~试验研究~
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固体法制备碳化锯渗层的灰口铸铁的耐磨性能 Fabio Edson Mariani', Gustavo Bortoluci de Assis',Luiz Carlos Casteletti'
AmadeuLombardiNetoGeorgeEdwardTotten
(1. Universidade de Sao Paulo, Sao Carlos, Sao Paulo, Brazil;2. Universidade Tecnologica
Federal do Parand, Londrina, Parand, Brazil; 3.Portland State University, Portland, Oregon, USA)
摘要：灰口铸铁由于其成本低廉、减振和切削加工性能良好获得应用。这些突出优点源自游离态石墨的
存在和液态金属的良好流动性，后者有利于制作形状复杂的薄壁铸件。适合的渗层能改善灰口铸铁的耐磨性，从而扩大其应用范围。高硬度的碳化钜可以达到这一目的。本文研究用的灰口铸铁试样成分为3.47%C-2.39%Si-0.55%Mn-0.15%Ni-0.65%Cu-Fe（余量），采用Fe-Ni合金、NH,CI和 Al,0，的粉末混合物进行热反应扩收渗锯，温度900℃，时间2h。碳化锯渗层的硬度可达2000HV，微黏着磨损和微磨粒磨损试验证明，固体渗锯处理可显著提高灰口铸铁的耐磨性。
关键词：灰口铸铁；渗锯；碳化；耐磨性
中图分类号：TG156.8；TC163
文献标识码：A
文章编号：1008-1690(2016)03-0027-04
WearPropertiesofaGrayCastIronCoatedwith
NiobiumCarbideProducedbyPackProcess
Fabio Edson Mariani',Gustavo Bortoluci de Assis',Luiz Carlos Casteletti'
Amadeu Lombardi Neto, George Edward Totten
(1. Universidade de Sao Paulo, Sao Carlos, Sao Paulo, Brazil;2. Universidade Tecnologica
Federal do Parana, Londrina, Parand, Brazil; 3. Portland State University, Portland, Oregon, USA)
Abstract: Gray cast iron is used mainly due to its low cost, high damping capacity and high machinability. These outstanding properties are due to the presence of free graphite and the high fluidity of the molten metal what allows the casting of complex parts with thin walls easily. Suitable coatings can increase their wear resistance while expanding its usability range. Niobium carbide, with its high hardness may be a good candidate for this purpose. In this work, samples of this material with the composition 3. 47% C-2. 39% Si-0. 55% Mn-0. 15% Ni-0. 65% Cu-balance Fe were subjected to niobizing powder thermo-reactive diffusion treatment using a coating mixture composed of Ferro-niobium, NH,Cl, Al,O, at 900 C for 2 hours. Layers hardnesses of 2 000 HV, typical for niobium carbides, were obtained. Micro-adhesive and micro-abrasive wear tests demonstrated a substantial increase in wear resistance obtained with this treatment.
Key words: gray cast iron; niobizing; niobium carbide; wear resistance
0引言
灰口铸铁是Fe-C-Si合金，石墨散布于基体中，占世界熔炼金属年产量的70%左右，约60×10°{1-2]。这与该材料的特性有关，如熔点低，液-固转变过程中收缩率小，可使零件接近要求的尺寸（最终形状），以及良好的切削加工性能和减振性能。
收稿日期：2016-01-07
《热处理》
万方数据
灰口铸铁的生产成本比钢低，广泛应用于承受振动的汽车零件、发动机座、离合圆盘、制动器和农业机械。零件表面耐磨损和/或耐腐蚀的提高能进一步扩大灰口铸铁的应用范围，而固体法可获得合乎要求的表面层。这种工艺方法之所以可行，是因为它可在大气压力下实施，且不需要PVD和CVD技术那样的昂贵设备，所以成本低3)。该工艺过程为通
2016年第31卷第3期
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