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The key step in the production of butt flanges - annealing
1. Whether the annealing temperature reaches the specified temperature. The welding flange treatment is generally a solution heat treatment, which is commonly called "annealing", and the temperature range is 1040~1120 °C. You can also observe through the observation hole of the annealing furnace. The flanged pipe fittings in the annealing zone should be in an incandescent state, but there is no softening and sagging.
Second, the welding flange is used to process the water vapor in the casting furnace. On the one hand, check whether the material of the furnace body is dry. When the furnace is installed for the first time, the material of the furnace body must be dried. Second, if there are too many water stains on the flanged pipe fittings entering the furnace, if there is a hole on the flange pipe fittings, do not leak water. Go in, or else destroy the atmosphere of the stove.
Third, the furnace body sealability. The soldering flange bright annealing furnace should be closed and isolated from the outside air; if hydrogen is used as the shielding gas, only one exhaust port is open (used to ignite the discharged hydrogen). The method of inspection can be applied to the joint gap of the annealing furnace with soapy water to see if it runs. The place where the gas is easy to run is the place where the annealing furnace enters the pipe and the place where the pipe is discharged. The sealing ring in this place is particularly easy to wear, and often Check frequently.
Fourth, protect the gas pressure. In order to prevent micro-leakage on the welding flange, the protective gas in the furnace should maintain a certain positive pressure. If it is hydrogen shielding gas, it generally requires more than 20kBar.
Fifth, the annealing atmosphere. For the welding flange, pure hydrogen is generally used as the annealing atmosphere, and the purity of the atmosphere is preferably 99.99% or more. If another part of the atmosphere is an inert gas, the purity can be lower, but it cannot contain too much oxygen or water vapor.