裝配圖步進(jìn)式加熱爐同步頂升液壓控制系統(tǒng)
裝配圖步進(jìn)式加熱爐同步頂升液壓控制系統(tǒng),裝配,步進(jìn),加熱爐,同步,液壓,控制系統(tǒng)
緒論
1 緒論
1.1 步進(jìn)式加熱爐
1.1.1 步進(jìn)式加熱爐概述
隨著西方資本主義社會在18世紀(jì)進(jìn)入工業(yè)革命以來，社會的發(fā)展進(jìn)入到了一個全新的速度。據(jù)統(tǒng)計(jì)在工業(yè)革命以前世界上人均鋼鐵的使用量是不足5kg。然而，現(xiàn)在的社會發(fā)展到人均鋼鐵擁有量為418kg。越來越多的鋼結(jié)構(gòu)出現(xiàn)在社會建設(shè)中。所以鋼鐵一直是現(xiàn)在社會發(fā)展的主要材料。甚至一度到了供不應(yīng)求的狀況。這樣就促使了鋼鐵產(chǎn)業(yè)的迅速壯大。至2007年，世界鋼鐵量已經(jīng)達(dá)到了近九億噸。但是由于技術(shù)有限，加上人們對鋼鐵的運(yùn)用越加廣泛，出現(xiàn)對鋼材更多更新的要求。所以鋼鐵的冶煉技術(shù)要不斷地改良。
1967 年第1 座步進(jìn)梁式加熱爐投產(chǎn)。中國1979年投產(chǎn)的步進(jìn)梁式爐長為32.5米，生產(chǎn)能力為每小時270頓。步進(jìn)梁式爐比推鋼爐具有許多優(yōu)點(diǎn)，因而成為新建軋鋼廠的首選爐型。熱軋寬帶鋼廠的規(guī)模正向大型化發(fā)展，步進(jìn)梁式爐的特點(diǎn)之一是爐長不受推鋼長度限制，因而能適應(yīng)軋機(jī)的小時產(chǎn)量增長的形勢。北京鋼鐵設(shè)計(jì)研究總院近20 年設(shè)計(jì)投產(chǎn)的40 余座步進(jìn)爐，已遍及熱連軋、型鋼、棒線材、帶鋼、無縫管、開坯、鍛壓等鋼廠以及鋼帶廠，1994年相繼投產(chǎn)的太鋼、梅山熱連軋廠的步進(jìn)梁式爐，額定產(chǎn)量分別為180 t/ h 和280 t/ h ，重慶鋼鐵設(shè)計(jì)研究院為攀鋼1450 熱連軋廠設(shè)計(jì)的步進(jìn)梁式爐，額定產(chǎn)量為150 t/ h ，也在1992 年投產(chǎn)。
早期加熱爐內(nèi)部是用一種連續(xù)式推鋼機(jī)，它的作用是將鋼錠或鋼坯依次推入爐內(nèi)。在端出料的加熱爐中，推鋼機(jī)可以將加熱好的鋼坯從加熱爐的另一端推出去。在側(cè)出料的加熱爐中，推鋼機(jī)將鋼坯推出至出料位置，再由出鋼機(jī)將鋼錠推出去；現(xiàn)在大多數(shù)采用的是步進(jìn)式移動裝置。步進(jìn)式加熱爐加熱溫度均勻，加熱時間快，產(chǎn)量高，生產(chǎn)靈活性大，必要時可以將爐內(nèi)坯料排空。加熱時，坯料下表面的水管黑印小，坯料溫度均勻，加熱的效率也比較高。加熱特殊鋼材是，能滿足對坯料表面質(zhì)量（氧化、脫碳、劃傷等）的高度要求；加熱大型板材時，由于板坯溫度均勻，有利于減少軋制時的厚度差。所以目前步進(jìn)式爐在熱軋板帶車間以及中小型軋鋼車間都得到了廣泛的應(yīng)用。
從上世紀(jì)50年代起由于步進(jìn)式加熱爐移動裝置的出現(xiàn)并且日漸成熟，在許多鋼板和小型型鋼生產(chǎn)中得到了很好的應(yīng)用。作為現(xiàn)代冶金行業(yè)普遍采用的一種加熱爐，他的優(yōu)點(diǎn)值得我們學(xué)習(xí)。
步進(jìn)式加熱爐的結(jié)構(gòu)
A、爐底結(jié)構(gòu)
從爐子的結(jié)構(gòu)看，步進(jìn)式加熱爐分為上加熱步進(jìn)式爐、上下加熱步進(jìn)式爐、雙步進(jìn)梁步進(jìn)式爐等。
上加熱步進(jìn)式爐顧名思義只有上部有加熱裝置，固定梁和移動梁是耐熱金屬制作的，固定爐底是耐火材料砌筑的。這種爐子基本上沒有水冷構(gòu)件，所以熱耗較低。這種爐子只能單面加熱，一般用于較薄鋼坯的加熱。
