水煤漿噴嘴熱沖蝕磨損機理研究

第23卷第5期摩擦學(xué)學(xué)報Vol 23, No 52003年9月TRIBOLOGYSep,2003水煤漿噴嘴熱沖蝕磨損機理研究丁澤良2,李劍峰1,鄧建新,艾興,張德威2(1.山東大學(xué)機被工程學(xué)院,山東濟南250061;2.株洲冼煤廠(chǎng),湖南株洲412005)摘要:采用1Cr18NiTi不銹鋼、YG8硬質(zhì)合金和Al2O3/(W,Ti)C陶瓷3種材料制備了水煤漿噴嘴,考察了其在水煤漿霧化和燃燒過(guò)程中的熱沖蝕磨損機理結果表明:噴嘴材料的硬度對水煤漿噴嘴的熱沖蝕磨損行為具有重要影響在相同條件下,高硬度的A12O3/(W,TC陶瓷噴嘴的沖蝕率最低YG8硬質(zhì)合金次之,硬度較低的1cr18NTi不銹鋼噴嘴的沖蝕率最高;在熱沖蝕磨損工況下,Cr18Ni9Ti不銹鋼水煤漿噴嘴主要呈現微切削特征,YG8硬質(zhì)合金水煤漿噴嘴主要呈現晶粒剝落特征,而A2O3(W,Ti)C陶瓷水煤漿噴嘴主要呈現研磨損傷和熱崩特征,關(guān)鍵詞:水煤漿;噴嘴;沖蝕磨損中圖分類(lèi)號:THl17.3文獻標識碼:A文章編號:104-0595(2003)05-044104水煤漿作為1種新型煤基代油液體燃料已廣泛2.52g/cm3,平均粒徑1m)和(W,T)C固溶體(株應用于我國電力、冶金和建材等行業(yè)的鍋爐和窯爐.洲硬質(zhì)合金廠(chǎng)提供,平均粒徑1.5m)按一定配比進(jìn)噴嘴是水煤漿燃燒器的關(guān)鍵部件之一,在水煤漿的霧行混合強化球磨(球磨后粉末平均粒徑<0.8μm);化和燃燒過(guò)程中噴嘴發(fā)生嚴重熱沖蝕磨損~4,為將混合粉末干燥后在流動(dòng)氮氣中過(guò)篩然后在氮氣氣了探索研制具有優(yōu)良抗熱沖蝕性能的水煤漿噴嘴,本氛中采用熱壓燒結工藝制備Al4O3/(W,Ti)C陶瓷材文作者分別選用Cr18NiTi不銹鋼、YG8硬質(zhì)合金料;燒結工藝參數:溫度為1600~1800℃,壓力為和A2O3/(W,Ti)C陶瓷3種材料制作了水煤漿噴32MPa,保溫時(shí)間8~20min.同時(shí)采用標準YG型嘴,并對其進(jìn)行了現場(chǎng)磨損試驗,進(jìn)而分析了其損傷硬質(zhì)合金YG8和國際標準材質(zhì)1Cr8NiTi不銹鋼機理制備水煤漿噴嘴,其性能列于表1.1實(shí)驗部分1.2沖蝕磨損試驗在2t/h蒸汽鍋爐(型號為DNS2-1.0-SM)上進(jìn)1.1噴嘴材料及試樣制備行沖蝕試驗噴嘴內孔直徑4.5mm,長(cháng)15mm.水煤以乙醇作為介質(zhì),將AO3粉末(該粉末密度為漿消耗量200kg/h,供漿壓力0.2MPa,霧化氣壓力表1水煤漿噴嘴材料的組成和性能Table 1sition and mDensity/gcm-1 Flexural strength/MPa Fracture toughness/MPa.m/2 Hardness/GPaI Cr18Ni9Ti75550(tensile strength)HB180~25011~1514.8Al O3/45%(W, Ti)C0.35~0.4MPa,爐膛最高溫度1300℃,水煤漿濃蝕率),以單位質(zhì)量的水煤漿所引起的噴嘴體積流失度65±2%發(fā)熱量為18.81~20.48MJ/kg、粘度為來(lái)表征沖蝕率W,W=m:/(d·m2)(其中m1為噴嘴1000~2500mPa,s、粒度40~120-m的沖蝕磨損質(zhì)量損失,d為噴嘴材料的密度,m2為燃采用萬(wàn)分之一電子天平稱(chēng)量沖蝕前后噴嘴的沖用水煤漿的質(zhì)量)采用掃描電子顯微鏡(SEM)觀(guān)察蝕磨損質(zhì)量損失進(jìn)而確定沖蝕磨損率(以下簡(jiǎn)稱(chēng)沖分析噴嘴沖蝕磨損表面的形貌基金項目,國家自然科學(xué)基金資助項目(50275088)收稿日期:2002125修回日期:20030401/聯(lián)系人鄧建新,e-mail:jxdeng@sdu,edu.cn作者簡(jiǎn)介鄧建新,男,1966年生,博士教授博導目前主要從事切削加工及可掌性陶瓷材料摩擦學(xué)及陶瓷刀具開(kāi)發(fā)等研究摩擦學(xué)學(xué)報第23卷YG8等3種噴嘴的沖蝕率隨時(shí)間變化的關(guān)系曲線(xiàn).可2結果與討論見(jiàn),3種噴嘴的沖蝕率均隨沖蝕時(shí)間的增加而迅速增圖1示出了1Cr18Ni9Ti、AlO3/(W,TiC和大,當沖蝕試驗時(shí)間達到8h以后趨沖蝕率的變化244872120Erusinn time / at(a)1Cr18Ni9Ti nozzle(b)YG8 and Al O,/(W, Ti)C nozzlesFig 1 Variation of CWS nozzle erosion rates with the operation time圖1水煤漿噴嘴沖蝕率隨時(shí)間的變化于平穩.