The invention provides a novel high-strength or ultrahigh-strength steel
laser-arc composite heat source
welding method, which belongs to the technical field of the
welding of high-strength or ultrahigh-strength steel. The method aims to solve the technical problem that the higher temperature needs to be adopted for preheating in order to prevent cold cracks during the
welding of the high-strength or ultrahigh-strength steel. The welding method mainly comprises the following steps: the
laser power is higher than 800 watts, a composite form that
laser (2) is ahead and
electric arc (3) follows is adopted along the welding direction, the filament spacing h is controlled to between 3 and 7 millimeters, and an included angle theta between an
electric arc welding gun (4) and the horizontal plane is between 45 and 60 DEG. When the method is used to weld, a composite heat source welding
pool is elongated and the oscillation of the
pool is sharpened, so that the solidification rate of
pool metal is reduced and grains are refined, thereby reducing the cold crack sensitivity during the
welding process of the high-strength or ultrahigh-strength steel. The welding method can reduce the preheating temperature of the welding of the high-strength or ultrahigh-strength steel, and even can realize high-strength non-preheating welding.