Stainless steel pipe annealing after the brightness determines the quality of the product. The impact of factors are more, of which five most important factors are as follows:
1. Does the annealing temperature reach the specified temperature? Stainless steel heat treatment is generally taken to solve the heat treatment, which is commonly known as the "annealing", the temperature range of 1040 ~ 1120 ℃ (Japanese standard). You can also observe the hole through the annealing furnace observation, the annealing area of stainless steel pipe should be incandescent state, but did not appear softening sagging.
2. Annealing atmosphere. Generally, pure hydrogen is used as the annealing atmosphere. The purity of the atmosphere is preferably over 99.99%. If the other part of the atmosphere is inert gas, the purity can be lower, but it can not contain too much oxygen and water vapor.
3. Furnace sealing. Bright annealing furnace should be closed, and the outside air isolation; the use of hydrogen as a protective gas, and only one exhaust port is through (to ignite the discharge of hydrogen). Check the method can be used soap water wiped in the various joints of the annealing furnace joints to see whether the run gas; one of the most easy to run the place where the furnace into the pipe and the place where the pipe, the place of the ring is particularly vulnerable to wear, Always check for regular changes.
4. Protection of gas pressure. In order to prevent the occurrence of micro-leakage, the furnace to protect the gas should maintain a certain positive pressure, if it is hydrogen protection gas, generally require more than 20kBar.
5. Furnace water vapor. On the one hand to check the furnace material is dry, the first furnace, the furnace material must be dried; the second is into the furnace stainless steel pipe is too much residual water stains, special pipe above if there are holes, then do not leak into, Or else put the stove atmosphere all destroyed.
To pay attention to these are basically these, normal, then should be back after the opening of about 20 meters of stainless steel pipe will begin to shine, the kind of reflective light.
