用户名: 密码: 验证码:
等离子熔覆—注射B_4C熔覆层组织及性能的研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
磨损是煤矿机械零部件在实际工况条件下最主要的失效形式。为了提高采煤机截齿、刮板输送机中部槽的使用性能及服役寿命,根据其失效形式,本文提出采用等离子熔覆—注射B4C技术在采煤机截齿前端表面制备一层低成本、高耐磨、厚约2-4mm的B4C增强Fe基熔覆层;在中部槽易磨损工作面,按其规格不同,熔覆一定数量、厚约2-4mm的条状熔覆层。通过熔覆—注射优化试验,确定了合适的B4C注射位置和合理的工艺参数,制备出了外观良好、性能优越的含B4C陶瓷相的复合熔覆层。
     采用金相显微镜、扫描电镜分析了熔覆层、界面和热影响区的组织特征;测试了熔覆层洛氏硬度,并进行耐磨性试验并对磨损形貌观察,评价了熔覆层的耐磨性能。研究了熔覆层的组织及性能的关系,分析了该熔覆层的磨损机理,并进行了生产试验。结果表明:
     (1)影响等离子熔覆—注射B4C的工艺因素很多,且存在交互作用,经过大量试验,最终优化的等离子熔覆—注射的工艺参数为:喷嘴与基材间的高度25~28mmm;离子气流量10L/min;送粉气流量7.5L/min;熔覆电流215A;熔覆速度420mm/min;送粉量67g/min;注射量12g/min;注射角度30°;注射位置距拖尾边缘的距离2-4mm,验证性试验表明,该工艺参数满足生产要求。
     (2)等离子熔覆—注射B4C熔覆层表面粗糙度大,这是由于涂层的表面内部镶嵌了粒度较大的B4C陶瓷颗粒。其内部组织具有明显的快速凝固特征,整体具有细小的晶体结构。熔覆层向边缘方向表现出不同的凝固组织形态,在界面处为平面晶,然后过渡为柱状晶,熔覆层表面由于注射B4C,对熔体产生激冷作用,B4C间隙中的组织细小、均匀。
     (3)混配B4C的铁基熔覆材料,在熔覆加工过程中B4C的剧烈气化导致熔覆层的形貌恶化。熔覆层很薄且不平整,熔覆层表面出现大量的气孔和裂纹。B4C熔化后,元素B、C重新发生冶金反应,形成大量条块状的CrB、Fe2B、(Cr,Fe)2B和(Fe, Cr)23(C,B)6等化合物。该熔覆层具有硬而脆的特点,测量洛氏硬度时,熔覆层表面出现被压头压碎、崩块的现象。
     (4)在实验室中的测试,等离子熔覆—注射B4C层的表层耐磨性是基体材料Q235的50倍,是16Mn钢的41倍,是42CrMo的22倍,是不含B4C陶瓷相熔覆层的20倍,是混配B4C熔覆层的3-4倍。说明熔覆层中存在B4C陶瓷相对于提高熔覆层的耐磨性来说是十分有效。熔覆—注射B4C复合层的磨损形式主要为微观切削、犁沟,且犁沟很浅,熔覆层耐磨性十分优异。
     (5)经过该项技术强化后的截齿,和普通的截齿相比,在同等工况下,其使用寿命可延长3-5倍。该工艺强化加工后的中部槽,和普通的中部槽相比,在同等工况下,其使用寿命可延长5-7倍。
The wear is the main failure mode for coal mining machinery during use.In order to improve the performance and service life of the middle trough of the scraper conveyor and cutting pick, by plasma cladding-injection B4C technology, high wear resistance, about2mm thickness was fabricated on the cutting pick surface, and2-4mm thick strip cladding layer was fabricated wear face in the middle slot, according to the failure form and shape of the cutting pick. Through the analysis of the process, a suitable the B4C injection position and reasonable process parameters was determined after several tests to verify. Finally a good appearance, superior performance containing B4C ceramic phase composite cladding layer was prepared.
     Microstructure of the coating, the interface and the heat-affected zone was examined by means of optical microscope (OM) and scanning electron microscope (SEM). Phase compositions were certified by SEM-EDS. The surface Rockwell of the coating were tested on the Rockwell hardness tester. Abrasive wear resistance test was performed to evaluate the wear-resistance property of the coating. The relationship of microstructure and properties, and the wear mechanisms of the cladding layer were studied. The results showed that:
     (1) The impact of plasma cladding-injection B4C process factors are many, and there were interactions, after a large number of tests ultimately optimized plasma cladding-injection process parameters:the height between the nozzle and the substrate:25-28mm; plasma gas flow.10L/min; feeding gas flow:7.5L/min; the cladding current:215A; cladding speeds:420mm/min; powder feed rate:67g/min; injection volume:12g/min; injection angle:30°; injection location away from the trailing edge distance:2~4mm, confirmatory test, the process parameters to meet production requirements.
