两种工艺下碳化钨在镍基自熔合金涂层中的性能研究

本文研究了激光熔覆和火焰喷焊的工艺条件下,两种混合型镍基碳化钨涂层中碳化钨的组织形貌变化,分析碳化钨分解和扩散机理。结果表明:激光熔覆工艺更容易促进碳化钨溶解,并在周围析出η相,从而导致涂层硬度低于火焰喷焊工艺。     

碳化钨增强镍基喷熔层耐磨性的研究

试验研究了不同含量的两种碳化钨粉末对镍基自熔合金喷熔层耐磨性的影响。结果表明，碳化钨粉末对喷熔层有显著的增强作用，其中质量分数为５０％铸造碳化钨的喷熔层耐磨性约为Ｎｉ６０喷熔层的９倍，合金高铬铸铁的１４倍，从组织上分析了耐磨性升高的原因。     

自熔合金粉末的研究

介绍了研制用于喷焊的镍基、钴基、铁基、碳化钨弥散型和铜基等 5类16个牌号的自熔合金粉末的化学成分、物理性能及喷焊层的金相显微组织、特性和用途。所研制的镍基合金中 ,铁含量增至 8%～ 15 % ;钴基合金中 ,加入了10 %～ 2 9%的镍和 7%～ 15 %的铁。从而节约大量镍和钴贵重元素 ,并降低合金的生产成本。     

等离子熔覆镍基合金及复合材料涂层的组织与性能研究

利用等离子表面熔覆工艺,在钢基表面获得了与基体呈冶金结合的镍基合金涂层、镍基+镍包碳化钨等涂层。利用光学电镜、扫描电镜以及能谱分析了上述涂层的组织及成分;采用维氏硬度计测定了涂层的维氏硬度;并比较了上述几种涂层的磨损性能。试验结果表明:等离子熔覆Ni基+30%镍包碳化钨的组织及性能优于其它涂层。     

铁镍稀土自熔性合金粉末研究与应用

研究应用成本较低的铁镍稀土自熔性合金粉末材料代替镍基自熔性合金粉末材料。通过对铁镍稀土自熔性合金粉末材料显微组织分析、摩擦性能和结合强度试验以及实际应用等工作，表明铁镍稀土自熔性合金粉末材料具有熔焊性能好、结合强度高、综合性能优良、成本低等特点。     

用自熔性合金粉末火焰喷焊工艺与现场研磨修复磨损轴实践

主要介绍自熔性合金粉末火焰喷焊与现场研磨的原理、工艺流程及其在首钢长钢连轧车间的应用。用自熔性合金粉末火焰喷焊与现场研磨的方法成功实现在规定时间内不离线现场修复进口剪臂轴。     

添加碲对Ni-Cr合金磨损性能影响的研究

研究在镍基自熔性合金粉末中加入微量的碲元素以稳定材料的硬度及抗磨损能力和综合性能.通过对碲镍铬自熔性合金材料进行显微组织分析、硬度测试分析、摩擦磨损行为以及磨损形貌分析,表明碲镍铬自熔性合金材料具有硬度高、耐磨损性能好等特点.     

稀土对铁基自熔合金自熔性的影响

制备了含稀土的铁基自熔合金并考察了这种自熔合金在氧－乙炔火焰喷焊过程中的自熔性。结果表明，适量的稀土可以非常显著地改善铁基自熔合金的自熔性。这可归因于稀土可降低铁基自熔合金中表面活性元素氧和硫的含量，从而改善了喷焊过程中合金熔滴间的相互润湿，加速了其向喷焊层融合，减少了合金熔滴表面生成氧化膜的可能性。     

钛表面厚碳化钨涂层研究进展

钛表面制备厚的碳化钨耐磨涂层的方法主要有喷焊、喷涂、激光熔覆3种。火焰喷焊可在钛表面制备2 400μm厚的WC耐磨涂层,涂层性能稳定,与基体为冶金结合;可通过预活化钛合金表面、增加重熔、中温回火等方式改善涂层性能。采用超音速火焰技术喷涂团聚烧结型的WC-Co粉末,可在钛表面制备4 153μm厚的耐磨层,涂层易出现W_2C脆性相、η反应相;通过工艺控制,涂层孔隙率可小于1%。采用激光熔覆可在钛表面制备2 900μm厚的WC耐磨层,涂层与基体虽为冶金结合,但存在裂纹、气孔等缺陷。3种方法均可制备毫米级厚的WC耐磨涂层,这种厚涂层将大大延长设备的使用寿命。     

