Grain boundaries of pipeline steel X42 were characterised by electron energy loss spectroscopy (EELS) and with energy dispersive X-ray spectroscopy using a high-resolution analytical electron microscope in order to elucidate its intergranular stress corrosion cracking mechanism. In these experiments, EELS was not a good method contrary to expectation. Carbon contamination on the specimen surface continues to be a issue. Argon plasma cleaning and Precision Ion Polishing System cleaning did not remove the carbon contamination from the sample surface. There were carbide precipitates along ferrite:ferrite grain boundaries, and manganese and carbon were segregated at the ferrite:ferrite grain boundary between the carbides. There was no measurable S and P segregation at the ferrite:ferrite grain boundary. There was no measurable Mn segregation at the ferrite:pearlite grain boundary, which is different to the result for X65 and X52.
Keywords: grain boundary, pipeline steel, X42, ferrite, pearlite, carbide, carbon, segregation