Microstructural investigations on simulated intercritical heat-affected zone of boron modified P91-steel

Abstract

Conventional P91 and boron modified P91-steels were considered in the present investigation. Using Gleeble, weld intercritical heat-affected zone (ICHAZ) was processed. Conventional microscopy was done along with electron back-scattered diffraction for both specimens. Lath boundary of martensite was more, and preferably oriented for P91B-ICHAZ than P91-ICHAZ. Lattice strain was high and lath mobility was low for P91B-ICHAZ in comparison to P91-ICHAZ. Large fraction of ferritic grain structure (39.1%) and small fraction of fresh martensitic grain structure (9.5%) in P91-ICHAZ, whereas small fraction of ferritic grain structure (10.7%) and large fraction of fresh martensitic grain structure (32.7%) in P91B-ICHAZ was observed. However, tempered martensite exhibited meager variation. These differences between ICHAZ simulations were attributed to the presence of 100ppm-boron in P91B-steel.

KEYWORDS:

• P91-steel
• P91B-steel
• effect of boron
• Gleeble simulation
• intercritical heat-affected zone
• electron back-scattered diffraction
• recrystallisation
• impression creep

Acknowledgements

The authors are grateful to Dr. Jaganathan Swaminanthan from CSIR-National Metallurgical Laboratory (Jamshedpur), for his incessant motivation and support throughout the duration of experimental work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Board of Research in Nuclear Sciences (BRNS) under Grant GAP-0260.