粉末粒径和烧结温度对K418高温合金多孔材料显微结构及性能影响

以气雾化K418镍基高温合金球形粉末为原料，经过粉末松装烧结制备出高温合金多孔材料。通过对多孔材料微观结构、渗透性能、毛细性能及压缩强度进行表征，研究了原始粉末粒径和烧结温度对多孔吸液芯样品显微结构及性能的影响。结果表明，随烧结温度增加，样品的平均孔径和孔隙率减小；在相同烧结温度下，随着原始粉末粒径增加，样品的平均孔径和孔隙率增大。在烧结温度为1230℃，粉末粒径为53～150μm的条件下，多孔材料样品综合性能最优，渗透率为13.69×10-15 m2，毛细压力为22.1 kPa，压缩强度为86 MPa。     

气雾化压力对3D打印用316L不锈钢粉末性能的影响

采用真空熔炼气雾化工艺制备3D打印用316L不锈钢粉末,通过调整雾化参数,研究了不同雾化压力对粉末化学成分、粒度分布、球形度、表面形貌、流动性及松装密度等特性的影响。结果表明:在保温温度(1560±20)℃、保温时间20 min、漏包温度(1050±30)℃、高纯氮气雾化及雾化压力3.0 MPa工艺参数下,制备得到的粉末性能可达到氧含量(质量分数)0.08%、中位径31.39μm、球形度0.75、流动性21.56 g/(50 s)及松装密度3.88 g/cm~3,基本满足不同金属3D打印技术对粉末材料性能的要求。     

316L不锈钢粉真空松装烧结的研究

研究了316L不锈钢粉注射成形等低压成形工艺的粉末真空松装烧结行为及其影响因素。通过添加石墨实现脱氧控碳,分析比较了气、水雾化粉真空松装还原烧结行为的差异。     

粉末松装烧结工艺对多孔铝棒组织、性能以及卷烟降温效果的影响

采用粉末松装烧结方法在不同烧结温度下制备多孔纯铝棒,研究粉末平均粒度与烧结温度对多孔纯铝棒的相对密度、硬度及显微组织的影响,并研究该铝棒对卷烟的降温效果。结果表明:纯铝棒材的相对密度和显微硬度随粉末的平均粒度增大呈先增大后略有减小再继续增大的趋势。在粉末平均粒度为48μm、烧结温度为600℃以及保温时间为2 h的条件下,烧结态纯铝棒的相对密度达到61.7%,维氏硬度达到33.89。相对密度和显微硬度随烧结温度的升高而增大。将松装烧结的纯铝棒材应用于卷烟,制成复合卷烟,可使卷烟燃烧锥中心的最高温度降低超过100℃,而且滤嘴温度升高并不明显。     

紧耦合气雾化技术制备选区激光熔化用18Ni300合金粉末的研究

基于紧耦合气雾化技术制备符合选区激光熔化用18Ni300合金粉末, 重点研究了雾化压力对粉末粒度(中值粒径, D₅₀)、粒度分布、球形度、氧含量、流动性和松装密度等特性的影响。结果表明: 雾化压力对上述粉末特性影响显著, 当雾化压力在3.5 MPa到4.5 MPa范围时, 随着压力的提高, 粉末粒度降低、表面形貌改善、流动性变好、松装密度增加。当雾化压力为4.5 MPa时, 所制备的粉末综合特性最优, 粉末粒度(D₅₀)为34 μm, 球形度为0.77, 氧含量为0.02%(质量分数), 流动性为17.4[s·(50g)-1], 松装密度为4.32g·cm-3, 15~53 μm粒径范围粉末收得率为38.1%, 满足选区激光熔化技术对金属粉末性能的要求。     

雾化压力对电极感应熔炼气雾化TC4粉末形貌与性能的影响

采用电极感应熔炼气雾化工艺,在3.5~7.0 MPa压力下制备高品质球形TC4合金粉末,利用激光粒度仪、扫描电镜、霍尔流速计、真实密度仪等,研究雾化压力对粒度53μm的细粉收得率、平均粒径、微观形貌、空心粉以及松装密度和流动性的影响。结果表明:在3.5~6.0 MPa压力范围内,随雾化压力增大,粉末的平均粒径逐渐减小,细粉收得率增加。当雾化压力为3.5 MPa时,粉末球形度较好,卫星球较少,平均粒径为69.4μm,细粉收率为23.0%,相对密度为99.1%,松装密度为2.40 g/cm~3,流动性为22.4 s/50 g。当雾化压力提高到6.0 MPa时,TC4合金粉末的平均粒径为48.6μm,细粉收得率为40.8%。进一步增大雾化压力时,粉末的平均粒径反而变大,细粉收得率降低,卫星球颗粒逐渐增多,球形度变差。粉末松装密度和流动性都随雾化压力增大而降低。     

