Mechanical properties of a 2-1/4 Cr-1 Mo steel tubesheet forging

Tensile and creep-rupture properties were determined on specimens taken from the cylindrical forging in the as-received condition and on pieces given a laboratory isothermal anneal. Near the external cylindrical surface, the microstructure was similar to that of the laboratory isothermally annealed steel and contained about 10 pct bainite. For specimens taken at intervals toward the center of the forging, the amount of bainite increased and went through a maximum of about 30 pct, then decreased to about 25 pct at the center. Strength also went through a maximum with distance into the forging. This nonuniformity was attributed to a nonuniformity of cooling rate. Strength changes were attributed to carbide precipitation reactions at elevated temperatures. 16 refs