The brightness of the stainless steel pipe after annealing determines the quality of the product.

There are many factors that affect its brightness. Here are the five most important factors for everyone:

1. Wether the annealing temperature reaches the specified temperature. The heat treatment of stainless steel pipe fittings is generally a solution heat treatment, which is usually called “annealing”. The temperature range is 1040 ~ 1120 degrees (Japanese standard). You can also observe through the observation hole of the annealing furnace.

The stainless steel pipe fittings in the annealing zone should be incandescent, but there is no softening sag.

2. Generally, pure hydrogen is used as the annealing atmosphere. The purity of the atmosphere is preferably above 99.99%. If the other part of the atmosphere is an inert gas, the purity can be lower, but it must not contain too much oxygen and water vapor.

3. Sealing of the furnace body The bright annealing furnace should be closed and isolated from the outside air; using hydrogen as a protective gas, only one exhaust port is open (used to ignite the discharged hydrogen).

The inspection method can be wiped with soapy water in the gaps of each joint of the annealing furnace to see if there is air leakage.

The place where the gas is most likely to leak is the place where the furnace enters the pipe and the place where the pipe exits. The seal ring in this place is particularly prone to wear and tear, and it is necessary to check frequently and change it frequently.

4. In order to prevent micro leakage, the protective gas pressure in the furnace should be maintained at a certain positive value. If it is hydrogen protective gas, it is generally required to be above 20K Bar.

5. Check whether the furnace material is dry. The furnace material must be dried for the first time, and then the stainless steel pipe before entering the furnace should not leave too much water stains. Do not let water in, otherwise the furnace atmosphere will be completely broken.

Generally, if it is normal, the stainless steel pipe that should be backed about 20 meters after the furnace will start to shine and reflect.

We have mentioned all the matters needing attention above, I hope that everyone can pay attention to it when producing.

Related: