The invention discloses a T-shaped double
arc welding backing process for a medium-thickness plate. The T-shaped double
arc welding backing process comprises the following steps of (1) the blanking ofan H-shaped steel web is performed, negative 3 mm to negative 5 mm remains, a double-sided K-shaped groove is formed in a full penetration weld, which is greater than 16 mm, of the H-shaped steel web, the
groove width is 16 mm to 18 mm, no root face is left in the groove, and the clearance of 4 mm to 6 mm is left; (2)
oxide skin, iron
rust and other impurities existing within a range of 50 mm onboth sides of the K-shaped groove position of the H-shaped steel web and the full penetration weld position at the middle of a
flange are cleared through
grinding, and a
metallic color is displayed; and (3) the clearance of 4 mm to 6 mm is left during the
assembly of the full penetration weld, a backing plate of 5 mm is adopted for controlling the clearance at intervals of 500 mm to 600 mm, a tackwelding point is positioned within 10 mm of the backing plate; the tack
welding intervals are consistent with the intervals of 500 mm to 600 mm among the backing plates, the length of the tack
welding point is 50 mm, and during the
assembly, the full penetration weld is shrunk by 3 mm to 5 mm on the section of the H-shaped steel web. According to the T-shaped double
arc welding backing process disclosed by the invention, the double-sided groove is formed in the H-shaped steel web, no root face is left, the clearance of 4 mm to 5 mm is left, the double arc backing
welding operation is performed, the air gouging operation is not needed, the welding quality and efficiency are greatly improved, and the production cost is reduced.