The annealing of stainless steel materials includes general annealing and bright annealing. Among them, the surface brightness of the stainless steel material after bright annealing is better. Both methods will not have any impact on the hardness. The premise is to anneal according to the original specifications. An annealing method to analyze in detail.
① General annealing
It refers to the annealing without the protection of gas, such as open furnace heating and continuous annealing. This type of annealed strip steel also needs to be pickled to remove the oxide scale formed on the surface during the annealing process. Corrosion, the surface roughness is reduced, so the gloss is poor, and the surface looks white and not bright.
② Bright annealing
There are two types of bright annealing:
☆ One type is annealing under the protection of full hydrogen, which is derived from electrolysis or third-party supply, with high purity and low dew point;
☆ The other is decomposed with ammonia. The decomposed gas enters the furnace as a protective gas after drying, and its purity and dew point are relatively poor;
The two methods are the same in that they both use hydrogen as a protective gas. The furnace structure is special. There is a thing called "muffle" inside. The flame first heats the "muffle" and then conducts heat by heat conduction. For strip steel, the oxidation of strip steel is avoided in this way, so the strip steel after bright annealing does not need to be pickled again, and the strip steel "basically" maintains the original roughness. bright.