Investigations on Formation of Shape Defects in Square Rolling of Uniform Thin Flat Sheet Product

Ling

et al. 2018

steel research int.

The present investigation devises a flatness control strategy for a five‐stand tandem cold rolling mill. In addition, intermediate roll shifting (IRS)–induced rigidity characteristics of the six‐high Universal Crown Control mill (UCM mill) as a key model for the automatic thickness and flatness control systems are established. A three‐dimensional elastic‐plastic finite element analysis for a strip rolling process is conducted when the UCM mill is subjected to different IRS values. The convergence and precision of the simulation model are verified using experimental data in a five‐stand tandem cold rolling line. Through a steady‐state rolling analysis of the process, the vertical and transverse rigidity characteristic curves of the roll‐stack, reduction strain field of the strip, variation in strip crown, elastic deflection of the rolls, and contact stress field between rolls are extracted. The results show that the IRS obviously changes the deflection curves of the rolls and then causes the variations in the exit thickness and transverse thickness difference of the strip. The nonuniform stress distribution between rolls caused by the increasingly IRS value lead to local stress concentration on the side of the roll. A mechanism for the effect of IRS on the rigidity characteristics of the mill is presented and discussed.

Section: Flatness Control Strategy Of a Five‐stand Tandem Cold Millmentioning

confidence: 99%

Numerical Analysis of Intermediate Roll Shifting–Induced Rigidity Characteristics of UCM Cold Rolling Mill

Ling

et al. 2018

steel research int.

“…In accordance with the Shohet discriminant, [26] the crown ratio change interval that does not produce obvious flatness defects can be determined ("dead flat"). Moazeni and Salimi [84,85] reported that the model of Shohet and Townsend could not accurately predict the position of the longitudinal stress peak of a narrow strip with negative crown because the effect of metal lateral flow was not considered. Wang et al [86] developed a flatness prediction model that takes into account the impact of lateral metal flow.…”

Section: Relationship Between Edc Crown Control and Flatness Controlmentioning

confidence: 99%

Development of Cold‐Rolling Edge‐Drop Control Technology for Electrical Steel: A Review

Wei

Sun

et al. 2023

steel research int.

As an emerging technology in the production of electrical steel, edge‐drop control (EDC) caters to the increasing requirements for the overall shape quality of strips. Herein this review, the development of EDC theory, method, and control system used in the cold‐rolling process is summarized. Also, in this review, research on EDC theory is found to be based on the 3D plastic deformation model of the strip, considering the lateral metal flow. Further, an analytical model and a numerical calculation method are employed to establish an edge‐drop calculation model with high accuracy and speed. Next, taper‐work‐roll shifting (T‐WRS), a conventional EDC technology, is found to have been greatly improved in actual production. However, T‐WRS technology involves coupling problems in terms of edge drop and crown and flatness control. Finally, the closed‐loop EDC is found to depend on the online WRS of multiple stands. Particularly, the genetic law of strip thickness in the continuous rolling process and the edge‐drop regulation characteristics of each stand in the continuous rolling mill are significant aspects; thus, a reasonable roll‐shifting control strategy must be formulated. Based on the reviewed research, the development prospect of EDC is characterized.

“…Kim, et al [45], pointed out that the pre-deformation at the entry of deformation zone exerts a significant effect on strip shape, and the finite element simulation results are close to the calculation results in consideration of the effect of pre-deformation. Through finite element softwares, Abdelkhalek, et al [44], Moazeni, et al [46], proved again the conclusion [47] that the transverse distribution of strip flow velocity at the exit of deformation zone is unevenly and must be considered when the transverse distribution of tension stress is calculated. The industrial data collected by Wang, et al [48], showed that the strip tension feedback mechanism exerts a significant effect on strip shape surely.…”

Section: Shape Mechanisms Explored In Depthmentioning

confidence: 99%

Research and Development Trend of Shape Control for Cold Rolling Strip

Liu

2017

Chin. J. Mech. Eng.

Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape control system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll optimization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully industrial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general, the four expected development trends of shape control for cold rolling strip in the future are intelligentization, coordination, refinement, and standardization. The proposed research provides new breakthrough directions for improving shape quality.