以高铬铸铁为例探讨抗磨白口铸铁件磨损特性

通过分析和揭示高铬白口铸铁磨损面受力状态与行为,磨损面基体组织中形成各类不同形貌的显微磨损面与形貌特征,各类显微磨屑在基体组织中形成与脱离磨损面基体组织机制,磨损面显微组织与特点等,提出了高铬白口铸铁磨损特性与机制及提高高铬白口铸铁抗磨性能的措施。     

耐磨铸铁30年发展展望

概述了含铌铸铁,含硼铸铁,含钒、钛、稀土白口铸铁,镍硬铸铁和高铬白口铸铁生产工艺的进展情况;介绍了在各种不同磨料磨损条件下高铬铸铁的化学成分及显微组织的恰当选择;指出通过细化碳化物,高铬白口铸铁的冲击韧性可以得到提高。     

B对Cr27型高铬白口铸铁组织和性能的影响

通过改变加入硼元素的含量,研究Cr27型高铬白口铸铁中碳化物和基体的改变对硬度、冲击性能以及耐磨性的影响,并对材料的冲蚀磨损机理做了进一步的解释。结果表明:随着硼含量的增加,碳化物逐渐粗化,高铬白口铸铁的冲蚀性能逐渐恶化。当硼含量为0.5%时,铸铁的综合力学性能达到最佳。     

在反复强烈冲击磨料磨损时高铬白口铸铁的化学成分及显微组织选择

在反复强烈冲击磨料磨损工况下，高铬白口铸铁通过热处理，使其具有马氏体（仅含少量残余奥氏体）基体组织，可提高高铬白口铸铁组织的抗冲击剥落能力。高铬白口铸铁含碳量应低一些（～2．2％），Cr／C控制在8左右，使铸铁具有较高的韧性和断裂韧性K1C，可以延缓铸铁裂纹的产生和扩展。     

黄河用水泵材质水沙磨损的研究

用沙粒磨损试验装置模拟黄河用水泵过流部件材质的磨损特性，对２０＃钢，１Ｃｒ１３不锈钢，２０Ｃｒ５Ｃｕ钢和高铬白口铸铁等四种材料进行对比试验。结果表明，高铬白口铸铁有良好的抗水沙磨损能力? 磨损试件表面微观分析表明，１Ｃｒ１３，２０Ｃｒ５Ｃｕ钢的表面有较集中的沿水流方向的划痕，其形貌显示出冲蚀坑；高铬铸铁没有观察到明显的划痕，其形貌是一部分突出，一部分呈冲蚀坑，并在碳化物突出部有断裂的划痕。     

高铬白口铸铁在磨料磨损中残余奥氏体的转变及其分布的X-ray研究

本文采用两种X-ray新方法对高铬白口铸铁经不同形式的磨料磨损后的残余奥氏体量及其沿层深分布梯度进行了精确测定,结果表明,这两种方法用于高铬铸铁的研究是成功的.     

亚临界热处理对高铬白口铸铁组织和耐磨性的影响

研究了亚临界处理温度和保温时间对高铬白口铸铁组织转变、硬度和耐磨性的影响，研究表明，铸态组织中含有大量残留奥氏体的高铬白口铸铁，在500～650℃之间进行热处理，其中的残留奥氏体在冷却到室温的过程中会转变成马氏体而造成高铬铸铁硬度升高。在适当的处理温度和保温时间下，高铬白口铸铁能得到最高的硬度，温度过高或保温时间过长都会导致其硬度下降。磨损试验结果表明，通过亚临界热处理高铬白口铸铁的耐磨性可以得到一定的改善。     

用深冷处理改善高铬铸铁的性能

将深冷处理工艺引入高铬铸铁的性能研究，初步探讨了深冷处理对材料宏观力学性能及耐磨性的影响。试验结果表明，适当的深冷处理能够提高高铬铸铁硬度、冲击疲劳抗力及滑动磨损与滚筒磨损性能，但作用效果有限。     

孕育处理对高铬白口铸铁中碳化物形态的影响

对高铬白口铸铁进行了孕育处理,探讨了高铬白口铸铁组织中碳化物形态的变化特征。研究结果表明：通过孕育处理,高铬白口铸铁中的一次碳化物形貌有明显改善,碳化物形貌为棒状,组织得到明显细化,表明该处理方法对高铬白口铸铁组织具有一定程度的改性作用。     

利用钒钛生铁生产中铬抗磨铸铁的试验研究

利用钒钛生铁开发了一种中铬抗磨铸铁.实验研究了化学成分中铬碳比、锰、硅以及热处理工艺时中铬抗磨白口铸铁组织和性能的影响,测试了该种铸铁的抗磨性.实验结果表明,所研制的中铬抗磨白口铸铁具有与高铬抗磨白口铸铁相当的组织和性能,但生产成本较高铬抗磨白口铸铁低,是一种经济实用的抗磨材料.     

