Required equipment
（flange)
One set of manual electric welding equipment, one handle angle grinder, one electric air hammer and one plane ruler.
Preparation before welding
(flange)
1. Check and debug the equipment to ensure the normal operation of the equipment; 2. Preparation φ 4.0j402 welding rod should be dried at 300 ℃ - 350 ℃ for one hour.
welding process
(flange)
1. Assemble the vertebral body and large flange together according to the requirements of the drawing, and then divide the large flange into 8 equal parts. 2. Because the flange is thick and the groove is large, segmented symmetrical and multi-layer welding is adopted.
Weld quality
(flange)
The weld strength shall at least reach the strength of base metal. The weld surface shall be flat and smooth without burn through, air hole, welding leakage, slag inclusion, undercut, incomplete welding and other defects. The reinforcement is less than 2mm.
Matters needing attention
(flange)
1. During priming, j506 welding rod must be used for manual surfacing and low current welding. Welding shall be carried out in strict accordance with the welding process. 2. After each position is welded, use a level ruler to clamp the deformation of the flange plane. 3. While welding, the weld shall be hammered with an air hammer to eliminate stress.
flange gasket
(flange)
Gasket is a ring made of material that can produce plastic deformation and has certain strength. Most gaskets are cut from non-metallic plates or made by professional factories according to the specified dimensions. Their materials are asbestos rubber plate, asbestos plate, Teflon plate, polyethylene plate, etc; Metal clad gaskets made by wrapping non-metallic materials such as asbestos with thin metal plates (white iron sheet and stainless steel); There is also a spiral wound gasket made of thin steel tape and asbestos tape. The most commonly used is the metal spiral wound gasket made of stainless steel tape and graphite. Asbestos can also be used for the spiral wound tape according to different service environments. Ordinary rubber gasket is suitable for occasions with temperature lower than 120 ℃; Asbestos rubber gasket is applicable to the occasions where the water vapor temperature is lower than 450 ℃, the oil temperature is lower than 350 ℃ and the pressure is lower than 5MPa. For general corrosive media, the most commonly used is acid resistant asbestos plate. In high-pressure equipment and pipelines, metal gaskets of lens type or other shapes made of copper, aluminum, No. 10 steel and stainless steel are used. The contact width between the high-pressure gasket and the sealing surface is very narrow (line contact), and the processing finish of the sealing surface and gasket is high.
Low pressure small diameter threaded flange, high pressure and low pressure large diameter are welded flanges. The thickness of flange plate and the diameter and quantity of connecting bolts under different pressures are different.
