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探讨了薄壁长简状粉末冶金零件成形模具的设计方法。经过改进的成形模结构,不仅提高零件薄壁段的密度,而且保证了各部位密度的均匀,具有实用价值。 相似文献
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柴油机油量控制套筒是一种结构复杂的机械零件,其外表面形状特殊,内表面分布若干台阶且具有较高的配合精度要求。本文基于粉末连续体,运用有限元Deform软件对油量控制套筒模具的不同改进方案(改进假芯棒、上浮动冲分型、设计漏粉穴、调整局部装粉系数)下的压坯密度进行模拟分析。通过数值模拟仿真数据对模具进行改进及尺寸优化,提高压坯密度分布的均匀性,实现采用粉末冶金近净成形的先进方法制造油量控制套筒,并满足其对精度、密度及性能的要求。 相似文献
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问:什么是粉末冶金组合烧结工艺? 答:当零件形状复杂,用粉末冶金传统工艺不能或很难压制成形,或零件上的某一部位有特殊性能要求时,将一个零件分成两个或两个以上形状简单的元件,然后在烧结过程中再使几个简单形状的元件组合为一个零件,这种工艺称为粉末冶金组合烧结工艺。问:粉末冶金组合烧结工艺有什么优越性? 答:(1)可以制造机械加工无法制造的或粉末冶金传统工艺很难成形或不能成形的复 相似文献
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在粉末冶金零件压制过程中,由于原材料、零件设计、模具设计、成形设备工装、模具组装、压制工艺等原因,而产生粉末冶金压制件(压坯)缺陷,如密度不合格、尺寸超差、裂纹等,最终导致粉末冶金零件批量报废.本文列举了在粉末冶金零件压制过程中常出现的各类压坯缺陷,并结合真实案例详细地分析了产生缺陷的原因,提出了克服压坯缺陷的方法和措施. 相似文献
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多平行小孔粉末冶金零件不仅成形困难,而且脱模也困难。本文介绍的成形模具,通过对压制芯杆及脱模筒等模具零件的特殊设计,不仅可以直接成形多平行小孔零件,而且可以交两次脱模为一次脱模,从而大大提高了生产效率。 相似文献
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Fe-Mo-B Enhanced Sintering of P/M 316L Stainless Steel 总被引:1,自引:0,他引:1
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. 相似文献
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从生产发展角度回顾了70年代以来,寻求优质铁粉的过程。概括地总结了本厂多年来应用水雾化铁粉的经验,及其在生产ρ ≥ 6.8g/cm3纺织机械粉末冶金零件中成功的应用情况。实践证明,水雾化铁粉的应用是改进工艺、不断提高零件性能的有效途径。 相似文献
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提高我国粉末冶金零件质量的浅见 总被引:1,自引:0,他引:1
材料的力学性能、零件尺寸精度以及两者的稳定性可以表征铁基粉末冶金零件的质量。原始粉末以及混合粉末的物理化学性能的稳定性对于保证零件的质量是极其重要的。用浸铜工艺来提高烧结钢强度和韧性是目前比较合适的方法。合理的烧结炉炉形,烧结气氛,以及严格的规范化的烧结工艺是保证零件质量的关键。同时必须重视提高烧结零件外观质量。本文从以上几个方面阐述了对提高我国粉末冶金产品质量的意见。 相似文献
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Archana Agrawal D. Bagchi S. Kumari B. D. Pandey 《Mineral Processing and Extractive Metallurgy Review》2013,34(2):136-162
In the present research, an effort has been made to prepare copper salt/powder from the copper bleed stream generated during the electrowinning of pure copper from the copper anode in a copper smelter. Various approaches have been opted for the complete recovery of copper values such as: evaporation–crystallization, electrolytic process, and direct hydrogen reduction. Physical and chemical properties of copper powder/salt produced from the large-scale experiments from actual plant and model solutions have been evaluated for P/M applications and compared with the standard properties. Thus, mixed crystal suitable for recycling back to the system as a makeup salt containing nickel in a tolerable range could be recovered by evaporation and crystallization of the bleed stream up, to 50%. Copper powder recovery by the electrolysis process at a current density of 700 A/m2 was about 95%. Scanning electron microscope examination showed that the powder was dendritic in nature. On annealing, the purity of the copper powder was found to be 99.95%. The annealed powder had apparent density of 3.04 g/cc, hydrogen loss 0.72%, and acid insoluble as 0.27%. On compaction of <104-µm sized powder, the green density was found to be 8.7 g/cc. Similarly, the recovery of the copper powder obtained from the model copper solution by the hydrogen reduction process was found to be >99% and the annealed powder had an apparent density of 3.50 g/cc, flow rate 35.6 g/min, hydrogen loss 0.195%, purity 99.8%, and green density of 8.57 g/cc while the powder from the actual plant solution was found to have an apparent density of 3.49 g/cc, flow rate 46.0 g/min, hydrogen loss 0.598%, purity 99.4%, and green density 8.57 g/cc for the powder < 100 µm in size. Thus, the properties of copper powder produced by hydrogen reduction and electrolytic route were compared and were found to be suitable for the P/M applications. 相似文献
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高密度铁基粉末冶金零部件制造原料的研究 总被引:1,自引:0,他引:1
温压粉末原料是采用温压成形技术制造高密度粉末冶金零件的基础和温压工艺的技术核心。高价格的进口温压粉末制约了我国高密度铁基粉末冶金零件的开发与应用,因此,必须开发出符合我国国情的温压粉末原料体系。作者根据我国资源特点,采用鞍钢产水雾化铁粉、水雾化低合金钢粉和攀枝花钢铁公司产转炉烟尘铁粉为原料,进行了制备相应体系的温压粉末原料和温压工艺参数优化的研究。以水雾化铁粉为原料设计制造的Fe-1.5Ni-0.5Mo-0.5Cu-0.6C粉末经637MPa压制,温压密度为7.46g/cm~3;压坯的回弹率为0.03%.在1150℃烧结40 min后,收缩率为0.025%。而以转炉烟尘铁粉设计制造的Fe-1.5Ni-0.5Mo-0.5Cu-0.6C粉末经686 MPa压制,压坯密度达7.35g/cm~3;以Fe-1.5Ni-0.5Mo水雾化合金钢粉为原料制造的Fe-1.5Ni-0.5Mo-1.5Cu-0.8C粉末在686 MPa时压制密度为7.35g/cm~3。这些粉末原料的设计为我国高强度铁基粉末冶金零部件的制造创造了条件。 相似文献
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