外文翻譯--輥縫潤滑工作輥冷卻及反剝系統(tǒng)在熱軋鋼機上的協(xié)調(diào)應(yīng)用(20210312234125)

1、附錄 ACoordinated Application of RollGap Lubrication,Work Roll Cooling and Antipeeling Systems in Hot Rolling MillsSurface quality requirements for hot rolled steel sheet have continued to become more stringent in recent years. This focus on sheet quality has developed in parallel with corresponding d

2、emands for increased productivity and reduced costs at the mill. Although not a panacea, roll gap lubrication systems have received increased attention in support of these objectives. Specifically, roll gap lubrication systems are used in combination with work roll cooling systems and antipeeling sy

3、stems to:Reduce rolling loads and thereby reduce potential for chatter.Reduce rolling torques and associated energy requirements.Enable redistribution of loads among stands to address chatter issues.Increase reductions to decrease final strip thickness.Reduce potential for rolled-in scale.Extend rol

4、ling campaign length.These systems must also be designed and operated in a manner that will:Assure good plating of the oil onto the work roll surface.Maintain stability of mill control systems.Minimize the environmental impact of vapor emissions and spent fluids.Prevent clogging of fluid supply line

5、s.The effective implementation of these systems can provide enhance control over the thermal and tribological conditions in the roll bite to achieve objectives for product quality and mill productivity. These systems have undergone development for a number of years and are now being implemented and

6、refined throughout the world. Overview of Chatter and Peeling on Roll Surfaces The early stands of steel hot finishing mills routinely operate at relatively high loads and relatively low speeds.These operating conditions represent a very aggressive environment for mill work rolls. High loads, combin

7、ed with other factors, can contribute to mill stand vibrations commonly known as chatter. These vibration produce cyclic loading conditions in the stand, which can produce visible marks on the roll surface. These marks are then transferred to the sheet, producing an undesirable surface quality.The e

8、ffective implementation of roll gap lubrication technology can make it possible to reduce and/or redistribute loads in the mill, thus decreasing or eliminating chatter. Furthermore, the strip surface temperatures that are the contact time between the strip and the work roll, impacts the temperatures

9、 that are reached on the roll surface. Higher temperaturesaccelerate the formation of oxides on the roll surface. Thin layers of these oxides can then be“peeled off”the roll surface by the alternating shear stresses associated with slip in the roll bite. When this occurs, it results in a roll surfac

10、e defect commonly called“peeling”.These peeling marks also negatively affect the strip surface quality , producing what is known as rolled-in scale. Solutions to the peeling problem involve establishing a balance between oxides growth and wear at a minimal thickness in the roll bite.Antipeeling and

11、work roll cooling technologies are utilized to achieve this balance. These technologies must be coordinated with the roll gap lubrication systems in order to assure optimal effectiveness of each technology.Overview of System Hardware and OperationThe work roll cooling headers are provided on both th

12、e entry and exit sides of the stand. The area of spray coverage in the roll is largest in the exit side. This provides the maximum cooling effect when the roll surface is at its highest temperature shortly after it rotates out of contact with the strip.Work roll cooling headers are also mounted on t

13、he entry side of the stand. These entry side headers are disabled when the roll gap lubrication headers are operated, so as not to wash off the oil before it can effectively plate onto the roll surface.The roll gap lubrication headers are also located on the entry side of the stand. They spray an oi

14、l/water dispersion onto the roll surface prior to its rotation through the stand entry wiper. As the water component of the dispersion is vaporized, the pressure that is exerted by the wiper enhances the plating of the oil onto the work roll surface.Configuring and operating the system in this manne

15、r ensures that the oil is plated onto the work roll surface so that it will enter the roll bite without being washed away. This oil provides the lubrication in the bite to reduce loading in the rolling process.Antipeeling headers are fitted on the entry side of the stand. These headers apply coolant

