Effect of vibration on the variation of residual stresses and impact energy in butt-welded joints

Abstract

The effect of vibration on the variation of residual stresses in butt-welded steel plates and on the impact energy in characteristic zones of a welded joint is analysed in this paper. An important segment occurring as a result of welding is the phenomenon of residual stresses in the welded joint zone. Residual stress measurements are conducted both on butt-welded plates that were not vibrated during welding and on plates simultaneously welded and vibrated. It is concluded that the vibration process noticeably decreases the level of stresses in the zone of the butt weld, i.e. the result is relaxation and plane stress state. Impact energy tests have shown that vibration favourably affects the total impact energy by increasing it both in specimens notched in the weld metal (WM) and in the heat-affected zone (HAZ). It is also concluded that the correlation between the distribution of crack initiation- and crack propagation energy, as vital components in the assessment of welded joint ductility, is improved.

Istraživanje uticaja vibracija na promenu zaostalih napona kod sučeono zavarenih čeličnih ploča i promena energije udara u karakterističnim zonama zavarenog spoja analizirana je u ovom radu. Bitan segment, koji se javlja kao posledica zavarivanja, je pojava zaostalih napona u zoni zavarenog spoja. Merenje zaostalih napona je rađeno na sučeono zavarenim pločama koje nisu vibrirane u toku zavarivanja i kod ploča koje su istovremeno zavarivane i vibrirane. Uočeno je da proces vibracija znatno smanjuje nivo zaostalih napona u zoni sučeono zavarenog spoja, odnosno, dolazi do relaksacije i uravnoteženja stanja napona. Ispitivanja energije udara su pokazala da vibracije pozitivno utiču na povećanje ukupne energije udara i kod epruveta sa zarezom u metalu šava i u zoni uticaja toplote. Uočen je i bolji odnos raspodele energije stvaranja i energije širenja prsline, kao važnih komponenti u oceni plastičnosti zavarenog spoja.