Effect of filler addition on solidification behaviour and hot tensile properties of GTA-welded tube joints of Super 304H austenitic stainless steel

Background Super 304H austenitic stainless steel tubes containing 2.3 to 3 (wt.%) of Cu are mainly used in superheaters and reheaters of ultra super critical boilers due their excellent corrosion and oxidation resistance. Cu addition causes precipitation strengthening effect by fine Cu-rich precipit...

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Bibliographic Details
Published in:International journal of mechanical and materials engineering 2015-12, Vol.10 (1), p.1-11, Article 25
Main Authors: Vinoth Kumar, M., Balasubramanian, V., Gourav Rao, A.
Format: Article
Language:English
Subjects:
Austenitic stainless steels
Borocarbides
Copper
Engineering
Gas tungsten arc welding
Mechanical Engineering
Original Article
Oxidation resistance
Structural Materials
Tensile properties
Theoretical and Applied Mechanics
Tube joints
Welded joints
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Summary:Background Super 304H austenitic stainless steel tubes containing 2.3 to 3 (wt.%) of Cu are mainly used in superheaters and reheaters of ultra super critical boilers due their excellent corrosion and oxidation resistance. Cu addition causes precipitation strengthening effect by fine Cu-rich precipitates which evolve during creep conditions and results in increased creep strength. The microstructural evolution of stainless steels during welding significantly affects the material properties. Methods In this work, solidification mode microstructure and hot tensile properties of autogenous and filler-added Super 304H gas tungsten arc (GTA) welded tube joints were correlated. Results Autogenous welds of Super 304H solidified as austenite with 1.57 % delta ferrite and intercellular (Fe,Cr) 23 (C,B) 6 borocarbides. In filler-added welds, the higher Ni equivalent and addition of carbide stabilizing elements (Nb,Mo) eliminated δ ferrite and segregation of B as borocarbides. Conclusions The filler-added welds exhibited superior tensile strength than autogenous welds at both room and high temperature.
ISSN:1823-0334
2198-2791
DOI:10.1186/s40712-015-0051-x