Research and Development Trend of Shape Control for Cold Rolling Strip

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 con- trol 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 opti- mization, 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 indus- trial 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 roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.

Optimization technology of scheduling for hot-rolling mill

To establish the rolling plan of cold-rolling flattening set is very complicated,it is restrained by several constraints of rolling schedule.Operator's subjective and other human factors also affect the rationality of plan arrangement seriously.Its result causes many abuses such as overusing transition strip,high-frequent roller switching,no-fully utilization of rollers,low arrangement rate of the plan.Therefore,we have initially developed a practical optimization model of rolling plan and schedule,which could be established and optimized by computer automatically,and a dynamic alignment module which have friendly UI according to the experience of operators.They have greatly enhanced the system usability.This system takes full advantage of relationship between the roller roughness and the rolling weight,reasonably arranges rolling based on different roughness demand,effectively enhances the use factor of roller and the smooth quality of steel string coil. A practical and effective scheduling optimization algorithm and rolling scheduling optimization applications system was developed based on the study of mixed hot rolling scheduling optimization model of carbon steel,stainless steel,stainless steel and carbon steel cross-rolling.The online application indicates that the model and algorithm is designed reasonable,practical and effective.This model system can significantly improve the scheduling efficiency and quality and it's also very positive in reducing heating energy consumption,enhancing the volume of units rolling plan,and optimizing the production of hot-rolled unit organization and planning and scheduling.

Textures variation of 3104 aluminum alloy sheetsunder different rolling conditions

The textures variation of 3104 aluminum alloy sheets during hot rolling, cold rolling, transverse cold rolling and cross shear rolling were investigated by means of X ray ODF analysis. The results show that the main texture component {100}<011> becomes stronger with the increase of hot rolling reduction. The cold rolling textures are composed of typical "copper type" texture components C {112}<111>, S {123}<634>, R/S {124}<211>, B {110}<112> and G {110}<001>, the orientation intensities increase with increasing cold rolling reduction. Compared to the conventional cold rolling with the same amount reduction, the transverse rolling reduces the orientation intensities of each cold rolling textures components, and strengthens the {001}<110> and {110}<uvw> texture components. During cross shear rolling process, notable difference of intensity of cold rolling textures components were observed from the slow roller side to the fast roller.

Effect of Kind Rolling on the Properties of Plasma-Formed Nitride Layers on Fe93Ni4Ti3

The nitriding behavior of cold rolled Fe93Ni4Ti3 specimens was compared with that of hot rolled specimens of the same materials. Radio frequency (rf) nitriding was performed for 10 minutes in a 10-2 mbar nitrogen atmosphere. The continuous plasma power was varied from 300-550 W in steps 50 W or less. Results of optical microscopy (OM), x-ray diffraction (XRD) and microhardness measurements (Hv) are presented and discussed with regard to the influence of kind rolling on the nitriding behavior, particularly nitride formation and nitride layer growth on mechanical properties. The results show a remarkable increase of nitrogen diffusivity and microhardness of cold rolled nitride samples. These best results may be attributed to enhancement of the defect and/or a compressive stress.

Internal oxidation of hot-rolled ultra-high strength steel and its effect on the surface quality of cold-rolled sheets

In this study,the scale and internal oxidation of hot-rolled ultra-high strength steel sheets were characterized.It was found that both the formation of the scale and the internal oxidation of Si and Mn depended on the coiling temperature and position of the steel sample on the strip coil.At a relatively high coiling temperature,a large amount of internal oxidation was observed on the samples cut from the middle of the coil.The depth of the internal oxidation zone exceeded 10 μm and a thin iron layer covering the scale was observed in some cases.Pickling and cold-rolling experiments were conducted on selected samples.Scale pickling was found to be greatly delayed by the formation of an iron layer,which frequently resulted in under-pickled defects.In addition,pickling of the entire internal oxidation zone was difficult,except at the grain boundaries,where the degree of internal Si and Mn oxidation was enriched.The surface of the cold-rolled steel sheet was ruined by the remaining oxidation zone in the subsurface of the pickled steel.The internal oxidation of hot-rolled ultra-high strength steel must be precisely controlled to improve the subsequent surface quality of cold-rolled steel.

