Due to its popularity and high crack sensitivity, 6061 aluminum alloy was selected as a test material for the newly developed double-sided arc welding (DSAW) process. The microstructure, crack sensitivity, and porosity of DSAW weldments were studied systematically. The percentage of fine equiaxed grains in the fully penetrated welds is greatly increased. Residual stresses are reduced. Porosity ...

The microstructure and residual stresses of an AA6040 Al to AZ31B Mg friction stir weld are studied using scanning electron microscopy and X-ray diffraction. The complex material flow promoted by the friction stir welding process results in a fine grained structure in the stir zone of both materials due to dynamic/recovery recrystallization. The interface between the materials is characterized ...

Within the scope of increase in cutting tools efficiency, a CW CO;! laser beam has been used for butt welding sintered tips containing cobalt and tungsten carbide to a medium carbon steel core. After optimization of the laser processing conditions, full penetrating, sound and homogeneous welds are observed. Hardness is found to be nearly constant across the entire weld bead cross-section. Micro...

Friction stir welding is a solid state joining process. High strength aluminum alloys are widely used in aircraft and marine industries. Generally, the mechanical properties of fusion welded aluminum joints are poor. As friction stir welding occurs in solid state, no solidification structures are created thereby eliminating the brittle and eutectic phases common in fusion welding of high streng...

Ill EXECUTIVE SUMMARY IV

A Fe-based filler material with the composition of Fe-20Ni-5Co-2.5Mn-0.2C was used for welding 9% Ni steel, and effect post-weld heat treatment on microstructure mechanical properties welded joints investigated. Post-weld joint performed in temperature range 200 to 600 ℃. After experimental selection, changes weld metal base were investigated detail at temperatures 350 Grain morphology, size, l...

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties investigated thoroughly. The performance failure modes exhibit a strong dependence on weld-nugget size. pull-out mode for MS1400 resistance welds does not follow the conventional size recommendation criteria of 4t0.5. Significant softening was observ...