Role of dissimilar IN617 nickel alloy consumable on microstructural and mechanical behavior of P91 welds joint
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(2020) 20:99
ORIGINAL ARTICLE
Role of dissimilar IN617 nickel alloy consumable on microstructural and mechanical behavior of P91 welds joint Sanjeev Kumar1 · Chandan Pandey2 · Amit Goyal1 Received: 24 May 2020 / Revised: 30 July 2020 / Accepted: 7 August 2020 © Wroclaw University of Science and Technology 2020
Abstract This paper investigates the metallurgical behavior and mechanical properties of the P91 steel welds joint. The joint of heatresistant P91 steel has been welded by the gas tungsten arc welding (GTAW) process using the dissimilar Inconel grade 617 filler. The P91 welds joints have been subjected to varying heat treatment regimes in the temperature range of 650–810 °C for 2 h. The normalizing-based tempering was also performed for the welded joint. The weld fusion zone (WFZ) with austenitic structure and heat-affected zones (HAZs) with martensitic structure was characterized using the optical microscope and scanning electron microscope (SEM). The detailed characterization of the weld metal and HAZ interface has also been performed for as-welded and post-weld heat treatment (PWHT) conditions. For mechanical properties of the welds joint, tensile testing and hardness testing were performed. The relationship between mechanical behavior and microstructure of the welded joint has been evaluated for as-welded and heat treatment conditions. The microstructure studies revealed the formation of an unmixed zone (UZ) close to the fusion line, and it was characterized as peninsula and island. The WFZ showed the complete austenitic mode of the solidification and revealed the austenitic structure with cellular and equiaxed grains in the center of the weld metal. The columnar and cellular dendrites were seen near the boat fusion line, i.e., interface of the weld metal and HAZ. The soft δ ferrite patches were observed near the fusion line in the area of HAZ and remain undissolved up to tempering temperature of 810 °C (PW 3). The dissolution of the ferrite patches was noticed for PW 4. The maximum and minimum tensile strength of the welds joint was measured 731 MPa and 502 MPa for PW 3 and PW 2, respectively. A uniform hardness variation in the transverse direction of the welded joint was observed for PW 3 and PW 4 conditions. The optimum combination of strength and ductility was obtained for the PW 3 condition. Keywords IN617 · Unmixed zone · Microstructure · Tensile properties · Austenite · Heat treatment
1 Introduction In several last decades, the demand for pollution-free power generation and higher efficiency of power generating units have led to the development of ultra-supercritical (USC) power plants having operating temperature and pressure of 650 °C and 30 MPa [1]. To fulfill the demand of USC plants, creep strength-enhanced ferritic/martensitic (CSEF/M) steels have developed with major alloying * Chandan Pandey [email protected]; [email protected] 1
Mechanical Department, SRM Institute of Science and Technology, Delhi NCR campus, Modinagar, Uttar Pradesh 201204, India
Department of Mech
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