Metal Flow and Defect Development in Rough Rolling on a Universal Rail Mill.

Autor: Umanskii, A. A., Yur'ev, A. B., Dumova, L. V.
Zdroj: Steel in Translation; Apr2022, Vol. 52 Issue 4, p401-407, 7p
Abstrakt: The metal flow and rolling of billet defects in the roughing stands of a universal rail mill are analyzed on a laboratory system. For box grooves and grooves of trapezium and horizontal trapezium types, the extension of the surface layers is found to be nonuniform in terms of width and length. Likewise, the extension in rolling is nonuniform over the billet cross section. In deformation, the extension is greatest in surface zones adjacent to the end of the billet. The nonuniformity of the extension over the cross section depends on the dimensional ratio (shape) of the deformation zone according to a power law. The removal of surface defects depends significantly on the extension and also on the configuration and orientation of the defects. The defect dimensions have no significant influence on their ease of erasure. Defects in the direction of rolling at the edges of the billet are most thoroughly eliminated (in terms of depth and width), while transverse defects are least effectively removed. With increase in the extension, any defect will be more thoroughly removed. Close to the lateral edges of the billet, the width (aperture) of transverse and inclined defects is increased. Longitudinal defects are further opened on the end sections of the billet. Analogously to surface defects, internal defects are more effectively removed as the extension increases. The degree to which they are removed is less than for surface defects. Defects in the middle of the sampler are least affected by rolling. The degree of their removal is inversely proportional to the distance from the surface. Regression equations may be written for the influence of the position and orientation of the defects and the extension in rolling on the degree of removal of internal and surface defects. They may be used in practice to predict the quality of the final product with variation in the rolling conditions. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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