How to anneal butt welded flanges

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2023-06-13 09:45

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The pressure of the protective gas for the welding flange is to avoid slight leakage of the welding flange. The protective gas in the furnace should be connected to a certain positive pressure, assuming it is a hydrogen protective gas, which is generally required to be above 20kBar. Annealing air, welding flanges generally use pure hydrogen gas as the annealing air, with a purity of over 99.99%. If the other part of the air is an inert gas, its purity can be lower, but it cannot contain too much oxygen and water vapor.
Regardless of whether the annealing temperature inside the welding flange reaches the specified temperature, the welding flange generally adopts solid solution heat treatment, which is commonly referred to as "annealing", with a temperature planning of 1040~1120 ℃. Investigation can also be conducted through the investigation holes of the process annealing furnace. The welded flange fittings in the annealed area should be incandescent, but without softening or sagging.
Welding flanges to treat water vapor in the casting furnace. On the one hand, check whether the furnace material is dry, and the furnace material needs to be dried for the first time. The second issue is whether there are too many water stains on the welded flange pipe fittings, especially if there are holes on the welded flange pipe fittings. Do not leak water inside, otherwise the air inside the furnace will be crushed.
The welding flange furnace should be sealed, and the bright annealing furnace for welding flanges should be sealed and isolated from external air; When hydrogen gas is used as a protective gas, an exhaust port opens. The inspection method can be to wipe the cracks on the joints of the annealing furnace with water to see if they have run away; The place where the gas briefly leaks is the inlet and outlet of the annealing furnace. The sealing ring in this area is particularly short-lived and needs to be checked and replaced frequently.

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German standard flange: How many flange connection methods are there?

Polishing method for dual phase steel flanges

PRE

German standard flange: How many flange connection methods are there?

Polishing method for dual phase steel flanges

2023-06-13

Stainless steel flanges are flanges that extend steel pipes, pipe fittings, etc. into the flanges and are connected to equipment or pipelines through fillet welds. The inner hole on one side of the flange is provided with a welding boss, and the welding boss is provided with an inner hole. The inner hole communicates with the inner hole in the center of the flange, and there is elasticity between the flange and the welding boss. The two top surfaces of the elastic ring are respectively combined with the flange and the welding boss. There are many screw holes on the flange. The screw holes are symmetrically distributed around the center of the flange. The stainless steel flange is made of stainless steel, followed by a polyethylene plastic layer, a rubber layer and a PVC layer. Here we take a look at the use of stainless steel flange precautions. 1. In order to prevent corrosion between eyes caused by heating of stainless steel flanges, the welding current should not be too large, about 20% less than carbon steel electrode, the arc should not be too long, the cooling speed is between the number of layers, and the narrow bead effect is better.

Advantages and disadvantages of flat welding flange

2023-06-13

Flat welded flanges are mainly used for gas valves and natural gas pipelines. Because the short neck can improve the rigidity and carrying capacity of the flange. Flat welded flanges are used for general media. Flat welding flange with neck is suitable for flammable, explosive, corrosive and toxic places. The sealing surface of flat welding flange can be convex surface, concave convex surface and tongue and groove surface. They are different in structure, sealing effect and strength. Flat welding flange is generally called flat plate, also known as lap welding flange. The connection between the flat welding flange and the pipe is to insert the pipe into the flange inner hole to the appropriate position before the lap welding. The characteristics of flat welding flange: flat welding flange not only saves space, reduces weight, but also ensures no leakage at the joint and good sealing performance. The reason for the reduced size of the compact flange is the reduced diameter of the seal, which will reduce the cross section of the sealing surface. The advantages of flat welding flanges are as follows:

Applicable scope and purpose of welding flange