與推鋼式加熱爐一樣，為了滿足加熱大鋼坯的需要，步進(jìn)式爐也逐步發(fā)展了下加熱的方式，出現(xiàn)了上下加熱的步進(jìn)式加熱爐。這種爐子相當(dāng)于把推鋼式爐的爐底水管改成了固定梁和移動梁。固定梁和移動梁都是用水冷立管支承的。梁也由水冷管構(gòu)成，外面用耐火可塑性包扎，上面有耐熱合金的鞍座式滑軌，類似推鋼式加熱爐的爐底縱水管。爐底是架空的，可以實(shí)現(xiàn)雙面加熱（步進(jìn)式爐鋼坯與鋼坯不是緊靠在一起，中間有空隙，可認(rèn)為是四面受熱）。下加熱一般只能用側(cè)燒嘴，因?yàn)榱⒅鶕踝×硕藷旎鹧娴姆较颍绻捎枚藷?，需要改變立柱的結(jié)構(gòu)型式。上加熱可以用軸向端燒嘴，也可以用側(cè)燒嘴或爐頂燒嘴供熱?？紤]到軸向燒嘴火焰沿長度方向的溫度分布和各段溫度的控制，某些大型步進(jìn)式爐在上加熱各段之間的邊界上有明顯的爐頂壓下，而下加熱各段間設(shè)有段墻，以免各段之間溫度的干擾；因此這樣的步進(jìn)式爐沿爐子長度溫度調(diào)節(jié)有更大的靈活性，如果爐子寬度較大，火焰長度又較短時，可以在爐頂上安裝平焰燒嘴。
B、傳動機(jī)構(gòu)
步進(jìn)式爐的關(guān)鍵設(shè)備是移動梁的傳動機(jī)構(gòu)。傳動方式分機(jī)械傳動和液壓傳動兩種。目前廣泛采用液壓傳動的方式?，F(xiàn)代大型加熱爐的移動梁及上面的鋼坯重達(dá)數(shù)百噸，使用液壓傳動機(jī)構(gòu)運(yùn)行穩(wěn)定，結(jié)構(gòu)簡單，運(yùn)行速度的控制比較準(zhǔn)確，占地面積小，設(shè)備重量輕，比機(jī)械傳動有明顯的優(yōu)點(diǎn)。液壓傳動機(jī)構(gòu)如圖2-12所示。圖2-12b、圖2-12c、圖2-12d三種結(jié)構(gòu)型式目前是比較常見的。我國應(yīng)用較普遍為圖2-12c所示的斜塊滑輪式。以斜塊滑輪式為例說明其動作的原理：步進(jìn)梁（移動梁）由升降用的下步進(jìn)梁和進(jìn)退用的上步梁兩部分組成。上步進(jìn)梁通過輥輪作用在下步進(jìn)梁上，下步進(jìn)梁通過傾斜滑塊支承在輥?zhàn)由?。上下步進(jìn)梁分別由兩個液壓油缸驅(qū)動，開始時上步進(jìn)梁固定不動，上升液壓缸驅(qū)動下步進(jìn)梁沿滑塊斜面抬高，完成上升運(yùn)動。然后上升液壓缸使下步進(jìn)梁固定不動，水平液壓缸牽動上步進(jìn)梁沿水平方向前進(jìn)，前進(jìn)行程完結(jié)時，以同樣方式完成下降和后退的動作，結(jié)束一個運(yùn)動周期。
為了避免升降過程中的振動和沖擊，在上升和下降及接受鋼坯時，步進(jìn)梁應(yīng)該中間減速。水平進(jìn)退時開始與停止也應(yīng)該考慮緩沖減速，以保證梁的運(yùn)動平穩(wěn)，避免鋼坯在梁上擦動。辦法是用變速油泵改變供油量來調(diào)整步進(jìn)梁的運(yùn)行速。由于步進(jìn)式爐很長，上下兩面溫度差過大，線膨脹的不同會造成大梁的彎曲和隆起。為了解決這個問題，目前一些爐子將大梁分成若干段，各段間留有一定的膨脹間隙，變形雖不能根本避免，但彎曲的程度大為減輕，不致影響爐子的正常工作。
C、密封機(jī)構(gòu)
為了保證步進(jìn)爐活動梁（床）能正常無阻礙地運(yùn)動，在活動梁（床）和固定梁（床）之間要有足夠的縫隙，縫隙一般為25mm或30mm，對步進(jìn)梁來說則在梁支撐（或水管）穿過爐底部分有保證它運(yùn)動的足夠大的開孔。這些縫隙或開孔的存在雖然是必要的，但也容易吸入冷風(fēng)，影響加熱質(zhì)量和降低燃料利用率，也可能造成爐氣外逸，危害爐底下部設(shè)備，對軋鋼用步進(jìn)爐則必須考慮密封問題，目前有兩種密封結(jié)構(gòu)，一是滑板式密封，一是水封，前者密封較差，尤其當(dāng)滑板受熱變形后更不能起到密封作用，水封是用得最多的結(jié)構(gòu)，密封效果比較好，水封由水封槽和水封刀兩部分組成，分開式和閉式兩種結(jié)構(gòu)，開式結(jié)構(gòu)有動床和定床二重水封刀，便于清渣；閉式結(jié)構(gòu)僅有動床水封刀，優(yōu)點(diǎn)是占用空間小，緊湊。動床端頭水封槽的寬度要保證大于動床水平行程的長度，水槽下部開有集渣斗，由爐底縫隙中掉落的氧化鐵皮隨水流定期放出。
