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遼寧科技大學(xué)本科生畢業(yè)設(shè)計外文翻譯 第10頁
中厚板軋機的自動化
1978年配置新的主傳動裝置的一新的寬厚板軋機杜伊斯堡進入運行。這個新的寬厚板軋機重360噸、支承輥直徑為2100毫米,寬度只有3.7米,這個新的寬厚板軋機極為堅固,而且也是歐洲第一個配備液壓厚度控制和過程計算機控制的厚板軋機。然而,隨著激光焊接技術(shù)在板材加工上的應(yīng)用和使用移動式起重機建設(shè)增加負載能力,已導(dǎo)致軋機的標(biāo)準越來越高,來要求厚板產(chǎn)品的平整度和厚度公差。因此,需要裝配新的液壓工作輥彎曲設(shè)備,密集的冷卻系統(tǒng),并不斷調(diào)整和優(yōu)化計算機模型,通過這些不斷改進才能得以達到上述要求。不過,限制了原來的電腦系統(tǒng),最終成為一個將來發(fā)展的障礙。
從1999年開始進行了廣泛的現(xiàn)代化計劃,其中包括新的控制系統(tǒng)、加熱爐、現(xiàn)代化的液壓系統(tǒng)等,被稱為現(xiàn)代化軋鋼過程計算機化。這包括基礎(chǔ)自動化(一級),即輥式搖床和側(cè)面導(dǎo)板、機電液壓調(diào)節(jié)系統(tǒng)、主傳動裝置、工作輥撓度,中間冷卻、密集的冷卻系統(tǒng)組成的最終冷卻為,以及完整的第二級物料跟蹤系統(tǒng),能量和過程的數(shù)據(jù)處理,第3級為儀表,爐模型和預(yù)測模型及穩(wěn)定的軋制過程。
為了能夠盡可能平穩(wěn)過渡到新的電腦系統(tǒng), 一個復(fù)雜的轉(zhuǎn)接系統(tǒng)安裝后, 應(yīng)該在不到兩分鐘時間內(nèi)就將舊系統(tǒng)轉(zhuǎn)換到新的電腦系統(tǒng),但這涉及平行安裝兩個獨立控制服務(wù)臺進行暫時控制。
工業(yè)解決方案和服務(wù)的現(xiàn)代化開始在2002年8月規(guī)劃。但一項重大挑戰(zhàn)是,實現(xiàn)現(xiàn)代化意味著幾個自動化系統(tǒng)應(yīng)具有綜合的控制中心,而且新的自動化技術(shù)的控制系統(tǒng)設(shè)計用于快速控制回路。,并且所有設(shè)備都要專為軋機環(huán)境而設(shè)計。
EGC軟件包用于機電間隙控制,電動機械的轉(zhuǎn)動可以被單獨進行位置控制或同步運動關(guān)閉離合器。為了提高實際位置采用螺桿式驅(qū)動器,新的位置傳感器已經(jīng)安裝,連接到自動化系統(tǒng)并通過系統(tǒng)總線壓。
厚度自動控制( AGC ) ,利用超級AGC系統(tǒng)實行前饋補償,使計算好的厚度誤差在鑒定前通過檢測。軋機張力標(biāo)定可由操作員通過新的HMI系統(tǒng)和在半自動模式下的運行,讓運動發(fā)起的操作機構(gòu)和部位增損的價值轉(zhuǎn)移到優(yōu)化過程系統(tǒng),如軋機剛度計算。事實上,由于不同負荷條件下,壓力分布在軋制時受到軋件材料的寬度的影響,因此顯示如圖1,壓力分布應(yīng)該根據(jù)拉伸曲線作相應(yīng)的調(diào)整。
如圖1 .軋輥撓度的繪制曲線
Trushape軋制是去年通過的規(guī)模和廣泛的變厚度剖面應(yīng)用于材料壁板序列。厚度曲線的計算方法是,通過優(yōu)化系統(tǒng)的進程,并轉(zhuǎn)交控制系統(tǒng)作為一個多曲面。實際長度通過導(dǎo)向裝置來調(diào)節(jié),并且理論和實際計算長度之間的偏差,要使其適應(yīng)厚度曲線。每個支點的多邊形曲線,用來驗證一套數(shù)據(jù)屬于合格數(shù)據(jù)的合理性。通過向板的位置,額外的厚度值被送到軋機機座上的AGC控制,但其中需要途經(jīng)一個快速模擬信號 。
設(shè)置點的工作輥彎輥系統(tǒng)和穩(wěn)定的的軋制力波動,是根據(jù)過程計算機,并轉(zhuǎn)交到了基礎(chǔ)自動化系統(tǒng)計算出參考值。對于所有四個彎曲缸這些參考值將傳送給工作輥彎輥控制系統(tǒng)。
液動的側(cè)面導(dǎo)板,在前面和后面的機座,已分別配備新的位置傳感器相連,新的自動化系統(tǒng)通過PROFIBUS DP。但在薄板軋制中,尤其重要的是要設(shè)計出一種優(yōu)化軋制和扭轉(zhuǎn)序列以免浪費時間和試件的溫度,并促進重復(fù)性生產(chǎn)。試件的中心設(shè)定被自動的設(shè)定為軋制序列的一部分,因此兩邊導(dǎo)向杠桿,是為了控制和監(jiān)督對稱運動。
