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 test method is not applicable to asm products. 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. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water More suitable alternatives are offered in Table 5, below.

ASTM A was designed for austenitic stainless steels, specifically the series alloys. There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA.

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

Intergranular Corrosion Tests for CRAs

The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N, N, N, and N All NEW posts will show up credited to their authors. Sensitization or undesirable intergranular precipitation may occur due to deleterious thermal cycles, because of welding or heat treatment, for example. NACE International Keywords weldnickel alloystest methodapplicabilitysensitizationintergranular corrosionG28 Downloads 2 in the last 30 days 17 since Show more detail.

For alloys not listed in this standard, it will atsm necessary to carry out some tests on material in various conditions to determine the threshold.

Intergranular Attack Testing – ASTM G28 – Colorado-Metallurgical-Services

Historical Version s – view previous versions of standard. Proceedings of an International Conference Submersible Technology: Some suggested criteria wstm the listed alloys are shown in Table 2, below.


The latter is a German test, but it is often called up in European projects. ASTM G28 method B is a more aggressive test than method A and is b28 for more corrosion resistant alloys, as listed in the document.

Warning statements are given in 5. I am working with incoloy and am trying to make some corrosion tests according to ASTM G28, which uses a solution of ferric sulphate with sulfuric acid.

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

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. Why were these tests designed? Table satm below shows the various methods for four common standards: The problem is that the sample was destroyed just six hours, including the test that is annealed solution.

Conducting the Tests When a test has been selected, follow the detailed directions in that standard for making up the test solution, xstm preparation of test samples and the finish to be used. The safe operation of ashm refineries in the United States is under constant r The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms.

Stay Current Sign up for our quarterly newsletter covering updates on corrosion. 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.

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.

Thanks for your answer. It is possible to have grain boundary precipitation without the presence of chromium-depleted zones, and indeed such a microstructure has been shown to be beneficial in avoiding intergranular stress corrosion cracking IGSCC in high temperature water in nuclear industry applications, although clearly this cannot be generalized.


None of these are identical and cross substitution of results is not possible. Good material should have a corrosion rate substantially less than the threshold value.

ASTM G28 test

Someone would have experience in this matter. When migrating the old forums over to our new forums we were unable to retain the identity of the authors, so the old posts will show up as “anonymous”.

So please participate and share knowledge just as you have in the past. This means that carbide formation during welding is highly unlikely, and modern CRAs should easily pass one of these tests. Materials shown to be susceptible may or may not be intergranularly corroded in other environments. The test solutions and exposures for some common intergranular corrosion tests.

Hence, it is normally only used for stainless steels intended for nuclear service, or another application involving nitric acid. The Tests Table 1 below shows the various methods for four common standards: The results of such tests are applied widely as acceptance tests for parent and welded materials, and as such are essentially used to confirm the suitability of these materials for service.

Moreover, my samples of incoloyaccording this test, should last for hours without intergranular corrosion. SEP also gives guidance on which of its methods apply to which alloys: From your description, it could be dilute sulfuric acid for which Incoloy is not suitable Hope this helps C. The specifications for bend testing are shown in Table 4. Testimonials Contact Us Sitemap.