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蒋晓云 《机械工人(热加工)》1997,(6):27-27
钢的淬透性是钢的重要性能指标之一。端淬试验是目前应用最为广泛的测定钢材淬透性的试验方法。这种试验方法的最终结果是绘制端淬曲线图。该图的横坐标为各端淬试验测点距试样水冷端的距离值,纵坐标为测点的硬度值。由钢的上限成分与下限成分硬度曲线构成淬透性带或端淬曲线,它具体地表示了某种钢号的淬透性。因此,获得准确、可靠的端淬曲线数 相似文献
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对高淬透性轴承钢GCr19SiMnMo的淬透性及下贝氏体含量不同的马氏体/贝氏体复合组织和马氏体组织的摩擦磨损性能进行了研究,并与GCr15钢、GCr15SiMn钢马氏体组织进行对比。结果表明:GCr19SiMnMo钢的端淬试样完全淬透,GCr15钢淬硬层深度为8.5 mm(J8.5=58),GCr15SiMn钢的淬硬层深度为18.5 mm(J18.5=58);GCr19SiMnMo钢的马氏体组织耐磨性最优且摩擦因数最小;不同下贝氏体含量GCr19SiMnMo钢的磨损率均比GCr15钢和GCr15SiMn钢低;GCr19SiMnMo钢组织中的下贝氏体含量对耐磨性有一定的影响,下贝氏体含量越少,耐磨性越好。 相似文献
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本研究针对直径90mm的大规格60Mn锻球在实际生产中出现的淬裂、淬硬性不够、淬硬深度小等问题进行了研究。分析了原锻造钢球的硬度分布及显微组织,研究了不同淬火温度及水、碱水两种不同淬火介质对60Mn锻球的淬硬性和淬透性的影响。结果表明:原锻球淬硬层硬度偏低,淬硬层较浅,淬火组织较为粗大,局部有网状铁素体;经790℃~810℃不同温度热处理,随淬火温度升高,硬度略有升高,且碱水淬火试样开裂倾向增大。直径90mm的60Mn锻球经800℃水淬、180℃的低温回火后,淬硬层最高硬度达62HRC,淬硬层深度可达18mm,淬硬性及淬透性均有明显改善。 相似文献
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本文利用标准C型缺口试样对8种常用高速重载齿轮用钢的变形倾向进行了试验,结果表明,钢材变形程度与晶粒度,马氏体相变点及淬透性等因素有明显的对应关系。 相似文献
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钢件在锻热淬火加热时通常处于奥氏体化高温区(1100~1300℃),因而导致奥氏体晶粒粗化,淬火后得到的马氏体也较粗大。尽管一般认为,锻热淬火前粗大的奥氏体晶粒有利于提高奥氏体的稳定性,延缓过冷奥氏体的分解,因而可提高钢的淬透性。然而在材料本身具备足够淬透性的条件下,仍然希望获得细小奥氏体组织,以改善淬火回火钢的强韧性配合。 1.试验方法试验用钢:45Cr钢、直径50mm;化学成分(wt%):0.46C、0.30Si、0.64Mn、0.96Cr、0.25Ni、0.02S、P。切割下料后,分别按以下两种工艺处理样品(截面尺寸:15×15mm)。工艺(1):将坯料加热到1150℃出炉始锻,一次成型至900℃终锻,停留3~5秒后入油淬火。淬火态试样的工艺为:下料→一次锻造成型并油淬; 相似文献
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WC cemented carbides are used extensively to improve abrasion resistance. Co content and WC grain size influence the mechanical properties of the cemented carbides. In this study, the effects of Co content and WC grain size of cemented carbide on wear were examined. We prepared 13 different cemented carbides with different Co content and WC grain size. Wear tests were carried out against 0.45% carbon steel under dry condition at 98 N and 232 mm/s. From the results, we found that wear increased with both Co content and WC grain size. Specific wear rate of the cemented carbides tested was in the range of 10−7 mm3/(N m). We discussed the wear properties with hardness and the mean free path of the cemented carbide. These two parameters alone cannot explain the wear property. 相似文献
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用Autosorb-1物理吸附分析仪测定矿物材料孔结构的应用研究 总被引:1,自引:0,他引:1
文章概述了孔分布的计算方法,对分子筛试样测试结果的分析表明分子民径12A和31A附近有重要吸附贡献,属典型的中孔基体,微孔物质的混合物。最后给出了海泡石等四种矿物材料孔结构的测定结果。 相似文献
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How to sample three-dimensional microstructure and effectively reduce experimental error is a challenging problem. Taking seven single-phase polycrystalline structures generated by 400×400×400 Potts Monte Carlo simulation as the study object, effects of sampling strategy on the determination of various characteristic parameters of the grain size distribution and grain topology distribution are studied. The mean voxel value (or volume) of individual grains in the three-dimensional simulated microstructure varies from 4.56×10(4) to 1.0×10(3) , and the number of grains contained in the structure varies from 63 901 to 1403. The results show that, a minimum of 200 sampled grains can ensure the relative error to be less than 5% for determination of the mean grain volume, the mean grain face number and the coefficient of variance of the distribution of grain size and the grain face number. Whereas for the coefficient of the skewness and the kurtosis of grain size distribution or grain face number distribution, a minimum of 800 sampled grains are required for the same error level. However, if some exceptional big grains appear, e.g. a grain larger than with eight multiples of mean grain volume and/or three multiples of mean grain face number, abnormal values of the two parameters would be resulted, even the number of examined grains is over 1000. 相似文献
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K.P. MINGARD B. ROEBUCK E.G. BENNETT M. THOMAS† B.P. WYNNE† & E.J. PALMIERE† 《Journal of microscopy》2007,227(3):298-308
The measurement of grain size by EBSD has been studied to enable representative quantification of the microstructure of hot deformed metal alloys with a wide grain size distributions. Variation in measured grain size as a function of EBSD step size and noise reduction techniques has been assessed. Increasing the EBSD step size from 5% to 20% of the approximate mean grain size results in a change in calculated arithmetic mean grain size of approximately 15% and standard noise reduction techniques can produce a further change in reported size of up to 20%. The distribution of measured grain size is found not to be log‐normal, with a long tail of very small sizes in agreement with a computer simulation of linear intercept and areal grain size measurements through randomly oriented grains. Comparison of EBSD with optical measurements of grain size on the same samples shows that, because of the ability of EBSD to distinguish twins and resolve much smaller grains a difference of up to 50% in measured grain size results. 相似文献