ASTM A262 PDF
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. Intergranular astk shows up as the dark black lines around the grain boundaries. Axtm an Enquiry Notice: Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined. How do you select the right ASTM corrosion testing method for your material? 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.
ASTM G28 lists alloys and specifies the test exposure for each.
ASTM A Intergranular Corrosion Testing and Analysis
Wilson Hardness Conversion Chart. Ast A is a common intergranular corrosion testing method that can quickly screen batches of material to determine corrosion susceptibility. Where a standard is included in a purchase specification, this must be followed, although it is advised that unsuitable tests, such as the Huey test for duplex and super austenitic stainless steels, are queried. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water 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 use and application.
These practices include five intergranular corrosion tests, namely: If materials with incorrect heat treatment enter service, they are liable to crack or fail by intergranular corrosion IGC much more rapidly than properly treated materials; ASTM A is a screening test to help find batches that are incorrectly processed. Selection of a Test Method The test methods in Table 1 were designed with specific alloys in mind, but the proliferation of new CRAs has meant that the selection a2662 a suitable test method is difficult.
The inch-pound equivalents are in parentheses and may be approximate. Choosing an Intergranular Corrosion Test Method Since high temperature processing such as heat treatment is a common practice, many manufacturers astmm 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.
This specification is for detecting susceptibility to intergranular attack IGA. 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.
For an alloy that is not listed, look for an alloy with a similar composition to a listed alloy to determine the most suitable test.
This method is a hour boiling test for “as received” specimens of stainless steel. The specifications for bend testing are shown in Table 4. It depends on which Practice is selected, but typically ranges from to days for different tests. The samples are etched after metallographic preparation for cross-sectional examination which is thoroughly viewed with a traverse from inside to outside diameters of rods and tubes, from face to face on plates, and across all zones such as weld metal, weld-affected zones, and base plates on specimens containing welds.
ISO is specifically for duplex and all austenitic stainless steels, and aastm ageing at two different temperatures:. Both of these tests should be followed by water quenching. Methods B and E are suggested for all grades of series austenitic alloys, while method F is suggested for cast type alloys.
The Copper Sulfate Test is especially effective for determining susceptibility to intergranular attack for low carbon steels. Classification of structure then provides either q262 or further testing required, which typically moves you to one of the next practices.
For many alloys, the onset is at 0. Because it can be run quickly for screening, we often run this test first. All five methods within this specification involve exposing specimens to a chemical mixture designed to encourage corrosive behavior. Suggested test methods for different corrosion resistant alloys.
Methods for preparing the test specimens, rapid screening tests, apparatus setup and testing procedures, and calculations and report contents are described for each testing practice. 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.
All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy. A bend test followed by a visual or micro-examination are used to determine “Pass” or “Fail” of test specimens.
SEP method 3 is a special environment only suitable for the Ni-Mo alloys, as described below, in section 4. Due to the variance of attack in different materials, numerous methods Practices B-F are used to assess 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.
Table 1 below shows the various methods for four common standards: Duplicate samples from both a62 of a sheet wstm are evaluated to determine if carburization results in intergranular attack. However, when a material is exposed to high temperatures for long periods of time, a process called sensitization may occur.
SEP also gives guidance on which of its methods apply to which alloys: 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.
At the conclusion off the test, specimens are either visually examined or measured for weight loss and compared to an established corrosion rate for that specific material type. Historical Version s – view previous versions of standard. It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes.
There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA.