Determination of the pearlite nodule size in eutectoid steels

A simple metallographic technique is described that permits the preferential etching of pearlite nodule boundaries in a fully pearlitic microstructure. Practical results are shown to be good enough for a quantitative assessment of the pearlite nodule size by the American Society for Testing Materials (ASTM) comparative grain size method. Arguments are presented that suggest that the pearlite nodule size should play an important role in determining the fracture toughness of eutectoid steels.