The welding process for flanges helps to fix two pipes, equipment, or flange pipe fittings to form a union. First, put on a gasket between the two weld flanges, and use the bolts to complete the connection. Welding is a crucial process for the connection and construction of high-pressure pipelines. The welded type flange is easy to use and can withstand high pressure. Welded flanges are used widely in metallurgical pipelines, power stations, natural gas, petroleum, and other fields.
There are two main systems for international pipeline flange standards.
American pipeline flange system represented by American ANSI pipeline flanges.
European pipeline flange system represented by German DIN (including the former Soviet Union).
In addition, there are Japanese JIS pipe flanges, but they are usually used for public works in Japan or on Japanese fabricated vessels.
Pipe flanges in various countries
The assembly and the large flanges within the assembly are joined as per the requirements of the drawings. The large flange is divided into eight equal parts. With large grooves and thick flanges, multi-layer and segment symmetry welding is useful. The welding result is required to have the strength of the base metal at a minimum. The surface of the weld must be smooth and flat, and there must not be any defects like an undercut, slag inclusion, lack of welding, gas holes, etc. The residual height is usually to be less than 2 mm.
When it reaches the bottom, use J506 electrodes for manual surfacing and low current welding. Carry on the welding in strict accordance with the welding process. After each welding position, a level gauge is useful to clamp the deformation of the flange plane, and the welding seam must be hammered with an air hammer in the welding process to achieve the effect of elimination stress.
Technical requirements for flange welding
The inclination on both sides of the neck and head of the butt welding flange must not exceed v=7. The performance parameters of the butt welding flange need strict control in the welding and manufacturing process.
When manufacturing welded flanges, the selection of specific performance regulations and parameters helps to ensure that certain methods and basic principles can be promoted and applied.
Butt welding flanges are not easy to deform and come with good sealing performance. There are requirements for relative ductility and rigidity. Butt welding flanges are applied to many fields. The horn-shaped structure is suitable for pipelines with great working pressure, great temperature, fluctuations, high-temperature, high-pressure, and ultra-low temperature pipelines. It is useful to connect pipelines and gate valves with PN exceeding 2.5MPa; it is also helpful for pipelines that contain explosive and flammable substances.
Does annealing temperature reach the required temperature?
Finalization of butt welding flanges after manufacture usually happens by heat treatment, quenching, and tempering. The temperature can range from 1120 to 1140 C as per industry standards. It is observable according to the inspection of the quenching furnace.
The butt welding flange generates water vapor in the forging furnace. Additionally, you can check whether the raw materials on the furnace wall are dry or not. During the furnace installation for the first time, the materials on the furnace wall must be air-dried. On the other hand, if you find holes in the flange pipe, check whether or not there are excessive watermarks on the flange pipe when entering the furnace. The presence of water must not be there otherwise as it will destroy the furnace’s atmosphere.
Butt welding flanges are used widely in pressure vessels, pharmaceutical facilities, industrial production, chemical plants, crude oil, power engineering, natural gas, etc. The price of carbon butt welding flanges are reasonable given the high pressure applications for which they serve. Stainless steel butt welding flange is high-pressure, and corrosion and heat resistant as well, though at a higher cost.
You can contact Texas Flange for any inquiries related to the manufacturing of welding flanges.