Hydrogen-induced Disbonding of Cladding (1st Report)

Relationship between Hydrogen Distributions and the Cracking in Clad Steel

Abstract

Hydrogen-induced disbonding of austenitic stainless steel cladding was investigated. The used test specimen was made from the heavy section 2 1/4Cr-1Mo steel plate weld-clad using type 309 strip with 75 mm width and type 347 strip with 150 mm width. And it was heated at 455°C in autoclave containing high pressure H₂ for hydrogen charging.
The results indidate that (1) the delayed cracking occurs when the specimen is rapidly cooled from hydrogen charging temperature, but it cannot occur above 100°C, (2) this type of cracking takes place in grain boundaries of cladding adjacent to the fusion line, (3) the susceptibility to cracking decreases by application of post-heating or by reducing the rate of cooling after hydrogen charging, (4) numerical analysis applied to hydrogen distribution may explain the behaviour of cracking.