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Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments

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Title Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments
 
Creator UNNIKRISHNAN, R
IDURY, KSNS
ISMAIL, TP
BHADAURIA, A
SHEKHAWAT, SK
KHATIRKAR, RK
SAPATE, SG
 
Subject 304L stainless steel
Microstructure
EBSD
HAZ
Residual stresses
DELTA-FERRITE CONTENT
WELD
BEHAVIOR
METAL
HAZ
 
Description Austenitic stainless steels are widely used in high performance pressure vessels, nuclear, chemical, process and medical industry due. to their very good corrosion resistance and superior mechanical properties. However, austenitic stainless steels are prone to sensitization when subjected to higher temperatures (673 K to 1173 K) during the manufacturing process (e.g. welding) and/or certain applications (e.g. pressure vessels). During sensitization, chromium in the matrix precipitates out as carbides and intermetallic compounds (sigma, chi and Laves phases) decreasing the corrosion resistance and mechanical properties. In the present investigation, 304L austenitic stainless steel was subjected to different heat inputs by shielded metal arc welding process using a standard 308L electrode. The microstructural developments were characterized by using optical microscopy and electron backscattered diffraction, while the residual stresses were measured by X-ray diffraction using the sin(2)psi method. It was observed that even at the highest heat input, shielded metal arc welding process does not result in significant precipitation of carbides or intermetallic phases. The ferrite content and grain size increased with increase in heat input. The grain size variation in the fusion zone/heat affected zone was not effectively captured by optical microscopy. This study shows that electron backscattered diffraction is necessary to bring out changes in the grain size quantitatively in the fusion zone/heat affected zone as it can consider twin boundaries as a part of grain in the calculation of grain size. The residual stresses were compressive in nature for the lowest heat input, while they were tensile at the highest heat input near the weld bead. The significant feature of the welded region and the base metal was the presence of a very strong texture. The texture in the heat affected zone was almost random. (C) 2014 Elsevier Inc. All rights reserved.
 
Publisher ELSEVIER SCIENCE INC
 
Date 2014-12-28T16:55:54Z
2014-12-28T16:55:54Z
2014
 
Type Article
 
Identifier MATERIALS CHARACTERIZATION, 9310-23
1044-5803
1873-4189
http://dx.doi.org/10.1016/j.matchar.2014.03.013
http://dspace.library.iitb.ac.in/jspui/handle/100/16939
 
Language English