High Temperature Oxidation and Hot Corrosion Behaviour of 9Cr 1Mo Ferritic Cold Rolled Steel in Air at 900°C under Cyclic Condition

The oxidation behaviour of 10%, 30%, and 50% cold rolled and unprocessed 9Cr 1Mo ferritic steels in air have been studied under isothermal conditions at a temperature of 900°C in a cyclic manner. Oxidation kinetics was established for all samples on which experiment was conducted in air at 900°C under cyclic conditions for 50 cycles by thermogravimetric technique. Each cycle consisted of 1 hour heating at 900°C followed by 20 min of cooling in air. 10% cold rolled sample followed parabolic rate of oxidation while 30% cold rolled sample showed accelerated rate of weight gain. X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray (SEM/EDAX) techniques were used to characterise the oxidized sample and their scales. 10% cold rolled steel was found to be more corrosion resistance than other in air oxidation for 50 cycles.

Hot-dip Galvanizing of Carbon Steel after Cold Rolling with Oxide Scale and Hydrogen Descaling

A new processing method for producing hot dip galvanized steel is designed and tested, in which pickling is skipped. Hot-rolled low carbon steel sheets are roiled with oxide scale in an experimental mill at room temperature, prior to annealing under a 20% hydrogen reducing atmosphere and galvanizing on a hot-dip galvanizing simulator. Micro-cracks formed in the oxide scale during cold rolling roughen the steel surface and enlarge the specific surface. Through-thickness cracks provide transport channels for hydrogen, and hence the reduction of oxide scale is en- hanced. When the sheet is dipped in the zinc bath, cracks are submerged by liquated zinc and the defects are not dis- tinct after hot-dip galvanizing. The overlay coating occludes with rough surface of the sheet, whereby a superior coat- ing adherence is realized.

Rectangular Section Control Technology for Silicon Steel Rolling

Rectangular section control technology （RSCT） was introduced to achieve high-precision profile control during silicon steel rolling. The RSCT principle and method were designed, and the whole RSCT control strategy was developed. Specifically, RSCT included roll contour design, roiling technology optimization, and control strategy development, aiming at both hot strip mills （HSMs） and cold strip mills （CSMs）. Firstly, through the high-performance variable crown （HVC） work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs, a hot strip with a stable crown and limited wedge, ：local spot, and single wave was obtained, which was suitable for cold rolling. Secondly, an approximately rectangular section was obtained by edge varying contact （EVC） work roll contour design, edge-drop setting control, and. closed loop control in the upper-stream, stands of CSMs. Moreover, complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs. In addition, the RSCT approach was applied in several silicon-steel production plants, where an outsicanding performance and remarkable economic benefits were observed.

Texture Evolution in Ferritic Rolled Ti-IF Steel During Cold Rolling

The texture evolution of ferritic hot rolled Ti-IF steel during cold rolling was investigated in which the reduction was from 15% to 85 %. It was found that α fibre texture was monotonously intensified with the increase in the cold rolling reduction, while y fibre texture changed in a different way. When the cold rolling reduction was in the range of 15 % -- 35 % or 45 % -- 75 %, γ fibre texture was strengthened ; however, when the cold rolling reduction was 35 %- 45 % or 75 %- 85%, the intensity of 7 fibre was reduced. The 7 fibre displayed a maximum intensity for the reduction of 75%, and the highest average plastic strain ratio was simultaneously obtained owing to the favorable recrystallization texture.

Texture of Cold Rolled Strip of Fe-3Si Steel Produced by Thin Slab Casting and Rolling

The hot rolled strip of Fe-3Si steel was experimentally produced by thin slab casting and rolling（TSCR） process in the laboratory.The texture evolution rule was investigated during hot rolling and cold rolling.The texture distribution of cold rolled strips with four kinds of cold rolling reduction schedules was observed through X-ray diffraction method,and the orientation density variation of 1/16 layer,1/8 layer,1/4 layer,and 1/2 layer in thickness was analyzed.The cold rolled texture of steel A with four kinds of cold rolling reduction schedules was mainly composed of α and γ fibers.Cold rolling reduction ratio of 70% was more beneficial for obtaining more γ fibers.The γ fiber texture orientation density of {111}01-1 and {111}1-1-2 was the largest on the 1/8 layer and 1/4 layer and the least on the 1/16 layer and 1/2 layer for steel B.The texture orientation density of {001}-{223}11-0 in the α fibers for steel C was increased,but the texture orientation density of {332}-{110}11-0 was low.