16、 directly onto the strip to reduce its surface temperature before it enters the roll gap.Because of the close proximity to the roll bite, there is a very little time for conduction to redistribute the temperature within the body of the strip. Hence, only the strip s surface temperature is significan

17、tly reduced before entering the roll bite, and temperature at the core of the strip remain essentially unchanged.The lower strip surface temperature also reduces the resulting roll surface temperature by reducing the driving force for conduction between them. This decreases the rate of formation oxi

18、des on the roll surface, which reduces the tendency for peeling.Roll Gap LubricationThe roll gap lubrication headers are supplied with oil/water dispersion. Separate systems are provided for top and bottom headers in each equipped mill stand. The water /oil dispersion is formed in a static mixer loc

19、ated just before the spray header. By creating the dispersion in close proximity to the header, the time for the oil to break out is minimized, and the length of piping subject to clogging by the dispersion is also reduced.The oil flow is provided by metering pumps and is enable only during rolling.

20、 Metering pump speed is regulated to maintain a specified volume flowrate for the process. Adjustable throttling valves regulate the water flowrate. Water flow is maintained, even when the oil is shut off, to help clear piping deposits and thereby prevent clogging.The headers spray width is adjusted

21、 to the width of the strip being rolled via air-operated shut off valves. This approach provides the dispersion only to the aea where it is required on the work roll barrel. By limiting the rolling operation, the volume of oil consumed, along with the associated operating cost, is minimized.This app

22、roach also addresses environmental; considerations, in that the volume of vapor emissions and the volume of waste fluids that require special disposal are reduced. The result is that the headers and spray nozzles provide uniform application of the dispersion to the top and bottom work rolls in the a

23、rea of contact with the strip.It should also be noted that water quality can significantly affect the performance of the oil/water dispersion. Therefore, the oil supplier must adapt the oil quality to the water quality.Impact of Roll Gap Lubrication and Operating PhilosophiesProperly designed roll g

24、ap lubrication systems reduce friction in the roll bite and thereby reduce the resulting rolling load. Although some variations exist, there are predominantly three philosophies that are followed in the operation of roll gap lubrication systems.The first philosophy is “body only”. It is typical of o

25、peration for the first stand of the finishing mill, although some roll gap lubrication systems follow this practice on other stands as well. In this philosophy, the oil flow is not enabled until after the strip has threaded through the stand. This provides a higher friction condition during threadin

26、g to reduce the potential for bite rejection.Note that when RGL is enabled, there is a significant reduction in rolling load. The oil flow is again disabled before tailout, so that any residual oil that remains on the roll surface can be consumed in the process. This restores the effective friction

27、to a higher level prior to threading of the next strip. It also results in a corresponding increase in the rolling load.This approach supports threading operations, but the significant changes in loading that correspond to the activation and deactivation of the roll gap lubrication system produce tr

28、ansients that must be addressedby the mill control systems. The impact of these transients will be discussed later.The second philosophy is “body and tail ”. This approach has historically been followed on stands F2-F7. Here, the roll gap lubrication system is enabled after threading, but it is not

29、disabled until tailout is completed. Operating in this manner still produces a load transient at the beginning of the coil, but it eliminates the one at the end.Impact of Oil Volume Flowrate on Rolling LoadThe load reduction that is afforded by roll gap lubrication depends on a number of factors, on

30、e of which is the volume flowrate of oil. Representativetests have been performed to analyze the effect of oil flowrate on rolling load at stands F2-F4. Note that roll gap lubrication is on only the upper work roll of stand F2.Also note that the loading reduction on each of the stands appears to be

31、approaching a limiting value asymptotically, as oil volume flowrate is increased. Hence, there is a limit to the benefit obtained with application oil application. Increasing oil application beyond this point would only increase operating cost and potential environmental issues while providing littl

32、e or no benefit.During these tests, only the upper header was operating on F2. Hence, the rolling force reduction may be different with both headers operating, but the trend of decreasing benefit with volume flowrate is still visible.Other loading and operating conditions, as well as other oil and w

