There are several different types of annealing processes that are used in various companies and metal working facilities. Bright annealing, or the ability to produce consistently bright, shiny surfaces on stainless steels is more than just an aesthetic issue, it is also essential for the life of the component and achieving the right durability within the component itself.
The End Results
There are many different metals that are typically annealed and can be better through bright annealing. The process involves heating the alloy, in most cases a stainless steel alloy, to a specific temperature. This temperature will soften the alloy and allow the grain structure within the metal to revert to the normal orientation. This, in essence, eliminates the internal stress that can be caused when processing an alloy that will lead to cracking and stress degeneration of the component over time.
All metals that go through annealing, including bright annealing, are going to naturally softer and easier to work with after the process. To prevent the metal from hardening after heating, the actual cooling process is carefully controlled to give the grains time to line-up correctly in the metal during the slow process. Fast cooling after heating leads to hardened metal, which is extremely difficult to bend, shape or work.
During the heating and the cooling process for bright annealing, the atmosphere is carefully controlled with a mixture of nitrogen and hydrogen. This eliminates the presence of oxygen and prevents the oxidation of the surface layer.
The result is that once the component or part has gone through the bright annealing it has the shiny, highly reflective surface associated with stainless steel. It is important to the surface of the components or parts to be completely clean and free from debris and irregularities before going into the furnace and through the process.
This includes the removal of any type of contaminants on the surface of the metal as well. Grease, oil, chemicals or any type of organic or inorganic materials will cause irregularities on the surface of the stainless steel component that can lead to oxidation, cracking or even pitting of the surface.
It is important to choose a company to complete any bright annealing requirements based on their experience, their professional reputation and their ability to handle the job to your schedule and timeframe. Choosing the more experienced company is always the best option and will result in perfect bright annealing of all components with every order.