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 .
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Contact us by Phone or Email to find out how we can help your industry. As 15 hours is a difficult test period isoo practice, and is only a minimum, conducting the test for 20 hours overnight means that the two tests are equivalent.
This document describes all three of these tests for four common standards, and describes the differences. Why were these tests designed?
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. 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.
This 6351-2 also points out which alloys the uso are intended for, and recommends the most appropriate test when none is specified. Get in Touch Contact us by Phone or Email to find out how we can help your industry. Where a standard is included in a purchase specification, this must be followed, although it is advised that unsuitable isi, such as the Huey test for duplex and super austenitic stainless steels, are queried.
6351-2 The Tests Table 1 below shows the various methods for four common standards: The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms.
It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes. The specifications for bend testing are shown in Table 4.
Methods B and E are suggested for all grades of series austenitic alloys, while method F is suggested for cast type alloys.
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. R Baboian, Corrosion Tests and Standards: 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.
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.
This test should be avoided for most CRAs, except in the circumstances described below, in section 4.
ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures:. Some standards require the test sample to be aged prior to testing, to 3561-2 the precipitation that might occur during welding.
This means that carbide formation during welding is highly unlikely, and modern CRAs should easily pass one of these tests. Table 1 below shows the various methods for four common standards: SEP also gives guidance on which of its methods apply to which alloys: ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: It does not say what to do about duplex or super austenitic alloys.
There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water 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.
ASTM G28 was designed for nickel-based alloys, and a list of applicable alloys for methods A and B is in the standard. The latter is a German test, but it is often called up in European projects. 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.
Intergranular Corrosion Tests for CRAs
Lso test methods for different corrosion resistant alloys. The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1. 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 36511-2 B is a more aggressive test than method A and is intended for more corrosion resistant alloys, as listed in the document. ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures: Alternatively, a welded test-piece in the as-welded condition may be tested. It can be seen that some 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 36512- and says which alloys should use which test methods as follows:.