Improved mechanical properties of Ti–6Al–4V alloy by electron beam welding process plus annealing treatments and its microstructural evolution

The applicability of ferritic stainless steel is restricted due to its low weldability, and this can be attributed to the severe grain growth in the weld zone during the solidification of the weld pool and formation of fully ferritic structure. This study aims to investigate the weldability of 18 mm thick AISI 409 ferritic stainless steel plates using an electron beam welding process without the use of filler metal. The joints were investigated for metallography characterization (microstructure, macrostructure, and microhardness) and mechanical behavior (tensile strength and impact toughness) in as-welded condition and after post-weld heat treatment at 550 ºC for 75 minutes. The weld zone exhibited large columnar grains in the direction perpendicular to the weld centerline and got refined after post-weld heat treatment. The ultimate tensile strength, yield strength, and microhardness of the weld zone were found higher than the base metal. The impact toughness of weld zone was found to be reduced by 45%, but the post-weld heat treatment improved the toughness by 40%. Results revealed that the electron beam welding process could be successfully employed for welding of AISI 409 ferritic stainless steel, which will increase its application range that requires thicker section of welded plates. Post-weld heat treatment was found to be advantageous for improving the microstructure and mechanical properties.

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Comparison of the mechanical properties and microstructural evolution in the HAZ of HSLA DOMEX 700MC welded by gas metal arc welding and electron beam welding

MATEC Web of Conferences ◽

10.1051/matecconf/201824401009 ◽

2018 ◽

Vol 244 ◽

pp. 01009 ◽

Cited By ~ 2

Author(s):

Peter Kopas ◽

Milan Sága ◽

Michal Jambor ◽

František Nový ◽

Libor Trško ◽

...

Keyword(s):

Mechanical Properties ◽

Electron Beam ◽

Microstructural Evolution ◽

Heat Affected Zone ◽

Electron Beam Welding ◽

Thermomechanical Processing ◽

Hsla Steel ◽

Gas Metal Arc Welding ◽

High Energy ◽

Industrial Applications

High strength low alloyed steels are nowadays an important group of engineering materials, with numerous industrial applications. Properly chosen chemical composition together with the thermomechanical processing allow to reach high mechanical properties, while the carbon content is maintained low. Resulting microstructure is therefore sensitive to the amount of the heat introduced to the metal during welding. During welding procedure, softening phenomenon can occur in the heat affected zones and it could lead to the degradation of the mechanical properties of the final joint. Nowadays, welding technologies based on the high energy electron beam are able to produce weld joints with very narrow heat affected zone. In this study, authors compare mechanical properties and the microstructural evolution in the heat affected zone of the GMAW and EB welded joint of the DOMEX 700MC HSLA steel. The carried out experiments showed that both evaluated technologies are able to produce joints with appropriate mechanical properties. Welded joints made by the EBW technique showed slightly better mechanical properties of the whole joint, as a result of the narrower HAZ.

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