The Design And Optimization Of Pass System For The Flat-bulb Steel

The flat-bulb steel is difficult to rolling because the asymmetric section structurewill lead to larger inhomogeneous deformation, but the design and optimization ofpass system is the key factor to solve inhomogeneous deformation in rolling ofasymmetric section steel. In the view of broad application prospects, the hugecommercial value and stable social demand of flat-bulb steel with high difficultyproduction for ship use, also based on the importance of design and optimization ofpass system for the production of ball flat steel, two typical flat-bulb steels,300×12and400×15, were designed by considering the existing pass theory. The cold rollingexperiments of two flat-bulb steels were carried out on two-high reversing mill inlaboratory. The pass system was repeatedly modified and optimized based on rollingtests. On the basis of the success of cold rolling experiment, the300×12flat-bulb steelwas selected for hot rolling experiments of EH36steel for verifying this pass system.By measuring the feature sizes of every pass sample, the results showed that thefinished product has reach the standard of GB/T9945-2001.In this paper, the cause of rolling defects and the deformation law of metalrolling are analyzed by combining theory and experiment. The distinctive and passsystem ball flat steel with independent intellectual property rights has beensuccessfully developed. The defects appeared in laboratory experiment, such astorsion, warping, trimming, pile-up and so on, are related to the design of pass systemand guide, the installation of roller, and the design and adjustment of guide etc.Different metal flow velocity on the surface in deformation zone could cause steelbend, and the main influence factors of flow velocity are roll diameter deviation,frictional drag and pressure value. The opened ball structure of H deep-cut pass hashigh cutting efficiency. The G transition deep-cut pass should adopt semi-enclosedball structure and set small deformation, which not only efficiently processes top ofball, but also can make steel shape transitions to forming pass. The opened and closedball structure should be arranged alternately in the forming passes to process the balland ensure the dimensional accuracy of finished product.