A Study on the Effect of Tempering Temperature on Tensile Properties of P92 Steel by Automated Ball Indentation Technique

Abstract

P92 steel was normalized at 1353 K for 30 minutes followed by air cooling and subsequently tempered at 1013, 1033 and 1053 K for 60 minutes each followed by air cooling. The effect of tempering temperatures on the tensile properties of P92 steel has been investigated using automated ball indentation technique (ABI) at different test temperatures in the range of 300 K-923 K. The yield strength (YS), ultimate tensile strength (UTS) and strength coefficient (K) were determined and these were found to decrease with increase in tempering and test temperatures. The decrease in strength was attributed to the increase in M precipitate size and lath width with higher tempering temperatures. The strain hardening exponent (n) decreased with increase in the test temperature which is confirmed by increased pile up around indentation. The ABI results were in good agreement with the results obtained from conventional tensile tests.