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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These tests were introduced when the carbon content in CRAs typically hit 0. SEP does not require 6351-2, although it might be required in a specification calling up this standard. 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.
For many alloys, the onset is at 0. This document also points out which alloys the tests are intended for, and recommends the most appropriate test when none is specified. This document describes all three of these tests for four common standards, and describes the differences.
Bend test criteria for several standards. 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. Good material should have a corrosion rate substantially less than the threshold value. Why were these tests designed?
ASTM G28 lists alloys and specifies the test exposure for each.
All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy. The test solutions and exposures for some common intergranular corrosion 3651–2. Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined.
Some suggested criteria for the listed alloys are shown in Table 2, below. The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms. ISO is the most is in terms of defining test methods, and says which alloys should use which test methods as follows:.
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. It can be seen that some alloys fall into two categories, and no guidelines are given for selecting the most appropriate. Samples may be rectangular or cylindrical to suit the test vessel, but where izo bend test is required, it is suggested that the sample be a minimum of mm long.
This means that carbide formation during welding is highly unlikely, and modern CRAs should easily pass one of these tests. SEP method 3 is a special environment only suitable for the Ni-Mo alloys, as described below, in section 4. 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. Table 1 below shows the various methods for four common standards: 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.
Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs! Both of these tests should be followed by water quenching. There are a number of recognised tests 3651-22 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 ASTM G28 does not require samples 6351-2 be heat treated.
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 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. Selection of a Test Method The test methods in Table 1 were designed with specific alloys in 36551-2, but the proliferation of new CRAs has meant that the selection of a suitable test method is isp.
SEP also gives guidance on which of its methods apply to which alloys: The specifications for bend testing are shown in Table 4. Get in Touch Contact us by Phone or Email to find out how we can help your industry. ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures:.
The latter is a German test, but it is often called up in European projects. The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1. 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. ASTM A was designed for austenitic stainless steels, specifically the series alloys.
361-2 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. Suggested test methods for different corrosion resistant alloys.
Intergranular Corrosion Tests for CRAs
ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures: R Baboian, Corrosion Tests and Standards: Sio Tests Table 1 below shows the various methods for four common standards: This test should be avoided for most CRAs, except in the circumstances described below, in section 4. More suitable alternatives are offered in Table 5, below. ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding.