1Department of Wood Processing Industry, Faculty of Forestry Sciences, Agricultural University of Tirana
*Corresponding author e-mail: email@example.com
The objective of this research was to determine the hardness of sessile oak (Quercus petraea, L) timber from forest stands growing in Albania. The study of the hardness in oak wood is important because it’s one of the main species used in the wood industry for production of fine furniture items. Hardness is a mechanical characteristic, defined as the timber resistance to any indentation and evaluated by the measurement of the penetration depth into the wood samples. It determines also the place where this wood sample will be used in the furniture itself. The Brinell hardness is measured in three main directions, longitudinal, tangential and radial, respectively. After the samples were prepared in the Wood technology laboratory situated in the Faculty of Forestry Sciences, they were divided into two groups. The samples of the first group consisted from 9 to 12 annual growth rings, whereas the samples of the second group comprised from 13 to 16 annual rings. Our measurements showed that average values of hardness in the samples of the first group were 97.37 N/mm2; 59.83 N/mm2; 60.61 N/mm2 in longitudinal, radial and tangential directions respectively. In addition the average values of hardness in samples of the second group were higher reaching values of 96.78 N/mm2, 61.53N/mm2 and 58.93N/mm2 along the longitudinal, radial and tangential directions. The findings of this study showed that, hardness of oak wood according to Brinell method was higher in longitudinal direction (97.1 N/mm2) and there is a slighter difference between tangential and radial direction respectively (59.8 N/mm2 and 60.6 N/mm2).
Keywords: Brinell hardness; oak wood; tangential; radial; longitudinal direction