The Paton Welding Journal, 2022, №03



2022 №03 (02)

DOI of Article 10.37434/tpwj2022.03.03

2022 №03 (04)

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The Paton Welding Journal, 2022, #3, 27-33 pages

Influence of welding modes on decarburization in the heat-affected zone of r91 steel in welded joints of dissimilar steels after high-temperature tempering

M.O. Nimko, V.Yu. Skulskyi, A.R. Gavryk, I.G. Osypenko

E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

Abstract
Carbon migration from the lower-alloyed to the higher-alloyed steel takes place in welded joints of dissimilar steels, as a result of difference in carbon chemical potential after tempering and in high-temperature service. Decarburization in the HAZ nearweld zone of the lower-alloyed steel can lead to formation of service defects and subsequent failure. From mass transfer theory it is known that in polycrystalline bodies the diffusion of interstitial elements, including carbon, occurs most rapidly along the grain boundaries. theoretically, reduction of carbon diffusion can be achieved by increasing the grain dimensions in the HAZ near-weld zone that will lead to reduction of the overall grain boundary area per a unit of volume in this zone. This work is a study of the influence of the angle of electrode inclination and welding current at deposition of austenitic metal on R91 steel on the width of the decarburized interlayer, forming at subsequent tempering at the temperatures of 700 and 760 °C. It is shown that the resultant decarburized interlayer becomes narrower with increase of the angle of electrode inclination and deposition current.
Keywords: carbon diffusion, dissimilar steel joint, HAZ, decarburized interlayer, grain boundaries

Received: 17.01.2022
Accepted: 16.05.2022

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