Stainless steel pipe after annealing brightness determines the quality of the products. Factors influencing the stainless steel pipe annealing after brightness is more, here are five important factors, for your reference.
1, whether the annealing temperature reaches the temperature. Stainless steel heat treatment are generally take the solid solution heat treatment, also is the people of the so-called “annealing” usually, temperature range is 1040 ~ 1120 ℃ (Japan standard). You can also through observing hole of annealing furnace and annealing the stainless steel pipe should be incandescent state, but did not appear to soften prolapse.
2, annealing atmosphere. Pure hydrogen gas is usually used as the annealing atmosphere, atmosphere best is more than 99.99% purity, if the other part is an inert gas atmosphere, can also lower purity, but absolutely can’t have too much oxygen and water vapor.
3, furnace body sealing. Bright annealing furnace should be closed, cut off from the air outside; Adopting hydrogen gas as shielding gas, only a vent is (used to ignite the discharge of hydrogen). Check method can wipe with soap and water in each joint cracks in annealing furnace, run to see if gas; One of the most easy to run gas place is where the annealing furnace into the pipe, the place of sealing ring particularly easy to wear, often should check in regularly.
4, shielding gas pressure. In order to prevent leakage, protection of gas should maintain a positive pressure in the furnace, if the hydrogen gas protection, general requirements above 20 kbar.
5, water vapor in the furnace. On the one hand, check whether the furnace material is dry, the first furnace, furnace material must be dry; The second is whether the stainless steel pipe into the furnace residue too much stain, special pipe above if there is one hole, don’t slack and went in, or we’ll get the furnace atmosphere all destroyed.
Source: Yaang Pipe Industry Co., Limited (www.yaang.com)