33、ater dispersion, may exhibit different volume flowrate requirements to approach this limiting point. Nevertheless, the general behavior of receiving diminishing returns for continued increasesin oil volume flowrate is expected to hold for these other applications as well.Control Systems and Roll Gap

34、 LubricationIt has been shown that significant changes in stand loading occur when roll gap lubrication is enabled during the rolling of a coil. These changes in loading will have a corresponding impact on roll stack deflections and mass flow in the mill. As a result, when adding roll gap lubricatio

35、n, the control systems for thickness control, for profile and flatness control, and for tension control must be simultaneously optimized in order to fully realize its benefits.Note that when the roll gap lubrication is enabled, the roll force reductions in these cases are on the order of 36and 44 pe

36、rcent, respectively. These are very significant drops in roll force, and they require a corresponding reduction in roll bending to maintain flat strip and strip profile.Furthermore, most of this roll force reduction occurs over a relatively short period of time. Hence, a rapid control response is re

37、quires from the bending systems to maintain good strip shape.Roll Gap Lubrication s Impact on ChatterMill chatter results from vibrations in a stand that subsequently mark the roll surfaces.Chatter problems are frequently addressed by reducing the load in the stand that is experiencing vibration. Th

38、is load reduction has historically been accomplished by decreasing the reduction that is taken on that stand. This approach requires a redistribution of reductions across the other mill stands, and consequently higher loading on those other stands.Other Potential Benefits of Roll Gap LubricationIt h

39、as been shown that roll gap lubrication provides the steel producer with a tool to reduce rolling loads and to correct certain types of chatter problems. Additional benefits, such as improved strip surface quality, extended roll life and other potential benefits, are also reported in literature.A de

40、tailed discussion of these topics is outside the scope of this paper; nevertheless,the following comment on the use of roll gap lubrication to enhance strip surface quality and extend roll life is offered for consideration of the reader.Roll gap lubrication systems may reduce strip surface contamina

41、tion from roll oxides and rolled-in strip scale.This reduction in power consumption is a benefit that is typically achieved with roll gap lubrication technology, but elimination of chatter and improved surface are more frequently cited as the justifiable benefits.ConclusionFollowing is a summary of

42、the main points concerning the application of roll gap lubrication of roll gap lubrication, work roll cooling and antipeeling systems. Roll Gap LubricationMust be applied in a manner that enables the oil to effectively plate onto the workroll surface.Can significantly reduce loading, torque and powe

43、r requirements in a stand by reducing friction in the roll bite.Will provide a means to directly reduce chatter by reducing load.Can also provide a means for redistributing loads among stands to address chatter problems.Can require significant control system responses to transients in flatness and m

44、ass flow if it is enable during rolling.Can be operated in conjunction with roll cooling and antipeeling systems to function through the length of the coil and thereby avoid these transients.Will enhance strip surface quality and rolling campaign length.Will not fix previously existing descaling pro

45、blems.Can be operated at a minimum effective volume and width to minimize cost and environment impact.Can be significantly affected in performance by changes in water composition and quality.Requires a more sophisticated setup model.Antipeeling SystemsReduce the strip surface temperature, and thus l

46、ower roll surface temperature.Reduce oxide formation and peeling as a result of the lower roll surface temperature.Can be used with roll gap lubrication without removing properly applied oils. Work Roll Cooling SystemsMust be most effective on the mill exit side, where roll surface temperature is hi

