“双层金属布”硬质涂层的微观组织与性能

柔性金属“贴布”涂层技术是近 1 0几年发展起来的一种新型金属表面改性技术。文章对用双层“金属贴布”法在钢件表面形成的涂层及其与钢结合界面的微观组织结构及性能进行了分析和讨论 ,并与单层“金属贴布”法进行了比较。结果表明 ,涂层中的相组成为WC相、α Co相、β Co相、γ Fe相及Ni相 ;其组织为WC相及粘结相组成的非均匀结构 ;涂层致密无气孔 ;双层“金属布”形成的涂层与钢基体发生成分互扩散形成冶金结合 ,且结合强度大于单层“金属布”制备的涂层的结合强度 ;双层“金属布”在烧结过程中的线收缩率比单层“布”小得多 ,当利用双层“布”技术进行圆环柱面烧结时涂层无裂纹及裂缝产生     

TiN涂层对不同高速钢耐磨和切削性能的影响

本文研究了不同程度合金化高速钢非涂层和物理气相沉积TiN涂层试样的抗干滑动磨损性能、磨损机理以及不同高速钢车刀片切削40Cr、GCr15和1Crl8Ni9Ti不锈钢时涂层和非涂层刀具的切削性能。试验表明,TiN涂层高速钢耐磨性较非涂层钢提高近一个数量级。低合金高速钢D950和Vasco Dyne的耐磨性不亚于通用高速钢M2。涂层试样磨损机理主要为粘附-接触疲劳剥落磨损。涂层刀具切削性能较非涂层刀具大为提高。涂层低合金高速钢刀具性能不亚于涂层通用高速钢M2。试验结果表明,TiN涂层的应用为高速钢特别是低合金高速钢的开发应用提供了广阔的前景,涂层刀具在中硬及难加工材料的切削加工方面有着应用的潜力。对PVD TiN涂层的微观组织,结构等也进行了研究。     

低合金高性能高速钢TiN涂层后的耐磨性及刀具切削性能的研究

本文研究了低合金高速钢W2Mo5Cr4V经TiN涂层后的耐磨性和切削性能,证实W2Mo5Cr4V钢的钨、钼、钒总含量虽仅为通用高速钢的60％左右,一次碳化物数量明显地少,但基体的性能(二次硬化、抗回火稳定性、高温性能等)与通用高速钢相当,加以TiN涂层后能获得与通用高速钢涂层后同样优良的耐磨性和刀具耐用度。本文还从磨损机制和切削力方面探讨了TiN涂层提高高速钢刀具耐用度的机制。     

镝对钨钼表面高速钢高温摩擦性的影响

采用双层辉光等离子渗金属技术在Q235钢表面渗入钨、钼、镝,并进行渗碳淬火和回火以形成表面高速钢层。然后与钨钼表面高速钢和强化4Cr13钢在HT-500型高温摩擦磨损实验机上进行高温摩擦实验。研究发现,对比钨钼表面高速钢和强化4Cr13钢发现,在相同摩擦条件下,表面稀土高速钢的耐磨性能更好。在20℃~500℃摩擦温度下,表面稀土高速钢的粘着和剥落现象较少,因此其摩擦曲线平稳,平均摩擦系数较小。在400℃、500℃时其磨损量分别是钨钼表面高速钢的0.36、0.53倍,是强化4Cr13钢的0.91、0.69倍,说明镝的添加可提高表面高速钢的高温耐磨性;摩擦温度升高,摩擦面氧化和软化更易发生,但稀土的作用使表面稀土高速钢强韧性好,不易发生塑性变形或脆性断裂,有效支撑氧化层发挥其润滑作用,在高温下表面稀土高速钢只发生磨粒磨损和氧化磨损。     

激光熔覆铁基涂层工艺参数的研究

以激光熔覆铁基涂层为研究对象,在MM-P2屏显式摩擦磨损试验机上进行摩擦磨损对比实验,分析了不同工艺参数下熔覆层形貌及熔覆涂层后磨损量的变化关系.结果表明:熔覆涂层后的表面硬度均在62HRC以上,远高于基体的硬度;熔覆层的形貌和质量主要影响因素是扫描速度,激光功率次之,并在此基础上采用能量密度进行表征,能量密度为60 J/mm2左右时的耐磨性最好,其最佳组合工艺参数为激光功率3.2 kW左右、扫描速度300 mm/min左右.激光功率过高,扫描速度过快都会导致熔覆层耐磨性能下降.      