Improvement of material properties and cladded flat product productivity with roll-bonding technology

Taking advantage of the progress of roll-bonding technology, the integrity of the material technology, and the development of the production and examination facilities of all the main carbon steels, stainless steels and specialty alloys in Baosteel, the cladded flat new products, which combined both properties of base material and clad material ,have been developed and produced in large quantities. The product categories includes heavy plates with high alloy content and homogeneous distribution in thickness and carbon steel plates cladded with all kinds of stainless steels ,nickel alloys ,and titanium alloys. The double-sided and single-sided cladding hot roiled strips and cold rolled sheets were also commercially produced. Due to the combined properties of both the cladding material and backing material, all products show obvious improvement in properties when compared with solid material. The comparability with the existing production process and equipment laid a very solid foundation for high productivity.

Influence of lateral displacement on strip shape during cold rolling

The theory of metal plastic deformation is an important part of the strip shape control theories. In order to control the shape and gauge accurately during cold thin strip rolling, the mechanism of the metal lateral flow must be revealed clearly. Therefore, the lateral displacement of thin strip was studied by the grid method. Those grids with a line thickness of 10 μm and clear boundaries were successfully manufactured on the strip surface using lithography. Then, the effects of reduction, front and back tension, and taper angle of the first intermediate roll on the metal lateral flow were studied. The strip shape was calculated with and without considering the lateral displacement; furthermore, the calculations were compared with the measured results. The results show that the calculations with considering the lateral displacement are closer to the measured results. In addition, the comparison of finite element analysis results with the experimental results indicates that the test method was reliable.

The new technical progress of hot dip galvanizing process without sink roll

In this paper,the recent state and problems of the sink roll in CGL are described.Several methods of increasing its operational life span are introduced,such as surface coating technology and sleeve material technology.Fundamentally they cannot solve the problems of surface quality caused by the contact between strip and roll.On this basis,the newly developed principle and solutions for hot dip galvanizing technology without sink roll are highly emphasized,they are Float Technology,Electromagnetic pump technology,Electromagnetic enclosed slot by high-frequency AC,Electromagnetic enclosed slot by high-frequency DC.A comparison among their functions and characteristics is made and the possibility of its application is also discussed.Finally it comes to a conclusion that electromagnetic enclosed slot represents the direction of a continuous hot-dip galvanizing steel strip in the the 21st century.It has a very broad application prospects.Baosteel Technology Center is focused on the research and development of this technology.As technology advances,industrial applications is possible.

Technologies for ultra-thin hot-rolled strip:a prospective review

Ultra-thin hot-rolled strip is the developing result of the modern plate and strip rolling technology and can be used to replace cold-rolled products for energy saving and emission reduction.This work reviews recent progress and breakthroughs in this field by focusing on three recent technologies,namely the conventional strip with hot coil box and endless rolling,thin slab continuous casting and rolling/semi endless rolling,and endless compact rolling.In summary,ensuring high-quality production is an important bottleneck for ultra-thin strip and ferritic hot rolling by endless compact rolling.This production technology has strong feasibility and broad prospects for future development.

BRILLIANT MOVEMENT AND GREAT PICTURE ROLL——Interview Mr.Wang Deye,director of Administration Commission of Guangzhou Economic and Technological Development Disrict.

Recent reports about economic and technological developmentdistrict brought me an idea to visit Wang Deye of director of Ad-ministration Commission of Guangzhou Economic and Technol-ogy District (GETDD).The reports gave me a definite informa-tion:There is a new shock wave of pioneering cause in GETDD.The development trend can not be held back and the zone willmarch ahead of all economic and technological development zonesin China again.Facing the new shock wave,how will people of GETDD reactand to add their achievements for a better future?After the removing of the "favorable policy" granted by Cen-tral government,how will they open a new sea route of "systemdrive" in the second poneering phase?Facing the new chance of Pearl River Delta Economic Area,how will they set up its forerunner image and utmost importance?

