| Abstract [eng] |
The main focus of the paper is to analyse the reason for the failure of the furniture springs, since the springs when tested did not provide sufficient fatigue resistance and to recommend possible solutions. It is also to be noted that only cost effective materials and coatings were used, since not many furniture making industries need components of high cost value. The tasks that were done to obtain the reason for the failure of the springs were as follows, the determination of the mechanical properties of the spring wire, analysis of the microstructure for identification of the microstructural defects, and the determination of quality requirements of spring wire. The material used for the experiment was EN 10270 according to the European standard and type of spring under investigation was the sagless or zig zag type furniture spring. For the tempering test, the spring wires were tempered both in company and in KTU laboratory and the results were compared from the specimen coloration. In tensile testing, the specimens were tested using the universal testing machine present in the KTU laboratory, the data from the test was logged using catman express software and from the data obtained the mechanical properties of the spring steel were investigated. Finally, the microscopic analysis of the spring steel was done, in which the specimen was investigated for surface and microstructural defects. The results obtained from the tests were then compared with their respective standards to know if they were within the permissible limit. Thus from the comparative results obtained from the tests, the recommendations for development of production and heat treatment of furniture steel springs were found out. |