含硼高速钢轧辊的组织和性能

 设计了5种高速钢轧辊材料,利用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)等分析手段,并通过硬度测试、冲击韧性试验和磨损试验,对含硼低合金高速钢轧辊材料在铸态、回火后的组织与性能及其耐磨性进行了系统研究。结果表明,含硼低合金高速钢轧辊材料铸态组织包括马氏体基体、残余奥氏体和不同种类的碳硼化合物,其铸态硬度大于HRC 64,碳硼化合物沿晶界呈网状分布。经RE-Mg-Ti复合变质处理后,晶界出现明显的颈缩和断网。对轧辊材料进行回火发现,随着回火温度的升高,轧辊硬度逐渐降低。相同条件下,未变质轧辊材料的韧性较变质轧辊材料韧性略低,加入过量的变质剂反而降低轧辊材料的韧性。磨损试验发现,经RE-Mg-Ti复合变质的含硼高速钢的耐磨性大于对比试样高碳高钒高速钢的耐磨性。     

激光熔覆改性铁基合金涂层的硬度和耐磨性能研究

为提高石油钻井行业中工件表面涂层的硬度和耐磨性,提升工件使用寿命,本文设计开发了含Cr、V元素的三种铁基激光粉末,通过激光熔覆加工工艺进行涂层制备,对铁基激光涂层的物相、硬度和摩擦磨损性能检测,成功开发了硬度高达60 HRC,摩擦系数为0.6094,15分钟50N载荷条件下磨损量仅为0.0007 g的高耐磨铁基激光熔覆涂层,满足石油钻井行业对于高硬度、高耐磨、长寿命的涂层需求。     

离心铸造高速钢轧辊的研究及其在棒线材轧机上的应用

由于普通合金铸铁轧辊硬度低、耐磨性差，而硬质合金轧辊尽管具有优异的耐磨性，但成本高，且脆性大，使用中易开裂和剥落。故以高碳高速钢为主要合金成分，采用离心铸造方法，开发了耐磨性能优良的高速钢轧辊，并着重解决了离心铸造高速钢轧辊生产过程易偏析和产生裂纹的难题。高速钢轧辊硬度达63～65HRC，辊面硬度差小于2HRC，冲击韧性大于14J／cm^2。用于高速线材轧机预精轧机组和棒材轧机精轧机组，使用寿命比合金铸铁轧辊提高6～10倍，接近硬质合金轧辊水平。     

涂层硬质合金耐磨性的研究

对涂层刀片和非涂层刀片做切削实验比较它们的耐磨性,研究其磨损机制。     

低合金高速钢W3Mo2Cr4V2NbNRE辊轮材料的组织和性能

针对高速线材轧机上常用的高碳高铬铸钢辊轮耐磨性低,使用寿命短,而普通高速钢辊轮和硬质合金辊轮成本较高的情况,研制出一种使用温度在550℃左右,复合添加氮、铌、稀土的低钨、钼含量的高速钢W3Mo2Cr4V2NbNRE辊轮材料.经1 250℃淬火,550℃3次回火后的硬度为HRC 64,550℃×20 h的热稳定性试验后的硬度为HRC 62,具有良好的红硬性.其耐磨性接近普通高速钢W18Cr4V辊轮的水平,而成本比普通高速钢低.     

Properties of the Coatings Fabricated by Plasma-Jet Hard-Facing by Dispersed Mechanical Engineering Wastes

The properties of the coatings fabricated by plasma-jet hard-facing with a powder mixture of the dispersed wastes of VK8 hard alloy, R6M5 high-speed steel, and Kh15N60 nichrome taken in the same proportions are studied. The microhardness and the wear resistance of coatings are higher than those of the 30KhGSA steel substrate by a factor of 1.4 and 1.3, respectively. The coatings have a very small number of pores, and the arithmetical mean deviation of the coating profile is Ra = 0.73.     