蒙乃尔布气元件多孔性能的研究

蒙乃尔合金凭借其优良的耐高温、抗腐蚀和良好的抗高温冲击,在化工、核工业、石化等诸多领域得到广泛应用。结合流化床布气元件的使用工况和对多孔性能要求,选用蒙乃尔合金粉末制备多孔气体布气板。通过对粉末性能、成形压力和烧结温度等影响最大孔径、透气度主要因素的分析,认为,球形蒙乃尔粉末有利于开孔的形成,能有效增大多孔气体分布板的透过性。结果表明,粉末粒度大、粒度范围窄、压制压力越低,所对应的最大孔径和透气度相对较大;反之,最大孔径和透气度相对较小。烧结工艺是影响蒙乃尔多孔布气元件性能的主要因素,利用球形蒙乃尔粉末制备多孔板时,需要进行慢速升温和梯度保温工艺实现烧结。根据布气元件的工况要求,烧结温度选在1 150℃~1 300℃之间较为理想。     

雾化6—6—3青铜粉粒度组成对松装密度影响的研究

采用正交试验研究方法，探讨了６－６－３雾化青铜粉末粒度组成对其松装密度影响规律，得出了３００目以下细粉对松装密度影响最显著的结论，并指交小的变化范围内通过调整粉末体的粒度组成，可以到调整粉末体松装密度的目的。     

水雾化Cu-0.3La预合金粉制备工艺研究

研究了水雾化工艺参数对Cu-0.3La预合金粉末的粒度分布、松装密度、流动性等物理性能的影响.结果表明:保持其它雾化参数不变,适当的提高高压水压力和熔融合金温度,均能使粉末细粉量增加、松装密度降低、流动性变差;而漏嘴直径的增大使得粉末变粗、松装密度增大、流动性有所提高;最佳雾化参数为熔融合金温度1200℃,水压20MP...     

铁锰无磁合金粉的水雾化法生产工艺研究

采用水雾化法制备铁锰无磁合金粉末, 分析了合金粉末含锰质量分数和雾化工艺对铁锰合金粉末性能的影响规律。结果表明: 水雾化法生产铁锰无磁合金粉的方案可行, 但锰质量分数不宜低于24%;在实验工况条件下, 雾化压力对松装密度的影响可以忽略不计, 雾化压力提高使产品流动性变差, 以15 MPa雾化压力进行生产时, 产品工艺性能(松装密度、流动性) 最好; 雾化压力的提高有助于提高产品烧结密度, 在满足产品流动性要求的前提下, 可以考虑通过提高雾化压力来提高产品烧结密度。     

粉末轧制多孔不锈钢薄壁焊接管材的研究

本文研究了用不锈钢粉末轧制多孔生带材,经烧结、卷曲和焊接等工艺生产多孔管材的方法。粒度大于5mm的气体雾化不锈钢丸经涡旋研磨机破碎成粒度组成为-100+250目的不锈钢粉末,再用上述工艺获得壁厚为0.8-1.2mm的多孔不锈钢管。其相对渗透性可达(3~7)×10-3L·N/cm2·min·mmH₂O,平均孔径为6-15μm。     

Cu粉特性对热导管烧结毛细结构性能的影响

研究热导管铜粉的松装密度、粉末粒度、粉末粒径分布对铜粉烧结的毛细结构体断裂强度、孔隙率、毛细力吸水通量的影响。结果表明:在烧结温度为980℃,烧结时间60 min的条件下松装烧结所得铜热导管毛细结构体综合性能良好,当铜粉松装密度2.1 g/cm~3,粒径范围100~250μm,其中粒径150~250μm的质量分数为40%~70%时,铜粉烧结毛细结构体的断裂强度为9.11~9.67 MPa,孔隙率52.6%~53.8%,毛细力吸水通量1.30×10~(-3)~1.42×10~(-3) g/(s·mm~2)。     

Particle bonding,annealing response,and mechanical properties of dynamically consolidated type 304 stainless steel powders

The nature of interparticle bonding in explosively consolidated, centrifugally atomized (CA), and vacuum gas-atomized (VGA) Type 304 stainless steel powders has been examined. Stress waves with sufficient amplitude to produce full density do not necessarily produce metallurgical bonds between particles; the local strain and strain rate are found to determine the degree of local heating and, in turn, the degree of particle fusion. Particle interaction is found to be limited to nearest neighbors. The as-consolidated CA material has approximately twice the ultimate tensile strength of mill-annealed wrought Type 304 stainless steel. Consolidated CA powder has a higher defect density than VGA powder consolidated under the same conditions; however, the VGA material recrystallizes at a lower temperature due to a lower concentration of carbides. Annealing explosively consolidated material produced from either powder results in sintering, improved particle bonding, and greater ductility.     