含稀土油浆泵耐磨涂层合金粉体材料的研究

采用气雾化方法制备了NiCrWRE油浆泵耐磨涂层用合金粉末。利用SEM、OM、XRD等技术研究了粉末的特性。探讨了稀土元素对NiCrWRE粉末性能的影响。试验结果表明，加入稀土元素可以获得致密化程度较高、分布均匀的组织，粉末形貌呈球形，流动性好，具有良好的喷焊性能，喷焊层与基体形成牢固的冶金结合。     

Mechanical properties of metal injection moulded 316L stainless steel using both prealloy and master alloy techniques

Abstract

Stainless steel 316L MIM components can be made from either prealloyed powders or from master alloys blended with carbonyl iron powder. In this study these two techniques were compared using prealloyed and master alloyed gas atomised powders of ? 16 μm and ? 22 μm sizes. Four different compounds were prepared, characterised and injection moulded into tensile bars. The bars were compared for green strength, green defects, sintered strength and microstructure. The green components are stronger when carbonyl iron powder is used with the gas atomised master alloy. This material also seems to be less susceptible to moulding defects. The sintering strength of the material produced using the pre-alloyed powder was higher than the master alloyed prepared material. Little difference in mechanical properties existed between the materials fabricated from gas atomised prealloyed ? 16 μm and the ? 22 μm powders. Also, the viscosity of the mixtures was higher for the ? 16 μm material and the master alloy mixtures than for the –22 μm gas atomised prealloyed powders.     

增强感应辊式强磁选机辊齿表面耐磨性的途径

电磁感应辊式强磁选机感应辊磨损较严重，为降低矿山生产成本，采用自熔性合金粉末热喷焊技术提高感应辊耐磨性取得成功。     

添加球磨粉末对铁基高温合金锻态显微组织与力学性能的影响

采用SEM、能谱分析、XRD、密度和室温拉伸性能测定相结合的方法,研究添加球磨粉末对铁基高温合金锻态组织和力学性能的影响.结果表明:添加球磨粉末的混合粉末锻造合金的显微组织由几百纳米的细晶粒和几十微米的粗晶粒组成,具有明显晶粒尺寸双峰分布特征,其中细晶粒的形成提高了合金的界面能,有利于元素的扩散、成分均匀化和孔隙的消除...     

表面合金化导板的研制和应用

分析了表面合金化工艺的特点和轧机导板对其材质的性能要求，提出了轧机导板采用表面合金化工艺是可行的。研究了熔剂加入量、浇注温度和合金粉粒度对表面合金层质量的影响。结果表明，选用合适的熔剂加入量、浇注温度和合金粉粒度，可得到理想的表面合金化层。工业应用表明，表面合金化导板的使用寿命比整体合金化导板提高３倍，同时还显著地降低了生产成本。     

Characterisation of functionally graded and VC/steel surface alloyed composites produced using powder metallurgy

Abstract

In this study, low carbon steel specimens with surface alloyed composites were produced by means of powder metallurgy. Vanadium carbide, graphite (1·2 wt-%) and Fe were used for the surface alloyed composite, while Fe and graphite (0·2 wt-%) were used for the low carbon steel side. The powder mixtures were compacted together in the same mould. On the surface alloyed side the vanadium carbide content was changed from 5 to 25 wt-%. Microstructural investigations including EDX and X-ray, hardness measurement and abrasive wear tests were performed. The results showed that V₈C₇ formed in the alloyed surface and carbon diffusion from the alloyed surface to the parent metal created a functionally graded material. The hardness values decreased towards the parent metal. Wear resistance increased as the vanadium carbide increased in the surface alloyed composite. Thus, a functionally graded steel having a surface composite that is resistant to abrasive wear can be obtained via the powder metallurgy route.     

Densification of Al 5083 Mechanically Alloyed Powder by Equal Channel Angular Pressing

Equal channel angular pressing (ECAP), one of the most important methods in SPD, is used for the consolidation of mechanically alloyed Al 5083 powder. This paper mainly focuses on the densification of Al 5083 mechanically alloyed powder by ECAP with and without application of back pressure up to three passes with four different routes at room temperature. Aluminum can is used to encapsulate the powder. The particle size, crystallite size, microstructure and density were evaluated by scanning electron microscope and X-ray diffraction peak profile analysis. The crystallite size was measured by Williamson Hall analysis. Density and hardness were increased with increasing number of passes and upon sintering after ECAP. Good densification as well as good powder bonding was observed after three passes of ECAP.     

WC-镍基自熔合金组合粉的研究与应用

研究了WC-镍基自熔合金组合粉的组成、制造工艺及各项性能。该类组合粉适合于氧乙炔焰及等离子喷焊法施工,喷焊工艺性能良好,其喷焊层具有优异的耐磨性和耐蚀性。指出喷焊层耐磨料磨损性受WC颗粒间距影响。