Manufacturing Technology Today

Open Access Open Access  Restricted Access Subscription Access
Open Access Open Access Open Access  Restricted Access Restricted Access Subscription Access

Notch Tensile Properties of Various Regions of Dissimilar Joints of Austenitic and Ferritic Steels


Affiliations
1 Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India
2 Materials Mechanics Section, Materials Technology Division,Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, India
     

   Subscribe/Renew Journal


In sodium cooled fast breeder reactor at Kalpakkam, the steam generators are constructed using modified 9Cr-1Mo (also called as Grade 91 or P91) ferritic steel because of its high temperature strength and resistance to stress corrosion cracking. The interconnecting sodium piping between reactor and steam generator is made up of AISI 316LN because of its high creep strength and corrosion resistance. Nickel based fillers (Inconel 82/182) are commonly used to weld the 316LN piping with steam generator. For a better structural integrity assessment of this dissimilar joint, the tensile properties of each region need to be evaluated. Evaluating the tensile properties of various regions by smooth tensile specimens is quite complex and time consuming. In the present investigation, the notch tensile properties of various regions were evaluated by placing a notch at the desired locations of the dissimilar metal weld joint (DMWJ). The dissimilar joint between P91 and 316LN is fabricated by manual metal arc welding (MMAW) process using Inconel 182 electrodes. Notch tensile properties of each region were evaluated by placing a notch at different locations (viz. weld metal, buttering, HAZ of P91 and HAZ of 316LN). Microhardness variation across the DMWJ was recorded. Microstructural features of various regions were characterized by optical and scanning electron microscope. From this investigation, it is found that the notch placed in the HAZ of P91 exhibited highest notch tensile strength than other regions. A non-uniform hardness distribution is observed across the DMWJ and the maximum hardness is recorded at the interface between P91 HAZ to Inconel 182 buttering. The hardness is minimum at the outer edge of HAZ of P91 side. Evolution of carbon enriched hard zone at the interface between P91 and Inconel 182 buttering could be the reason for highest notch tensile strength.

Keywords

Dissimilar Metal Weld Joint, Notch Tensile Test, Microhardness, Microstructure.
User
Subscription Login to verify subscription
Notifications
Font Size

  • Kumar, P; Pai, A: An overview of welding aspects and challenges during manufacture of Intermediate Heat Exchangers for 500MWe Prototype Fast Breeder Reactor, 'Procedia Eng.', vol. 86, 2014, 173-183.

  • Sarikka, Teemu; Ahonen, Matias; Mouginot, Nevasmaa, Roman; arjalainen-Roikonen, Päivi K; Ehrnstén, Ulla; Hänninen, Hannu:Microstructural, mechanical, and fracture mechanical characterization of SA 508-Alloy 182 dissimilar metal weld in view of mismatch state, 'International Journal of Pressure Vessels and Piping', vol. 145, 2016, 13-22.

  • Jang, C; Lee, J; Sung Kim, J; Eun Jin, T: Mechanical Property Variation Within Inconel 82/182 Dissimilar Metal Weld Between Low Alloy Steel and 316 Stainless Steel, 'Int. J. Pressure Vessels Piping', vol. 85, no. 9, 2008, 635-646.

  • Kim, JW; Lee, K; Kim, JS; Byun, TS: Local Mechanical Properties of Alloy 82/182 Dissimilar Weld Joint Between SA508 Gr.1a and F316 SS at RT and 320°C, 'J. Nucl. Mater.', vol. 384, no. 3, 2009, 212–221.

  • Pandey, S; Prasad, R; Singh, PK; Rathod, DW: Investigation on Dissimilar Metal Welds of SA312 Type 304LN Pipe (Extruded) and SA508Gr.3Cl.1 Pipe (Forged), Bhabha Atomic Research Centre, Mumbai, India, Report No. 2008/36/107-BRNS/4038A, 2014.

  • Zhang, ZL; Hauge, M; Thaulowa, C; Ødegård, J: A notched cross weld tensile testing method for determining true stress–strain curves for weldments, 'Engineering Fracture Mechanics', vol. 69, no. 3, 2000, 353-366.

  • Wendell B. Jones C. R. HillsD. H. Polonis,; Microstructural evolution of modified 9Cr-1Mo steel, 'Metallurgical Transactions A', vol. 22, no. 5, 1991, 1049-1058.

  • Wang, HT; Wang, GZ; Xuan, FZ; Liu, CJ; Tu, ST: Local mechanical properties of a dissimilar metal welded joint in nuclear powersystems”, Materials Science and Engineering: A, vol. 568, 2013, 108-117.

  • Rathod, Dinesh W; Sunil Pandey, Singh, PK; Rajesh Prasad: Mechanical Properties Variations and Comparative Analysis of Dissimilar Metal Pipe Welds in Pressure Vessel System of Nuclear Plants, 'ASME J. Pressure Vessel Technol.', vol. 138, no. 1, 2015, 1-9.


Abstract Views: 261

PDF Views: 5




  • Notch Tensile Properties of Various Regions of Dissimilar Joints of Austenitic and Ferritic Steels

Abstract Views: 261  |  PDF Views: 5

Authors

K. Karthick
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India
S. Malarvizhi
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India
V. Balasubramanian
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, India
S. A. Krishnan
Materials Mechanics Section, Materials Technology Division,Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, India
Shaju K. Albert
Materials Mechanics Section, Materials Technology Division,Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, India

Abstract


In sodium cooled fast breeder reactor at Kalpakkam, the steam generators are constructed using modified 9Cr-1Mo (also called as Grade 91 or P91) ferritic steel because of its high temperature strength and resistance to stress corrosion cracking. The interconnecting sodium piping between reactor and steam generator is made up of AISI 316LN because of its high creep strength and corrosion resistance. Nickel based fillers (Inconel 82/182) are commonly used to weld the 316LN piping with steam generator. For a better structural integrity assessment of this dissimilar joint, the tensile properties of each region need to be evaluated. Evaluating the tensile properties of various regions by smooth tensile specimens is quite complex and time consuming. In the present investigation, the notch tensile properties of various regions were evaluated by placing a notch at the desired locations of the dissimilar metal weld joint (DMWJ). The dissimilar joint between P91 and 316LN is fabricated by manual metal arc welding (MMAW) process using Inconel 182 electrodes. Notch tensile properties of each region were evaluated by placing a notch at different locations (viz. weld metal, buttering, HAZ of P91 and HAZ of 316LN). Microhardness variation across the DMWJ was recorded. Microstructural features of various regions were characterized by optical and scanning electron microscope. From this investigation, it is found that the notch placed in the HAZ of P91 exhibited highest notch tensile strength than other regions. A non-uniform hardness distribution is observed across the DMWJ and the maximum hardness is recorded at the interface between P91 HAZ to Inconel 182 buttering. The hardness is minimum at the outer edge of HAZ of P91 side. Evolution of carbon enriched hard zone at the interface between P91 and Inconel 182 buttering could be the reason for highest notch tensile strength.

Keywords


Dissimilar Metal Weld Joint, Notch Tensile Test, Microhardness, Microstructure.

References