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本文采用真空反应烧结合成出Mo2FeB2硬质颗粒,并采用感应熔覆技术在钢基体表面成功制备出以Mo2FeB2为强化相的硬质涂层,并对其组织结构、界面相容性和耐磨性进行了研究。结果表明,在1 350℃真空烧结30min所制得Mo2FeB2硬质相颗粒分布均匀致密且硬度高;感应熔覆Mo2FeB2/Fe涂层的硬质相最佳含量为50%质量分数,涂层组织分布均匀孔洞较少,硬度高达65.5HRC,涂层与基体结合良好。磨损试验表明,Mo2FeB2强化层具有比YG8硬质合金更好的耐磨性。 相似文献
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采用金相观察、扫描电镜及透射电子显微镜分析、硬度测试、室温冲击测试和拉伸测试等研究了碳元素的添加对中铬合金钢组织及力学性能的影响。结果表明,碳含量会明显影响中铬合金钢的基体组织及第二相碳化物等的析出。随着碳含量的增加,经热处理后的合金钢组织中的马氏体逐渐由板条状转变为片状,碳化物不断增加,在中铬合金钢基体中均匀分布,对晶粒变细起到一定的促进作用,残余奥氏体受到铬系碳化物变化的影响,其占比先增加后减少。中铬合金钢试样的硬度随着碳含量的增加整体呈现出先急剧增大后基本稳定,最后又明显增加的变化规律。高碳含量下合金钢的室温冲击吸收功明显降低。研究结果表明通过改变碳元素含量可以实现中铬合金钢力学性能的宽幅调控。 相似文献
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用原位烧结法制备了不同V与Ti原子比(0,0.2,0.4,0.8)的(Ti,V)C35CrMo钢结硬质合金.研究了V含量对钢结硬质合金组织及力学性能的影响.用SEM 观察试样的微观组织特征、断口形貌和磨损形貌.结果表明:V含量影响钢结硬质合金硬质相的形态、大小、体积分数,进而影响合金的力学性能.V与Ti的原子比为0.2时硬质相最小;随着V含量增加,硬质相趋于圆整、并增大.断口形貌特征为硬质相解理、基体准解理及韧窝.基体形变磨损和硬质相脱落是钢结硬质合金的磨料磨损机理.V与Ti的原子比为0.2时抗弯强度及耐磨性最高. 相似文献
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将脉冲电流作用于铁素体不锈钢,发现经过脉冲电流处理后等轴晶比例大幅增加,晶粒明显缩小。建立了考虑集肤效应的三维电磁场瞬态有限元模型,利用ANSYS软件对电极及熔体内的电场、磁场、电磁力分布进行了计算,结果表明,由于集肤效应使得电磁场主要集中在电极周围和熔体上部,且在脉宽的后期电磁场的方向由于涡流的存在而发生变化;电极间距对熔体电磁场均匀性具有较大影响;随着脉冲电流的脉宽减小,熔体上部的电磁场增强,但集肤深度也越小,同时作用时间缩短。 相似文献
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介绍了矿热炉开炉的一般方法和两种开炉新工艺。通过对电极内部热应力产生和分布规律的分析,提出了直接电烘炉法在开炉中防止电极硬断的措施;对直接电焙电极的可行性进行分析后认为,电极壳的实际电流密度小于6.1A/mm^2的情况下送电焙烧电极不会击穿电极壳。将两种新开炉方法分别应用在电炉上实践,取得了较好效果。 相似文献
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《钢铁冶炼》2013,40(5):374-378
AbstractAn experimental study with respect to the influence of electric current pulse (ECP) on the solidification structure of molten silicon steel was investigated with a copper mould designed to simulate the twin roll casting process. The experimental results showed that the application of ECP can increase the proportion of equiaxed grains up to 67·5%. The mechanism of exerting ECP is also discussed. It can be confirmed that the application of ECP on twin roll casting could effectively improve the solidification structure of silicon steel strip. 相似文献
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The evolution of eutectic carbide in as-cast M2 high-speed steel on different deforming conditions was investigated. Initially, specimens were deformed by hot compression in the range of 1223 to 1398K at strain rates of 0.01 to 1.0s-1. In a series of continuous deformation tests the flow stress curves were determined for the downstream process simulation. Subsequently, metallographic examination was carried out before and after deformed specimens for carbides analysis. As-cast microstructure is characterized as a spherical matrix of austenite and a continuous network of rodlike or irregular eutectic carbide, whereas deformed microstructure has broken carbide network and smaller granular products on all experimental conditions. It suggests that eutectic carbides fracture to particles during hot deformation by thermomechanical disintegration, while diffusion-controlled phase transformation was not remarkable. Combination with numerical simulation, the relationship between breakdown ratio of carbide network and deforming parameters were concluded. Strain was the most important one to shatter eutectic carbides and disperse products. Furthermore, critical strain values were obtained, beyond which carbide network disappeared, and fractured carbides kept a stable profile and deformed with matrix coordinately. A higher temperature or lower strain rate resulted in a lower critical strain. 相似文献
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无钟炉顶设备主要通过改变溜槽倾角以调整布料矩阵,最终改变炉料在高炉内的分布。此外,炉料分布还受溜槽形状的影响,不同形状的溜槽,其料面偏析情况不同。为探究不同溜槽下的布料偏析现象,针对常见圆方比例不同的3种类型溜槽、带储料槽型溜槽以及破损溜槽,运用离散单元法对溜槽表面和布料特征进行研究,探究在不同溜槽下炉料的偏析现象和溜槽受力情况。模拟结果表明,相对于圆形出口溜槽,方形出口溜槽料流宽度小,分布均匀,更有利于精准布料;带储料槽溜槽可以减小炉料对溜槽的冲刷,延长溜槽寿命;破损溜槽料流宽度较大,炉料分布不均匀,会加大炉料在料面上的偏析。 相似文献
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G. A. FINKELSTEIN A. D. SHULOYAKOV 《Mineral Processing and Extractive Metallurgy Review》2013,34(3):167-174
Abstract Although electric pulse disintergration possesses a number of advantages over mechanical means of comminution (efficient liberation of monominerals from polymineral rocks, high purity of products, no metal contaminants), a serious drawback putting a limit to its commercial use is its energy inefficiency. Calculations of energy consumption in terms of increased surface area of fragments resulting from disintergration indicated that specific consumption of energy in electric pulse disintegration is within 0.00135–0.00067 Wh/cm2. To disintegrate a cube with 4 cm side down to ? 2 + 0 mm size requires work amounting to 20 kWh/t as compared to 3–10 kWh/t of commercial and 15–17 k Wh/t of laboratory mechanical facilities. Analysis of energy distribution proved that the total electrical efficiency of electric pulse disintegration is as low as 0.01–0.08 of the amount consumed from power supply main. Specific energy consumption per 1 cm2 of increased surface area is 0.4–0.5 J.cm-2. 相似文献
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由于金属凝固过程中选分结晶的作用,不可避免地会出现成分不均匀现象。连铸过程中由于强制冷却,这种成分不均匀现象更为严重。这不仅影响了铸坯和铸锭后续加工性能,并影响了最终产品质量和性能的均匀性和稳定性。研究和生产实践表明,细化凝固组织是解决成分不均匀性的有效手段。脉冲电磁场因能耗低、施加方便、细晶效果显著,近年来得到了广泛关注,有望成为冶金界广泛应用的凝固组织细化和均质化技术。分别介绍脉冲电流、脉冲磁场和脉冲磁致振荡3种脉冲电磁场凝固组织细化和均质化技术的研究现状和应用进展。 相似文献