這里不得不提到的是，之所以在20世紀(jì)50年代才采用（相對于鋼鐵鋼鐵行業(yè)來說），是因?yàn)橐簤簜鲃颖旧淼奶厥獠胖率蛊浒l(fā)展較為緩慢。到20世紀(jì)初液壓傳動技術(shù)從理論到實(shí)際運(yùn)用才基本成熟。在21世紀(jì)液壓技術(shù)的運(yùn)用則標(biāo)志著一個國家基礎(chǔ)工業(yè)發(fā)展水平。在步進(jìn)式加熱爐移動裝置液壓傳動系統(tǒng)中，液壓傳動作為提供動梁運(yùn)動的動力源起著至關(guān)重要的作用。如何設(shè)計(jì)高質(zhì)量的液壓裝置則直接成為影響鋼坯的燒結(jié)質(zhì)量。
早期加熱爐內(nèi)部是用一種連續(xù)式推鋼機(jī)，它的作用是將鋼錠或鋼坯依次推入爐內(nèi)。在端出料的加熱爐中，推鋼機(jī)可以將加熱好的鋼坯從加熱爐的另一端推出去。在側(cè)出料的加熱爐中，推鋼機(jī)將鋼坯推出至出料位置，再由出鋼機(jī)將鋼錠推出去；現(xiàn)在大多數(shù)采用的是步進(jìn)式移動裝置。步進(jìn)式加熱爐加熱溫度均勻，加熱時間快，產(chǎn)量高，生產(chǎn)靈活性大，必要時可以將爐內(nèi)坯料排空。加熱時，坯料下表面的水管黑印小，坯料溫度均勻，加熱的效率也比較高。加熱特殊鋼材是，能滿足對坯料表面質(zhì)量（氧化、脫碳、劃傷等）的高度要求；加熱大型板材時，由于板坯溫度均勻，有利于減少軋制時的厚度差。所以目前步進(jìn)式爐在熱軋板帶車間以及中小型軋鋼車間都得到了廣泛的應(yīng)用。
加熱爐步進(jìn)式移動裝置液壓傳動系統(tǒng)主要是由動梁和靜梁組成。當(dāng)鋼坯被推進(jìn)加熱爐后將其置于靜梁上的，此時鋼坯開始被加熱升溫。加熱爐是軋鋼工業(yè)必須配備的熱處理設(shè)備。隨著工業(yè)自動化技術(shù)的不斷發(fā)展，現(xiàn)代化的軋鋼廠應(yīng)該配置大型化的、高度自動化的步進(jìn)梁式加熱爐，其生產(chǎn)應(yīng)符合高產(chǎn)、優(yōu)質(zhì)、低耗、節(jié)能、無公害以及生產(chǎn)操作自動化的工藝要求，以提高其產(chǎn)品的質(zhì)量，增強(qiáng)產(chǎn)品的市場競爭力?！ ∥覈堜摴I(yè)的加熱爐型有推鋼式爐和步進(jìn)式爐兩種，但推鋼式爐有長度短、產(chǎn)量低，燒損大，操作不當(dāng)時會粘鋼造成生產(chǎn)上的問題，難以實(shí)現(xiàn)管理自動化。由于推鋼式爐有難以克服的缺點(diǎn)，而步進(jìn)梁式爐是靠專用的步進(jìn)機(jī)構(gòu)，在爐內(nèi)做矩形運(yùn)動來移送鋼管，鋼管之間可以留出空隙，鋼管和步進(jìn)梁之間沒有摩擦，出爐鋼管通過托出裝置出爐，完全消除了滑軌擦痕，鋼管加熱斷面溫差小、加熱均勻，爐長不受限制，產(chǎn)量高，生產(chǎn)操作靈活等特點(diǎn)，其生產(chǎn)符合高產(chǎn)、優(yōu)質(zhì)、低耗、節(jié)能、無公害以及生產(chǎn)操作自動化的工藝要求。全連續(xù)、全自動化步進(jìn)式加熱爐。
1.1.2 選題背景
軋鋼廠在熱軋鋼材時，需要對鋼坯進(jìn)行加熱。為了更好的保證鋼材表面質(zhì)量，使鋼坯受熱均勻，采用了步進(jìn)加熱方式。
鋼坯在加熱過程中其前移為矩形運(yùn)動；即活動梁上升，將鋼坯從固定梁上托起；活動梁前移，使鋼坯前步進(jìn)一次；活動梁下降，將鋼坯放在固定梁上；活動梁后退到原始位置完成一個工作循環(huán)。
步進(jìn)加熱克服了直推式加熱時鋼坯下表面與支撐梁（固定梁）移動摩擦所產(chǎn)生的表面磨損；同時，克服了直推式的鋼坯間相互靠攏的情況，可以使鋼坯散開通過爐底，有利于鋼坯的加熱。由于步進(jìn)加熱獨(dú)特的優(yōu)越性，使其在現(xiàn)代冶金工廠得到了廣泛的應(yīng)用。步進(jìn)式鋼坯加熱爐產(chǎn)品質(zhì)量好，熱效率高，操作靈活，適用于多種型材坯料的連續(xù)式加熱。
