Evaluation of effect of spheroidization heat treatment on mechanical properties via small punch test

Abstract

Due to the long time high temperature thermal action, pearlite heat-resistant steel 15CrMo is prone to pearlite spheroidization, which reduces its strength and makes it difficult to meet the actual service requirements. Therefore, quantifying the effect of pearlite spheroidization is an important factor in evaluating the high temperature performance of 15CrMo steel. In this study, the mechanical properties of 15CrMo steel were tested by uniaxial tension (UT), small punch tensile (SPT) test; the microstructure of 15CrMo steel after spheroidization heat treatment (SHT) was obtained by image processing technique to obtain the geometric characteristic parameters of pearlite spheroidization phase (PSP); the influence of spheroidization characteristics and properties were analyzed by mathematical and statistical analysis, and the results showed that the PSP size had the greatest influence on the properties; based on this, the linear relationship models between the spheroidization parameters and the mechanical properties of UT and SPT results were established with high accuracy of prediction.