Find the most up-to-date version of ISO at Engineering ISOpdf – Download as PDF File .pdf) or read online. ASTM A method E is sometimes called the Strauss test, and is the same as ISO method A, except for the duration. As 15 hours is a difficult test period .
|Published (Last):||23 April 2009|
|PDF File Size:||16.72 Mb|
|ePub File Size:||9.39 Mb|
|Price:||Free* [*Free Regsitration Required]|
Methods B and E are suggested for all grades of series austenitic alloys, while method F is suggested for cast type alloys. R Baboian, Corrosion Tests and Standards: ASTM A was designed for austenitic stainless steels, specifically the series alloys. This means that carbide formation during welding is highly unlikely, and modern CRAs should easily pass one of these tests.
The specifications for bend testing are shown in Table 4. Contact us by Phone or Email to find out how we can help your industry. The test solutions and exposures for some common intergranular corrosion tests. Alternatively, a welded test-piece in the as-welded condition may be tested. 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 of a suitable test method is difficult.
Samples may be rectangular or cylindrical to suit the test vessel, but where a bend test is required, it is suggested that the sample be a minimum of mm long. More suitable alternatives are offered in Table 5, below. Get in Touch Contact us by Phone or Email to find out how we can help your industry.
Intergranular Corrosion Tests for CRAs
The Tests Table 1 below shows the various methods for four common standards: ASTM G28 does not require samples to be heat treated. 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. Conducting the Tests When a test has been selected, follow the detailed directions in that 36511-2 for making up the test solution, the preparation of test samples and the finish to be used.
When izo 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.
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. Table 1 below shows the various methods for four common standards: 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.
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. Both of these tests should be followed by water quenching.
It does not say what to do about duplex or super austenitic alloys. All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy.
Make an Enquiry Notice: ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows:. The test methods in Table 1 were designed with specific alloys in mind, but the proliferation of new CRAs has meant that the selection of a suitable test method isso difficult.
Good material should have a corrosion rate substantially less than the threshold value. It can be seen that ieo alloys fall into two categories, and no guidelines are given for selecting the most appropriate. ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: The latter is a German test, iwo it is often called up 351-2 European projects.
ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures: These tests were introduced when the carbon content in CRAs typically hit 0. It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes.
Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs! For alloys not listed in this standard, it will be necessary to carry out some tests on material in various conditions to determine the threshold. ASTM G28 lists alloys and specifies the test exposure for each. The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1.
Where a bend test is required, the sample must be bent over a mandrel of a diameter related to the specimen diameter, without any cracking, as determined by inspection under a low power microscope and a microsection in any suspicious areas. The Huey test method C is only for molybdenum-free grades, such as L, as alloys with molybdenum show high rates of attack in this test.
Bend test criteria for several standards. Test Samples Samples may be rectangular or cylindrical to suit the test vessel, but where a bend test is required, it is suggested that the sample be a minimum of mm long.
ASTM G28 was designed for nickel-based is, and a list of applicable alloys for methods A and B is in the standard. Suggested test methods for different corrosion resistant alloys. SEP also gives guidance on which of its methods apply to which alloys: Some suggested criteria for the listed alloys are shown in Table 2, below. There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA.
For many alloys, the onset is at 0. Why were these tests designed? ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different isoo.