Everything You Want To Know About Passivation

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NADCAP certified passivation refers to a common
but extremely important procedure that is used
during the manufacture of stainless steel
components. When talking about passivation the
emphasis is paced both on the actual process as
well as that type of characteristics that it
imparts. A lot of care usually has to be taken
because a great deal of damage can easily occur
if any of the components are not handled
correctly whether it is during their
transportation or storage. You can understand
this fragility if you know how the process of
NADCAP certified passivation takes place as well
as what it does. Even though passivation can
occur on its own on some forms of stainless
steel, the NADCAP certified passivation process
was developed so as to make sure there is a sort
of infirmity in the process.
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The NADCAP certified passivation process involves
the use of an oxidizing agent like nitric acid so
as to create a film layer that is basically a few
atoms thick. Since such a layer is chemically
inert it will basically reduce the reactivity of
stainless steel. As soon as the process of
passivation has been accomplished, some
additional machining will easily remove that thin
layer that will have been created during the
procedure. This removal will not simply occur on
the surface that was worked upon but also on the
flying chips of the material whether it is from a
cutting tool or the part that will become damaged
in other regions where they could land or
ricochet.
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In addition to the mechanical removal of NADCAP
gold electroplating that could come as a result
of re-machining, cutting fluids that are normally
applied to reduce the damage caused by heat as
well as flushing away the chips are also bad news
to this thin layer. It is a common occurrence for
sulfides or any other chemicals that are used in
those cutting fluids to actually enhance the
release of chips away from the cutting area. Such
compounds will actually further weaken the
passivation layer and penetrate it thereby
initiating the process of corrosion if any of
these happenings are suspected it is preferable
that re-passivation is considered.
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It is also important to remember that as a matter
of fact, any parts that have gone through the
process of NADCAP metal finishing should not
under any circumstances be heat treated. The
process of heat treating will definitely alter
the crystalline structure of the metal and which
will affect its strength, hardness, elasticity
and ductility. While it may appear for many that
stainless steel parts have the innate ability to
handle any kind of handling process, it is good
to note that the NADCAP certified passivation
layer is very fragile and can easily come off.
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