Stainless steel tube optical brightness after annealing determines the quality of steel pipe. There are many factors affecting the light, but mainly in the following five factors,

1. Whether the reach the required temperature, annealing temperature. Stainless steel heat treatment is generally take the solution heat treatment, also is the people often call “annealing”, the temperature range of 1050~1100 DEG C. You can observe through the observation hole of annealing furnace, shall be incandescent state annealing zone of stainless steel tube, but no softening posies.

2. Annealing atmosphere. Generally use pure hydrogen as the annealing atmosphere, the atmosphere of the best purity is more than 99.99%, if the atmosphere is another part of the inert gas, the purity can also be a little bit lower, but cannot contain too much oxygen, water vapor.

3. Furnace body sealing. Bright annealing furnace should be closed, isolated from the outside air; using hydrogen as protective gas, only one outlet is connected (used to ignite the hydrogen discharge). Inspection method can be used soapy water wipe in the annealing furnace of each joint, to see whether the running gas; one of the most easy to run gas place is the annealing furnace tube and out tube into the local place, the sealing ring of this place is especially easy to wear, should always check the often change.

4. The protection of gas pressure. In order to prevent the emergence of micro leakage, gas furnace protection should maintain a positive pressure, if protection of hydrogen gas, generally require more than 20kBar.

5. Furnace water vapor. On the one hand to check whether the material drying furnace body, first installed furnace, furnace body material must be dry; the two is whether excessive residual water into the furnace of the stainless steel tube, special pipe above if there are holes, don’t leak into, or put the furnace atmosphere has completely wrecked.