Stress corrosion cracking (SCC) of high tensile fasteners in boiler feed water systems has been associated with the deleterious effects of certain lubricants. This paper describes test work undertaken to simulate the observed failures under controlled conditions and ultimately ascertain the factors affecting the cracking mechanism. The work consisted of immersing small pre-bent beam specimens of fastener grade steel into various solution environments comprising a number of common fastener lubricants with feed water. These environments were held at ～100°Cand the specimens were regularly examined for evidence of SCC to rank their susceptibility. It was found that thermal breakdown of the lubricants exacerbated their effect, so, to gage this, one of the most aggressive lubricants was subjected to various heat treatments to thermally accelerate its break down to form a SCC environment. Finally, wedge opening load specimens which were manufactured from the fastener grade steel and immersed in the heat-treated lubricant and feed water environments, showed evidence of SCC, as expected.
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