Study on hydrogen embrittlement of hard chromium plated high strength steel.

The hydrogen embrittlement of high strength steels has been studied. The slow deflection fracture test with the flat rectanguler specimens and the stress rupture test with the notched tensile specimens were carried out in order to evaluate degree of hydrogen embrittlement. Effect of baking operation for hydrogen relief was investigated with high strength steels having different strength levels. Several informations which are beneficial to practical hard chromium plating has been established. Correlation between the slow deflection fracture test and the stress rupture test was obtained. The hydrogen embrittlement fracture surfaces due to hard chromium plating were studied by scanning electron microscopy and typical intergranular cracking was observed.