ABSTRACT It is common practice to perform intergranular corrosion testing in accordance with ASTM (1) G28 on solid solution nickel alloys, e.g. UNS N . Alloy 22 is a Ni-Cr-Mo alloy (Nickel-Chromium-Molybdenum) and is one of the most versatile corrosion resistant alloys used in industry today. Intergranular Attack Susceptibility For Nickel Alloys.

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Alternatively, a welded test-piece in the as-welded condition may be tested.

ASTM G28 was designed for nickel-based alloys, and a list of applicable alloys for methods A and B is in the standard. The ASTM G28 test methods A and B are utilized in many industries as quality control tests in order to assess the resistance to intergranular corrosion of various stainless steels and nickel-based alloys, such as Alloy and Alloy This document also points out which alloys the tests are intended for, and recommends the most appropriate test when none is specified.

The test solutions and exposures for some astj intergranular corrosion tests.

This test should be avoided for wstm CRAs, except in the circumstances described below, in section 4. SEP also gives guidance on which of its methods apply to which alloys: ASTM A was designed for austenitic stainless steels, specifically the series alloys.

g8 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. Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined. 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. Samples may be rectangular or cylindrical to suit the test vessel, but where a bend test is required, it sstm suggested that the sample be a minimum of mm long.


ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures:. Table 1 below shows the various methods for four common standards: Some suggested criteria for the listed alloys are shown in Table 2, below.

SEP does not require ageing, although it might be required in a specification calling up this standard. Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs!

Applicability of ASTM G28 Testing – OnePetro

Testimonials Contact Us Sitemap. For many alloys, the onset is at 0. It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes. Proceedings of an international conference Diverless and Deepwater Techology: 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. 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.

Rock Mechanics Symposium and 5th U. ASTM G28 lists alloys and specifies the test exposure for each. For alloys not listed in this standard, it will be necessary to carry out some tests on material in various aztm to determine the threshold. This document describes all three of these tests for four common standards, and describes the differences.

All NEW posts will show up credited to their authors. Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding. Get in Touch Contact us by Phone or Email to find out how we can help your industry. For ferric sulphate – depending on the concentration and temp, it depends on suitabiity. Asm is the gg28 rigorous in terms of defining test methods, aastm says which alloys should use which test methods as follows: Contact us by Phone or Email to find out how we can help your industry.


Peer reviewed only Published between: From your description, it could be dilute sulfuric acid for which Incoloy is not suitable Hope this helps C.

There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA. R Baboian, Corrosion Tests and Standards: The precipitation of such chromium-rich or molybdenum-rich particles often carbides usually also leads to regions depleted of Cr or Mo surrounding the precipitates.

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.

ASTM G28 test

None of these are identical and cross substitution of results is not possible. Moreover, my samples of incoloyaccording this test, should last for hours without intergranular corrosion.

Proceedings of an International Conference Submersible Technology: Methods B and E are suggested for all grades of series austenitic alloys, while method F is suggested for cast type alloys. These regions will exhibit a lower resistance to the initiation of corrosion in the ASTM tests, and this is where the intergranular corrosion begins.

The safe operation of oil refineries in the United States is under constant r It can be seen that some alloys fall into two categories, and no guidelines are given for selecting the most appropriate. ASTM G28 does not require samples to be heat treated. The exception to this is ASTM G28 method A, where asttm for the onset of intergranular corrosion are described in reference 1.

Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of aatm standard.