Welding in Vibration Conditions – Critical Approach

Abstract

Vibratory stabilisation has been used in production practice for a relatively long time now. The use of vibratory stabilisation provides technical and economic advantages where high dimensional stability of welded structures is required. For many years, research magazines have been reporting of attempted welding in vibration conditions. The article provides the overview of reference publications concerned with this issue as well as presents related tests performed by the author. The publications cited in the article inform about the effect of vibration on the distribution of welding stresses, strength-related properties and on the manner of weld formation. However, varying views presented in the abovenamed publications do not unequivocally confirm the efficiency of welding on vibration conditions. The foregoing inspired the author to carry out research including welding tests involving ferritic steel S355 and performed in various conditions of vibration having specified frequency. The tests involved the determination of the distribution of welding stresses as well as included metallographic examinations, toughness tests and hardness measurements. The research revealed the lack of the effect of vibration on the distribution of welding stresses, hardness and toughness of welds. No changes in the microstructure of welds were observed either. The conclusions formulated on the basis of the research did not recommend, generally, the welding of ferritic steels in vibration conditions. Keywords: vibratory stabilisation, welding in vibration conditionsdoi: 10.17729/ebis.2017.3/1 Present StateThe vibration-based method used to increase dimensional stability has found applications in the making of welded machinery structures. The most favourable effect as regards dimensional stability is obtained when vibration is of resonant frequency. Vibration-induced stresses accelerate processes of microrelaxation and phase transformations at ambient temperature and, as a result, delayed strains. Vibration, as it were, "provokes" strains so that, after mechanical treatment, structures do not undergo unallowed deformations. When selecting structures to be subjected to vibratory stabilisation it should be noted that the vibration-triggered reduction of welding internal stresses is insignificant [1][2][3][4][5].