Study on Microstructural Characterization, Mechanical Properties and Residual Stress of GTAW Dissimilar Joints of P91 and P22 Steels

Anupam Sauraw; Atul Kumar Sharma; Dariusz Fydrych; Sachin Sirohi; Ankur Gupta; Aleksandra Świerczyńska; Chandan Pandey; Grzegorz Rogalski

doi:10.3390/ma14216591

Study on Microstructural Characterization, Mechanical Properties and Residual Stress of GTAW Dissimilar Joints of P91 and P22 Steels

Materials (Basel). 2021 Nov 2;14(21):6591. doi: 10.3390/ma14216591.

Authors

Anupam Sauraw¹, Atul Kumar Sharma¹, Dariusz Fydrych², Sachin Sirohi³, Ankur Gupta¹, Aleksandra Świerczyńska², Chandan Pandey¹, Grzegorz Rogalski²

Affiliations

¹ Department of Mechanical Engineering, Indian Institute of Technology Jodhpur N.H. 62, Nagaur Road, Karwar, Jodhpur 342037, India.
² Institute of Manufacturing and Materials Technology, Faculty of Mechanical Engineering and Ship Technology, Gdańsk University of Technology, Gabriela Narutowicza Street 11/12, 80-233 Gdańsk, Poland.
³ Mechanical Department, SRM Institute of Science and Technology, Delhi NCR Campus, Modinagar 201204, India.

Abstract

This article deals with the dissimilar joining of two different grade Cr-Mo steel (2.25Cr-1Mo: P22 and modified 9Cr-1Mo: P91) for power plant application. The dissimilar butt-welded joint was produced for conventional V groove design by using the gas tungsten arc welding (GTAW) process with the application of an ERNiCrMo-3 Ni-based super alloy filler. A microstructure characterization was performed to measure the inhomogeneity in the microstructure and element diffusion across the interface in a welded joint. The experiments were also performed to evaluate the mechanical properties of the dissimilar welded joint in as-welded (AW) and post-weld heat treatment (PWHT) conditions. An acceptable level of the mechanical properties was obtained for the AW joint. After PWHT, a significant level of the element diffusion across the interface of the weld metal and P22 steel was observed, resulting in heterogeneity in microstructure near the interface, which was also supported by the hardness variation. Inhomogeneity in mechanical properties (impact strength and hardness) was measured across the weldments for the AW joint and was reduced after the PWHT. The tensile test results indicate an acceptable level of tensile properties for the welded joint in both AW and PWHT conditions and failure was noticed in the weak region of the P22 steel instead of the weld metal.

Keywords: ERNiCrMo-3; GTAW welding; P22 steel; P91 steel; dissimilar welded joint; mechanical properties; microstructure; stress.