為Trushape軋制和正常運轉(zhuǎn)的超級AGC,準確的材料跟蹤是必需的。幾個傳感器用于同步計算材料的位置。為長度計算,新的增量編碼器的主要驅(qū)動器已安裝完畢。
在熱軋制道次之間等待間隔是必要的,在某些情況下為使第二個或第三塊被同時地軋制,自動化系統(tǒng)可以跟蹤不同的插入位置。這些控制自動化系統(tǒng),用來協(xié)調(diào)軋制順序,確定哪些材料必須遷離或延遲軋制,并決定哪種材料將繼續(xù)在軋機上被軋制。由于中間介質(zhì)和終軋溫度在技術(shù)要求上非常重要,因此需要協(xié)調(diào)軋制制度,使其達到最佳化。為減少間隔時間,在熱軋軋制時,中間冷卻區(qū)和快速冷卻區(qū)應(yīng)該設(shè)置妥當(dāng)。根據(jù)這個溫度要求,就必須把冷卻水用到板材上。將計算出的必要參數(shù)的2級系統(tǒng),轉(zhuǎn)交到過程自動化系統(tǒng)。許多不同的冷卻時刻表必須予以考慮各種材料的收縮范圍和制品的工藝流程?,F(xiàn)有儀器可測量中心線厚度和溫度變化圖,交叉寬度已經(jīng)完全集成在新的自動化系統(tǒng)。
兩種模式的裝置操作是可以適用的。在人工模式下的所有動作和速度,是指由操作者決定; 此模式也用于換輥,校準和維修。正規(guī)的運作模式,是指在自動模式下完成軋制順序和跟蹤的自動控制。唯一的人工干預(yù)需要的是倒置試件,因為缺乏幾何位置監(jiān)測設(shè)備因此這是必要的。
為了允許并聯(lián)運行設(shè)備,在轉(zhuǎn)換期間,一種新型主操作臺的軋機被預(yù)先安裝在一提升控制臺后面,經(jīng)過熱試驗,舊工作臺被拆除,而新的操作臺轉(zhuǎn)到終點位置。
控制系統(tǒng)的溝通需要利用光纖電纜外面的電器室建立一個新的廠內(nèi)網(wǎng)絡(luò)。該可視化系統(tǒng)的程序已被重新設(shè)計,而余下的自動化系統(tǒng)為了操作者的方便已被納入。強大的快速巡檢功能PDA系統(tǒng)已安裝,連接通過光導(dǎo)纖維的控制系統(tǒng)特性自動巡檢程序已經(jīng)實施,并通過校正和評價非標(biāo)準事件。
新的第2級過程優(yōu)化系統(tǒng)包括材料跟蹤,第3級接口接收和發(fā)送數(shù)據(jù)的能量生產(chǎn)報告中,接口的加熱爐和加速冷卻過程模型以及過程模型軋機功能說明如下。
奧鋼聯(lián)(VAI.)鋼板生產(chǎn)和工藝技術(shù)訣竅結(jié)合了奧鋼聯(lián)鋼板廣泛的生產(chǎn)和加工的知識和經(jīng)驗。 奧鋼聯(lián),其中包括自1974年一直從事中厚板軋機生產(chǎn)的前克萊西姆公司和戴維。在現(xiàn)行制度下,林茨獨立研制的奧鋼聯(lián)于1999年啟動??傊?,在鋼板世界各地的生產(chǎn)者中,奧鋼聯(lián)生產(chǎn)占了了近40個裝置。
VAI鋼板生產(chǎn)是一個實時的數(shù)學(xué)模型,目的是為了設(shè)計優(yōu)化軋制過程中的可逆軋機。其主要職責(zé)是確定最優(yōu)軋制的生產(chǎn)率和產(chǎn)品質(zhì)量,考慮到軋機的物理限制和軋制工藝,并計算每個軋制道次的予設(shè)定程序 (輥縫,力量,速度,彎曲等) 。
計算板型設(shè)計要求有初步的產(chǎn)品特性(大小,溫度和材料特性) ,最終性能和設(shè)備參數(shù)尺寸?;疚锢砟P褪怯脕碓谲堉七^程中,預(yù)測產(chǎn)品和軋機的品質(zhì)。一個先進的軋機和最佳化戰(zhàn)略決定了軋制制度,為了滿足企業(yè)的生產(chǎn)力和產(chǎn)品質(zhì)量標(biāo)準。最后,自動校正是應(yīng)用在軋制過程中,在軋制期間由傳感器將測量到的尺寸傳輸?shù)娇刂葡到y(tǒng)來實現(xiàn)寬度自動控制。
與VAI.Plate不同的顯著特點有:在軋制時,每一次的操作和周期性的延誤的重新計算,都可對程序進行修改,考慮到軋制過程中的偏差,壓力模型的自適應(yīng)和實際的板坯軋制溫度,最優(yōu)的軋制程序不能被確定,只能在每次軋制中制定出??焖賰?yōu)化技術(shù)可實現(xiàn)在完全實時的基礎(chǔ)上重新設(shè)定程序,因為板形是中厚板的重要質(zhì)量指標(biāo),所以要采取具體的優(yōu)化方法來保證平坦度如圖2所示。另外,軋機的限制(最大沖擊力或力矩)和其他工藝因素也必須考慮在優(yōu)化設(shè)計內(nèi)。
圖2.軋制力F和相對輪廓P分別越過出口厚度
