PSI - Issue 16

Andrii Kotliarenko et al. / Procedia Structural Integrity 16 (2019) 223–229 Andrii Kotliarenko et al. / Structural Integrity Procedia 00 (2019) 000 – 000

228

6

It can be assumed that at low loading rate of the specimen at temperature T = + 650 °C not only significantly decreases the mechanical properties, but also includes cracking of hot-work steel. Perhaps this behavior of hot-work steel is due to the active loading, which supports a rather slow tension. Then the manifestation of such cracking the metal and at lower test temperatures can not be ruled out.

3.4. Numerical Calculation

Preliminary data on the distribution of temperatures and stress-strain state in the reactor vessel for a number of variable parameters were obtained. On Fig. 5a the axisymmetric model used for finite element calculation is shown. а b с

Fig. 5. Axisymmetric model of vessel (a). Temperatures distributions in the melting zone at an outside wall temperature of +1 00°C for a model with (b) 50% (c) 25% of the residual thickness of the reactor wall.

а

b

Fig. 6. Strains distribution on the thickness of the wall in the melting zone for the model with (a) 50% and (b) 25% of the residual thickness of the wall of the body.

Fig. 6 shows the distributions of strains in the thickness of the reactor wall in the melting area for a model with (a) 50% and (b) 25% residual thickness of the its wall.

4. Discussion and Conclusion

The results of experimental studies of material behavior at different temperatures and loading rates were obtained. It was found that at low loading rate of specimen at temperature + 650 °C the material mechanical properties decrease and a brittle fracture (cracking) of steel is observed.