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41.
42.
本文分析了离心复合铸造轧辊生产过程中离心机停机温度和时间对轧辊质量的影响 ,提出了用先进的红外测温技术来预报停机温度和时间 ,以实现微机监控适时停机 ,保证轧辊内外层熔合良好 ;同时指出了红外测温技术在离心复合铸造轧辊生产上的应用前景 相似文献
43.
介绍应用中频快速感应加热方法对弹簧钢、轴承钢、工模具钢等冷变形抗力大的材料及某些异型材在再结晶温度以下进行温轧的成功经验。利用快速加热还可对轧后需保持原有组织和特性的材料进行轧制。 相似文献
44.
On The Measurement of Temperature in Material Removal Processes 总被引:5,自引:0,他引:5
Because it is key to understanding the performance of material removal processes and resultant workpiece quality, the measurement of temperature during material removal is done extensively. We review several widely used temperature measurement methods and show how they can be applied to temperature monitoring during material removal. Since there is little documentation on measurement uncertainties as relates to material removal, this paper outlines the physics of each method, detailing the sources and evaluation of uncertainty. Finally, using criteria critical in measuring material removal, methods are compared, and the results presented in guide-format for participants in this field of work. 相似文献
45.
L. Filice F. Micari S. Rizzuti D. Umbrello 《International Journal of Machine Tools and Manufacture》2007,47(3-4):709-714
Despite the development of high performance finite element-based codes, the simulation of machining still represents a very hard task due to the geometric complexity of the real chip-tool systems and the high cutting speed that requires very long simulation times. For these reasons, many aspects related to machining are not very clear and so easy to simulate. In this paper a rigorous investigation on the role played by the implemented friction model within a 2D simulation of orthogonal cutting was carried out, taking into account different models proposed by the researchers in the last years. The main simulation results were compared with experimental measurements in order to verify if it is possible to identify the best model. Once the comparison with mechanical variables was completed, a subsequent study on temperature predictions utilizing the above friction models was executed as well. The results of this integrated numerical and experimental work are carefully reported in the paper. 相似文献
46.
红外辐射吸收法测量火焰温度 总被引:3,自引:0,他引:3
简述了几种温度测量的方法,介绍了红外辐射吸收法测温原理及实验装置,并对稳定的煤气火焰进行温度测量,试图在此基础上测量固体推进剂火焰的温度。 相似文献
47.
This study investigates the effects of cement type, curing temperature, and age on the relationships between dynamic and static elastic moduli or compressive strength. Based on the investigation, new relationship equations are proposed. The impact-echo method is used to measure the resonant frequency of specimens from which the dynamic elastic modulus is calculated. Types I and V cement concrete specimens with water-cement ratios of 0.40 and 0.50 are cured isothermally at 10, 23, and 50 °C and tested at 1, 3, 7, and 28 days.Cement type and age do not have a significant influence on the relationship between dynamic and static elastic moduli, but the ratio of static to dynamic elastic modulus approaches 1 as temperature increases. The initial chord elastic modulus, which is measured at low strain level, is similar to the dynamic elastic modulus. The relationship between dynamic elastic modulus and compressive strength has the same tendency as the relationship between dynamic and static elastic moduli for various cement types, temperatures, and ages. 相似文献
48.
介绍了焦炭高温反应炉的温控工艺及程控曲线,给出了程控曲线的控制结构、主回路以及实现多套PI参数控制的方法。 相似文献
49.
针对北京东方化工厂乙烯装置汽油分馏塔、稀释蒸汽发生系统以及急冷水、酸性水pH值等在运行中出现的问题,说明了问题的原因所在。通过优化操作、改造等方式对系统进行了整改,阐述了整改后的效果。 相似文献
50.
Calcium silicate hydrate is a porous hydrate that is sensitive to temperature and readily loses strength at elevated temperatures. Mechanical and chemical changes in the microstructure, due to escaping water, can significantly affect the mechanical properties, but these changes occur over different temperature ranges. By measuring Young's modulus as a function of temperature using the dynamic mechanical analyzer, the temperature range in which the greatest change in stiffness occurs can be identified. Additional mineralogy, pore size distribution, and composition analysis from high temperature X-ray diffraction, nitrogen sorption, and thermogravimetric analysis will demonstrate the changes in the microstructure. The results demonstrate that over 90% of the loss in stiffness occurs below 120 °C. Therefore, the damage is due to microcracking caused by pore water expansion and evaporation and not the change in mineralogy or composition. More damage, as indicated by greater loss in stiffness, occurs in stiffer and less permeable samples where higher stresses can develop. 相似文献