Brittle fracture in heat-affected zones of girth welds of modern line pipe steel (X100)

Anne-Sophie Bilat (1) , Anne-Françoise Gourgues-Lorenzon (1) , Jacques Besson (1) , G. Richard (2) , André Pineau (1)

1 CDM - Centre des Matériaux
2 Serimer Dasa

Girth welds of modern line pipe steel, such as X100, issued from a pulsed automatic gas metal arc welding, were tested to check their performance in artic temperature conditions. It is shown that an impact specimen at -20 °C with a notch placed in the middle of the fusion line could break at low energy (<40 J). The brittle zone is located in the coarse-grained heat-affected zone of the weld. The reproduction of two heat-affected zones with a thermal-mechanical simulator, Gleeble 1500, allows to determine the mechanical behaviour of representative microstructures of the welded joint. Tension tests with or without notch and impact tests are performed between -196 °C and 20 °C. This experimental database is used to fit materials constitutive equations which are used in a finite element code to predict the fracture of the welded joint.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Anne-Sophie Bilat, Anne-Françoise Gourgues-Lorenzon, Jacques Besson, G. Richard, André Pineau. Brittle fracture in heat-affected zones of girth welds of modern line pipe steel (X100). Fracture of nano and engineering materials and structures, ECF 16, Jul 2006, Alexandroupolis, Greece. 7 p. ⟨hal-00146312⟩