The effect of temperature on the changes of precipitates in low-alloy steel

Investigations on the microstructure of low-alloy steel in the as-received condition and after 70 000 h ageing at 550 and 600°C were carried out. For the recorded images of the microstructure, a quantitative analysis of precipitates was performed. On that basis, a statistical analysis of collected data was made with the aim of estimating parameters of selected theoretical statistical distribution. Then, the forecast for average precipitate diameter and standard deviation of such a distribution for the time of 100 000 h at 550 and 600°C was calculated. The obtained results of investigations confirm the possibility of using, in evaluation of degradation degree for materials in use, the forecasting methods derived from mathematical statistics.