Waterside tube cracking is one of the major reasons for carbon steel boiler tube failure. Previous
research has shown that the waterside cracking depends on environmental factors such as temperature,
and dissolved oxygen. Failure analysis of failed industrial boiler tubes have shown that grain size and
decarburized layer on the inner tube surface may play important roles on SAC cracking. Carbons steel
samples were heat-treated to produce different microstructure features. A recirculation autoclave
facility was set up, in which slow strain rate tests (SSRT) were carried out on heat-treated tensile
samples to investigate the role of environment and microstructure on SAC crack initiation and
propagation under simulated boiler water environment.