《等离子堆焊碳化钨强化镍基合金组织与性能研究_夏厚福》由会员分享，可在线阅读，更多相关《等离子堆焊碳化钨强化镍基合金组织与性能研究_夏厚福（104页珍藏版）》请在金锄头文库上搜索。
1、犬il硿-大莩DALIAN UNIVERSITY OF TECHNOLOGY颀士莩位坨文MASTERAL DISSERTATION等离子堆焊碳化钨强化镍基合金组织与性能研究学科专业材料加工工程作者姓名?指导教师?M_一答辩日期2014年6月硕士学位论文等离子堆悍碳化钨强化镍基合金组织与性能研究Microstructure and Wear Behavior of Ni-based HardfacingReinfored With Tungsten Carbides by PTAW作者姓名:夏厚福学科、专业:材料加工工程学号:21105051指导教师:邓德伟完成曰期:2014年5月式遠理工夫嗲D
2、alian University of Technology大连理工大学学位论文独创性声明作者郑重声明:所呈交的学位论文,是本人在导师的指导下进行研究工作所取得的成果。尽我所知,除文中已经注明引用内容和致谢的地方外,本论文不包含其他个人或集体已经发表的研究成果,也不包含其他已申请学位或其他用途使用过的成果。与我一同工作的同志对本研究所做的贡献均巳在论文中做了明确的说明并表示了谢意。若有不实之处,本人愿意承担相关法律责任。学位论文题目:M HiSf扉柳tMM觀_fl作者签名: 夏谣搞日期:TWf年/月夕日大3?理工大学硕士学位论文摘 要为了提高材料表面耐磨性,通常在其表面堆焊耐磨合金,有时为了获
3、得特殊的性能,如高的耐应力磨损性能,可添加硬质合金粒子进行强化。对镍基合金而言,常添加的硬质粒子为碳化钨。其原因为:一方面碳化钨具有高的耐腐蚀性、高硬度、高熔点、可焊性好、具有一定的塑性变形等特点;躬一方面镍基合金与碳化钨颗粒之间有较好的润湿性。本课题选用等离子堆焊技术,其原因为:等离子堆焊技术具有稀释率和变形小、焊道平整、工艺稳定、冶金结合好、致_无缺陷、易于实现自动化等优点。本文来用等离子堆焊技术在奥氏体不锈钢钢板表面堆焊碳化钨强化镍基耐磨合金,使用光学显微镜(0M)、带能谱分析的扫描电子显微镜(SEM)、电子探针(EPMA)、X射线衍射仪(XRD)、X射线荧光光谱分析伩(XRF)、红外碳
4、硫分析伩、显微硬度计、磨损试验机等设备研宄合金堆焊层的显微组织和耐磨性能。研究了堆焊电流对镍基合金堆掉层组织与性能的影响。结果表明.随着堆焊电流的增大堆焊层中的枝晶组织变得越来越不明显,堆焊层中依次出现鱼骨状组织、羽毛状组织和点状群落组织,并且硬度也随之降低。研究了添加不同含量和形状碳代钨强化镍基合金堆焊层组织与性能。在显微组织方面,随着碳化钨含量的增加,堆焊肩中出现了针状、块状、条状及骨架状组织,并且均含有W元素;在耐磨性能方面,随着1碳化钨添加量增大,合金堆焊层的耐磨性能也随之提高,且球形碳化钨的强化效果优予不规则碳化钨。研宄了堆焊电流对碳化钨强化镍基合金堆焊层组织与性能的影响。堆焊电流不
5、同,元素凝固时扩散程度也不同,最终导致堆焊层中出现不同形态的组织。在耐磨性能方面,堆焊层的耐磨性并不是堆焊电流的单调函数,它与电流及试验载荷大小相关。同时,在堆焊层中观察到了不同程度溶解的破化钨,这些溶解的碳化钨进入到镍基合金基体中,与基体中元素进行反应,形成各种不同形状的复杂化合物,并且随着堆辉电流的增大,碳化钨溶解现象越来越明显。关键词:等离子堆焊;镍基耐磨合金;碳化钨;显微组织:耐磨性等离子堆焊碳化钨强化镍基合金组织与性能研宄Studies on Microstructure and Properties of Ni-based HardfacingReinforeced With Tu
6、ngsten Carbides by PTAWAbstractIn order to improve the surface wear resistance, the abrasion-resistant alloy wasdeposited on the surface of material. Sometimes for special performance, such as high stressabrasion resistance, it can be adding carbide particle in it. For the Ni-based hardfacing, theca
7、rbide particle usually was tungsten carbides. There are some reasons for this. On the onehand, the tungsten carbides has high corrosion resistance, high hardness, high melting point,good weldability and plastic deformation. On the other hand, the Ni-based alloy has goodwettability with tungsten carb
8、ides. It adopts plasma transferred arc welding (PTAW) in thispaper, the reason is that it has lower dilution and deformation, good weld formation, processstability, easy to realize automation, excellent bonding with substrate and dense anddefect-free deposits.The Ni-based hardfacings reinforeced wit
9、h tungsten carbides were deposited onaustenitic stainless steel substrate by plasma transferred arc welding (PTAW). The opticalmicroscope (OM),scanning electron microscope (SEM) with Energy Disperse Spectroscopy(EDS), electron probe microanalyzer (EPMA), X-ray diffraction (XRD), X-ray fluorescencesp
10、ectrum analyzer (XRF), infrared carbon sulfur analyzer, microhardness tester and slidingwear tester were employed to analysis the microstrcture and wear resistance.The influence of current on microstructure and wear resistance of Ni-based hardfacingwas studied. The results indicated that dendrites c
11、onstituents was becoming more and moreunconspicuous, the herringbone, feathery and dot community structure were appeared incoatings and the microhardness was decreased with the increase of the current.The microstructure and wear resistance of the Ni-based alloy reinforced with differentcontent and s
12、hape of tungsten carbide were researched. In the aspect of microstructure,with theincreasing content of tungsten carbides, in the shape of acicular constituent, block tissue, longflake and skeleton structures, which including element of W, were precipitated in coatings. Interms of wear resistance, t
13、he wear resistance of coatings increased, with the increasing content oftungsten carbides. At the same time, the reinforcement effect of spherical tungsten carbide wasbetter than the irregular tungsten carbides.The influence of current on microstructure and wear resistance of Ni-based hardfacingrein
14、forced with tungsten carbides were researched. In different welding current, the diffusionrate of element was different during the solidification of coatings, leading to various forms ofiiorganization appeared in the coatings. In terms of wear resistance, the wear resistance of coatingwas not monoto
15、nic function of current, it related to the current and the size of the test load. Thedissolved tungsten carbides with different degree were found in coatings. They reacted with theelements of Ni-based alloys to form low melting eutectics, which precipitated in different shapes.What is more, the dissolved phenomenon of tungsten carbides was more obviously with theincrease of the current.Key
