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基于TiC、VC的高显微硬度,利用药皮中钛铁、钒铁、石墨等组分的高温电弧冶金反应在堆焊层中生成碳化物硬质相。系统研究了药皮组分对堆焊层硬度和合金元素过渡系数的影响,利用扫描电镜(SEM)、电子探针(EMPA)观察和分析了堆焊层中碳化物的分布、形貌和成分。结果表明:随着药皮中钛铁、钒铁、石墨组分的增加,堆焊层硬度提高,但当石墨组分超过12%时,堆焊层硬度下降。随着药皮中钛铁、钒铁、石墨组分增加,熔敷金属中Ti、V、C元素含量不断提高,Ti、V、C元素过渡系数提高,但V、C元素过渡系数分别在钒铁12%、石墨14%时达到最大。 相似文献
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碳化钛抗裂堆焊焊条的研制 总被引:5,自引:1,他引:5
采用H08A焊芯,Fe-Ti、TiO2、石墨等药皮组分,通过电弧冶金反应,成功地在堆焊层中沉淀出TiC等超硬质点,使堆焊层具有很高的耐磨性,突出的抗裂性,工艺性能良好,价格便宜,是堆焊焊条类型的新突破。 相似文献
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Cr5系堆焊合金碳、铬过渡形式对高温磨损性能影响的研究 总被引:1,自引:0,他引:1
在轧辊堆焊复合制造中,为节约贵重碳化物及提高堆焊材料的性价比,在堆焊熔敷金属成分基本保持不变的条件下,利用埋弧堆焊研究药芯焊丝碳、铬不同加入方式对堆焊合金微观组织与性能的影响。通过磨损试样前后硬度、高温拉伸、常温韧性与高温磨损量的量化,结合磨损前后金相组织、扫描电镜等辅助手段分析微观组织、加入方式与耐磨性之间的关系;结果表明:堆焊金属600℃的高温耐磨性能与合金高温强度及硬度呈正比,并随合金韧性的增加耐磨性能提高;直接加石墨和铬粉的药芯焊丝堆焊熔敷金属的耐磨性能优于在焊丝中直接加碳化铬的堆焊熔敷金属。高温磨损是合金氧化、切削、疲劳开裂与剥离等多种因素作用的结果,理想的高温耐磨堆焊材料不仅与采用的堆焊合金系有关,还与堆焊金属的显微组织、抗氧化性能及高温强韧性等因素有关。同时得出改变合金的加入方式是不添加变质剂及外加激振法外,能够促使组织均匀及强化熔敷金属的另一种方式。 相似文献
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焊条药皮中采用石墨、钛铁、钒铁、钼铁等组分,通过电弧冶金反应生成具有高硬度的TiC、VC、MoC等碳化物颗粒,研制出具有硬度高、耐磨性好的耐磨堆焊焊条。探讨了焊条药皮中石墨、钛铁、钒铁、钼铁等组分含量对焊条工艺性及堆焊层硬度的影响。利用X射线衍射、光学显微镜(OM)和电子探针(EMPA)对堆焊层显微组织和碳化物形成进行了分析。研究结果表明,碳化物颗粒为TiC-VC-MoC复合碳化物颗粒,并且碳化物颗粒弥散分布在基体上。焊前不预热,焊后不缓冷连续堆焊不产生裂纹。堆焊层硬度达到HRC59以上,具有高的耐磨性,相对耐磨性优于D317焊条。 相似文献
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Dry sliding wear of an AA 6061 alloy reinforced with both modified SiC particles and metal coated carbon fibres has been studied. SiC particles were used to increase the hardness of the composite while short carbon fibres are supposed to act as a solid lubricant. SiC particles were coated with a silica layer deposited through a sol–gel procedure to increase the processability of the composite and to enhance the particle–matrix interfacial resistance. The metallic coatings on carbon fibres were made of copper or nickel phosphorus which was deposited through an electroless process. The metallic coatings favoured the wetting of the fibres during processing and then dissolved in the aluminium matrix forming intermetallic compounds that increased its hardness. Wear behaviour of AA 6061–20%SiC and AA 6061–20%SiC–2%C was compared with that of the composites with the same reinforcement content but using coated particles and fibres. The influence that the modification of the matrix because of the incorporation of coatings on the reinforcements had on the mild wear behaviour was investigated. The wear resistance of the composites increased when carbon fibres were added as secondary reinforcement and when coated reinforcements were used. 相似文献
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堆焊合金中合金元素 Cr 和 V 与堆焊层中的 C 形成 Cr7C3及 VC 等硬质相,在此基础上加入B 元素,形成相应的 TiB2,可进一步增加其硬度和耐磨性;因此,在高 Cr 合金中加入 B4C 制成粉芯,用埋弧焊堆焊的方法得到合金,测量宏观硬度并且观察了显微组织。结果显示,随着 B4C 含量增加,试样中硬质相比例增加,提高了试样的硬度,一定程度上增加了耐磨性(B4C 含量1.5%-3.5%为宜);但 B4C 含量过高(B4C 含量达到3.0%左右),晶界偏析加大,易导致堆焊层开裂。 相似文献
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研制了一种新型高铬铸铁堆焊药芯焊丝,其单道单层堆焊室温硬度为HRC48左右,便于切削加工,焊道层金属具有良好的抗裂性。该焊丝的最大特点是堆焊时采用普通埋弧焊机,不需加入任何保护气体和焊剂即能顺利进行堆焊,节省了保护气体或焊剂,简化了操作过程。介绍了焊丝设计原理及堆焊层金属的有关性能。 相似文献
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研制了5种用于炉底辊堆焊修复用的不锈钢药芯焊丝,分析了堆焊金属的化学成分,观察了其显微组织,并对堆焊金属表面进行了探伤,着重探讨了高碳铬铁和重稀土硅铁加入量对焊丝热裂敏感性的影响。结果表明:向焊丝药粉中单独加入适量高碳铬铁后,堆焊金属组织由单相奥氏体转变为由奥氏体和碳化物组成的两相组织,阻断了凝固过程中的晶间液膜,可防止热裂纹的产生;而适量添加重稀土硅铁亦可达到防止热裂纹的目的,但过量添加反而会增加热裂纹倾向;较佳的加入量(质量分数)为8%的高碳铬铁或3%的高碳铬铁和0.5%重稀土硅铁。 相似文献