步進(jìn)式連續(xù)加熱爐靠爐底或水冷金屬梁的上升、前進(jìn)、下降、后退的動作把料坯一步一步地移送前進(jìn)的連續(xù)加熱爐。爐子有固定爐底和步進(jìn)爐底，或者有固定梁和步進(jìn)梁。前者叫做步進(jìn)底式爐，后者叫做步進(jìn)梁式爐。
加熱爐爐床由固定梁和步進(jìn)梁組成。步進(jìn)梁由雙重輪對的多軸框架支撐，外側(cè)走輪由升降缸驅(qū)動，從而使步進(jìn)梁作上升或者下降運(yùn)動。上層托輪直接托住步進(jìn)梁，而步進(jìn)梁直接由另一液壓缸帶動，可在托輪上作前進(jìn)和后退運(yùn)動，從而使步進(jìn)梁作前進(jìn)和后退運(yùn)動。
通過缸的操作，使步進(jìn)梁做矩形跡運(yùn)動，各段運(yùn)動的形式可以調(diào)節(jié)，操作方式可以連續(xù)或者手動操作。同一液壓油源提供步進(jìn)梁傳動，可以同時或交替動作；并可以逆向運(yùn)動，用作為倒空爐內(nèi)鋼坯之用。
液壓傳動有著其不可替代的優(yōu)越性，主要表現(xiàn)在：
A、可以獲得很大的輸出力或力矩，而結(jié)構(gòu)并不復(fù)雜；
B、可以實(shí)現(xiàn)較大范圍的無級調(diào)速，且可在運(yùn)行中直接調(diào)節(jié)；
C、易于實(shí)現(xiàn)過載保護(hù)；
D、動作靈敏，啟動，停止和換向響應(yīng)快，沖擊??；
E、自潤滑性能好；
F、易于實(shí)現(xiàn)通用化，系列化和標(biāo)準(zhǔn)化，設(shè)計(jì)組裝周期短；
G、易于實(shí)現(xiàn)自動化與智能化與數(shù)控技術(shù)相結(jié)合。
本課題的設(shè)計(jì)內(nèi)容是設(shè)計(jì)一個步進(jìn)式加熱爐同步頂升的液壓系統(tǒng)。
1.1.3 設(shè)計(jì)目的
由于步進(jìn)爐的特點(diǎn)是步進(jìn)周期短，運(yùn)動速度較高，慣性負(fù)載大，連續(xù)工作，可靠性要求高等，所以根據(jù)這些特點(diǎn)系統(tǒng)采用液壓控制比較適宜。
當(dāng)今，隨著液壓機(jī)械自動化程度的飛速發(fā)展，液壓元件應(yīng)用數(shù)量急劇增加，元件小型化，系統(tǒng)集成化是必然的發(fā)展趨勢。特別是近十年來，液壓技術(shù)與傳感技術(shù)，微電子技術(shù)緊密結(jié)合，出現(xiàn)了許多諸如電液比例控制閥，數(shù)字閥，電認(rèn)伺服液壓缸等機(jī)（液）電一體化元器件，使液壓技術(shù)在高壓，告訴，大功率，節(jié)能高效，低噪聲，使用壽命長，高度集成化方面取得了重大進(jìn)展。
所以，隨著冶金軋鋼工藝自動化程度的不斷提高，步進(jìn)式加熱爐以其靈活的加熱方式，加熱質(zhì)量好，爐長不受限制，操作方便，易于實(shí)現(xiàn)自動控制等優(yōu)點(diǎn)，被愈來愈多新建的軋鋼加熱爐采用。液壓傳動傳動因其體積小，負(fù)荷大，易于實(shí)現(xiàn)機(jī)電一體化控制等優(yōu)勢，在步進(jìn)式加熱爐中有廣泛的應(yīng)用。
步進(jìn)式加熱爐有著其他加熱爐無法比擬的優(yōu)點(diǎn)，諸如，不拱鋼，不粘鋼，氧化燒損少，脫碳少，加熱時間短，加熱操作靈活，易于和軋制節(jié)奏相匹配，加熱過程中不劃傷，爐子長度不受限制（從理論上講）自動化程度高，易于采用計(jì)算機(jī)控制等優(yōu)點(diǎn)。
因此盡管步進(jìn)爐第一次投資費(fèi)用較高，但是1967年4月由美國德蘭公司設(shè)計(jì)的二面供熱的步進(jìn)梁式爐首先在美國格蘭那特城鋼鐵公司問世以來，接著同年5月由日本中外爐公司為名古屋鋼鐵廠設(shè)計(jì)的世界上第二座步進(jìn)梁式爐又相繼投產(chǎn)，以后步進(jìn)式加熱爐在世界上獲得了長足的發(fā)展。
和推鋼式連續(xù)加熱爐相比，步進(jìn)式爐具有以下優(yōu)點(diǎn)：
（1）加熱靈活。在爐長一定的情況下，爐內(nèi)坯料數(shù)目是可變的。而在連續(xù)加熱爐中則是不可變的，那樣加熱時間就受到限制。例如爐子產(chǎn)量降低一半時，則
