of the top structure of the rail track, including to qualitative indicators of their component elements. However, according to available data, the main causes of defects in the manufacture of these elements are unsatisfactory geometry and variation of residual stresses in the original blanks – switch point and guardrail rails. The above makes the task of improving the quality of switch point and guardrail rails. The practical experience of development of new profiles in the conditions of universal rail-rolling mill of "EVRAZ ZSMK", launched in 2013, shows that the greatest difficulties arise in the process of working out the modes of rolling rails having a pronounced asymmetrical shape. Such profiles include switch point and guardrail rails. The article describes the stages of development and improvement of rolling modes of switch point and guardrail rails. Significant disadvantages of the scheme rolling of switch point rails made by the supplier of the equipment of rail mill, necessitated the development of a new mode of rolling, the main distinctive features of which were: the use of an intensifi ed mode of rolling in the first breakdown rolling stand; reducing the number of passes in the second breakdown rolling stand; applying the second breakdown rolling stand split rail sloping caliber with the connectors on the diagonal instead of the split rail caliber of the closed type. Adaptability the use of a new mode of rolling is substantiated by calculations of the rolling force, carried out using a previously developed methodology by the authors. In the process of developing the scheme of rolling guardrail rails as the main object for improvements chose the final stage of rolling rails in universal cages. According to the developed scheme of production guardrail rails rolling is carried out sequentially in the universal four-roll caliber, preauxiliary an open two-roll mill four-roll pass and the finishing pass. Based on the results of the simulation of the flow of the metal, confi rmed the practical results of rolling guardrail rails, the findings about the optimal intervals of the vertical and horizontal compressions of the head formed by the rail profile, ensuring the fulfillment of the required value of the external radii of the mating surfaces. Pilot testing and introduction of new modes of rolling of switch point and guardrail rails showed significant improvement of technical and economic indicators. With regard to the switch point rails, an increase in the productivity of the mill by 39.8 t/h and a decrease in the rejection of ready-made rails on the defect "captivity" by 0.5% were recorded, which resulted in a total economic effect of 30 million rubles/year. For guardrail rails was an increase in the quality of profi les and reduce twisting of roll at the exit of the fi nishing pass. |
Ключевые слова | Asymmetric rail profiles, universal rail mill, continuous group of rolling stands, rolling mode, metal forming, rail gauges |
Библиографический список | 1. Stammbach R. Das Walzen von Tragern und Shinen ant Triogerusten der Kontintraseum Universalwalzmverfahren. Kalibreur. 1968. No. 9. |
Language of full-text | русский |
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