這主要是由于在磨損過(guò)程進(jìn)入穩定階段之前率較高,而高硬度陶瓷和硬質(zhì)合金材料在相同條件下存在明顯的快速磨損階段,在該階段沖蝕磨損率受到的沖蝕率很小.因此,高硬度的Al2O3/W,T)C表面平整度及表層材料在沖擊載荷作用下發(fā)生調整和YG8噴嘴的沖蝕率很小,而低硬度的1Cr8Ni9Ti等多種因素的顯著(zhù)影響水煤漿對噴嘴的沖蝕屬于低噴嘴的沖蝕率很大.角度沖蝕,低硬度的韌性材料在低角度沖蝕下的沖蝕圖2為1Cr18Ni9Ti、Al2O3/(W,Ti)C和YG8等(a)1Crl8Ni9Ti nozzleCb)yG8 nozzle(c) Al,O,/(W, Ti)C nozzleFig 2 Optical photos of exit bore surfaces of the eroded nozzles圖2水煤漿噴嘴出口沖蝕磨損表面形貌金相照片3種噴嘴出口沖蝕磨損表面形貌金相照片,可見(jiàn),比1Cr8Ni9Ti更硬的大量礦物質(zhì),其在噴嘴內壁產(chǎn)1Crl8Ni9Ti噴嘴沖蝕后孔徑顯著(zhù)增大,而YG8和生犁削作用,從而使噴嘴內壁表面形成大量犁溝.因Al2O3/(W,Ti)C噴嘴沖蝕后的孔徑變化很小,但此,可以認為1Cr18N9Ti不銹鋼噴嘴的沖蝕磨損機Al2O3/(W,Ti)C噴嘴出口處出現了明顯的剝落現理主要表現為微觀(guān)切削象.由于在燃燒過(guò)程中水煤漿噴嘴內部存在髙溫度梯由圖3(b)可見(jiàn),YG8硬質(zhì)合金噴嘴磨損表面存度和熱應力,而陶瓷材料的抗熱沖擊性能遠不如金屬在許多凹坑這是由于YG8中含有熔點(diǎn)較低的金屬材料,因此,陶瓷噴嘴出口處的剝落現象主要歸因于粘結相Co,在水煤漿燃燒高溫作用下,粘結相Co變噴嘴內部較大的熱應力這同圖1所示的陶瓷噴嘴在軟,很容易被煤粉中的硬質(zhì)顆粒沖蝕掉,從而在沖蝕初始階段較大的沖蝕率相一致磨損表面留下大量空洞凹坑以及凸起的wC顆粒圖3示出了3種噴嘴內壁沖蝕磨損表面形貌從AloO3/(W,Ti)C陶瓷噴嘴內壁磨損表面SEM照片.可見(jiàn)1Cr18NiTi不銹鋼噴嘴磨損表面存SEM形貌照片可見(jiàn),噴嘴磨損表面非常光滑,其晶相在大量犁溝和溝槽[圖3(a)].這是由于煤粉中含有組織分布清晰可見(jiàn)[圖3(c)].電子探針?lè )治鼋Y果表第5期丁澤良等:水煤漿噴嘴熱沖蝕磨損機理硏究4413決efie (akv. 25:5tk 1626(a) ICr18N9Ti nozzle(b)YG8 nozzle(c)Al, O,/(W, Ti)C ceramic nozzleFig 3 SEM micrograph of the worn bore surface of nozzles圖3嗩唏內壁磨損表面形貌SEM照片明圖中白色部分為(W,Ti)C,黑色部分為Al2O3由[2] Deng Jian-xin, Feng Yi-hua, Ding Ze.Liang, Wear behavior of于A(yíng)I1O3/(W,T)C陶瓷材料熔點(diǎn)及硬度遠比水煤漿ceramic nozzles in sand blasting treatment [J]. Journal of the屮硬質(zhì)煤粉顆粒的高因而表現出很強的抗低角沖蝕European Ceramic Socicty, 2003, 23(2): 323-3293] Ji Gang-cheng(紀崗呂), L i Chang-j(李長(cháng)久), Wang Yu能力,此時(shí)水煤漿的沖蝕作用近似于煤粉中的硬質(zhì)顆yue(王豫躍). Effect of spray conditions on erosion粒對陶瓷噴嘴內壁表面的硏磨作用,從而形成出非常performance of high velocity axygen fuel sprayed CriC2-NiCr光滑的沖蝕磨損表面coatings(噴涂工藝條件對超音速火焰噴涂CrC:NCr涂層沖logy(岸擦學(xué)學(xué)報),202,223結論a.材料硬度對水煤漿噴嘴的熱沖蝕磨損行為[4 Ding Ze-liang, Deng Jian- xin, Li Jian-feng. Wear behavior ofceramic nozzles in abrasive jet machining [C]. The 6th具有顯著(zhù)影響在相同的試驗條件下,具有高硬度的International Conference on Progress of Machine TechnologyAl2O3/(W,Ti)C陶瓷噴嘴的沖蝕率最小,YG8硬質(zhì)Xi'’an,2002.385-390.合金次之,硬度較低的1Cr18N9T不銹鋼噴嘴的沖5] Reshetnyak H, Kuybarsep. Mechanical properties of hard損率最大etals and their erosive wear resistance [J]. Wear, 1994.b.