Fe-Mo-B Enhanced Sintering of P/M 316L Stainless Steel

Liquid-phase enhanced sintering of powder metallurgy（P/M）316L stainless steel by addition of sintering aids was studied.2%-8% of pre-alloyed Fe-Mo-B powder with two different particle sizes was added as sintering aids,and the specimens were sintered in vacuum at 1 200-1 350 ℃.The results show that the fine Fe-Mo-B powder（5-10 μm）has stronger activated effect.The sintered density increases with the increase in sintering aid content or sintering temperature.Warm compaction has a better effect on the control of dimensional precision of compacts.The prealloyed Fe-Mo-B powder deviated from Mo2FeB2 component can also be sintering aid of P/M 316L stainless steel.     

Tribological Characteristics of Materials Based on Bronze for Small Friction Assemblies

The effect of the fineness of atomized nonspherical bronze powder and compaction pressure on the porosity and pore size of sintered materials is studied. The optimum sintering temperature for achieving the maximum strength and porosity of bronze carcasses is determined. The effect of bronze original porosity and powder particle size on the wear resistance and friction coefficient of sintered carcasses impregnated with polymer and oil under dry friction conditions and a self-lubricating regime is established.     

焦粉粒度对烧结烟气中CO排放的影响

摘要：针对钢铁企业大气污染物排放问题,生态环境部提出了NOx、SO2、烟气颗粒物等超低排放的要求,京津冀地区在此基础上对烧结工序的CO排放浓度也做了相应要求。为探究不同粒度焦粉对烧结烟气中CO排放的影响,进行烧结杯实验,使用紫外差分烟气分析仪实时测定烧结烟气中CO浓度,并测定烧结矿的性能指标。结果表明：焦粉粒径小于1mm时,生料层透气性差,焦粉燃烧不完全,CO排放量大,随着焦粉粒径增大,制粒得到强化,生料层透气性、氧化性气氛得到改善,在焦粉粒径达到3～4mm时达到最佳,较小于1mm降低约41%;随着粒径增大,烧结矿强度、成品率均有所增加,冶金性能得到改善,在焦粉粒径达到2～3mm时,综合性能达到最优。     

Effect of ultrasonic refining upon the processing properties of atomized stainless steel powder

Conclusions Ultrasonic treatment in an aqueous solution containing 10% HN0₃ and 2% HF markedly increases the apparent density of the Krasnopakhorsk Plant atomized stainless steel powder and improves its flowability and compressibility. It also has a pronounced beneficial effect upon the physicomechanical properties of sintered parts.Translated from Poroshkovaya Metallurgiya, No. 10(178), pp. 82–84, October, 1977.     

Microstructure and mechanical properties of microwave sintered austenitic stainless steel

The objective of this work is focused on understanding the effect of microwave heating on sintering of 316L powders. The stainless steel samples were prepared from prealloyed powders of 316L. The powder samples were compacted at a pressure of 560 MPa and sintered at 1300°C in a microwave furnace of 2.4 GHz and 2KW capacity in nitrogen atmosphere. The sintering time was varied from 10 to 20 minutes in order to study the effect of sintering time on sintering behavior and mechanical properties of the sintered samples. The sintered samples were subjected to optical metallography, hardness testing, tensile testing and fractogrphy. The average density of sintered stainless steels was 92% of the theoretical density, approximately 18% increment from green density for 20 min. sintering time. Microstructural analysis showed the regularly distributed porosity with very small grains. The hardness value was in the range of 365VHN to 396VHN and tensile strength, in the range of 255MPa to 580 MPa. Fractographs for these steels revealed mixed mode of fracture.     

电解铁粉的制备及压缩烧结性能

摘要：以电解铁片为原料制备了电解铁粉并且研究了其纯度及硬度，同时以某电解厂生产的电解铁粉为原料，研究了电解铁粉的压缩及烧结性能。结果表明，最佳因素组合下电解得到的电解铁片及电解铁粉纯度(质量分数)分别达到99.98%和99.99%；电解铁粉压坯密度随着压制压力的增加而增大，粒径大的铁粉更利于压制成型，但会导致孔隙尺寸大变大且分布不均匀；铁粉烧结坯密度随着烧结温度的升高而增大，同时随保温时间增加增长缓慢，因此在实际生产中应通过适当提高烧结温度和缩短烧结时间，进而提高烧结效率。     

Preparation of Nanocrystalline 430L Stainless Steel by HEBM and SPS

Preparation of nanocrystalline 430L stainless steel by both high-energy ball milling and spark plasma sintering technique has been investigated. The results have shown that the hardness can be improved markedly with an increase in sintering temperature and holding time. The lower the apparent porosity of nanocrystalline 430L stainless steel, the higher is the Vickers-hardness. The tensile strength reached a maximum value of 713 MPa when the sampie was sintered at 1 173 K for 10 min, and then it evidently decreased with an increase in sintering temperature and holding time because of the growth of crystalline grain.