Production Of Hot Rolled Strip Research Articles

Analysis of flatness and critical crown of hot-rolled strip based on thermal–mechanical coupled residual stress analytical model

Analysis of flatness and critical crown of hot-rolled strip based on thermal–mechanical coupled residual stress analytical model

Steel Strip Defect Sample Generation Method Based on Fusible Feature GAN Model under Few Samples.

Due to the shortage of defect samples and the high cost of labelling during the process of hot-rolled strip production in the metallurgical industry, it is difficult to obtain a large quantity of defect data with diversity, which seriously affects the identification accuracy of different types of defects on the steel surface. To address the problem of insufficient defect sample data in the task of strip steel defect identification and classification, this paper proposes the Strip Steel Surface Defect-ConSinGAN (SDE-ConSinGAN) model for strip steel defect identification which is based on a single-image model trained by the generative adversarial network (GAN) and which builds a framework of image-feature cutting and splicing. The model aims to reduce training time by dynamically adjusting the number of iterations for different training stages. The detailed defect features of training samples are highlighted by introducing a new size-adjustment function and increasing the channel attention mechanism. In addition, real image features will be cut and synthesized to obtain new images with multiple defect features for training. The emergence of new images is able to richen generated samples. Eventually, the generated simulated samples can be directly used in deep-learning-based automatic classification of surface defects in cold-rolled thin strips. The experimental results show that, when SDE-ConSinGAN is used to enrich the image dataset, the generated defect images have higher quality and more diversity than the current methods do.

Predicting stress and flatness in hot-rolled strips during run-out table cooling

Flatness defects are complicated issues that occur during hot-rolled strip production. With more research on flatness control during the rolling process, flatness control technology during the rolling stage has improved. However, there is no online method for measuring strip flatness during the cooling stage after rolling. Therefore, this study focused on the evolution of stress and flatness of steel strips during run-out table cooling. Providing guidance for strip flatness controlled during run-out table cooling. A fully coupled finite element model based on temperature, phase transitions, and strain was developed. The calculated results of the model were in good agreement with the measured data. Furthermore, the patterns of evolution of stresses and flatness of the steel strip during run-out table cooling were obtained. The results showed that large compressive stresses formed along the edge region, as well as small tensile stresses in the middle region, causing edge wave defects to occur. With an increase in the initial temperature drop distance of the strip edge area, the edge wave degree also increased. Moreover, the cooling efficiencies of the upper and lower steel strip surfaces were not consistent, resulting in uneven distributions of stresses along the thickness of the material. Finally, the longitudinal and transverse warpage phenomena during the cooling process were discussed in detail.

Dynamic rolling model based on uniform deformation

Abstract Accurate prediction of rolling force is a core point during the hot-rolled strip production. In-depth research on static rolling processes has been carried out in the past. Most models, however, can only be used under static conditions. Therefore, it is challenging to research the dynamic rolling process. This paper presents a dynamic rolling model for hot rolling. Firstly, the strip dynamic velocity model and the dynamic boundary condition model are established, and then the total power equation of the dynamic rolling process is solved based on the energy method. Furthermore, by minimizing the total power function, the dynamic rolling force equation can be obtained. Finally, the effectiveness of the proposed dynamic model is verified by hot strip rolling plant experiments and finite element simulations. The results show that the dynamic model of this paper has higher prediction accuracy and can be applied to the research on the dynamic hot rolling process. Besides, the influence of the vertical velocity of the rolls on the dynamic rolling force and influencing factors of dynamic rolling force are discussed.

P.691 Impairment of the process of thinking on different stages of schizophrenia in connection with the magnocellular and the parvocellularneural systems

Accurate prediction of rolling force is a core point during the hot-rolled strip production. In-depth research on static rolling processes has been carried out in the past. Most models, however, can only be used under static conditions. Therefore, it is challenging to research the dynamic rolling process. This paper presents a dynamic rolling model for hot rolling. Firstly, the strip dynamic velocity model and the dynamic boundary condition model are established, and then the total power equation of the dynamic rolling process is solved based on the energy method. Furthermore, by minimizing the total power function, the dynamic rolling force equation can be obtained. Finally, the effectiveness of the proposed dynamic model is verified by hot strip rolling plant experiments and finite element simulations. The results show that the dynamic model of this paper has higher prediction accuracy and can be applied to the research on the dynamic hot rolling process. Besides, the influence of the vertical velocity of the rolls on the dynamic rolling force and influencing factors of dynamic rolling force are discussed.

Advanced Technology of Combined Thin Slab Continuous Casting and Steel Strip Hot Rolling

On the basis of proceedings of an international symposium on casting and rolling complexes the latest solutions for hot-rolled strip production by a combined process of continuous thin slab casting and rolling are reviewed. Advanced developments in the field of equipment and technologies are presented. The main tendencies and future tasks on this subject are noted.

