Intergranular Corrosion Test (IGC) per ASTM A At TCR Engineering Services, several methods exist for the testing of intergranular corrosion. To conduct. Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels. ASTM A is the specification which governs five practices used to determine if the. Abstract. A detailed study of AISI and stainless steels (SSs) has been conducted to correlate the degree of sensitization (DOS) measured by the.
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Rockwell or Superficial Hardness. For example, many low-carbon and stabilized stainless steels e. Contact us now for pricing or a quote! Xstm A testing is a popular method of choice due to the variety of practices available and the relatively short turnaround for results. This document describes all three of these tests for four common standards, and describes the differences. This document also points out which alloys the tests are intended for, and recommends the most appropriate test when none is specified.
Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs! Classification of the structure after A Practice A analysis will determine if the material is acceptable or if additional testing is required.
All five methods within this specification involve exposing specimens to a chemical mixture designed to encourage corrosive behavior. Historical Version s – view previous versions of standard.
Typical examination magnification is X to X. Practice F, is a hour weight-loss based analysis that provides a quantitative measure of the materials performance, and is commonly used to analyze as-received stainless steels.
ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at axtm different temperatures:. For an alloy that is not listed, look for an xstm with a similar composition to a listed alloy to determine the most suitable test.
Choosing the correct method s rely on a complete understanding of your material and processes, as well as the concept of corrosion itself. When a test has been selected, follow the detailed directions in that standard for making up the test solution, the preparation of test samples and the finish to be used. Choosing an Intergranular Corrosion Test Method 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 show signs of corrosion susceptibility.
Intergranular Corrosion Tests for CRAs
Some specific hazards statements are given in There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA. See Appendix X1 for information regarding test selection.
ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: These practices include five intergranular corrosion tests, namely: In SEM analysis, intergranular corrosion is clear by the dark lines where a62 grain boundaries are eaten away. There are other requirements in these standards over details that are not discussed in this document, and these should be followed, such as conducting bend tests. 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.
Alternatively, a welded test-piece in the as-welded condition may be tested.
Share on Tumblr Print. Both of these tests should be followed by water quenching.
Intergranular Corrosion Testing: An Overview of ASTM A262
All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy. As 15 hours is a difficult test period in practice, and is only a minimum, conducting the test for 20 hours overnight means that the two tests are equivalent.
The specifications for bend testing are shown in Table 4. 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 to intergranular attack sensitization. Good material should have a corrosion rate substantially less than the threshold value. It can be seen that some alloys fall into two categories, and no guidelines are given for selecting the most appropriate.
The inch-pound equivalents are in parentheses and may be approximate. The Copper Sulfate Test is especially effective for determining susceptibility to intergranular attack for low carbon steels.
Strauss test specimens are boiled in a Copper Sulfate – Sulfuric Acid mixture for 15 hours. Bend test criteria for several standards. These tests were introduced when the carbon content in CRAs typically hit 0.
For example, in asttm oxidizing solutions, intergranular attack can occur due to intermetallic phases, while attack of carbides may atsm somewhat less oxidizing solutions. Contact us by Phone or Email to find out how we can help your industry. 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.
Intergranular Attack – ASTM A – Colorado-Metallurgical-Services
The ASTM A tests can determine if the proper heat treatment was performed or if the alloys are in danger of intergranular corrosion occurring in use. Some suggested criteria for the listed alloys are shown in Table 2, below.
Please refer to the specification for more details. Historical Version a2262 – view previous versions of standard Work Item s – proposed revisions of this standard Translated Version s: