Posted by: arnoldeng
in Default Category on Nov 18, 2011
Although the beauty of stainless steel on aerostructures is that you don't generally need to put any type of coating on it, when you are using this material in any sort of industrial process, it may be prone to free iron contamination. With a process known as passivation, you can remove these iron compounds with the use of a chemical dissolution, such as a treatment with acid solution. This helps enhance the performance level of stainless steel or other materials, preventing premature corrosion or deterioration and increasing the material's lifespan.
cnc machinery is a combination of a cleaning process, because it removes the iron compounds from aero-structures, and is also a protective coating at the same time because it prevents the buildup of any further iron compounds or oxidation. This process begins with a thorough cleaning of the material that is being treated, which is capable of removing coolants, grease, oil, or any other residues that are left behind on the surface of the steel. When steel is used in fabricating machines, they can leave behind their mark in minute amounts. Any type of cleaning can be used to start this process, whether it is soaking the steel in an alkaline solution, or cleaning it with solvents that are specifically designed for this purpose.
After these various residues are removed, the next step to passivate the steel is to place it into a passivating solution. These are usually based on nitric acid, although there are alternative options including citric acid for a more environmentally friendly solution. These will vary in terms of temperature, the concentration of the nitric acid or other passivating agent, and the time that the steel must spend in this immersion. In general the period will range for anywhere from 20 minutes to an hour, depending on the concentration. There are many different variables to include in this length of time.
