ASTM A380-99 PDF

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1 This practice is under the jurisdiction of ASTM Committee A01 on Steel, Last previous edition approved in as A – 99 (). Standard. Standard number, ASTM-A ; ASTM-A Title, Standard Practice for Cleaning, Descaling, and Passivation of Stainless. May 2nd, – Below is a technical summary of specification ASTM A 99 Advanced Plating Technologies is not. Gold plating is an exceptional finish for.

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Typical chemical treatment involves exposing the stainless steel surface to an oxidizing acid solution in which the significant variables are time, temperature, and concentration. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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Citric acid is a less hazardous method and has environmental benefits in terms of ‘NOx’ fume emission and waste acid disposal.

Failure to develop and maintain this passive film renders the surface active, or possessing corrosion resistance similar to conventional steel’s or cast iron’s. Best performance is achieved with a Cr-Fe ratio of the surface oxide of more than 1.

Once the surface is cleaned and the bulk composition of the stainless steel is exposed to air or an oxygen-containing chemical environment, the passive film forms immediately. Related Links Suppliers of Passivating Products. Passivation of stainless steels Introduction 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.

Acid concentrations up to 50 percent can be used, and the solution and residual effluent must be monitored closely.

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On one hand, ASTM A notes that “Passivation is a process by which a stainless steel will spontaneously form a chemically inactive surface when exposed to air or other oxygen-containing environments. 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.

Naturally occurring conditions such air or aerated water will do this and so under many exposure conditions stainless steels will naturally self-passivate. EDTA is a chelating agent that keeps iron in solution over a wide pH range. In addition, visual inspection of internal surfaces is often impossible because aztm the configuration of the item. Office and Postal Address: This condition can be measured using electrochemical techniques as a potential of 0.

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Bright annealing entails heating the stainless steel to a suitably high temperature usually more than 1, degrees F, or 1, degrees C in a reducing atmosphere such as dry hydrogen gas. Some of the various meanings associated with the term passivation that are in common usage include the s380-99. Stainless steel owes its corrosion asm to its ready oxidation to form this protective xstm however, stainless steel’s exposure to an oxidizing environment at higher temperatures or to a more highly oxidizing environment at a given temperature will result in the formation of an oxide heat tint of increasing thickness, ranging in color from a light straw to a dark black.

Unless otherwise specified, it is this definition of passivation that is taken as the meaning of a specified requirement for passivation.

ASTM A Passivation Standard | Able Electropolishing

Passivation is the process of forming a protective oxide film on stainless steel. 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. Organic contaminants are volatilized and most metal oxides including those of iron, nickel, and chromium will be reduced, resulting in a clean, oxide-free surface. Today, it remains the only North American publication devoted to this industry and it has become the most trusted source of information for tube and pipe professionals.

This solution has high reactivity with free iron, is less sensitive to exposure time, is far less corrosive to other materials, is less costly, and is considered environmentally friendly when used properly.

Stainless steels cannot be passivated unless the steel surface is clean and free from contamination and scale from welding operations. The degree of cleanness required on a surface depends on the application.

Although they apply primarily to materials in the composition ranges of the austenitic, ferritic, and martensitic stainless steels, the practices described may also be useful for cleaning other metals if due consideration is given to corrosion and possible metallurgical effects. More Content by Carl R. For more specific safety precautions see 7. Link to Active This link will always route to the current Active version of the standard.

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Keeping stainless steels stainless

Specific treatments are however also specified. The thicker this heat tint oxide is, the greater the probability that corrosion will occur beneath the oxide film. While very effective as a passivator, this solution may have environmental ramifications. It is essential that the entire surface be in a passive condition. Unless otherwise specified, it is this definition of passivation that is taken as the ast of a specified requirement for passivation.

In the interior of an orbitally welded section of L, the inner surface of the weld bead, and the adjacent Atsm, are covered with a varicolored oxide film, or heat tint. Methods are described for the detection of free iron and transparent chemical and oily deposits.

This adtm will accelerate the rate of metal dissolution into the surrounding electrolyte. Figure 2 After removal of the heat tint oxide, evidence of in-service pitting in the HAZ is apparent.

Meaningful tests to establish the degree of cleanness of a surface are few, and those are often difficult to administer and to evaluate objectively. Passivation treatments are sometimes specified, but it is important to consider whether this is strictly necessary or not.

Asfm Popular Content This Week Fabrication, additive manufacturing companies produce part for airliner Solving the skills gap one class at a time Top 5 in —Articles about waterjet cutting 3D scanning—The first step in making a dream come to fruition SLM Solutions white paper: In order to avoid aa380-99 in the setting of requirements, it may be necessary for the purchaser to define precisely the intended meaning of passivation.

Article: Passivation of stainless steels

While it is essential that surface contamination be removed completely, it is the latter interpretation of passivation that relates zstm establishing the corrosion resistance of stainless steels. This process is described in a general way in 6. On the other hand, ASTM A also notes a308-99 “Passivation is removal of exogenous or free iron or iron compounds from the surface of a stainless steel by chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination but will not significantly affect the stainless steel itself.