Modeling the Welding Process of the Low Alloy Ferritic Steels T/P23 and T/P24

Abstract

In this paper a model based on transport equations is proposed to study the weldability of low alloy ferritic steels T/P23 and T/P24. The model was numerically implemented by using the finite volume method (FVM) in an open source computational code to simulate the influence of the heat input, base metal thickness and preheating temperature on the thermal evolution and the cooling rate during the welding process. Meanwhile, it was possible to evaluate qualitatively the microstructure at the heat affected zone (HAZ) of these steels when a single weld bead was deposited on their surface and calculate the maximum hardness reached at this region. A double-ellipsoid heat source model for power density distribution was used in order to obtain a good estimate of the cooling rate and evolution of the fusion zone (FZ). The results are discussed and good agreement between experimental and simulated results was obtained for temperature distribution

Effects of Local Heat Input Conditions on the Thermophysical Properties of Super Duplex Stainless Steels (SDSS)

“…The model takes into account the heat transfer by radiation, convection and conduction. The mass transfer due to consumable deposition and dilution within metal base melting and solidification are considered and the properties changes due to local composition and temperature are taken into account [9][10][11][12] . The temperature distribution is obtained by solving the energy conservation, shown in Equation (1) 9-12…”

“…The heat input is supplied by the moving torch. We assume the well-known double-ellipsoid model [9][10][11][12][13]22 . The heat source is a combination of two ellipses in the front and rear quadrants.…”

“…Furthermore, the computer code used has been continuously updated by the authors and applied for different materials and welding conditions 3,6,[9][10][11][12] . In this paper we introduce new features to improve the model capability such as routines for kinetics of phase transformations for super duplex stainless steels 7,8 .…”

“…However, for large equipments and welding pieces it is common to use multiple pass welding procedure and some regions can relay into the gap of temperature and time suitable to form the deleterious phases. Thus, the design of an adequate welding procedure is important to make or repair the equipment to work under safety conditions [9][10][11][12] . In this work we propose an approach that could help on this task.…”

“…Models capable of predicting the local conditions and possibility of deleterious phases being formed are welcome and can drive good practice for avoiding the non-uniformity of properties [12][13][14][15][16][17][18][19][20][21][22] . This paper is focused on this challenge.…”