1 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Last previous edition approved in as A – 99 (). May 2nd, – Below is a technical summary of specification ASTM A 99 Advanced Plating Technologies is not. Gold plating is an exceptional finish for. BOOK ID: ECUadPJ && Download Book Pdf Astm A Finish Free. Passivation Services â€“ Welcome to Scott Metal Finishing. ASTM A 99 Advanced.
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The standard also allows any combination of citric acid concentration, temperature and time, provided that asfm passivation test criteria can be met.
The degree of cleanness required on a surface depends on the application. Office and Postal Address: The standard notes that the high carbon martensitic stainless steels, such as C, are not suitable for acid passivation as they can be attacked or be subject to hydrogen embrittlement.
Process Class Stainless Steel Types C1 or C2 Austenitics, austenitic precipitation hardening and duplex C3 High chromium martensitics Atm Ferritics, martensitics and martensitic precipitation hardening. Visual inspection is suitable for the detection of gross contamination, scale, rust, and particulates, but may not reveal the presence of thin films of oil or residual chemical films.
ASTM A Passivation Standard | Able Electropolishing
Passivation treatments are sometimes specified, but it is important to consider whether this is strictly necessary or not. It was at one time considered that an oxidizing treatment was necessary to establish this passive film, but it is now accepted that this film will form spontaneously in an oxygen-containing environment providing that the surface has been thoroughly cleaned or descaled.
Unless otherwise specified, it is this definition of passivation that is taken as the meaning of a specified requirement for passivation.
On the other hand, some of the practices may be applicable for these purposes. Stainless steels are designed to naturally self-passivate whenever a clean surface is exposed to an environment that can provide enough oxygen to form the chromium rich oxide surface layer, on which the corrosion resistance of these alloys depends.
In some cases, no more than degreasing or removal of gross contamination is necessary. These recommendations are presented as procedures for guidance when it is recognized that for a particular service it is desired to remove surface contaminants that may impair the normal corrosion resistance, or result in the later contamination of the particular stainless steel grade, or cause product contamination. Related Links Z380 of Passivating Products.
In addition, this standard also includes citric acid treatments. Specific treatments are however also specified. Unlike ASTM A, the standard does not require specific solutions for particular stainless steel grades or types, although 3 specific treatments are identified.
Citric acid passivation as an alternative to nitric acid treatments Citric acid treatments can also be considered as an alternative to nitric acid as both provide the oxidising conditions necessary for passivation. Methods are described for the detection of free iron and transparent chemical and oily deposits. In order to avoid ambiguity in the setting of requirements, it may be necessary for the purchaser to define precisely the intended meaning of passivation.
Range C Time mins. This process is described in a general way in 6. For more specific safety precautions see 7. Nitric acid alone can be used to remove light surface iron contamination after which the acid facilitates the passivation of the cleaned steel surface.
Specifications for passivation treatments for stainless steels Traditionally the American standards have been used. Some of the various meanings associated with the term passivation that are in common usage include the following: The treatments are then defined by the process classes.
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ASTM A380 Passivation Standard
Such ashm treatment is generally not necessary for the formation of the passive film. In the case sstm classes C3 and C4, a two step process is defined, with a clean water rinse between the two steps, shown in the table below.
Stainless steels cannot be passivated unless the steel surface is clean and free from contamination and scale from welding operations. It therefore in no way precludes the necessity for careful planning and judgment in the selection and implementation of such procedures. Naturally occurring conditions such air or aerated water will do this and so under many exposure conditions stainless steels will naturally self-passivate.
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Meaningful tests to establish the degree of cleanness of a surface are few, and those are often difficult to administer and 999 evaluate objectively.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and qstm the applicability of regulatory limitations prior to use.
Pickling, passivation and removing iron contamination with nitric acid Passivation treatments are sometimes specified, but it is important to consider whether this is strictly necessary or not.