爐內(nèi)坯料加熱時間就會延長一倍，對有些鋼種來說這是不利的，而步進(jìn)爐在爐子小時產(chǎn)量變化的情況下可以通過改變坯料間距離來達(dá)到改變或保持加熱時間不變的目的。
（2）加熱質(zhì)量好。因?yàn)樵诓竭M(jìn)爐內(nèi)可以使坯料間保留一定的間隙，這樣擴(kuò)大了坯料受熱面，加熱溫度比較均勻，鋼坯表面一般沒有劃傷的情況，兩面加熱時坯料下表面水管黑印的影響比—般推鋼式連續(xù)加熱爐的要小些。
（3）爐長不受限制。對連續(xù)加熱爐來說爐長受到推鋼長度的限制，而步進(jìn)爐則不受限制。而且對于不利于推鋼的細(xì)長坯料、圓棒、彎曲坯料等均可在步進(jìn)爐內(nèi)加熱。
（4）操作方便。改善了勞動條件，在必要時可以將爐內(nèi)坯料全部或部分退出爐外，開爐時間可縮短；由于不容易粘鋼，因此可減輕繁重的體力勞動；和軋機(jī)配合比較方便、靈活。
（5）可以準(zhǔn)確地控制爐內(nèi)坯料的位置，便于實(shí)現(xiàn)自動化操作。
尤其是近10多年來，隨著軋鋼技術(shù)向著連續(xù)化，大型化，自動化，多品種，高精度的發(fā)展，步進(jìn)式加熱爐為適應(yīng)工藝的要求，也朝著大型化，多功能，高產(chǎn)，低消耗和操作集成自動化的方向邁進(jìn)。
可以預(yù)見，隨著液壓技術(shù)的不斷進(jìn)步，更加高自動化的加熱爐會被人們所應(yīng)用。
1.1.4 設(shè)計(jì)方案
步進(jìn)爐的機(jī)械結(jié)構(gòu)采用的是斜坡滾輪式液壓傳動。水平移動和升降都由液壓缸驅(qū)動,步進(jìn)框架下面的滾輪沿斜臺面升降。
這種結(jié)構(gòu)有兩層框架,下層是提升框架。上層為水平移動框架。在提升框架的上面和下面均安有滾輪,每個下滾輪放在一個斜臺面上,上滾輪供平移框架移動用，移動缸通過曲柄連桿和旋轉(zhuǎn)接頭與上框架連接,提升缸用旋轉(zhuǎn)接頭直接與下框架連接。下框架用斜面輥導(dǎo)向,上框架用水平輥導(dǎo)向。
加熱爐的步進(jìn)機(jī)構(gòu)和液壓系統(tǒng)主要由雙層步進(jìn)框架，液壓缸，液壓泵以及各種閥件組成。如圖：上一層為行進(jìn)框架，下一層為升降框架。行進(jìn)框架是通過支撐輥和輥道落在升降框架上，升降框架也通過支撐輥和輥道落在基礎(chǔ)上。當(dāng)升降框架在在升降液壓缸驅(qū)動下沿斜軌道左升降運(yùn)動時，步進(jìn)梁和行進(jìn)框架也一起作垂直方向的升降運(yùn)動，在平移液壓缸的驅(qū)動下，在水平方向作進(jìn)退運(yùn)動，從而完成整個周期循環(huán)動作。
液壓系統(tǒng)的改進(jìn)
對原有系統(tǒng)中舉升液壓缸水平拉動動梁上升的部分，可以改為將此液壓缸放置在爐底，同時讓液壓缸與上升滾輪的斜面保持同樣的斜度。這樣就有效的解決了拉力大，液壓缸有桿腔推動無桿腔做大功率運(yùn)動的情況，同時也減小了液壓缸的尺寸，便于設(shè)計(jì)和安裝。
步進(jìn)梁動作如圖1所示：
圖1 步進(jìn)梁動作示意圖
步進(jìn)梁的升降和平移均采用電液比例閥來控制，其優(yōu)點(diǎn)是控制調(diào)整靈活方便，工作平穩(wěn)。在設(shè)計(jì)過程中，應(yīng)該考慮到步進(jìn)梁平移時可能會產(chǎn)生很大的慣性沖擊，實(shí)現(xiàn)加速、減速、勻速，從而實(shí)現(xiàn)動梁對熱坯的輕托、輕放，以及通過加、減速有效降低動梁因運(yùn)動慣性引起的機(jī)械沖擊，下降的時候依靠自身自重下降。
通過PLC編程設(shè)置加減速曲線，既避免了沖擊對設(shè)備造成的傷害，又提高了系統(tǒng)的定位精度，通過PLC控制達(dá)到同步頂升精度要求。
步進(jìn)梁動作軌跡如圖2所示：
圖2 步進(jìn)梁動作軌跡圖
1 introduction
1.1 Step into the furnace
1.1.1 Step into the furnace overview
