SEDL / STP / STP733-EB / STP33425S

Hydrogen-Induced Brittle Fracture of Type 304L Austenitic Stainless Steel

Caskey, GR
Metallurgist, Savannah River Laboratory, E. I. du Pont de Nemours and Co., Aiken, S.C.

Pages: 12    Published: Jan 1981

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Abstract

Type 304L stainless steel supersaturated with hydrogen gas fails in tension at 200 to 250 K by brittle fracture. Fracture surfaces exhibit isolated facets oriented 0 to 30 deg to the tensile axis. These facets have many of the characteristics of cleavage fracture. The threefold symmetry of Laue back-reflection photographs and trace analysis of deformation bands on the facets demonstrate that fracture is along {111} planes. The fracture paths were identified as coherent twin boundaries on polished sections through facets and on microcracks across interior grains. Although twin-boundary parting is not commonly observed in alloys with a face-centered cubic (FCC) lattice, these observations for Type 304L stainless steel and similar observations of Nitronic-40 and Tenelon demonstrate that parting is possible in austenitic steels under some circumstances.