国内铜板带发展现状与热轧技术的创新方向分析

文章论述了国内铜板带行业的发展现状,指出铜板带的热轧应分别从理论和技术,生产和工艺,设备设计制造,生产线配置和工程设计等方面进行基础性的研究和改进,并在工程项目的实践中不断创新。

中锰钢热轧与冷轧退火工艺下组织与性能差异综述

中锰钢作为第三代先进高强钢的代表,由于其优异的力学性能已成为一个研究的热点。同一种中锰钢经过不同的轧制和热处理产生不同的微观组织进而导致其力学性能存在差异。因此,研究不同的热加工工艺下其微观组织与力学性能之间的关系至关重要。本文综述了中锰钢在热轧和冷轧退火工艺下的组织演变,重点阐述了微观组织与静拉伸力学性能、抗氢脆性能、低温冲击韧性之间关系方面的研究进展,并对提高中锰钢各种力学性能的方法进行了比较,最后对中锰钢未来的强韧性研究和发展方向进行了展望。

不同除鳞工艺对热轧带钢热镀锌质量的影响

目的研究酸洗、湿法抛丸技术(Eco-Pickled Surface,EPS)、EPS+纤维刷工艺(EPS+plus)和干抛丸4种不同除鳞工艺对Q235B热轧带钢热镀锌质量的影响机理和规律,并将EPS和EPS+plus工艺处理后的热轧带钢在带钢热镀锌生产线上试制,实现大规模生产。方法采用粗糙度轮廓仪测量4种表面除鳞处理后的Q235B钢板表面粗糙度,利用扫描电镜分析表面形貌及氧化皮残留情况。通过实验室热镀锌实验,观察镀锌层表面形貌,利用场发射电子探针(EF-EPMA)分析锌层截面形貌及成分面分布;通过折弯实验评定锌层结合力;去除表面镀锌层,计算锌消耗量,观察脱锌后表面抑制层形貌,并用能谱对其进行成分分析。将Q235B热轧带钢在鞍钢金固EPS生产线上进行EPS和EPS+plus处理后,分别在热镀锌生产线进行镀锌和镀锌铝镁工业试制,并对生产试制卷进行力学、折弯及杯突检测,以评定质量。结果酸洗、EPS、EPS+plus和干抛丸4种工艺处理后钢板表面粗糙度分别为1.4442、3.3305、2.3964、4.3388μm。EPS处理试样表面未发现有氧化铁皮的残留,EPS+plus处理试样仅有极少量的氧化铁皮残留。EPS和EPS+plus工艺处理钢板热镀锌试样基体与锌层之间均能形成连续较致密的抑制层,锌层结合力评为1级,且锌消耗量较小,分别为148.3、123.5g/m^(2)。结论EPS和EPS+plus工艺处理后钢板镀锌质量优于酸洗和干抛丸工艺,EPS和EPS+plus工艺处理后在热镀锌生产线上试制的实验卷满足镀锌质量要求。

轧制工艺对TA15钛合金板微观组织及拉伸力学性能的影响

对比研究了采用包套轧制工艺及普通冷轧工艺制备的TA15钛合金薄板的纵、横向微观组织及室温和高温拉伸力学性能。研究表明:两种工艺获得的钛合金板纵、横向微观组织的物相、尺寸、体积占比相似,纵向维氏硬度较横向的高。热轧工艺与冷轧工艺制备的钛合金板相比,力学性能更加优异、力学性能纵横向差异小、综合性能更好、室温屈服强度更高,呈现出“横向大于纵向、热轧大于冷轧”的对比特征。热轧工艺可弱化织构的方向,使成品钛合金板呈现出“强度高、屈强比大、纵横差小”的拉伸力学性能特性。

基于ABAQUS二次开发的6016铝合金热连轧过程有限元分析

通过ABAQUS建立了6016铝合金热连轧有限元模型,在VUSDFLD用户子程序的基础上,用Fortran语言编写了静态再结晶函数,二次开发了ABAQUS软件。通过引入材料本构模型以及再结晶晶粒演变模型,实现了6016铝合金热连轧过程热、力及微观组织多参数耦合。利用该模型研究了多道次(17道次)热连轧过程中6016铝合金等效应力场、等效应变场、温度场和组织的演变,并通过实验验证了热连轧过程中的再结晶行为。结果表明:与心部相比,轧板表面温度低、变形大、再结晶百分数低、晶粒尺寸大。触换热系数是影响热连轧过程温度场变化的主要因素,应力场及轧制力与摩擦因数、接触面积等因素相关;在轧制温度和塑性变形的综合作用下, 6016铝合金发生再结晶。模拟结果与实际生产数据对比表明,该数值计算模型符合实际生产。