Nitric Acid, ASTM A, Practice C, (Huey Test) The specimens are boiled for five periods, each of 48 hours, in a 65 per cent solution of nitric acid. The corrosion. employed to measure the relative susceptibility of austenitic stainless steels to intergranular attack. ASTM A Practice C, boiling nitric acid test is also known . Ferric Sulfate – Sulfuric Acid, ASTM A – Practice B (Stretcher Test). Ferric Sulfate Nitric Acid, ASTM A, Practice C, (Huey Test). Nitric Acid, ASTM A

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Please specify the maximum allowable corrosion rate and any available data on the sensitizing heat treatment performed.

Intergranular Corrosion Testing: An Overview of ASTM A262

Learn more about our laboratories – where they are located; the unique capabilities they have and how they can help you solve practce technical and commercial challenges. Like what you saw? From macroscopic imaging to Scanning Electron Microscopy, Element provides turnkey metallographic services using state-of-the-art equipment. Some specific hazards statements are given in This specification covers the standard practices for detecting susceptibility to intergranular attack in austenitic stainless steels.

Practice A, the oxalic acid etch test is used as a rapid technique to screen samples of certain stainless steel grades to ensure they are not susceptible pdactice intergranular attack sensitization.

ASTM A Testing: An Overview of Intergranular Corrosion | Element

Based on your materials, application, and requirements, the other a2622 methods provide specific focuses. Intergranular corrosion shows up as the dark black lines around the grain boundaries. Please refer to the specification for more details. In everyday applications, corrosion varies by materials and solutions.

Link to Active This link will always route to the current Active version of the standard.

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Because it can be run quickly for screening, we often run this test first. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its pfactice and application. Since high temperature processing such as heat treatment is a common practice, many manufacturers wish to perform intergranular corrosion qualification testing on each batch, to ensure that the material has been processed correctly and does not ast signs of corrosion susceptibility.

The Huey test works well to analyze chromium depleted regions and intermetallic precipitates, such as sigma phase, and is also used for materials in strongly oxidizing environments such as nitric acid. Due to the variance of attack in different materials, numerous methods Practices B-F are used to assess intergranular corrosion. Metals like stainless steels and aluminum contain elements such as niobium and chromium, often integrated because of their natural corrosion resistance.


The chart below comes from the ASTM A standard for selection of the appropriate test by alloy type:. Practice B, also known as the Streicher test, uses weight loss analysis to provide a quantitative measure of the materials performance.

Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. G2MT Labs is one of the few labs to offer all five ASTM A corrosion testing practices, as well as the expertise to help you determine which tests to use, what to do if a test fails, and other corrosion consulting as needed.

Zstm of the structure after A Practice A analysis will determine if the material is acceptable or if additional testing is required. This website uses cookies to improve user experience. 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. Historical Version aa262 – view previous versions of standard. These tests are often run as a qualification test to ensure each batch of stainless steel is properly prepared.

These tests do not provide a basis for predicting resistance to forms of corrosion other than intergranular, such as general corrosion, pitting, or stress-corrosion cracking.

ASTM A Intergranular Corrosion Testing and Analysis

To understand intergranular corrosion testing praftice intergranular attack commonly abbreviated as IGC or IGAit is important to understand what causes the process to occur. Practice F, is a hour weight-loss based analysis that provides a quantitative measure pracctice the materials performance, and is commonly used to analyze as-received stainless steels.

In many cases we can reduce that to as little as 24 hours more than the required testing time if you need fast results. How do you select the right ASTM corrosion testing method for your material? If you are not sure, please contact us for assistance. This practice includes boiling the sample for 24 to hours in the solution above, and measures the materials performance pgactice.


It is typically used for stainless alloys such as andCr-Ni-Mo stainless alloys, and nickel alloys to evaluate the intergranular attack associated with the precipitation of chromium carbides at grain boundaries.

This simple etching technique is used as a quick screening method to ensure that a material is free of intergranular corrosion susceptibility.

This method is a hour boiling test for “as received” specimens of stainless steel. The oxalic acid test is commonly used before the Strauss test to determine if a sample is susceptible; samples that pass method A will generally show low corrosion rates in the Strauss test.

ASTM A is a common intergranular corrosion testing method that can quickly screen batches of material to determine corrosion susceptibility. In SEM analysis, intergranular corrosion is clear by the awtm lines where the grain boundaries are eaten away. Share on Tumblr Print.

The weight loss is calculated after each step, and reveals if the sample has been properly heat-treated. View more articles about Aerospace Oil and Gas Transportation. The first zstm fastest step is the ASTM A Practice A, a rapid same-day screening method in Oxalic acid to determine the susceptibility to intergranular corrosion.

Practice E, the Strauss test, is performed to assess attack associated with chromium-rich carbide formation; it does not detect susceptibility to sigma phase formation. At the conclusion off the test, specimens are either visually examined or measured for weight aetm and compared to an established corrosion rate for that specific material type.

ASTM does not give any warranty express or implied or make any representation that the pracitce of this abstract are accurate, complete or up to date. Work Item s – proposed revisions of this standard. The bent samples are examined at low magnification, where the appearance of cracks or fissures indicate intergranular attack.

All five methods praxtice this specification involve exposing specimens to a chemical mixture designed to encourage corrosive behavior. This abstract is a brief summary of the referenced standard. What is your typical turnaround time? The test uses a visual inspection of the surface of the bent specimen to determine pass or fail.

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