Fatigue Crack Growth and Fracture Toughness Properties of 304 Stainless Steel Pipe for LNG Transmission

The fatigue crack growth rate and fracture toughness tests of type 304 stainless steel were studied over a temperature range of -162℃ to room temperature. Girth weld metal specimens were fabricated using a combination of gas-tungsten-arc-welding and shielded-metal-arc-welding. The seam weld metal was made with submerged arc welding. Fatigue crack growth rate tests were conducted using compact tension specimens in accordance with ASTM E647. Fracture toughness was evaluated through CTOD tests with three point bend specimens. The CTOD values were affected by crack orientation with respect to the rolling direction, but orientation had no influence on fatigue crack growth rates. The fatigue crack growth rates and the CTOD values decreased with decreasing test temperature.