مقاله جوشکاری RESISTANCE SPOT WELDING OF MAGNESIUM ALLOY SHEETS WITH COVER PLATES

مقاله جوشکاری با عنوان:

RESISTANCE SPOT WELDING OF MAGNESIUM
ALLOY SHEETS WITH COVER PLATES

S. Satonaka, C. Iwamoto, G.-i. Murakami
and Y. Matsumoto

چکیده مقاله:

Lightweight materials such as high-strength steels and aluminum alloys are widely used in automotive components
for the purposes of weight reduction and consequent higher fuel effi ciency. As new alloys have been
developed, magnesium alloys have become attractive for the production of automotive components due to
their unique properties, such as high specifi c strength, damping capacity, and recyclability. In the assembly
process of these materials, resistance spot welding (RSW) is used to construct thin sheet structures. Although
RSW of steel sheets with high weld quality has already been established, the following problems remain with
regard to RSW of magnesium alloys: high welding current, degeneration of electrodes, and blowholes and
expulsion in or around the nugget. In this study, RSW with cover plates was applied to magnesium alloy sheets
to investigate the performance of spot-welded joints. The weld quality was evaluated based on the tensile
shear strength of the joints, the shape and the size of the nugget, and the appearance of blowholes and
expulsion. Since RSW with cover plates is similar to conductive heat resistance seam welding (CHRSMW),
the results showed that RSW with cover plates enabled the spot welding of a magnesium alloy with a large
nugget and high tensile shear strength in the joint. It was also shown that blowhole-free spot welds with a
large nugget and high tensile shear strength were obtained for welding currents above 8 000 A with a long
down-slope time of welding current and a high electrode force.

مقاله جوشکاری Parametric Studies and Finite Element Analysis of Welded Steel in Resistance Spot Welding Process

مقاله جوشکاری با عنوان : Parametric Studies and Finite Element Analysis of Welded Steel in Resistance Spot Welding Process

Kishore, N.1*, Sreenu, S.2, Ramachandran, N.3, Allesu, K.

چکیده :

Resistance Spot Welding (RSW) is a widely used joining process for fabricating sheet assemblies in the automotive,
marine and aerospace industries. Modern vehicles contain 2000-5000 spot welded points. The main requirements of
these automobile parts are corrosion resistance of chassis, the high strength values of sheets used, the stiffness of
welded joints when exposed to an external force and the ability to absorb impacts, along with low cost and comfort.
In RSW, electrodes travel on a predetermined path and make contact with the sheets at selected weld points to apply
force. Electric current is then turned on and flows through the sheets clamped between the electrodes. Due to the
contact resistance to current flow, the temperature rises from resistance heating. When the temperature reaches the
desired fusing temperature, a molten nugget is formed, the current is shut off after a designated time to allow the
nugget to cool down and solidification of the weld spot occurs under pressure. It is proposed to study the effect of
various parameters on nugget dimensions and strength of the weld joint in RSW and concentrating on different
material and thicknesses to get good weld joint at low cost and compared with analytical part done in Ansys.