Assessment of the Blue Brittleness Range of Steel

A brief analysis of the temperature range and origin of blue brittleness of structural steels is carried out. It is pointed out that the blue brittleness gives rise to a change in all mechanical characteristics of steel. In this case, the strength characteristics increase, while the ductility characteristics decrease in the narrow temperature range of blue brittleness. It is established that the hardness varies similar to the strength and can be used as a diagnostic parameter for determining the blue brittleness temperature range. For three grades of structural steel, experiments were carried out to determine the temperature range of blue brittleness by tensile testing specimens when heated to different temperatures. A method for the efficient determination of the blue brittleness temperature range is proposed that is based on the change in the Brinell hardness obtained by instrumented indentation. This method eliminates the need to manufacture and test tensile specimens and saves the material and labor cost.