What problems should pay attention to when processing butt welded flange?

There are the problems we should pay attention to when processing butt welded flange:

1.Annealing air. The pure hydrogen is generally used as annealing air for butt welding flange. The air purity is over 99.99%. If the other part of the air is inert gas, the purity can also be lower, but it can not contain excessive oxygen and water vapor.

2.Whether the annealing temperature of butt-welded flange reaches the specified temperature or not,the treatment of butt-welded flange generally adopts the solution heat treatment, which is commonly called “annealing”, and the temperature scale is 1040-1120 C. You can also look through the annealing furnace to see that the flange fittings in the annealing zone should be incandescent, but not softening and sagging.

ANSI B16.47 ASTM A105 blind flanges

ANSI B16.47 ASTM A105 blind flanges

3.The protection gas pressure of butt-welding flange. In order to prevent the slight leakage of butt-welding flange, the protection gas in furnace should be connected with the necessary positive pressure. If the protection gas is hydrogen, it generally requires more than 20 kBar.

4.Water vapor in forging furnace for butt-welded flange processing, on the one hand, checks whether the material of furnace body is dry or not, initial loading, the material of furnace body must be dried; on the other hand, whether there are excessive water stains left on the flange pipe fittings entering the furnace, if there are holes above the flange pipe fittings, do not leak in, or the furnace air will be completely crushed.

5.The sealability of butt-welded flange furnace body. The bright annealing furnace of butt-welded flange should be blocked, and only one outlet is open. Inspection can be done by plastering soap water on the cracks in the joints of annealing furnace to keep away from the outside air; using hydrogen as a protective gas to see if it runs; where the easy runaway place is the place where the annealing furnace enters and exits the tubes, where the sealing rings are particularly easy to wear and tear, and it is necessary to check frequently for replacement.

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