Stainless Steel Cleaning, Pickling and Passivation
WestChem has developed a specific process with specific chemistry to provide the ideal treatment for stainless steel products. The process can be applied to whether the stainless steel is being painted or unpainted.
The Nature of Stainless Steel
Stainless steel is essentially an iron alloy that is composed of at least 10.5% chromium and less than 1.2% carbon. The chromium properties provide stainless steel with superior corrosion resistance.
The main requirement for stainless steels is that they should be corrosion resistant for a specified application or environment. The selection of a particular “type” and “grade” of stainless steel must initially meet the corrosion resistance requirements. Additional mechanical or physical properties may also need to be considered to achieve the overall service performance requirements.
Prepares the substrate by removing rust, grease, oils and other foreign deposits. The cleaning phase will brighten up the surface of the stainless steel. Degreasing the substrate is essential for proper pickling and uniform formation of the passive layer.
Pickling removes the passive layer in addition to a small amount of metal from the surface of the stainless steel. After pickling, they surface of the stainless will start to oxidize when exposed to oxygen in the air. It is this critical process that restores the corrosion resistance of the stainless steel.
Although this process occurs natually on the surface of stainless steel, it is often useful to accelerate and assist in the development of the passivation layer. Passivation occurs when chromium oxidizes with the oxygen in the air to form a corrosion resistant passivation layer. This process can be accelerated and assisted with a passivation product, ensuring the development of a uniform and thick passive layer.