47、ghest.Must be disabled on the mill entry side when roll gap lubrication is applied there.附錄 B 輥縫潤滑，工作輥冷卻及反剝系統(tǒng)在熱軋鋼機上的協(xié)調(diào)應(yīng)用對于熱軋薄板表面質(zhì)量的需求近年來要求越來越高。 在軋鋼機上這種對薄板 質(zhì)量的要求已經(jīng)發(fā)展為與提高工業(yè)生產(chǎn)力的一致要求和降低成本同等重要。 輥縫 潤滑系統(tǒng)雖然不是靈丹妙藥，但在這些客觀事實的支持下得到越來越多的關(guān)注。 特別是輥縫潤滑系統(tǒng)已和工作輥冷卻系統(tǒng)及反剝系統(tǒng)聯(lián)合使用，如：減少軋制負(fù)荷，因此降低潛在的軋制帶來的噪音； 根據(jù)能量條件降低軋制扭矩； 能夠在軋機

48、間重新分配負(fù)荷，解決噪音問題； 加大變形量，降低最后的軋件厚度； 減少潛在的壓入尺度；增加軋制長度。這些系統(tǒng)必須按照如下的方法設(shè)計和操作： 在工作輥表面上保證高質(zhì)量的潤滑油噴涂； 保持軋鋼機控制系統(tǒng)的穩(wěn)定性； 使水汽的蒸發(fā)和液體的消耗這些環(huán)境的影響達到最?。?防止液體供應(yīng)線上的障礙。通過控制軋制時的溫度和摩擦條件， 這些系統(tǒng)的有效執(zhí)行能夠加大控制， 以 使產(chǎn)品質(zhì)量及軋鋼機生產(chǎn)力提高。 這些系統(tǒng)已經(jīng)經(jīng)歷了很多年的發(fā)展， 現(xiàn)在已經(jīng) 應(yīng)用于全世界。噪音及軋輥表面剝落的概述早期的熱軋鋼機常規(guī)操作標(biāo)準(zhǔn)是相對高的載荷和相對低的速度。 這種操作條 件對于軋機的工作輥是一個非常好的環(huán)境。 重載與其他一些因素相

49、結(jié)合， 能夠?qū)?致軋機持久的振動， 通常被認(rèn)為是噪音。 這些振動產(chǎn)生持久的周期載荷， 它們能 在軋輥表面產(chǎn)生明顯的痕跡。 然后這些痕跡被轉(zhuǎn)移到鋼板上， 進而生產(chǎn)出令人不 滿意的鋼板表面質(zhì)量。輥縫潤滑技術(shù)的有效施行使在軋機上減少或者重新分配載荷成為可能， 因而降低或消除噪音。此外，軋件表面溫度，軋件和工作輥的接觸時間，溫度影響已 經(jīng)到達了軋輥的表面。高溫加快了在軋輥表面上氧化物的形成。這些氧化層通過 交替的剪切壓力與軋輥咬入結(jié)合能夠在軋輥表面剝落。當(dāng)這種情況發(fā)生時，它的結(jié)果是在軋輥的表面產(chǎn)生了 缺陷，通常叫做“剝落”。這些剝落的痕跡消極地影響了軋件的表面質(zhì)量， 產(chǎn)生了所謂的壓入尺度。解 決剝落問

50、題需要在軋輥咬入的最小厚度上建立氧化層增長和剝落的平衡。反剝落和工作輥冷卻技術(shù)在達到這種平衡上派上用場。為了保證每種技術(shù)達 到最佳的效果這些技術(shù)必須與輥縫潤滑系統(tǒng)相協(xié)調(diào)。系統(tǒng)硬件及操作的概述工作輥冷卻端在機架進出口都有分布。在軋輥上噴射面積最大的在出口處。 這種布置在軋輥表面溫度達到最高時提供了最有效的冷卻效果一瞬間軋輥旋轉(zhuǎn) 與軋件分離。工作輥冷卻端也被安裝在機架的入口處。當(dāng)輥縫潤滑端被應(yīng)用時這些入口端 冷卻就會失去作用，因此在它有效地噴涂到軋輥表面之前不要沖刷掉潤滑油。輥縫潤滑端也被安裝在機架的入口側(cè)。它們噴射的油或者是水通過入口的管 道優(yōu)先噴射到軋制的表面。隨著水分的蒸發(fā)，被管道利用的壓力

