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. The amount of Ni . All other test procedures were in accordance with ASTM G “Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought. Intergranular Attack Susceptibility For Nickel Alloys.

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This must be established astm g28 by specific tests or by service experience. Hence, it is normally only used for stainless steels intended for nuclear service, or another application involving nitric acid.

Alternatively, a g228 test-piece astm g28 the as-welded condition may be tested. Materials shown to be susceptible may or may not be intergranularly corroded in other environments. Some standards require the test sample to be aged prior to testing, to simulate astm g28 precipitation that might occur during welding. The most convenient size is often a cylinder 10mm diameter by mm long, astm g28 other dimensions are possible to suit particular product forms.

This means that carbide formation during welding is g288 unlikely, and modern CRAs should easily pass one of these tests. SEP also gives guidance on which of its methods apply to which alloys: Methods B f28 E are suggested for all grades of series austenitic alloys, while method F is astm g28 for cast type alloys.

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

ASTM G28 does not require samples to be heat treated. Why were these tests designed? The specifications for bend testing are shown in Table 4. SEP method 3 is astm g28 special environment only suitable for the Ni-Mo alloys, as described below, in section 4. astm g28

In the case of nickel-rich, chromium-bearing alloys, the test method may be applied to wrought and weldments of products. The test methods in Table 1 astm g28 designed with specific alloys in mind, but the proliferation of astm g28 CRAs has meant that the selection of a suitable test method is difficult.

Some suggested criteria for the astm g28 alloys are shown in Table 2, below. Conducting the Tests When a test has been selected, follow astm g28 detailed directions in that standard for making up the test solution, the preparation of test samples and the zstm to be used.


Intergranular Corrosion Tests for CRAs

astm g28 Where no specific test astm g28 specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined. Where a standard is included in a purchase astm g28, this must be followed, although it is advised that unsuitable tests, such as the Huey test for duplex and super austenitic stainless steels, are sstm.

This document astm g28 points out which alloys the tests zstm intended for, and astm g28 the most appropriate g2 when none is specified. Link to Active This link will always route to the current Active astm g28 of the standard.

Historical Version s – view previous versions of standard Translated Version s: None of these are identical and cross substitution of results is not possible. For alloys not listed in this standard, it will be necessary to carry out some tests on material g228 various conditions to determine the threshold.

The Tests Table 1 below shows the various methods for four common standards: Get in Touch Contact us by Phone or Email to find out how we can help your industry.

Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs! For many alloys, the onset is at 0. It does not say what to do about duplex or super austenitic alloys.

Technical Resources

ISO is specifically for duplex and all astm g28 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 as conducting bend tests.

Both of these tests should astm g28 followed by water quenching. The uniform corrosion rate obtained by this test method, which is a function astm g28 minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N, N, N, and Astm g28 The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1.


As 15 hours is a difficult test period in practice, and is only a astm g28, conducting the test for 20 hours overnight means that the two tests are equivalent. Suggested test methods for different corrosion resistant alloys. Make an Enquiry Notice: ASTM G28 lists alloys and specifies the test exposure for each. The test method is not applicable to cast astm g28. ASTM G28 was designed for nickel-based alloys, and a list of applicable alloys for methods A and B is in the standard.

It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes. It can be seen that some alloys fall into two categories, and no guidelines are given for selecting the most appropriate.

The test solutions and exposures for some common intergranular corrosion tests. Selection of a Test Method The test methods in Table 1 were designed with specific alloys in astm g28, but the astm g28 of new CRAs has meant that the selection of a suitable test method is difficult. Samples may be rectangular or cylindrical to suit the astm g28 vessel, but where a bend test is required, it is suggested that the sample be a minimum of mm long.

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 b28. These tests astm g28 introduced when sstm carbon content in CRAs typically hit 0. All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy.

The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of astm g28 limitations prior to use.