As western capitalist society in the 18 th century since the industrial revolution, the development of the society entered a new speed. According to the statistics in the industrial revolution in the world before the usage of the per capita steel is less than 5 kg. However, now of the social development to the ownership for 418 kg per capita steel. More and more steel structure appear in socialist construction. So steel has been now the main material of social development. And even once the shortage of supply. This prompted the steel industry is growing rapidly. To the year 2007, the world GangTieLiang has reached nearly nine hundred million tons. But because technology Co., LTD, add people to use more widely, steel emergence of steel more demand. So the steel and iron the smelting technology constantly improved.
The first step in 1967 a beam furnace put into production. China 1979 years of production walking beam furnace is 32.5 meters long, production capacity of 270 tons per hour. Walking beam furnace stove than push steel have many advantages, thus become the first choice of rolling mills new furnace type. The scale of the steel rolling broadband is large development, walking beam furnace is one of the characteristics of furnace long from push steel, and can adapt to limit the length of mill production growth hour of the situation. Beijing steel design research institute nearly 20 years design of production more than 40 buildings stepping furnace, already pervaded strip, finances, great wire, strip steel, seamless tube, KaiPi, forging and other steel and steel belt factory, in 1994 have put in taigang, meishan strip factory of walking beam furnace rated output, respectively for 180 t/h and 280 t/h, chongqing iron and steel institute of design for pangang during the 1450 factory design walking beam furnace, rated output for 150 t/h, also put into production in 1992.
