Observations on the Arc Welding and Gas Cutting of High-Tensile Low-Alloy Structural Steels

Abstract

High-tensile structural steels generally contain relatively small additions of alloying elements which affect their welding properties because of hardening effects. The paper gives data regarding the composition and test values of some typical high-tensile steels, together with results on metallic-arc welded joints. Laboratory cracking tests to determine the weldability of steel plate are described, and their utility is demonstrated. The composition and inherent grain size of the steel, together with the conditions of welding, affect the properties of the heat-transformed zone. It is desirable to limit the carbon content to 0·20 per cent; and for single-run fillets the use of a relatively slow welding speed of 4–6 inches per minute, with a fillet size of not less than half the thickness of the plate, has given the best results in the authors' work. The properties of various covered electrodes have been studied. Carburization experiments on all-weld metal reveal interesting differences between electrodes. The cutting of these steels by gas is considered, in so far as most of the factors influencing weld hardness may operate, to produce cut edges having hard surfaces of reduced ductility.