Sinan FANK, Mehmet DEMİRKOL

Kuvvet dönüştürücülerde ısıl ve mekanik işlemlerin histerisiz hatasına etkisi

Yay elemanının yapısal özellikleri kuvvet dönüştürücülerinin performans özelliklerini etkilemektedir. Bu çalışma, çok kullanılan bir yay elamanı malzemesi olan AISl 4340 çeliğine uygulanan farklı ısıl ve mekanik işlemler sonrası elde edilen iç yapısal özelliklerin kuvvet dönüştürücünün histerisiz performansına etkisini araştırmaya yöneliktir. Deney sonuçlarına göre, histerisiz hatasının malzemenin sertliğine paralel olarak iyileştiği, aynı sertlikteki beynitik yapının temperlenmiş martenzitik yapıya göre daha iyi performans gösterdiği, çevrimsel zorlama ile sert yapıda kötüleştiği, yumuşak yapılarda ise iyileştiği görülmüştür. Ön plastik şekil değişimi ile histerisiz hatasında iyileşme, ön sürünme uygulanması ile kötüleşme görüldüğü belirlenmiştir.

Effect of heat and thermo-machanical pre-treatments on hysteresis performance of force transducers

Different mechanical and heat treatment processes can be applied on the spring element of a force transducer, in order to obtain good and satisfactory performance. The manufacturers are generally focused on the improvement of performance by applying different heat and mechanical treatments on spring material, and no information is in free circulation regarding the process-performance relationships of transducers due to tight competition in the market. Mechanical behavior of spring element of force transducers is playing a crucial role to obtain good performance in measurements. The application of different heat treatments changes the microstructure of spring material, which is very effective in the improvement of performance properties of force transducers such as hysteresis error and creep response. Present study covers the attempts of changing microstructure of AISI4340 steel by using different heat and thermo mechanical treatments and measuring the performance of force transducers related with the structural properties of spring element. The measurement results have shown that; hysteresis characteristics were improved with increasing hardness of specimens, which were quenched and tempered only. Bainite has an advantage over tempered martensite at the same hardness level from hysteresis performance point of view. Prestraining has beneficial effects on the improvement of hysteresis characteristics, while pre-creep deformation has adverse effect. Cyclic stressing improved hysteresis properties only in soft structures.

PDF

___

Alexopoulos, P. S., Cho, C. W., Hu, C. P., Li, Che- Yu, (1981). Determination of the Anelastic Modulus for Several Metals, Acta Metallurgica, 29, 4, 549-577.
Allgeier, T., (1994). Factors Influencing the Mechanical Hysteresis in Stainless Steel Load Cells, A Thesis for the Doctor of Phylosopy, Glamorgan University, England.
Bakkal, M., (1999). İyon Nitrürlemenin Ostemperlenmiş AISI 8660 Çeliğinin Mekanik Özelliklerine Etkisi, Yüksek Lisans Tezi, İ.T.Ü. Fen Bilimleri Enstitüsü, İstanbul.
Bhadeshia, H. K. D. H., (2001). Bainite in Steel, The Institute of Materials, U.K.
Bray, A., Barbato, G., Levi, R., (1990). Theory And Practice Of Force Measurement, Academic Press, London.
Demirkol, M., (1991). Mekanik Metalurji Ders Notları, İTÜ Makine Fakültesi, İstanbul.
EN-10002-3, (1994). Metalic Materials - Tensile Testing - Part 3 - Calibration of Force Proving Instruments Used for the Verification System of the Uniaxial Testing Machine, European Standard.
Firma Yayını, (1988). Strain Gage Based Transducers, Their Design And Construction, Measurement Group Inc., USA.
Hull, D, (1975). Introduction to Dislocation, Pergamon Press, Oxford.
Kawai, M., (1984). Problems Raised By Improvments in Load Cell Accuracy, Proceedingfs of 10th International Conference of IMEKO, Kobe, Japan, September 11-14, 59-62.
Katalog, Transducer Class Strain Gages, Measurement Group Inc., USA.
Klesnil, M., Lukas, P., (1980). Fatigue of Metallic Materials, Elsevier Science, New York.
Krauss, G., (1980). Principles of Heat Treatment of Steel, ASM, Metal Park, Ohio.
Lakhtin, Y., (Çevirenler:Şerif, O., Altaç, Z), (1994). Fiziksel Metalurji ve Isıl İşlemler, Osman Gazi Üniv., Eskişehir.
Özbay, H. Ö., Ural., K., (1997). Gerinim Ölçerli Kuvvet Dönüşt. Aranan malzeme Özellikleri, II. Ulusal Ölçümbilim Kongresi, Eskişehir, 137-144.
Source Book On Industrial Alloy And Engineering Data, (1983). ASM, Metal Park, Ohio.
Technical Note, (1978). Strain Gage Installation Proced. for Transducers, Measur. Group Inc., USA.
Technical Note, (1992). Strain Gage Thermal Output And Gage Factor Variation With Temperature, Measurement Group Inc., USA.
Wood, W. A., (1971). The Study Of Metal Structure And Their Mechanical Proporties, Pergamon Press, New York.