激光熔敷Ni60／WC合金层的腐蚀磨损特性

研究了４５钢表面激光熔敷镍基ＷＣ合金层的耐蚀性及在不同冲击速度和不同浓度酸性介质下的腐蚀磨损特性。结果表明，激光熔敷Ｎｉ６０／ＷＣ合金层不论耐蚀性还是抗腐蚀磨损性能同于２Ｃｒ１３不锈钢。应用微机对试验结果进行逐步回归分析，得出了影响因素与腐蚀磨损速度的害量关系，并探讨了熔敷层的腐蚀磨损过程。     

Comparison of microstructure and property of high chromium bearing steel with and without nitrogen addition

Microstructure and property of bearing steel with and without nitrogen addition were investigated by microstructural observation and hardness measurement after different heat treatment processing. Based on the microstructural observation of both 9Cr18 steel and X90N steel,it was found that nitrogen addition could effectively reduce the amount and size of coarse carbides and also refine the original austenite grain size. Due to addition of nitrogen,more austenite phase was found in X90N steel than in 9Cr18 steel. The retained austenite of X90N steel after quenching at 1 050 °C could be reduced from about 60% to about 7% by cold treatment at-73 °C and subsequent tempering,and thus finally increased the hardness up to 60 HRC after low temperature tempering and to 63 HRC after high temperature tempering. Furthermore,both the wear and corrosion resistance of X90N steel were found much more superior than those of 9Cr18 steel,which was attributed to the addition of nitrogen. It was proposed at last that nitrogen alloying into the high chromium bearing steel was a promising way not only to refine the size of both carbides and austenite,but also to achieve high hardness,high wear property and improved corrosion resistance of the stainless bearing steel.     

High-Temperature Sliding Wear Testing of Cathodic Arc Physical Vapor Deposition AlTiN- and AlTiON-Coated Hot Work Tool Steels

Thin hard coatings provide the much needed protection for steel thixoforming tools that must resist wear at high temperatures. The wear resistance of AlTiN- and AlTiON-coated hot work tool steel was investigated at 1023 K (750 °C), measured to be the cavity surface temperature shortly after the steel slurry was forced into the thixoforming die. The wear tests were repeated in exactly the same fashion with uncoated tool steel samples to identify the impact of AlTiN and AlTiON coatings on the high-temperature wear performance of X32CrMoV33 tool steel. The nature, the thickness, and the adherence of the oxide scales impact the tribological behavior. The poor adherence and limited ductility of ferrous oxides promote the failure of the oxide scale impairing the resistance to wear of the hot work tool steel at elevated temperatures. The substantial softening in the X32CrMoV33 hot work tool steel is also critical in the wear volume loss it suffers. AlTiN and AlTiON coatings, on the other hand, form a stable and protective oxide surface layer at high temperatures and therefore provide an enhanced resistance to oxidation. The latter is relatively more resistant to oxidation and is thus the better of the two coatings tested in the present work.     

YC09-切削加工喷涂层的硬质合金刀具材料

YC09合金是为解决热喷涂层的切削加工而设计制造的一种新型的高耐磨性硬质合金刀具材料。本文简述了热喷涂材料的种类、特性以及切削加工时对刀具材料的要求;介绍了YC09硬质合金刀具材料成分、组织结构及使用结果。YC09合金具有超细晶粒组织,硬度为HRA94,抗弯强度大于120kgf/mm2。将YC09合金与国内外几种高耐磨性刀具牌号进行了对比,通过实例说明YC03刀具材料在切削加工热喷涂层时,具有比其它合金更为显著的优点。     

Mechanical and tribological properties of TiN and SiCN nanocomposite coatings deposited using methyltrichlorosilane