51、增強了潤滑油噴 涂到工作輥表面的能力。用這個方法裝配和操作這個系統(tǒng)，確保了潤滑油噴涂到工作輥的表面， 以便 在潤滑油沒有被沖刷掉時進入咬入。為了減小在軋制過程中的載荷，這種油在咬 入時提供了潤滑劑。反剝落端也被安裝在機架的入口側(cè)。反剝落端在軋件進入輥縫前運用冷卻劑 直接噴到軋件上降低它的表面溫度。因為與軋輥咬入處非常接近，在軋件內(nèi)部僅有非常少的時間傳導(dǎo)、分配溫度。 因此，僅僅軋件表面的溫度在進入軋輥咬入之前真正地降低了， 而軋件中心部分 的溫度仍然保持不變。通過減小軋輥和軋件間的軋制力，相對低的軋件表面溫度也可以降低軋輥表 面溫度。這樣降低了在軋輥表面氧化物形成速度，也減少了剝落的傾向輥縫潤滑

52、輥縫潤滑頭部供給分散的油或水。 每臺軋機都在上輥和下輥上提供了分離系 統(tǒng)。在噴射前水或油形成靜態(tài)的混合物。 通過在非常接近軋輥頭部的地方噴射潤 滑油，使?jié)櫥偷牡温鋾r間達到最小，通過噴射也可以減少輸送的長度。潤滑油僅僅在軋制過程中由計量泵供應(yīng)。為了保證潤滑油流動是特定的值， 對于軋制過程計量泵的速度是一個定值。適當(dāng)調(diào)節(jié)管道的閥可調(diào)整水流動的速 度。即使油管關(guān)閉， 水的流動也是持續(xù)的， 幫助清理管道的沉淀物從而阻止障礙 物。頭部噴射寬度的調(diào)整是根據(jù)軋件被軋制的寬度經(jīng)過氣流閥關(guān)閉的。 這種方法 僅在工作輥需要的地方提供噴射的潤滑油。 通過限制噴涂的寬度和僅在軋輥軋 制時供油，油量的消耗和與之相關(guān)的

53、操作費用都達到最小。這種方法亦考慮到了環(huán)境的因素， 需要特殊處理的水汽的蒸發(fā)體積和污水排 放的體積減少了。這樣做的結(jié)果是頭部和噴嘴在工作輥上輥和下輥與軋件連接處 供給相同量的潤滑油。需注意的是，水的質(zhì)量能夠在很大程度上影響水油分布的工作情況。因此， 供油系統(tǒng)必須使油的質(zhì)量適應(yīng)水的質(zhì)量。輥縫潤滑及操作系統(tǒng)的影響正確地設(shè)計輥縫潤滑系統(tǒng)可以減少軋輥咬入時的摩擦，從而減少軋制的負(fù) 荷。盡管有一些變化存在， 在輥縫潤滑系統(tǒng)操作上主要有三種操作系統(tǒng)。 第一種 是“只有輥身” 操作系統(tǒng)模型。 盡管一些輥縫潤滑系統(tǒng)也在其它架軋機上用這種 方法，但對于第一架和最后一架軋機這是一種典型的操作系統(tǒng)模型。 在這種操作 模型中潤滑油不流動直到軋件通過軋機， 這樣在軋制過程中提供了一個高摩擦條 件，減少了咬入障礙的潛在可能性。需要注意的是，當(dāng)RGL可操作時，軋制載荷顯著地減少。軋件尾部出來之前， 潤滑油仍然是不可流動的， 以便殘留的潤滑油保留在軋輥的表面在軋制過程中被 消耗。這種重建給下一個軋件的軋制帶來了高程度的摩擦條件， 也導(dǎo)致了軋制負(fù) 荷的增加。這種方法提供了一種線性操作， 與輥縫潤滑系統(tǒng)活動端和不動端相配的負(fù)荷 產(chǎn)