1) The specifications and model of the matching flange are the same; when connecting with the equipment flange, they should be matched according to their specifications;
2) The flange connection is coaxial and parallel, and the flange surface is perpendicular to the center of the pipe;
3) The fastening bolts have the same specifications and the same direction, and the exposed length of the bolt is 1/2 bolt diameter or flush with the nut
4) The nut is placed on the valve side when connecting the valve;
5) The top two screw holes of the horizontal pipe flange are kept horizontal, and the two screw holes of the vertical pipe flange against the wall are parallel to the wall.

Flange connection is to fix two pipes, pipe fittings or equipments on a flange first. Between the two flanges, add a flange gasket and fasten them together with bolts to complete the connection. . Some pipe fittings and equipment already come with flanges, which also belong to flange connections. Flange connection is an important connection method for pipeline construction. The flange connection is easy to use and can withstand greater pressure. In industrial pipelines, in the home, the diameter of the pipeline is small, and it is low pressure, and the flange connection is not visible. If in a boiler room or production site, there are flanged pipes and equipment everywhere.

According to the connection method, the flange connection can be divided into: plate flat welding flange, flat welding flange with neck, butt welding flange with neck, socket welding flange, threaded flange, flange cover, butt welding ring with neck Loose sleeve flange, flat welded ring loose sleeve flange, ring groove flange and flange cover, large diameter flat flange, large diameter high neck flange, figure eight blind plate, butt welding ring loose sleeve flange, etc.

Flange welding process
Required equipment
A set of manual electric welding equipment, a handle angle grinder, an electric air hammer and a flat ruler.
Preparation before welding
1. Check the commissioning equipment to ensure that the equipment is operating normally;
2. Prepare φ4.0J402 electrode is best to dry at 300 ℃ -350 ℃ for one hour.

Welding process
1. Assembly Assemble the vertebral body and the large flange together according to the drawings, and divide the large flange into 8 equal parts on average.
2. Welding Because the flange is thicker and the groove is larger, segmental symmetry and multi-layer welding are used.

Weld quality
It is required that the strength of the weld be at least the strength of the base material. The surface of the welding seam is smooth and smooth, without defects such as burn-through, air holes, welding leakage, slag inclusion, undercut and under-welding. The height is less than 2mm. Precautions
1. Be sure to use J506 electrode for manual surfacing and low current welding when making the primer. Welding in strict accordance with the welding process.
2. After each welding position, use a level to clamp the deformation of the flange plane.
3. While welding, hammer the weld with an air hammer to eliminate the stress.