Bright Annealing Prevents Rust and Treats Discoloration
As the name suggests, stainless steel is a rustproof (strictly speaking, rust-resistant) metal. It doesn’t stain. This is because the chromium in stainless steel combines with oxygen in the air to form a passive film on the surface. Well, this is the case normally. But the intense heat from welding actually destroys this chromium film. It is very clearly seen in the unappealing discoloration from the weld area. Corrosion and rust can progress from the discolored area, and causing this so called “stainless” steel to rust.
Bright Annealing Equipment
This machine, which our company purchased several years ago, can be used in such cases. This equipment performs bright annealing, reduction treatment, and diffusion bonding of stainless steel parts (strainers and filters).
It consists of a continuous heating furnace and control panel, and the treated material is conveyed by a heat-resistant steel mesh belt for non-oxidation heat treatment. This is opposed to oxidizing treatments such as conventional welding.
Before and After Bright Annealing
When wire mesh is welded through conventional means, the welded area becomes discolored as evident on the left image. Bright annealing reduces oxides by heating and cooling in a reducing atmosphere of hydrogen, and the discolored areas can be removed.
Products that have undergone bright annealing treatment are free from rust and discoloration, and last for a long time. Consider bright annealing mesh for your project, if you are looking to build a filter with extended longevity.