不同热处理下滑动速度对SiCp/Al复合材料摩擦学性能影响研究

SiCp/Al复合材料非匀质性微观结构使其摩损机制较传统匀质材料更为复杂,不同工况及热处理工艺下复合材料的摩擦学性能也存在差异。以SiCp/2024Al复合材料为研究对象,进行球-面接触干滑动摩擦磨损实验,探究它在不同热处理状态及滑动速率下的摩擦磨损性能及磨损机制。结果表明:热处理对复合材料力学性能和摩擦学性能有显著影响,固溶+人工时效态复合材料具有更高的强度、硬度及耐磨性;滑动速度影响复合材料的表面接触性质及磨损程度,摩擦因数和磨损量随滑动速度提高逐渐增大;随滑动速度增加,复合材料主要磨损机制由剥层磨损向磨粒磨损转变,而磨损机制的转变明显加快了复合材料的磨损,在实际应用中应尽量避免此现象发生。     

Tribology of nitriding layer, TiN coatings and their complex on AISI D2 steel

The sliding wear and impact wear resistances of D2 steel with nitriding layer, PVD titanium nitride coating and their duplex treatment were investigated. The experimental results suggest that the duplex treatment has the best sliding and impact wear resistances under experimental conditions. And the wear resistance of PVD titanium nitride is better than that of nitriding. The impact wear resistance and wear mechanism of all three surface layers remain unchanged under impact load of 0.2 J or 1 J. All samples end with the same symptom of flaking.     

激光熔覆TiC增强FeAl金属间化合物基复合材料涂层磨损性研究

利用激光熔覆技术在1Cr18Ni9Ti奥氏体不锈钢表面制得了以TiC为增强相、以FeAl 金属间化合物为基体的耐磨复合材料涂层，研究了激光熔覆。FiC／FeAl复合材料涂层在干滑动磨损条件下的耐磨性能及磨损机制。结果表明：随着载荷和滑动速率的增加，TiC／FeAl金属间化合物基复合材料涂层的磨损速率增加，其磨损机制随着载荷的增加逐渐由磨料磨损向粘着磨损转变；激光熔覆层中TiC体积分数的增加，一方面提高了涂层的磨料磨损抗力，另一方面降低了熔覆层表面与对磨材料之间的粘着倾向，提高了TiC／FeAl涂层的滑动磨损性能。激光熔覆TiC/FeAl金属间化合物基复合材料涂层具有优异的耐磨性能并随TiC体积分数的增加而提高。     

HVOF喷涂WC-10Co4Cr涂层的性能及滑动磨损机理

目的研究WC-10Co4Cr涂层的耐滑动磨损性能及机理。方法在0Cr13Ni5Mo不锈钢基体上,采用超音速火焰喷涂(HVOF)制备了WC-10Co4Cr金属陶瓷涂层。分析了WC-10Co4Cr涂层的物相组成、显微组织,并测试了其硬度、结合强度、孔隙率及在560 r/min和1120 r/min转速下的滑动磨损性能。结果涂层的显微硬度为1325HV0.2,结合强度为72 MPa。涂层组织致密,孔隙率为0.76%。在560 r/min下磨损10h,涂层与基体的磨损失重比为1:138.36;在1120 r/min下磨损10 h,涂层与基体的磨损失重比为1:127.44。结论在滑动摩擦磨损的初期,涂层的磨损失效机制主要表现为磨粒磨损。随着滑动速度的增大,涂层的磨损失效机制主要表现为疲劳磨损。     

放电等离子烧结铁基非晶涂层的滑动与冲蚀磨损性能

目的研究放电等离子烧结的Fe_(48)Cr_(15)Mo_(14)Y_2C_(15)B_6非晶涂层在滑动和冲刷条件下的耐磨性。方法利用放电等离子烧结(SPS)技术,制备Fe基非晶态合金涂层。通过滑动磨损实验和冲蚀磨损试验,分别评价非晶涂层的滑动磨损性能和冲蚀磨损性能,并通过X射线衍射仪和扫描电子显微镜分析非晶涂层的组织结构以及磨损形貌。结果非晶涂层在滑动摩擦条件下,随着载荷由10 N增加至20 N,磨损率由0.089×10~(-3)mm~3/m上升到0.216×10~(-3)mm~3/m,但摩擦系数由0.841减小到0.778。非晶涂层在冲蚀磨损条件下的体积磨损率随着冲蚀角度(30°~90°)的增加,先增大后减小,45°时达到极大值(15.80 mm~3/h)。磨损表面形貌表明,铁基非晶的滑动磨损机制主要是疲劳磨损和粘着磨损,冲蚀磨损机制主要表现为构成涂层的粉末颗粒的脆性剥落。结论与常用AISI 52100轴承钢相比,SPS制备的非晶涂层在滑动摩擦条件下有着显著的低磨损率和低摩擦系数,但在冲蚀磨损条件下的耐磨性能较差。     