為進一步提高產(chǎn)量,除了要有良好的厚度和寬度精度,板形(平坦度)也是生產(chǎn)過程中一個關(guān)鍵因素,特別是普通鋼板和厚板。為了控制軋制時的板形,在最后一次軋制時,可按雙楔縱剖面軋制。簡單的計算楔形輪廓的高度和長度的方法是利用板寬度和板坯寬度比例。另一種辦法是采用統(tǒng)計方法來確定一個線性回歸公式,楔高度取決于板坯尺寸,通過數(shù)字和其他參數(shù)。VAI.Plate,在每次通過時計算外部形狀的演變,中間考慮到輥縫形狀(交叉輪廓)及橫向剖面的板塊和使用垂直邊的效果。數(shù)學(xué)優(yōu)化方法是用來尋找最佳的參數(shù)設(shè)定立場限值( AGC )方式所計算,它最后形成的最偏離預(yù)期(大多是長方形)形狀。所以,縱軋輪廓在某些情況下會顯示出更復(fù)雜的形狀,而不是標(biāo)準的雙楔曲線。
一個實時的,完全三維計算熱凸度和磨損的確切輥形狀為軋輥變形模型提供了精確的輸入,確保每道工序的精軋機張力和輥縫剖面計算準確。實際上,在線算出全部軋輥變形,不采用簡化,以減少計算時間,提供準確詳細的三維有限元模型并改善輪候時間及可實現(xiàn)軋制速度優(yōu)化。
以上就是對厚板軋機自動控制系統(tǒng)的一些簡單介紹。
Plate mill automation
The restart of TKS Plate Mill, Duisburg
Jochen Bobbert1, Thomas Kraxberger, Karl Scho rkhuber and Dietmar Auzinger
The recent upgrading by VAI of automation equipment at the 3.9 m plate mill of ThyssenKrupp Stahl (TKS) in Duisburg-Su¨d, Germany involved the installation of new equipment during regular maintenance shut-downs and caused no additional loss of production. To maintain full production capabilities, a switch-over unit was used to provide a seamless transition to the new automation system.
In 1978, a new rolling mill stand with a new main drive entered operation at the Heavy Plate Mill of Thyssen StahlAG in Duisburg Hu?ttenheim. With a rolling mill stand weight of 360 t and a backup roll diameter of 2100 mm at a width of only 3.7 m, the stand was extremely stiff and was also one of the first heavy plate stands in Europe to be equipped with hydraulic thickness control and a process computer,enabling tighter tolerances. However,the increasing implementation of laser welding in plate processing and the increased load capacities in mobile crane construction have led to ever higher requirements for flatness and thickness tolerances of plates.Installation of hydraulic work roll bending, intensive cooling systems and continuous adjustment and optimisation of the computer models allowed continuous improvement to be achieved. However, the limits of the original computer system eventually became a barrier to further progress.
