Effects of heat input on microstructure and mechanical properties of Fe–2Cr–Mo–0.12C steel

ABSTRACT

Thermal simulated specimens with the heat inputs of 20, 50 and 80 kJ/cm were used to investigate the effects of heat input on the microstructure and mechanical properties of the Fe–2Cr–Mo–0.12C pressure-vessel steel. The results indicated that the microstructures in the coarse-grained heat affected zone of tested steels with various heat inputs were mainly consisted of lath martensite and bainite ferrite. As the heat input increased, the fraction of martensite decreased and the bainite ferrite fraction increased. The toughness (tested at −40°C) and hardness for the heat input of 50 kJ/cm were 102 J and 346 HV, respectively, which was attributed to the high-volume fraction (60%) of the high-angle grain-boundary and the fine bainite lath.

This paper is part of a thematic issue on Nuclear Materials.

KEYWORDS:

• Welding heat input
• coarse-grained heat affected zone
• pressure-vessel steel
• mechanical properties
• toughness
• bainite ferrite
• precipitation behaviour
• prior austenite grain

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Qi-wen Wang http://orcid.org/0000-0003-3936-5552

Jie Chen http://orcid.org/0000-0002-5126-0924

Xing-yang Tu http://orcid.org/0000-0001-6710-0012

Additional information

Funding

The authors are very grateful to the financial support of the National Natural Science Foundation of China (51274062) and Research Fund for the Doctoral Program of Higher Education of China (20130042110040).