     (2) Plasma cladding-the injection the B4C layer of surface roughness is large, this is due to the larger particle size of B4C ceramic particles inside of the coating. Its organization has obvious rapid solidification characteristics overall having a fine crystal structure. Different microstructure morphology appears in the cladding layer to the edge direction, at the interface plane crystal, then the transition of columnar crystals, the surface of the cladding layer due to the injection of B4C melt, B4C clearance organization also has a small, uniform features.
     (3) Mixed B4C Fe-based cladding materials, in the process the B4C gasification causes deterioration of the morphology of the cladding layer. Cladding layer is very thin and not flat, the surface of the cladding layer pores and cracks. In B4C melted, the elements B, C re metallurgical reaction occurs, forming a large number of blocks the CrB、Fe2B、(Cr,Fe)2B and (Fe,Cr)23(C,B)6and so on. The cladding layer has a hard and brittle characteristic, the surface of the cladding layer appears the phenomenon of collapse block crushed by the pressure head when measurement of Rockwell hardness.
     (4) In the laboratory test, plasma cladding-the B4C layer surface of the injection wear resistance is50times to the matrix material Q235,41times to16Mn steel,22times to42CrMo,20times to the cladding layer excluding B4C ceramic phase,3-4times to mixed B4C cladding layer. That's to say, the B4C ceramic phase is present in the cladding layer is very effective for improving the wear resistance of the cladding layer. Cladding-injection B4C composite layer wear mainly in the form of micro cutting furrows, furrows very shallow, very excellent wear resistance of the cladding layer.
     (5) After the technology enhanced the middle trough of the scraper conveyor and cutting pick, used in the production performance and in the same conditions, cutting pick's life can be extended to3-5times, the middle trough's life may be extended to5-7times.
引文
[1]胡社荣,彭纪超等.大地构造理论和中国4次煤田预测与潜力评价[J].煤田与勘探.2012年6月第40卷,第3期:1-5页
    [2]梁椿豪.太原西山白家庄矿有限公司[J].山西冶金2004,94(2):19-20
    [3]沈承金,沈亚郯,史云珠.表面技术在煤矿防护中的应用[J].表面技术,1998,27(4):35-36,17
    [4]赵文轸.煤矿液压支柱腐蚀失效分析[J].腐蚀与防护,1996(4):168-171
    [5]梁椿豪.太原西山白家庄矿有限公司[J].山西冶金2004,94(2):19-20
    [6]李晓豁.采煤机和摇进机截齿的失效分析[J].矿山机械,1999.8:20-21
    [7]康晓敏,张平,李贵轩.采煤机截齿失效研究与实践[J].矿山机械,2002,9:32-33
    [8]高彩云,赵运才.矿用截齿失效原因及对策探讨[J].矿山机城,2000,12:25
    [9]王新.提高掘进机截齿可靠性的途径[J].煤矿机械,2010,5:179-181
    [10]胡元哲.刮板输送机中部槽磨损失效分析与抗磨措施[J].矿山机城2009年第1期第37卷:33-35
    [11]赵运才,李伟,张正旺.中部槽磨损失效的摩擦学系统分析[J].煤矿机械,2007年8月,第28卷第8期:57-58
    [12]高志,潘红良主编.表面科学与工程[M].上海:华南理工大学出版社,2006:38
    [13]宣天鹏编著.材料表面功能镀覆层及其应用[M].北京:机械工业出版社2008年.44
    [14]徐滨士,刘世参等.中国材料工程大典[M],第16卷,材料表面工程上,北京化工出版社,2006年1月第一版:52-65
    [15]高志,潘红良主编.表面科学与工程[M].上海:华南理工大学出版社作者:38