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采用电火花表面沉积(ESD)技术,选用YG-8硬质合金和石墨两种电极,对2Cr13不锈钢进行表面强化处理。研究了强化层深度的影响因素,采用辉光放电谱仪(GDS)测试强化层元素分布,用X射线衍射仪(XRD)分析组织结构,用球盘磨损试验机评价耐磨性能,用喷砂型冲蚀装置评价冲蚀性能。结果表明:强化层与基体为冶金结合,其深度随电源电压增加而增大,Ar气保护能有效地降低强化层中N、O含量。石墨电极强化层存在大量的Fe3C、奥氏体和少量石墨;硬质合金电极强化层存在大量的W2C、Co6W6C和WC1-x。经YG-8和C电极强化后,2Cr13不锈钢表面的硬度大幅度提高,摩擦系数明显降低,粘着磨损得到有效的控制,耐磨性能得到显著的改善。在10°小冲蚀角条件下,强化层明显提高了基体的抗石英砂冲蚀性能,而90°垂直冲蚀时,强化层的抗冲蚀性能却不及基体,原因是强化层韧性不及基材。 相似文献
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为了研究汽车驱动桥壳表面损伤后的堆焊修复层能否满足再制造的要求,选用H13CrMoA和ER50-6焊丝并采用亚激光瞬间熔工艺,在汽车驱动桥壳片表面制备不同厚度的堆焊层。利用金属磁记忆检测仪和扫描电镜分析堆焊试样的应力分布和断面组织特征,同时测试堆焊试样的硬度并进行渗透、磁粉和X射线三种无损检测。结果表明:ER50-6堆焊试样的堆焊层与母材硬度相近,母材热影响区未发生局部软化,堆焊层与母材结合良好,不存在焊接缺陷和应力集中区,应力分布不均匀程度低于H13CrMoA堆焊试样。
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采用D207焊条用手工电弧焊在45号钢基体材料上进行堆焊试验,对堆焊层的金相显微组织进行了分析,对堆焊熔敷金属的硬度和磨损性能进行了测试。结果表明:采用D207焊条堆焊后,其熔敷金属层的硬度与耐磨性能均高于基体材料,大大提升了基体材料的各项性能,可用于45号钢零部件的修复。 相似文献
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Reddy G. Chandrakanth K. Rajkumar Sivanandam Aravindan 《The International Journal of Advanced Manufacturing Technology》2010,48(5-8):645-653
The significant requirements such as wear resistance and better tribological properties in addition to good electrical conductivity necessitate the development of copper-based advanced metal matrix composites for electrical sliding contact applications. Though the addition of graphite to copper matrix induces self-lubricating property, the strength of the composite reduces. The improvement in the strength of the composite can be achieved by reinforcing harder ceramic particles such as SiC, TiC, and Al2O3. In this paper, the development of hybrid composite of copper metal matrix reinforced with TiC and graphite particles through microwave processing was investigated. The effects of TiC (5, 10, and 15 vol.%) and graphite (5 and 10 vol.%) reinforcements on physical and mechanical properties of microwave-sintered copper–TiC–graphite hybrid composites are discussed in detail. Micrographs show the uniform distribution of reinforcements in copper matrix. Microwave-sintered composites exhibited higher relative density, sintered density, and hardness compared with conventionally sintered ones. 相似文献
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采用正交回归设计、最优化方法相结合,开发成功ZWZY5配方设计系统。该系统选用L18(21×37)正交表拟订试验方案,采用正交多项式回归方法建立焊条性能回归方程;然后,将回归方程作为目标函数,进行最优化计算,求得性能指标最佳的焊条配方。用该系统研制成功EDC68等10多种电焊条,EDC68堆焊焊条,可进行不预热或低温预热(150~350 ℃)堆焊,其堆焊层不开裂或轻微开裂。并具有高硬度、高耐磨、高韧性和耐冲击等优良综合性能,其常温硬度不小于66 HRC,一般可达68~71 HRC。批量用于经受高应力、强冲击以及剧烈磨损的混凝土泵耐磨板堆焊,没有脆性掉块现象,泵送高度180 m时,可泵送混凝土13 000 m3左右,远远超过了国内外其他耐磨焊条所堆焊耐磨板的使用寿命。 相似文献
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High speed dry friction experiments of graphite fiber/Cu-Sn matrix composites against steel were conducted at sliding velocities up to 235 m s?1. The composite samples were prepared by the method of liquid metal infiltration. It has been determined that the friction coefficient and the wear rate depend on the amount of tin in the matrix, orientation of fibers relative to the sliding surface, the sliding velocity, the graphite grain size and the degree of liquid metal infiltration within the fibers. The increase in tin content leads to a decrease in both friction and wear due to an increase in matrix hardness. Specimens tested with the fibers oriented perpendicular to the sliding surface exhibit better frictional behavior than those with fibers parallel to the sliding surface. Both friction coefficient and wear rate reach a minimum value at a velocity between about 120 and 180 m s?1. Large graphite grain size and poor liquid metal infiltration within the fibers have a detrimental effect on wear. 相似文献