The last stage of an extensive modernisation program, begun in 1999,which included new control systems for the reheating furnaces,modernisation of the stand hydraulics,etc., was the modernisation of the rolling process computer. This included the ‘basic automation’ (level 1) – i.e. The co-ordination of the roller tables and side guides, the electromechanical and hydraulic adjustment system, the main drive, the work roll bending, the intermediate cooling, the intensive cooling system for the final cooling – as well as the complete level 2 system for material tracking, PDI and process data handling, interfaces to level 3 – gauges,furnace model – and process model sfor the rolling process.
To make the transition to the new computer system as smooth as possible, a complex switch-over system was installed which allowed transfer from the old to the new computer and vice versa in less than two minutes. This involved the parallel installation of two independent control desks in the temporarily cramped control pulpit.
VOEST-ALPINE Industrieanlagenba(VAI)Industrial Solutions and Services –began planning the modernisation in August 2002. A major challenge wasthat past modernisations meant several automation systems had to beintegrated to act as one production unit.
The ‘heart’ of the new automation is the technological control systemdesigned for fast control loops. All equipment is designed for the millenvironment.
The EGC SW package is used for electro mechanical gap control. The electromechanical screws can be controlled individually in position control or in synchronous movement with closed clutch. To enhance the actual position reading of the screw-down drives, new position transducers have been installed,connected to the automation system via Profibus DP.
The automatic gauge control (AGC) uses Super AGC, which implements feed-forward compensation of precalculated thickness errors identified during the preceding pass.
The mill stretch calibration can be selected by the operator via the new HMI system and runs in semiautomatic mode, whereby movements are initiated by the operator and all measured force and position values aretransferred to the process optimisation system, where the mill modulus is calculated. Due to the fact that different load conditions prevail since the pressure distribution during rolling is restricted to the width of the rolling stock, the stretch curve has to be adapted accordingly, as shown in Fig. 1. The effective mill stretch,comprising roll stack deformation and net elongation of the stand, is calculated individually for each pass.
1. Adaption of stretch curve for roll stack deflection
During TruShape rolling, which is the last pass of the sizing and broadsiding sequence, a variable thickness profile is applied to the material. The thickness curve is calculated by the process optimisation system and forwarded to the control system as a polygon curve.During the previous pass, the actual length is measured by the tracking and the deviation between the actual and the calculated length is taken to adaptthe thickness curve. For each supporting point of the polygon curve, aset of data (length position, forward slip, expected roll force and additionalthickness) is part of the pass schedule.According to the plate position, an additional thickness value is sent to the stand AGC controller via a fast analoguesignal.
The set-point for the work rollbending system and the sensitivitiesfor roll force fluctuations are calculated by the process computer and forwarded to the basic automation system which calculates referencevalues for all four bending cylinders;these reference values are transmitted to the work roll bending control system.
The hydraulically operated side guides, in front and behind the mill stand respectively, have been equipped with new position transducers,
connected to the new automation system via Profibus DP. For thin gauge
rolling in particular it is important to design an optimised rolling and reversing sequence, so as not to lose time and therefore temperature of the piece, and to promote reproducible production. The centring of the piece is done automatically as part of the rolling sequence, whereby both side guide levers are controlled and supervised forsymmetrical movement.
For TruShape rolling and for properfunctioning of the Super AGC, accurate material tracking is mandatory. Several sensors are used to synchronise the calculated material position. For the length calculation, new incremental encoders for the main drives have been installed.
In thermo-mechanical rolling waiting intervals between passes arenecessary in certain instances. To enable a second or a third piece to be rolled simultaneously, the automation system can track the position of the different pieces. In those cases the coordination function organises the rolling sequence, determining which material must be moved from and to the delay tables and decides whichmaterial will continue rolling at the rolling mill. Since the intermediate and finishing temperatures for these products are technologically very important, mill coordination is performed in close coordination with optimisation of the pass schedule.
To reduce the waiting time during thermo-mechanical rolling,intermediate cooling areas and fast cooling areas are installed. According to the target temperature, water may be applied to the plate, the necessary parameters being calculated by the level 2 system and forwarded to the process automation system. Many different cooling schedules must be considered given the range of materialsand products processed.
The existing instrumentation for measurement of centreline thickness and temperature profile across the width has been completely integrated in the new automation system.
