Sigma Spot Welding of Aluminum Alloy Sheets

Abstract

Since a new interest is being aroused in alumiuum rolling stocks in recent years the domestic rolling stock makers have started a serious study of the Sigma Spot Welding for aluminum alloys as a part of thier shop practice researches with considern the attention paid to its practical application.
The author has investigated various welding factors (weld current, arc voltage, arc time, argon flow, etc.), weld joint strengths, X-ray inspection data, weld section contours, etc. in respect to 2 mm +4mm plate combination of an aluminum alloy (52S-O) with a view to applying this welding process to sections where a spot welding is not practicable at joints between external panels and carbody framework of aluminum rolling stocks, in future, and has selected an optimum welding condition for this type of welding work. He has, also, touched on the peripheral cracks around nuggets, which have developed on the test pieces in this experiment.