Introduction of Slip-on Flange Forging Methods
This technical article introduces us about some main forging methods of slip-on flanges according to the movement of the forging die.
How to Correctly Select Flange
This technical article introduces us in details about that some main ways and methods that we can choose and select flanges correctly.
Thin-walled SS Tube Is Increasingly Widely Used
With the implementation of reform and opening policy and the development of economy, thin-walled stainless steel tubes are more and more popular.
Venezuela's Manufacturer Will Set Up Factories in Cuba
The company is evaluating the factory of the pipeline construction project, thus it is going to set up factories in Cuba.
NDRC: Increase Gas Imports and Oil Reserves in Winter
The National Development and Reform Commission decided to increase gas imports and oil reserves in this winter in the meeting held on November 13.
Factors Deciding Welding Heat Conduction of Large Flanges
Welding of large flange is connected parts between pipes and pipes at pipe end, with gasket sealing. Welding of large flange is also called welding flange, with holes on it, bolt makes two flanges connected closely, which is a kind of disc parts, and it is the most common in pipeline engineering.
Welding of large flanges with good thermal conductivity needs high upset speed (150-200 - mm/s). For the same kind of metal, if temperature gradient of the interface zone is large, it also needs to increase upset speed because the cooling speed of joint is fast. Upsetting force usually represents by pressure per unit of area, which is called as upset pressure. Upset pressure should guarantee to squeeze liquid metal in the interface and generate certain plastic deformation in the joint.
Because large flanges have good comprehensive performance, they are widely used in chemical industry, construction, water supply, water drainage, oil, light and heavy industry, freeze, sanitary, plumbing, fire protection, electric power, aerospace, shipbuilding and other foundation engineering.
If upset pressure is much too small when large flanges are welded, deformation will be insufficient; otherwise, deformation will be too much, and crystal will bend severely, reducing impact toughness of the joint. Because high flash rate can lead to increase of temperature gradient, special steel flanges need larger upset pressure (150-400mpa) when welding metals (copper, aluminum alloy) with good thermal conductivity.
Generally, large flange welding applies manual arc welding, but the curve road is irregular and it’s easy to bite edge and burning on ring edge, even machining cannot eliminate it, causing poor appearance quality. Generally it is dissimilar steel welding, which is difficult. Defects like bite edge or lack of penetration will occur if welding current is out of control. If large convex flange and weld joint need processing, deposited metal between ring and flange will be less in this case.
