Welded flange semi-finished products, at the top of the flange body straight wall edge section of a boss ring, the convex ring end face and the flange body face flush, the convex ring is in butt welded flange forging the forging blank. When the surfacing is done, the inner wall of the flange body under the lug boss is firstly welded, and then the boss ring is machined along the inner wall of the flange, and then the inner wall of the straight edge is welded. The convex ring is added at the inner wall of the straight edge to enhance the strength of the straight side section. Therefore, when the butt welding flange is welded, the deformation of the straight side section will be very small or almost no deformation. After surfacing, the boss ring is machined again, and the structure and dimension of the welding flange are not changed.
Welded flange, is integrally molded with the chassis and chassis is provided with a bulge of diversion hole in a central position of the chassis and the bulge, a plurality of through holes are evenly distributed on the chassis, convex conical, diversion hole is fixedly connected in a wall lining ring made of stainless steel, the chassis and the raised material is carbon steel. A welding flange bulges of the main part of the chassis and its molding are made from carbon steel, chassis and raised to meet the strength requirements, at the same time in order to flange corrosion resistance, diversion hole is arranged on the chassis and the bulge is fixedly connected with the inner wall lining ring made of stainless steel, this design greatly reduces the production cost.