Development of Microalloyed Steels Through Thin Slab Casting and Rolling (TSCR) Route

Thin slab casting and rolling (TSCR) route of hot rolled strip production is identified with certain hurdles in the processing of microalloyed steels of different levels of strength. First of all, precipitates formed during casting may undergo partial dissolution in tunnel furnace, leaving the valuable microalloying elements out of solution prior to commencement of hot rolling. Secondly, difficulty in complete recrystallization may lead to microstructural inhomogeneity in the form of mixed grain structures which is detrimental to strip performance. Such difficulties are not typically encountered in conventional casting and hot rolling of thick slabs. This paper summarizes the studies of various researchers about microalloying behaviour during production of strips through TSCR route. Along with this, the experiences of developing microalloyed steels of different strength levels through TSCR route of TATA Steel, Jamshedpur have been discussed.

Danieli Universal Endless (DUE)

Over the last 25 years, the thin slab casting and rolling process has been gaining a major market share in the production of hot rolled strip, progressively eroding the areas previously of exclusive domain of conventional mills. This is mainly thanks to the competitiveness of the process over conventional ones and to the growing ability of this technology to cover the majority of market niches well beyond the boundaries of the commodity market. After having significantly contributed to the continuous expansion of this production mode and after an extensive campaign of research and physical testing in reference plants, Danieli has progressively developed a new generation of thin slab casting and rolling layout over the years, marking a new phase in the evolution of this process. The new step-ahead is a new development within the Quality Strip Production (QSP) family, which is the Danieli’s strip-quality-oriented thin slab based plants. What makes this new concept different is the ability of “universal” rolling modes thanks to the fact that now, within one single plant, it is possible to perform different rolling modes, making this plant a major technology innovation compared to the previous generation. This new approach can be seen as the natural evolution of the original successful Danieli concepts that marked the progress of the thin slab route, namely the application of the vertical curved design thin slab caster and the separation of the rolling stands into high reduction units and finishing units.

Development of a Press-Hardened Steel Suitable for Thin Slab Direct Rolling Processing

The thin slab casting and direct rolling process is a hot-rolled strip production method which has maintained commercial quality steel grades as a major material in many industrial applications due to its low processing cost. Few innovative products have however been developed specifically for production by thin slab direct rolling. Press hardening or hot press forming steel grades which are now widely used to produce structural automotive steel parts requiring ultra-high strength and formability may however offer an opportunity for thin slab direct rolling-specific ultra-high strength products. In this work, a newly designed press hardening steel grade developed specifically for thin slab direct rolling processing is presented. The press hardening steel has a high nitrogen content compared with press hardening steel grades produced by conventional steelmaking routes. Boron and titanium which are key alloying additions in conventional press hardening steel such as the 22MnB5 press hardening steel grade are not utilized. Cr is added in the press hardening steel to obtain the required hardenability. The properties of the new thin slab direct rolling-specific 22MnCrN5 press hardening steel grade are reviewed. The evolution of the microstructure and mechanical properties with increasing amounts of Cr additions from 0.6 to 1.4 wt pct and the effect of the cooling rate during die-quenching were studied by means of laboratory simulations. The selection of the optimum chemical composition range for the thin slab direct rolling-specific 22MnCrN5 steel in press hardening heat treatment conditions is discussed.

Improving the performance of multistage technological systems

Improvement in the production of hot-rolled strip is considered. The influence of the steel’s chemical composition on the product’s mechanical properties is considered.

Effectiveness of active and pseudo-active methods of slowing the cooling of the starting stock on a hot strip mill

Hot-strip mills (HSMs) continue to occupy the leading position in the production of hot-rolled strip. One remaining bottleneck in HSM lines is the intermediate roller conveyor, where the slab being rolled undergoes significant (nonuniform in the length direction) cooling. Passive methods of shielding the metal are widely used on continuous HSMs to slow the metal’s cooling. In recent years, data have appeared on active methods of regulating the thermal state of the slab on the conveyor: continuous tunnel furnaces and pseudo-active shields. This article analyzes the thermal and energy efficiency of these methods of maintaining slab temperature. It is shown that a continuous tunnel furnace solves this problem with a very low energy efficiency.

New technologies and equipment in Gipromez projects to improve the quality of steel

In 2007–2008, the company Gipromez developed plans for the construction of ladle-furnace units and steelvacuum-degassing units in the converter shops at the Novolipetsk Metallurgical Combine and the electric steelmaking shop of the Oskolskii Electrometallurgical Combine. Another Gipromez project of interest is the casting-rolling mini-mill being built in the town of Yartsevo (Smolensk Region). In 2008, the company completed a feasibility study of organizing the production of hot-rolled strip at the Lysva Metallurgical Plant in order to provide the plant with its own high-quality starting strip for the subsequent application of corrosion-resistant coatings.

VAI Steckel mill technology. Economical and flexible production of hot-rolled strip and plates

Thanks to many technological developments, modern Steckel mills are not only characterized by increased capacities and extended product ranges, but can also deliver plates in addition to hot-rolled strip. Some recent examples of supplies by VOEST-ALPINE Industrieanalgenbau (VAI) show possible Steckel configurations and introduce the innovative solutions developed at these occasions. These examples demonstrate the flexibility and economical efficiency of this technology.