Factors affecting quality of dissimilar plate submerged arc welds

Submerged arc welding of stainless steel to carbon steel plate can produce a number of quality problems. These problems are lack of penetration defects, low ferrite numbers in the weld metal, and presence of martensite in the microstructure. It has been established that the position of the electrode wire in the weld preparation is critical to the integrity of the weld. Offsetting the wire position to the stainless steel side of the preparation has two effects. First, it exposes more stainless steel to the arc for a second side pass, which results in increased penetration and removes the potential for occurrence of lack of penetration defects. Second, it alters the dilution of the weld metal, which governs the ferrite number of the weld metal, and it also controls the final microstructure of the weld metal. It has been established that a high ferrite number (>60) consumable wire should be used to produce a satisfactory weld.