在高溫低角度水煤漿沖蝕磨損條件下,[61 Xue Qun-ji(薛群基),1iu Hui-wen(劉惠文). Tribology oflCr]8Ni9Ti不銹鋼噴嘴主要呈現微觀(guān)切削特征,Ceramics I, Frietion and wear of ceramies(陶瓷摩擦學(xué)1.陶YG8硬質(zhì)合金噴嘴主要呈現晶粒脫落特征,而瓷的摩擦磨損)[]. Tribology(摩擦學(xué)學(xué)報),1995,15(4)Al2O3/(W,TiC陶瓷噴嘴主要呈現熱崩和硏磨損傷376-384特征[7] Sun Jia-shu(孫家樞), Wang Xiao-tong《王小同), Guo De-zhan(郭大展). Impact erosion wear behaviour and參考文獻mathematic model of plasma spray ceramic coating by solidparticles(幾種等離子噴涂陶瓷涂層之間固體粒子沖蝕磨損的[1] Ding Ze-liang(丁澤良), Li Jian-feng(李劍峰), Deng jian-xin持性與數學(xué)模型)[J. Tribology《摩擦學(xué)學(xué)報),199,14(鄧建新). Study on application of coal water slurry nozzles(1):57-54.eral(水煤漿噴嘴材料的應用研究)J]. Coal PrcparationTechnology(選煤技術(shù)),2002,(6):13-15444摩擦學(xué)學(xué)報第23卷Thermal erosion Wear Behavior of Nozzles in CoalWater Slurry burningING Ze-liang 2, LI Jian-feng, DENG Jian-xin, AI Xing, ZHANG De-wei(1. School of Mechanical Engineering, Shandong University, Jinan 250061, ChinaZhuzhou Coal Preparation Plant, Zhuzhou 412005, ChinAbstract: Al,O,/(W, Ti)C ceramic composite was prepared by hot pressing technique. Then the nozzles usedin the coal water slurry burning were made from the resulting ceramic composite and 1Cr18Ni9Ti stainlesssteel and YG8 cemented carbide. The erosion behaviors of the nozzles in the coal water slurry buring wereted on a dnS -1. 0-SMboiler, at a coalof 200 kg/h andconcentration of (65+2)%, a slurry-feeding pressure of 0. 2 MPa, pulverized gas pressure of 0. 35-0. 4MPa, andemperature of 1 300 C. The eroded bore surface morphologies of the nozzlescroscope. Results showed that the hardness of the nozzles playedimportant role in determining the erosion-resistance in the coal water slurry(CwS)burning. The Al,O3W, Ti)C nozzles with high hardness exhibited lower erosion rates, while the 1Cr18Ni9Ti stainless steelnozzles with low hardness showed higher erosion rates under the same test conditions. The nozzle made from1Cr18Ni9Ti stainless steel was dominated by plowing and micro-cutting, that made from YG 8 cementedcarbide was characterized by grain peeling off, and the one made from the Al2O, /(w, Ti)C ceramic compositewas dominated by thermal shock and grindeyi nozZle i erosionAuthor:DENGJian-xin,male,bornin1966,Ph.D,Professor,e-mail:ixdeng@sdu.edu.cn.