Vol.7, No1, 2007, pp. 21-28
 UDC 621.642-988-112.81:539.42

LOADING CONDITION EFFECT ON THE FRACTURE OF WELDED THIN-WALLED STORAGE TANK

Nada Filipović 1

Katarina Gerić 2

Stojan Sedmak 3

1 Zavod za zavarivanje, Belgrade

2 Faculty of Technical Sciences, University of Novi Sad, Serbia

3 Faculty of Tehnology and Metallurgy, University of Belgrade, Serbia

Abstract

Loading conditions can affect significantly the fracture mode of storage tanks in service. Two different fracture mechanisms experienced in service of thin-walled pressure vessels of the same wall thickness (8 mm) are presented. Brittle fracture of the storage tank made of structural steel S355J2G3 (EN 10025) and transition temperature –20°C occurred during the first proof pressure test with nitrogen. Due to overloading and temperature increase, a mobile storage tank for ammonia transportation, made of microalloyed steel TSt 460 (DIN EN 10113-2), failed by a ductile mechanism. In both cases, although they exhibited different fracture mechanisms, the crack was initiated in the heat-affected-zone of the welded joint.

Keywords: brittle fracture, ductile fracture, pressure vessel, welded joint, heat-affected-zone, loading condition

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