The paper examines nanocomposite coatings based on TiN and SiCN obtained by plasma-enhanced chemical vapor deposition (PECVD) using methyltrichlorosilane (MTCS) as one of the precursors. The nanocomposite coatings demonstrate four types of structures depending on deposition modes: nc-TiN, nc-TiN/a-SiCN, nc-TiNC/nc-TiSi₂/a-SiCN, and nc-TiNC/nc-TiCl₂/a-SiCN. The nanohardness and elastic modulus of the coatings reach 31 and 350 GPa, respectively. The coatings on substrates of hard alloys, high-speed steel, and silicon increase the nanohardness of the base from 10 to 100%. The correlation between the H/E ratio and wear resistance is not observed. The coatings deposited at low radiofrequency powers demonstrate good adhesion to silicon substrates. It is shown that the use of MTCS as the main precursor allows one to obtain hard and wear-resistant nanocomposite coatings. __________ Translated from Poroshkovaya Metallurgiya, Vol. 47, No. 1–2 (459), pp. 125–133, 2008.     

超音速火焰喷涂 WC-Cr3C2-M 涂层性能 及其在液压支架立柱上的应用研究

分别采用电镀和超音速火焰喷涂在27SiMn钢表面制备了硬铬和WC-Cr_3C_2-M涂层,测试了两种涂层的机械性能以及磨损和腐蚀性能,并将WC-Cr_3C_2-M涂层在煤矿的液压支架的立柱上井下应用。结果表明:相对于电镀硬铬涂层,采用超音速火焰喷涂工艺制备的WC-Cr_3C_2-M涂层与基体结合强度高,孔隙率低,表现出更高的硬度、耐磨和抗腐蚀性能。WC-Cr_3C_2-M涂层在井下实际工况下防护效果显著,可以代替会给环境带来严重污染的电镀硬铬,用于煤矿井下的液压支架的表面防护。     

Surface Hardening of Hard Tungsten-Carbide Alloys: A Review

Russian and non-Russian research on the surface hardening of hard tungsten-carbide alloys to improve the wear resistance is reviewed. There is great scope for improving the wear resistance and durability of hard-alloy components by surface strengthening on the basis of various coatings, including coatings with 100-nm structural components. On hard tungsten-carbide alloys, the most common coatings consist of titanium carbide TiC and nitride TiN, characterized by high lattice binding energy and high melting point. If such coatings are applied to hard-alloy tools, the frictional coefficient is reduced by a factor of 1.5–2.0 when cutting steel. The use of a TiN + ZrN ion-plasma coating reduces the frictional coefficient by a factor of 5.9. At present, multilayer coatings are widely employed. The most widespread are TiN + TiC and Al₂O₃ + TiC coatings. Their wear is proportional to the coating thickness. These multilayer coatings still leave room for improvement in the wear resistance of hard alloys. In Russia, the potential of hard alloys with a strength gradient from a ductile and high-strength core to a wear-resistant surface is being explored. At the Research Institute of Refractory Metals and Hard Alloys, a method has been developed for producing alloys with variable cobalt content over the thickness of the cutting insert. That permits change in alloy composition from VK20 to VK2 over the sample thickness. Correspondingly, the wear resistance of the insert’s working section is equivalent to that of VK2 alloy, while the base is able to withstand considerable flexural stress. Recently, cutting tools with a diamond coating on hard alloys have been adopted in practice. To increase the durability of hard-alloy VK inserts, strengthening based on concentrated energy fluxes may be employed. Examples include treatment of hard-alloy surfaces by γ quanta, ion beams, and laser beams, electroexplosive alloying, and electrospark strengthening.     

硬质涂层抗喷砂型冲蚀磨损研究现状

为减少材料和能源的损耗, 延长零部件使用寿命, 硬质涂层被应用于喷砂型冲蚀磨损环境。 本文介绍了喷 砂型冲蚀磨损的危害和硬质涂层的应用情况, 综述了硬质涂层力学性能、 基体材料性能、 粒子特性和喷砂参数等 对涂层抗喷砂型冲蚀磨损的影响趋势, 总结了喷砂型冲蚀磨损的动力学模拟和冲击试验的研究情况, 指出了涂层 硬度和韧性以及基体与涂层性能的匹配有助于提高涂层抗喷砂型冲蚀磨损, 展望了通过数字模拟与试验验证相结 合的方式获得各种硬质涂层抗喷砂型冲击磨损机理模型的前景。