【作者】 赵冠琳；

【导师】 邹增大；

【作者基本信息】 山东大学 ， 材料加工工程， 2008， 硕士

【摘要】 在冶金、矿山、发电等行业中,存在严重的设备磨损问题,造成设备过早地损坏,消耗浪费了大量的能源、材料、人力等。在易磨损部件表面熔覆具有高硬度、高耐磨性的涂层成为这些领域修复部件、提高零件使用寿命的重要途径。本文将钛铁、钒铁、石墨等组分按一定比例混合均匀后预置在普通碳钢表面上,采用激光熔覆的方法,制备出原位合成TiC-VC增强的铁基熔覆层。采用透射电镜、电子探针、X射线衍射仪等测试手段及耐磨性试验,对熔覆层的微观组织结构和磨损性能进行了系统分析,讨论了合金粉末中钛铁、钒铁、石墨等的加入量对熔覆层组织及硬度的影响,并对熔覆层的耐磨机制进行了分析。钛铁、钒铁及石墨等组分配制的合金粉末,在激光的作用下,发生化学冶金反应,原位生成TiC-VC弥散分布的硬质相增强铁基熔覆层。本文研究了预置涂层厚度、激光熔覆功率、扫描速度、光斑直径以及多道熔覆时的搭接率等对熔覆层的成形和耐磨性能的影响。试验结果指出,当预置涂层厚度为1.5mm,熔覆用功率为2.2kW,扫描速度为300mm/min,光斑直径3mm,熔覆过程采用氩气进行保护,氩气流量为20L/min时,熔覆后可以得到表面较为平整且没有裂纹和气孔,与母材呈冶金结合的单道熔覆层;多道熔覆时,当搭接率在30%～40%左右时,可以得到成形较好的大面积的熔覆层。熔覆用合金粉木中的组分及含量影响着熔覆层中原位反应生成TiC、VC的数量、尺寸、分布及熔覆层的耐磨性能等。当组分中Ti:V:C的摩尔比在1:1.8:3.36时,熔覆层中生成了大量的树枝状分布的TiC-VC复合颗粒增强铁基基体,在相同的磨损条件下,磨损体积约为普通碳钢的1/22。更多还原

【Abstract】 There are serious equipment wearing problems during the field of metallurgy, mining and power station. The wearing problem causes the equipments premature failure and wastes vast scale of energy, materials, human powers and so on. The method of developing high hardness and wear resistant coatings on the surface of equipments is a important way to repair and prolong the equipments’ life. Using the 5kW CO₂ laser, in-situ synthesis TiC-VC particles reinforced Fe-based alloy composite coating has been prepared by using laser cladding with preplaced ferrotitanium, ferrovanadium and graphite. The microstructure and wear properties of the composite coatings were investigated by transmission electron microscopy （TEM）, electron probe microanalyzer （EPMA）, X-ray diffractometer （XRD） and skimming wear machine. The effect of the amount of Fe-Ti,Fe-V and C on the microstructure and properties were also studied.The results showed that TiC-VC carbides could be directly formed by metallurgy reaction among Fe-Ti,Fe-V and graphite during the progress of laser cladding. Those carbides were dispersively distributed in the hardfacing metal.Cladding parameters affected the formation and wear-resisting property of coating. By testing and comparing, we selected the proper cladding parameters as following: the thickness of the preseted coating was 1.2mm, the laser cladding power was 2.2kW, the laser scanning speed was 300mm/min, the laser spot diameter was 3mm, argon shield was selected and the argon flow rate was 20L/min, the lap rate was 30%-40%.The microstructure and wear properties were affected obviously by the amount of Fe-Ti,Fe-V and graphite. The layer containing large quantity and evenly distribution carbides could be obtained when the mol ratio of Ti:V:C was selected as 1:1.8:3.36. During the same wearing condition, the wear capacity of the matrix metal was about 22 times than the cladding layer reinforced by TiC-VC particles.更多还原