Extraordinary advances have been made during the past four decades in improving steel weld metal properties.Welding processes have been developed which further lower the nitrogen, oxygen and hydrogen contents of arc deposited weld metals.Simultaneously, metallurgical techniques have been perfected which permit the manufacturer to provide controlled, high-purity alloys of the required compositions for use as both base and welding filler metals.These advances have made possible the production of welds with a combination of high strength and toughness that was previously impossible to attain.As a consequence the use of welded, high strength, ductile, tough, alloy steels has become practical.