Early heating furnace interior is a continuous type push with steel machine, it is the role of ingot or billet in turn push in charging. In the end the material, the furnace of steel machine can push will heating good from the other end of the billet reheating furnace out. In side out of the furnace of material, push the steel billet machine will be launched to the material position, again by the steel ingot machine will be out; Now most use is stepping type mobile device. Step into the furnace heating temperature even, heating time fast, high output, and big production flexibility and may, when necessary, will furnace empty blank. Heated, the blank of the surface of the water pipes under small black imprint, blank temperature even, heating efficiency is high. Heating special steel is, can be met on the surface quality of the blank (oxidation, decarburization, scratch, etc) height requirements; Heating large panel, as the slab temperature even, to reduce the thickness different rolling. So now stepping type furnace in the hot rolled strip workshop and small and medium-sized steel rolling workshop have been widely used.
From the 1950 s due to step into the furnace and the emergence of the mobile devices to mature, in many steel plate and small steel production are a good application. As a modern metallurgy industry is generally used a furnace, and his advantage worth learning.
Step into the structure of the furnace
A, furnace bottom structure
From the structure of the stove, see the step furnace is divided into heating stepping type furnace, heating up and down the step type furnace, double walking beam stepping type furnace, etc.
On the step heating furnace heating device upside has only just as its name implies, fixed beam and mobile leung is heat-resistant metal production, fixed furnace bottom is refractory lining. The stove is basically no water-cooling elements, so the heat consumption is low. The stove can only single heating, general for a thin billet heating.
And pushed steel as furnace, in order to meet the need of the billet heating big, stepping type furnace is also gradually development under the heating of the heat of the up and down, appeared to step into the furnace. The stove is equivalent to push steel type furnace of furnace bottom water pipe into a fixed beam and mobile beam. Fixed beam and mobile beam with water-cooled stand pipe support. By water cooling tube beam also form, with refractory plasticity bandage, outside a heat resistant alloy above the saddle type slippery course, similar to the guide on pusher-type reheating furnace of furnace bottom longitudinal pipe. Furnace bottom is of built on stilts, can realize double heating (step type furnace and billet is not close to the billet together, and there is a gap, can think is heated) all. Heating under general can only use side burner, because pillar blocking the end burner flame direction, if want to the burner, the need to change the structure of the pillar type. Heat can be used on axial end burner, you can also use the burner or top burner heating. Considering the axial burner flame along the length direction the temperature distribution and the control of the temperature, some each large step type furnace in each of the boundary between the heating furnace roof are clearly under pressure, and heating under paragraphs with between wall, in order to avoid the interference between each temperature; So this step type furnace stove temperature control along the length of the more flexibility, if the stove is larger, the flame length and width of the relatively short time, can be installed on the roof in flat flame burner.
B, a transmission mechanism
Stepping type furnace is the key equipment moving beam transmission mechanism. The transmission way points mechanical transmission and hydraulic pressure drive two kinds. So far as the widely used hydraulic transmission way. Modern large-scale furnace mobile beam and the above billet weighs hundreds of tons, use hydraulic transmission mechanism, stable operation, the structure is simple, the operation speed control is accurate, cover an area of an area small, equipment, light weight, than the mechanical transmission has obvious advantages. Hydraulic transmission mechanism as shown in figure 2 to 12 as shown. Figure 2 to 12 b, figure 2 to 12 c, figure 2 to 12 d three structural type is now more common. Our country to apply more common for figure 2 to 12 c shows the inclined piece of slippery wheel. To the piece of slippery wheel as an example of the action principle: walking beam (mobile beam by lifting the use under) walking beam and the crust with a beam of two parts. Crust beam through the roll wheel, the next step into the role the beam, the next step beam by tilting the slider bearing in the roll. Fluctuation walking beam respectively by two hydraulic oil cylinder driving, beginning crust beam stationary, and rising hydraulic cylinder drive walking beam along the slider cant drive up, finish up movement. Then rises hydraulic cylinder makes the next step beam stationary, and level hydraulic cylinder will affect beam along horizontal direction, forward trip ends, in the same way down the action of a back and finish, ending a movement cycle.
