Dongshang stainless produce bright annealing stainless steel tube both welded tube and seamless tube, stainless grades include 304/304L, 316/316L, 321, 904L and duplex steels, there is oxidation film outside of tube after bright annealed finish to prevent tube from corrosion.
Bright annealing stainless steel tube Specifications
- Welded: A249, A269, A789, EN10217-7
- Seamless: A213, A269, A789
- Grade: 304, 304L, 316, 316L, 321, 2205
- Finishing: Bright annealing
- OD: 3 mm – 50.8 mm;
- Thickness: 0.3 mm – 3 mm
- Forms: round, U bend, coiling
- Application: Heat exchanger, boiler, condenser, cooler, heater
Bright Annealed Definition
Bright annealing (BA) refers to stainless steel material is heated in closed furnace in reducing atmosphere of inert gases, common Hydrogen gas, after fast annealing, rapid cooling, stainless steel has a protective layer on the outer surface, no reflect in open air environment, this layer can resist corrosion attack. In general, material surface is more smooth and brighter.
Bright Annealing Tube
Tube is processed in bright annealing finish, in this process, some factors are important for quality tube, if bright annealing process is not proper, that will result in crack, then may corrosion.
Before Bright Annealing
The surface of the tube must be clean, no other foreign matter, any matter left on the tubing surface can cause damage during the process.
Annealing atmosphere should be free from Oxygen, isolating material, creating a vacuum condition. Inserted gas, common dry hydrogen or argon, can obtain bright result.
Annealing temperature should be noticed depending on different stainless grades, commonly Austenitic steels annealing temperature is at least 1040 degree, soak time is not important. high temperature must be required to have brighter appearance. Heating is done as fast as possible, slow heat results in oxidation.
Some Ferritic stainless steels require lower annealing temperature, such as TP439, cannot be effectively bright annealed, Water quenching will cause scale formation.
After bright annealed, it comes to the final steps of sizing and straightening, stainless steel tube surface perform bright appearance, it is unnecessary to pickling for bright annealed tube.