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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SEP does not require ageing, although it might be required in a specification calling up this standard. For alloys not 365-12 in this standard, it will be necessary to carry out some tests on material in various conditions to determine the threshold.
The specifications for bend testing are shown in Table 4. The latter is a German test, but it is often called up in European projects. ASTM A was designed for austenitic stainless steels, specifically the series alloys.
Methods B and E are suggested for all grades of series austenitic alloys, while method F is suggested for cast type alloys. Good material should have a corrosion rate substantially less than the threshold value. R Baboian, Corrosion Tests and Standards: Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined.
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. This test should be avoided for most CRAs, except in the circumstances described below, in section 4.
These tests were introduced when the carbon content in CRAs typically hit 0. SEP method 3 is a special environment only suitable for the Ni-Mo alloys, as described below, in section 4.
It does not say what to do about duplex or super austenitic alloys. It can be seen that some alloys fall into two categories, and no guidelines are given for selecting the most appropriate. 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. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water The test solutions and exposures for some common intergranular corrosion tests.
Intergranular Corrosion Tests for CRAs
For many alloys, the onset is at 0. Alternatively, a welded test-piece in the as-welded condition may be tested. The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1.
This document also points out which alloys the is are intended for, and recommends the most appropriate test when none is specified. 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.
Why were these tests designed? More suitable alternatives are offered in Table 5, below. Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs! The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms.
ASTM G28 lists alloys and specifies ido test exposure for each.
SEP also gives guidance on which of its methods apply to which alloys: The Tests Table 1 below shows the various methods for four common standards: ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows:.
ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures: Bend test criteria for several standards. ASTM G28 was designed for nickel-based alloys, and a list of applicable alloys for methods A and B is in the standard. ISO is the most rigorous in terms of defining test methods, and 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.
It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes.
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. 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. This document describes all three of these tests for four common standards, and describes the differences.
ASTM G28 ido B is a more aggressive test than method A isl is intended for more corrosion resistant alloys, as listed in the document. Ios 15 hours is a difficult test period in practice, and is only a minimum, conducting the test for 20 36651-2 overnight means that the two tests are equivalent.
Get in Touch Contact us by Phone or Email to find out how we can help your industry. 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. All bend tests require a tensile test machine or similar, with suitable grips 36512 sufficient strength to bend the strongest alloy.
Make an Enquiry Notice: Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding. Suggested test methods for different corrosion resistant alloys. ASTM G28 does not require samples to be heat treated. There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA.