An investigation of the effect of time and temperature on the properties of a normalized steel

Abstract

A steel used for both API normalized grades E and N-80 tubular products was normalized at three different temperatures (793, 849, and 904°C) and for four different times ( 5min., 20 min., 1 hour, and 2 hours) at each temperature. The samples were then evaluated for impact toughness, yield and tensile strength, elongation, hardness, fatigue strength and microstructure.

The lowest normalizing temperatures of 793°C produced significant improvements in yield and tensile strength, impact toughness and fatigue strength over the sames normalized at 849 and 904°C. The superior mechanical properties of the samples normalized at 793°C were attributed to their finer grain size and more uniform carbide dispersion that were observed in the metallographic study.