Parametric Analysis for Minimizing the Edge Waves in the Roll Forming

To identify the cause of edge waves and to minimize them, which are frequently occurring on the steel pipe manufacturing site, the shape of the edge part of skelp has been confirmed according to a design variable and operating condition. In particular, parametric studies were carried out on the variation in the thickness of skelp, tskelp, the roll gap between upper and bottom rolls, troll, at the forming stage 1, Forming 1, the roll shape, toffset, of the Forming 1, and the material property of skelp to study the generation of edge waves, because these parameters have been determined by field engineers extemporaneously without any physical estimation. For this purpose, the roll design and operating conditions used in the field were applied to the finite element analysis model, and the distribution of contact force between the rolls and skelp, and the distribution of effective plastic strain on the skelp were investigated. The fact that adjusting to tskelp and troll arbitrarily without changing to the roll shape can cause not only the edge waves but also the center waves, was carried out. Especially, the edge waves were reduced without the irregular contact pressure by changing the surface of the upper roll that is offset by target tskelp in the normal direction of the surface of the bottom roll in the Forming 1, when the target thickness is tskelp. Moreover, there is no significant difference in the vertical load applied to the rolls when high-strength steels are used or when low-strength steels are used, it is necessary to predict the local maximum and minimum of contact pressure between the skelp and rolls and the shape of the upper roll of the Forming 1 should be modified to decrease irregular contact pressure instead of any design modifications.

Flatness Detection and Roll Shape Adjustment of Cold Rolled Material

Cold rolling rules according to the fixed incoming crown distribution of each crown control, raw material convexity fluctuations will destroy convex degree program, light is left with the residual stress, heavy waves. This paper discusses test incoming convexity, convexity control allocation method of residual stress.

Analyse and Control Research about the Cause of Shape Defects on Hot-Rolled Strip Steel

Strip shape defects, especially the crown problem, once appeared in the production of hot-rolled strip steel in SG Company. The macroscopic characteristic is the thickness difference occurred between the center and edge cross section of hot-rolled plate. Morphological characteristics and forming reasons can be got by analyzing roll wear. Research shows that the main reason for the formation of crown is excessive attrition of work roll in later period, which leading to smaller roll shape. Therefore, shape defects have been effectively controlled after introducing CVC roll contour technology to optimize roll shape. Quality qualified rate of strip shape of hot-rolled strip steel is more than 99.6% percent, and it has been successfully put into application of hot rolling mill.

Study on Design Parameters of Whole-Roll Shape Detecting Roll

For the shape defects detection problem of the cold-rolled strip, the design parameters of whole-roll shape detecting roll were studied. The pre-pressure models were derived with the theory of elasticity and shell mechanics, and the pressure transmission performance of shape detecting roll was calculated. The correctness of the theoretical formula was verified by experiment. The design parameters presented by this paper would help to further improve the design standards and performance of the whole-roll shape detecting roll.

Tapered Work Roll Shape Design and Optimization for Cold Tandem Rolling Mill

K-WRS technology has a better edge drop control effect in cold tandem rolling mill, but it still exists some problems such as contact pressure peak beyond the limit, transition peak and the uneven distribution of contact pressure between the rolls in practical application. In this paper, tapered work roll shape is designed and optimized. The simulation analysis shows that the optimized roll shape not only can effectively control the edge drop of strip，but also can improve the contact pressure between the rolls. At the same time, it also can reduce the influence on the flatness control from the edge drop control.

An Advanced Strip Flatness Forecast and Simulation System for Hot Tandem Mill

Taken hot tandem mill as research object, based on complete flatness control theary, in order to improve flatness control technology, an advanced strip flatness forecast and simulation system for hot tandem mill is developed through theoretical analysis, mathematical modeling, computer simulation and industrial validation. The simulation system’s outputs include flatness, on-load roll gap, rolling force distribution, contact pressure between rolls, strip’s temperature evolution, thermal roll shape and roll wear shape, which can be applied to mill type selection, flatness control performance analysis, preset control, roll shape optimization, virtual rolling, and so on. The simulation system can provide research and development platform for flatness control technology’ improvement and independent innovation, and has important significance to improve the flatness control level of hot tandem mill.