    [16]J. A. Vreeling, V. Ocelik. Y. T. Pei, etal. Laser melt injection in aluminum alloys on the role of the oxide skin[J].Acta Materialia.2000,48 (17):4225-4233
    [17]赵敏海,郭面焕等.外加颗粒增强表层复合材料制备方法[J].焊接学报2007年2月,第28卷第2期
    [18]A. B. Kloosterman, B. J. Kooli, D. E. Hosson. Electron microscopy of reaction layers between SiC and Ti-6A1-4V after laser embedding[J].Acta Materialia.1998,46 (17): 620-621
    [19]Y. T. Pei, V Ocelik, D. E. Hosson. SiCp/Ti6A14V functionally graded materials produced by laser melt injection[J]. Acta Materialia.2002 (8):2035-2051
    [20]J. A. Vreeling, V. Ocelik, J. T. M., D. E. Hosson. Ti-6A1-4V strengthened by laser melt injection of WCp particles [J]. Acta Materialia.2002,50 (19):4913-4924
    [21]汪志健.等离子熔化-注射技术制备金属基固体自润滑表层复合材料[D].硕士学位论文,哈尔滨工业大学,2006
    [22]王长柏.等离子熔化一注射WC-CO耐磨复合表层研究,硕士学位论文,哈尔滨工业大学,2006
    [23]张艳良.等离子熔—喷制备WC增强表层复合材料[D],中国农业大学,2005
    [24]赵敏海,刘爱国,郭面焕.等离子熔化-注射WC金属陶瓷层组织研究.热处理技术与设备.2007,28(5):17-20
    [25]李志杰.氩弧熔化-注射NiCr-Cr3C2表层复合材料的研究[D].哈尔滨工业大学硕士论文.2007:53
    [26]魏晶慧.氩弧熔覆-注射WC-8Co表层复合材料制备[D].哈尔滨工业大学硕士论文.2008:52
    [27]常杰.氩弧熔覆-注射金刚石复合涂层研究[D],哈尔滨工业大学硕士论文,2010
    [28]朱润生.自熔性合金粉末的研究[J].粉末冶金工业,2000,(2):7-14
    [29]王建青.等离子喷焊超厚耐磨涂层的研究[[)].泰安:山东矿业学院,1999
    [30]钱苗根.材料表面技术及其应用手册[M].北京:机械工业出版社,1998,353-372
    [31]徐滨士,朱绍华.表面工程的理论与技术[M].北京:国防工业出版社,1999,230-290
    [32]侯清宇,高甲生.铁基合金等离子堆焊研究进展[J].安徽工业大学学报,2003,20(1):14-16
    [33]张兵权.等离子束流表面熔覆层显微组织与耐磨性的研究[D].[硕士学位论文],郑州:郑州大学,2011
    [34]刘邦武,李惠琪,张丽民.等离子束表面冶金技术冶金过程研究[J1,纳米与新材料专辑,2004,18(10):192-19
    [35]于洪爱.等离子束表面冶金机理的研究[D].硕士论文,山东科技大学,2006
    [36]Tsirkas S A, Papanikons P, Kermanidis T. Numerical simulation of the laser welding process in buttjiont specimens [J]. Journal of Materials Processing Technology,2003,13 (1):59-69
    [37]Male AT, Pan C. Processing effects in plasma forming of sheet metal[J]. Annals of the CIRP,2000,49 (1):213~216
    [38]陈颢.等离子束表面冶金机理研究及铁基稀土涂层制备[[)].[博士学位论文].北京:北京科技大学,2007
    [39]马立.等离子弧焊接熔池流场与温度场三维数值模拟[D],硕士学位论文,天津大学2006年1月
    [40]殷凤良.等离子弧焊接过程的数值模拟[D],天津大学,2007
    [41]刘洪华.45钢等离子喷涂AT_13涂层激光熔覆温度场数值模拟和性能研究[D],吉林大学,硕士毕业论文,2008,4
    [42]赵玉珍.焊接熔池的流体动力学行为及凝固组织模拟[D].北京工业大学工学博士学位论文.2004:2-78
    [43]钱苗根,姚寿山,张少宗.现代表面技术[M].机械工业出版社,1994:148
    [44]赵敏海.等离子熔化-注射制备碳化物增强涂层组织及耐磨性能研究[D].博士研究生,哈尔滨工业大学,2008
    [45]杨会龙.高频感应熔覆截齿耐磨层的试验研究[D].[硕士学位论文],郑州:郑州大学,2011
    [46]Delia. A. Effect of Austenitizing Conditions on the Impact Properties of an Alloyed Austempered Ductile Iron of Initially Ferritic Matrix Structure[J]. Damage Mech,1998, 7 (2):103~128
    [47]秦秀丽.低合金钢表现铸渗强化的试验研究[D].[硕士学位论文],郑州:郑州大学,2010
    [48]周寤生,孟寿康,周庆德.等温淬火球墨铸铁滑动摩擦磨损性能的研究[J].现代铸铁,1992(2)
    [49]Bela V.Kovacs.Sr. Austempered Ductile Iron Fact and Fiction[J]. Modern Casting, March 1990
    [50]徐滨士,刘世参等.中国材料工程大典,材料表面工程上[M],北京化工出版社,2006,第16卷,62-64

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700