In order to avoid in the process of lifting vibration and impact, in the up and down and accept billet, walking beam should slow down among. When a start and stop the level should be considered a buffer to slow down, to ensure the smooth movement of the beam, avoid the beam slab wipe move. Way is to change the flow of variable speed pump to adjust walking beam operation speed. Due to step into type furnace is very long, excessive temperature difference fluctuation two sides, the different linear expansion will cause the beam bending and uplift. In order to solve this problem, the beam will present some into segments, paragraphs with the expansion of the gap between certain deformation, though, but can't avoid bending degree is reduced greatly, and not affect the normal work of the stove.
C, seal institutions
In order to guarantee the step furnace activities (bed) can beam normal unimpeded movement in activities, (bed) and beam fixed beam (bed) to have enough between the gap, gap is commonly 25 mm or 30 mm, the step for the beam supporting beams is (or conduit) through the furnace bottom part is that it sports large enough the holes. Those cracks or although the existence of hole is necessary, but also easy to inhaled air cooling, heating quality and reduce the influence fuel efficiency, also may cause furnace gas to escape and harm the furnace of steel rolling equipment, under to step into the oven with sealing problem must be considered, there are two sealing structure, a slide type is a water seal, is, the former seal is bad, especially when a skateboard heated deformation after sealing function, couldn't be more water is the most used structure, sealed effect is better, the water seal water and water to seal groove by the sword of two parts, the separation of type and closed two kinds of structure, type structure have move bed and fixed bed double sword for clear water, slag; Closed structure only move water bed knife, take up the space is little, the advantages of compact. Move the width of the slot water bed end to ensure that more than moving bed the length of the water level, the trip has set a slag, open by a crack in the furnace bottom dropped oxidized scale with flow out regularly.
Have to mention here, are used only in the 1950 s (relatively) steel industry, for steel because of the special hydraulic drive itself that made its develop very slowly. To the 20 th century hydraulic transmission technology from theory to practice of using just basic mature. In the 21 st century hydraulic technology application will mark a national base level of industrial development. In step furnace mobile device hydraulic transmission systems, hydraulic transmission as providing dynamic beam the power source of the sports plays a vital role. How to design and high quality hydraulic device is directly affect the quality of a billet sintering.
Early heating furnace interior is a continuous type push with steel machine, it is the role of ingot or billet in turn push in charging. In the end the material, the furnace of steel machine can push will heating good from the other end of the billet reheating furnace out. In side out of the furnace of material, push the steel billet machine will be launched to the material position, again by the steel ingot machine will be out; Now most use is stepping type mobile device. Step into the furnace heating temperature even, heating time fast, high output, and big production flexibility and may, when necessary, will furnace empty blank. Heated, the blank of the surface of the water pipes under small black imprint, blank temperature even, heating efficiency is high. Heating special steel is, can be met on the surface quality of the blank (oxidation, decarburization, scratch, etc) height requirements; Heating large panel, as the slab temperature even, to reduce the thickness different rolling. So now stepping type furnace in the hot rolled strip workshop and small and medium-sized steel rolling workshop have been widely used.
Heating furnace stepping type mobile device hydraulic transmission system is mainly composed of dynamic and static beam of beam. When billet reheating furnace was pushed it in the static beam, this time the billet heating temperature began to be. Heating furnace of steel rolling industry is must be equipped with heat treatment equipment. With the continuous development of industrial automation technology, modern rolling mills shall be equipped with large, highly automated walking beam furnace, the production should be consistent with high yield, good quality and low consumption, energy saving, pollution-free, and production automatic operation process requirement, in order to improve the quality of its products, enhance the market competitiveness of products. The heating furnace of steel rolling industry in our country, which has pushed steel type furnace and step into the furnace two kinds, but pushed steel type furnace is short, low yield of length, the burning of the big, improper operation will stick by the problem on the steel production to realize the automation management. Due to push steel type furnace is difficult to overcome shortcomings, and walking beam furnace is special stepping on organization, in furnace rectangular steel pipe to do exercise to leave space between, steel pipe, steel tube and can be walking beam no friction between steel pipe, come out by over to completely eliminate the device slippery course scratching, steel tube heating section temperature difference is small, even heating furnace, long is not limited, high output, and production operation is flexible and other characteristics, its production meet high yield, high quality, and low consumption, energy saving, pollution-free, and production automatic operation process requirement. The continuous, full automatic step furnace.
1.1.2 To choose a background
In the hot rolling steel rolling mills, need on billet heating. In order to better ensure steel surface quality, make the billet is heated evenly, using a step heating mode.
Billet heating process goes forward in the movement for rectangular; That activity, from rising beam slab fixed beam raise; Activities, before the forward beam slab step one time. Activities, will be put down beam slab fixed beam; Beam back to the original position activities to compl
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