Evaluation of Changes of Mechanical Properties of Selected Cr-Ni-Mo Steels for Heavy Forgings during Long Time Annealing

Abstract:

The effect of long dwell time at elevated temperatures on two types of steels used for production of heavy forgings was evaluated. Microstructural changes and mechanical properties were monitored in temperature interval of 200 - 700 °C in order to avoid the possibility of grain boundary embrittlement during long dwell time at the processing temperature. Samples of the evaluated steels 26NiCrMoV14-5 and 22CrNiMoWV8-8 were being austenitized for 2 hours at temperature of 1200 °C and oil quenched. Subsequently the annealing at selected temperatures for 100 hours was applied. Tensile test, hardness and impact energy measurements were used for the evaluation. The results of mechanical testing, structural and fracture surface analyses indicate that for steels 26NiCrMoV145 and 22CrMoNiWV8-8 there exist a temperature interval of 300 - 400 °C and 500 600 °C respectively showing the toughness decrease.

• Periodical: Materials Science Forum (Volume 891)
• Pages: 149-154
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.891.149
• Online since: March 2017
• Authors: Jakub Horník*, Petr Zuna, Jaroslav Málek
• Keywords: Embrittlement, Microscopy, Microstructure, Precipitation

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