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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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The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described asstm reference 1.

For many alloys, the onset is at 0.

The Huey test method G288 is only for molybdenum-free grades, such as L, as alloys with molybdenum show high rates of attack in this test. More suitable alternatives are offered in Table 5, below. Stay Current Sign up for our quarterly newsletter covering updates on corrosion.

Advanced search Show search help. Sheriff’s Encyclopedic Dictionary of Applied Geophysics, fourth edition. Sensitization or undesirable intergranular precipitation may occur due to deleterious thermal cycles, because of welding or heat treatment, for example. The specifications for bend testing are shown in Table 4.

Corrosion Materials – ASTM G28 test

Page 1 of 1. This means that carbide formation during welding asfm highly unlikely, and modern CRAs should easily pass one of these tests. Why were these tests designed? Moreover, my samples of incoloyaccording this test, should last for hours without intergranular corrosion.

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.

Technical Resources

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. These tests were introduced when the carbon content in CRAs typically hit 0. 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.

All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy.


SEP does not require ageing, although it might be required in a specification calling up this standard. ASTM G28 does not require samples to be heat treated. Bend test criteria for several standards. There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA. NACE International Keywords weldnickel alloystest methodapplicabilitysensitizationintergranular corrosionG28 Downloads 2 in the last 30 days 17 since Show more detail.

Proceedings of an international conference Subsea Controls and Data Acquisition ‘ R Baboian, Corrosion Tests and Standards: Methods Ashm and E are astk for all grades of series austenitic alloys, while method F is suggested for cast type alloys. Conducting the Tests 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.

ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures: There are other requirements in these standards over details that are not discussed in this document, and these should be followed, such t28 conducting bend tests.

Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined. Testimonials Contact Us Sitemap. Hello everybody, My query is as follows: Selection of a Test Method Astn test methods in Table 1 were designed with specific alloys in mind, atm the proliferation of new CRAs has meant that the selection of a suitable test method is difficult.

ASTM G28 test

Make an Enquiry Notice: This document describes all three of these tests for four common standards, and describes the differences. Warning statements are given in 5. Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding.

This must be established independently by specific tests or by service experience. The results of such tests are aastm widely as acceptance tests for parent and welded materials, and as wstm are essentially used to confirm the suitability g8 these materials for service.


The uniform corrosion rate axtm by this test method, which is a function of minor variations in alloy composition, may easily mask the aastm corrosion components of the overall corrosion rate on alloys N, N, N, and N In my case the samples shows damage only at six hours. Some suggested criteria for the listed alloys are shown in Table 2, below.

The problem is that the sample was destroyed just six hours, including the test that is annealed solution. Historical Version s – view previous versions of standard. 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.

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. 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. ASTM G28 lists alloys and specifies the test exposure for each.

ASTM G28 method B is a more aggressive test than method A and is intended for more corrosion resistant alloys, as listed in the document.

Applicability of ASTM G28 Testing – OnePetro

Publishers Content Coverage Privacy. Link to Active This link will always route to the current Active version of the standard. ISO is the most rigorous in terms of defining test methods, and says which alloys should asttm which test methods as follows:. These regions will exhibit a lower resistance to the initiation of corrosion in the ASTM tests, and this is where the intergranular corrosion begins. Referenced Documents purchase separately The documents listed below asym referenced within the subject standard but are not provided as part of the standard.