There are many factors that affect the brightness of stainless steel pipes after annealing. The main factors include the temperature, atmosphere, seal, air pressure and water vapor content in the furnace. These factors are described in detail below.
The first is to look at the annealing temperature, to see if it has reached the corresponding temperature. Because the stainless steel pipe solution heat treatment is usually taken in heat treatment, annealing treatment is usually said, the best treatment is the temperature range of 1040-1120 DEG C, or the observation hole is observed in the annealing furnace that appear as incandescent state but did not appear to soften the sagging state as the most suitable annealing zone of stainless steel pipe.
You can also look at the annealing atmosphere. Anneal is usually used pure hydrogen as annealing atmosphere. The purity of atmosphere is better than 99.99%. If the atmosphere is inert gas, the purity of the whole atmosphere is lower, but there must be no excess oxygen and water vapor.
The third aspect is to see the sealing of the furnace body. Because the bright annealing furnace should be closed and isolated from the outside air. It uses hydrogen as a protective gas. Generally, there is only one exhaust port outside, which is used to ignite the discharged hydrogen. Check tightness can be used when the stove soap in the annealing furnace each joint, observe whether the gas leakage phenomenon; one of the most easy to run gas area is the annealing furnace inlet pipe and the outlet seal, this part of the very easy to wear in the long-term use, often need to check if there is a problem immediately change.
The fourth aspect is to protect the gas pressure in the furnace. In order to avoid the micro leakage, the furnace should ensure that the gas should always maintain a certain positive pressure. If it is a hydrogen protective gas, it usually requires 20kBar above.
The last major factor is the content of water vapor in the furnace. On the one hand to check the furnace material is not dry, in the first furnace, furnace material must be rapid drying; second is to check into the furnace of stainless steel pipe is left too much water, especially if there is a hole on the pipe, you will not be able to Water Leakage in, otherwise it will completely destroy the furnace atmosphere.
If these are done in the comparison, in the normal annealing process, blow back 20 meters of stainless steel pipe will start to glow and glare.
Source: China Stainless Steel Pipess Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)