Two modes of plant operation are possible. In manual mode all movements and speed references are initiated by the operator; this mode is also used for roll change, calibration and light maintenance. The regular mode of operation for production is automatic mode where the complete rolling sequence and tracking is controlled automatically. The only manual intervention required is the turning of the piece, which is required because of the lack of geometrical position monitoring equipment.
To allow parallel operation of the plant during the switchover period, a new main control desk for the mill stand area was pre-installed in an elevated position behind the existing desk; after hot testing, the old desk was dismantled and the new control desk shifted to the final position.
For communication between the control systems a new plant networkwas established, making use of fibre optical cables outside the electrical rooms. The visualisation system has been redesigned for the entire process and the remaining automation systems have been incorporated for operators’convenience. For fast data logging functions a powerful PDA system has been installed, which is connected via fibre optics to the control systems.Different automatic data logging routines have been implemented tosupport commissioning, tuning and evaluation of non-standard incidents.
The new level 2 process optimisation system comprises material tracking,interfaces to level 3 for receiving PDI data and sending production reports,interfaces to the reheat furnace and accelerated cooling process models as well as to gauges, and the process model and mill pacing functions described below.
VAI. Plate plus integrates extensive production and process know-how and VAI.plate plus integrates extensive production and process know-how and experience. VAI, including the former Clecim and Davy, has been involved in plate mills since 1974. The current system, developed independently by VAI-Linz, was launched in 1999. In all,VAI has made nearly 40 installations at plate producers throughout the world.
VAI.plateplus is a real-time mathematical model designed to optimise the rolling process in a reversing plate mill. Its major role is to determine an optimal rolling schedule in terms of productivity and product quality, taking into account the mill physical constraints and rolling practices, and to calculate the presets for each pass (roll gap, force, speed,bending, etc.).
Calculating a pass schedule requires the initial product properties (dimensions, temperature and material properties), the final properties and plant parameters (dimensions, rolls and constraints). Basic physical models are used to predict the behaviour of both product (temperature, flow stress,rolling force and torque, shape and dimensions) and rolling mill (roll thermal crown and wear, mill stretch, roll gap shape) during the rolling process. A sophisticated rolling and optimisation strategy determines the rolling schedule, to meet the productivity and product quality criteria as a function of mill and product constraints and the imposed rolling practices. Finally, an automatic self-correction is applied,based on the measurements transmitted by sensors during rolling.
The particular features distinguishing VAI.Plate plus include:
Recalculation during each pass and cyclically during delays makes it possible to revise a schedule during the rolling operation, taking into account deviations in the process and benefiting from pass-to-passadaptation of the flow stress model and the actual plate temperature – the optimal schedule is never definitive and can be modified at each pass N fast optimisation techniques make it possible to recalculate the schedule fully on a real time basis, to make the presets available for the next pass. During the last phase, in which flatness and profile areimportant features for thin plates, a specific optimisation strategyensures that the relative profile is kept constant to prevent waves on the plate (Fig. 2); mill restrictions(maximum force or torque) and other process factors must also be taken into account in the optimization.
2 .Flatness diagram indicating roll force F and relative profile p for individualpasses over pass exit thickness
Besides excellent thickness and width performance, outer shape (plan view) is a key factor for further improvement of yield, i.e. the rati between customer plate mass and slab mass. To influence the shape that develops during rolling, a double-wedge longitudinal profile can be rolled during the last passes before the two standard 90u turns of the plate. Simple solutions calculate the height and length of this wedge profile, principally using the ratio between plate width and slab width.
A further approach applies statistical methods to determine a linear regression formula for wedge height depending on dimensions, pass numbers, and other parameters.VAI.TruShapeplus calculates the evolution of the outer shape during each pass, taking into account roll gap shape (cross-profile), transverse profile of the plate and the effect of using a vertical edger stand. A mathematical optimisation method is used to find an optimal parameter set within stand limits (AGC) for which the calculated final shape has the least deviation from the desired (mostly rectangular) shape. As a consequence, the longitudinal contour rolled in certain passes may show a more complex shape than the standard double-wedge curve.
A real time, fully three-dimensional calculation of the thermal crown and wear for the precise roll shape provides a precise input for the roll stack deformation model, ensuring precise mill stretch and roll gapprofile calculation for each pass.VAI.rsd3D calculates the full rollstack deformation online without using simplifications to reducecomputing time, in effect offering the accuracy of a detailed 3D finiteelement model can be achieved.
That's right Plate Mill automatic control system introduced some simple.