EVALUATION OF Al-Si/POLYESTER ABRADABLE SEAL COATING

ＥＶＡＬＵＡＴＩＯＮＯＦＡｌ－Ｓｉ／ＰＯＬＹＥＳＴＥＲＡＢＲＡＤＡＢＬＥＳＥＡＬＣＯＡＴＩＮＧ￥ＹｉＭａｏｚｈｏｎｇ；ＺｈａｎｇＸｉａｎｌｏｎｇ；ＪｉＧｅｎｇｓｈｕｎ；ＨｅＪｉａｗｅｎ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｆｏｒＭｅｃｈａｎｉｃａｌＢ...     

Dry wear behavior of rheo-casting Al–16Si–4Cu–0.5Mg alloy

Dry wear behavior of the rheo-casting Al–16Si–4Cu–0.5Mg alloy was investigated by micro-scratch and dry sliding wear tests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of the alloy were carried out by optical microscope and scanning electron microscope. The microstructural analysis showed that via rheo-processing, the primary Si was refined and rounded, eutectics dispersed more homogenously, and even the skeleton AlFeMnSi phase was fragmented into facet shape. Micro-scratch test showed that the microstructural refinement resulted in better wear resistance. Dry sliding wear test revealed that the rheo-processed sample exhibit obviously superior wear resistance because of the microstructure improvement. The dominant mechanism in mild wear condition is abrasion, but it turned to adhesion and oxidation in high applied load and fast sliding velocity conditions.     

NiCrBSiWCe合金粉末喷熔层滑动磨损特性研究

采用热喷熔方法在45钢表面制备了NiCrBSiWCe合金粉末喷熔层,在SRV磨损试验机上进行小振幅滑动磨损试验研究.结果表明,NiCrBSiWCe合金喷熔层的摩擦磨损性能明显高于SAE52100钢.在较低载荷和滑动速度较低下,小振幅滑动磨损机理为磨损表面的划痕、裂纹和疲劳脱层.而在较高滑动速度下,小振幅滑动磨损机理为磨损表面的氧化磨屑层的形成,含稀土的磨屑层阻碍了喷熔层小振幅滑动磨损.     

Dry sliding wear behavior of Al 2219/SiCp-Gr hybrid metal matrix composites

The dry sliding wear behavior of Al 2219 alloy and Al 2219/SiCp/Gr hybrid composites are investigated under similar conditions. The composites are fabricated using the liquid metallurgy technique. The dry sliding wear test is carried out for sliding speeds up to 6 m/s and for normal loads up to 60 N using a pin on disc apparatus. It is found that the addition of SiCp and graphite reinforcements increases the wear resistance of the composites. The wear rate decreases with the increase in SiCp reinforcement content. As speed increases, the wear rate decreases initially and then increases. The wear rate increases with the increase in load. Scanning electron microscopy micrographs of the worn surface are used to predict the nature of the wear mechanism. Abrasion is the principle wear mechanism for the composites at low sliding speeds and loads. At higher loads, the wear mechanism changes to delamination.     

The influence of HVAF powder feedstock characteristics on the sliding wear behaviour of WC-NiCr coatings

In this paper, the HVAF technique was used to deposit coatings with mechanically milled nano and micron blended WC-NiCr powders. The mechanically milled nano powder was produced using the high-energy ball milling process. Due to low particle heating and high particle velocity in the HVAF process, the fine and dense microstructure of the mechanically milled powder remains almost unchanged after spraying. The sliding wear resistance of the two coatings was evaluated by ball-on-disc tests. It was found that the sliding wear resistance of the coating produced using mechanically milled powders was greatly improved compared with the coating produced using micron blended powder. The sliding wear resistance of the coating produced using mechanically milled powder was about two hundred times than that of the coating produced using blended powder. The coefficient of friction for the coating produced using mechanically milled powder increased steadily from 0.22 to 0.51, while for the coating produced using blended powder it attained a steady value of 0.58. Both the coating produced using mechanically milled powder and blended powder were characterized in terms of their microstructure by X-ray diffraction, and scanning electron microscopy in the as-sprayed state as well as after sliding wear. The sliding wear mechanism was also discussed.