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<正>目前,工业廉金属热电偶(以下简称"热电偶")依据JJG351-1996《工作用廉金属热电偶检定规程》进行检测。但是,测量结果不确定度偏大,其主要原因:(1)未放置均温块的管式热电偶检定炉(以下简称"管式炉"),空载时温场的技术指标符合JJG351-1996的要求,满载时温场的技术指标不符合JJG351-1996的要求(测试结果见一、1和一、2);(2)检测时管式炉温场的波动大。针对这些问题,笔者设计了杯式高温合金均温块(以下简称"杯式均温块")与管式炉配套使用,既提高了温场的技术指标,减小了温场的波动,又可满足不同直径热电偶的检 相似文献
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本文对我院建立的标准热电偶自动检定系统进行技术指标全面分析和不确定度评定,论证了该自动检定系统具有性能先进,自动化程度高的特点,完全能代替人工检定,开展标准热电偶的检定要求。 相似文献
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水平连铸工艺制取锌及其合金线坯的过程中,对熔体温度测控精度有较高要求,但是浸入熔体中的测温热电偶金属保护管,容易被熔锌及其合金侵蚀,造成熔体温度测控失效。本文采用在热电偶金属保护管表面热喷涂一层Mo-B合金层,同时涂衬一层非有机密封材料,试验表明,在热电偶金属保护管热喷涂一层0.1-0.2mm、且硼含量在10%左右的Mo-B合金喷涂层,能起到最佳的耐侵蚀性能,寿命最长可达1000h。 相似文献
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N型热电偶是近20年廉金属热电偶合金材料研究方面取得的重要成果,有明显的优点.而作为温度传感器,热电偶在长期使用过程中的热电稳定性是人们最为关心的问题.本文通过对N型热电偶合金丝及N型铠装热电偶的长期稳定性试验的考核,结果无论是用氧化铝绝缘的裸丝N型热电偶,还是铠装N型热电偶,在有关标准推荐的长期最高工作温度下试验,热电偶均呈现了良好的长期稳定性.故表明N型铠装热电偶的长期稳定性能良好,大有取代K型热电偶成为工业测温的主要热电偶品种的趋势. 相似文献
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工程图纸矢量化与识别技术在工时定额制定中的应用 总被引:5,自引:0,他引:5
首先将编码技术引入到工时定额制定中,通过代码将影响工序时定额的因素特征化、系统化,在此基础上,提出了基于工程图纸矢量化与识别技术的工时定额制度方法,并应用工程图纸识别技术,研究了工时定额制定系统,包括分类编码系统,代码生成系统,计算机辅助工时定额编定系统。 相似文献
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This paper is based on the Finite Element Analysis (FEA) to study the AZ31B Magnesium Alloy welding temperature filed, using a convenient, non-contact and fast response measured temperature method—Infrared Radiation (IR), the welding temperature field of AZ31B magnesium alloy plate in Gas Tungsten Arc Welding (GTAW) is measured by IR, the isothermal map of magnesium alloy plate is measured using IR device. The cooling curves are measured by thermocouple. Experiments and simulations by FEA are carried out to investigate the welding temperature field. The simulated results showed good agreement with the experiment ones. 相似文献
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O. Ongrai J. V. Pearce G. Machin S. J. Sweeney 《International Journal of Thermophysics》2010,31(8-9):1506-1516
The Pt/Pd thermocouple has demonstrated superior thermoelectric drift and homogeneity performance over conventional Pt–Rh/Pt thermocouples. Here, we present a systematic comparison of the drift and homogeneity performance of Pt/Pd and Type R thermocouples by ageing the thermocouples at 1350 °C for a total of 500 h and measuring the performance at regular intervals during this time. The thermocouples studied were one Pt/Pd thermocouple, one Type R thermocouple and one ‘special’ Type R thermocouple which was given the same preparatory annealing treatment as the Pt/Pd thermocouple prior to use. The thermoelectric stability of each thermocouple was measured at the freezing point of Ag (961.78 °C) and the melting point of Co–C eutectic (1324.29 °C). The thermoelectric homogeneity of the thermocouples was also measured. Two difference methods were used by withdrawing the thermocouple from the Ag cell and by moving a localized heat source along the thermocouple. The long-term drift of the Pt/Pd thermocouple was around 50 mK (Ag) and 65 mK (Co–C) after the first 100 h ageing at 1350 °C, followed by a further 25 mK (Ag) and 35 mK (Co–C) over the subsequent 400 h ageing. This drift performance and inhomogeneity were an order of magnitude lower than for the two Type R thermocouples. The Type R thermocouple which was given the ‘special’ preparatory treatment was about 50 % more stable than the conventional Type R thermocouple. 相似文献
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This paper presents results of measurements of the specific heat and electrical resistivity of a 53%Ni-47%Ti superconducting alloy. Both properties were measured by a contact variant of the millisecond-resolution pulse calorimeter. W5%Re/W25%Re thermocouple thermometry enabled study from ambient temperature to 2000 K. Results are discussed, and their uncertainty is estimated. 相似文献
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报道了以稀磁铜铁合金热电偶为感染元件的一种智能低温仪表,其测温范围为3~273K。叙述了该仪器的工作原理,并对利用单片机进行非线性处理,零点自校正和冷端温度补偿等问题进行了分析。 相似文献
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N. P. Moiseeva 《Measurement Techniques》2004,47(9):915-919
Thermocouples with electrodes of pure metals - platinum, gold, and palladium, which are superior in accuracy and stability to standard platinum-rhodium alloy thermocouples, are considered. It is shown that a gold–platinum thermocouple may be an alternative to a high-temperature platinum resistance thermometer.Translated from Izmeritelnaya Tekhnika, No. 9, pp. 46–49, September, 2004. 相似文献
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钛合金是航空航天领域主要的轻质结构材料,强度高,但不易成形且回弹大,而电磁成形技术的发展为钛合金零件的精密高效成形提供了新的有效途径.从高速增塑、成形工艺、数值仿真3个方面综述了电磁成形技术在钛合金板材成形的应用研究情况,并结合笔者的研究经历对钛合金电磁成形中存在的问题进行了简要分析.在此基础上,着重综述了电磁成形技术下材料的成形性能与变形机理,进而综述了钛合金电磁胀形、电磁翻边工艺研究进展,并介绍了钛合金电磁成形多物理场耦合仿真技术,最后对未来钛合金板材电磁成形技术的发展进行了展望.电磁成形技术可以提高钛合金板材的成形性能;厚度接近集肤深度的高导电性低强度板材是优质的驱动片.为了进一步促进电磁成形技术在钛合金板材成形中的应用,需要开发更高强度的磁体线圈以及更优的驱动方式. 相似文献