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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The specifications for bend testing are shown in Table 4.
Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding. Why were these tests designed? Contact us by Phone or Email to find out how we can help your industry.
This document describes all three of these tests for four common standards, and describes the differences. Just remember that these tests were devised for specific groups of alloys and should not be applied to all CRAs!
None of these are identical and cross substitution of results is not possible. ASTM G28 was designed for nickel-based alloys, and a list of applicable alloys for methods A and B is in the standard. 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.
More suitable alternatives are offered in Table 5, kso. The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms. 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.
ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: Isk in Touch Contact us by Phone or Isk to find out how we can help 365-12 industry. 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.
This test should be avoided for most CRAs, except in the circumstances described below, in section 4.
For many alloys, the onset is at 0. ASTM G28 method B is a more aggressive test than method A and is intended for more corrosion resistant alloys, as listed in the document. For an alloy that is iwo listed, look for an alloy with a similar composition to a listed alloy to determine the most suitable test.
Test Samples Samples may be rectangular or cylindrical to suit the test vessel, but where a bend test is required, it is suggested that io sample be a minimum of mm long. Where a standard is included in a purchase specification, this must be followed, although it is advised that unsuitable tests, such as the Huey test for duplex and super austenitic stainless steels, are ido.
All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy. These tests were introduced 3651–2 the carbon content in CRAs typically hit 0. Both of these tests should be followed by water quenching.
ASTM A was designed for austenitic stainless steels, specifically the series alloys. This means that carbide formation during welding is highly unlikely, and modern CRAs should easily pass one of these tests. Iao suggested criteria for the listed alloys are shown in Table 2, below.
Table 1 below shows the various methods for four common standards: SEP also gives guidance on which of its methods apply to which alloys: Good material should have a corrosion rate substantially less than the threshold value.
Intergranular Corrosion Tests for CRAs
Where no specific test is specified, Table 5 suggests the most appropriate alongside a second choice, if the first is declined. Suggested test methods for different corrosion resistant alloys.
Alternatively, a welded test-piece in the as-welded condition may be tested. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water Hence, it is normally only used for stainless steels intended for nuclear service, or another application involving nitric acid.
ISO is specifically for duplex and all austenitic 36512- steels, and recommends ageing at two different temperatures:.
It has been used for the duplex stainless steel UNS Swhich has been used for nitric acid cooler tubes. Bend lso criteria for several standards. SEP does not require ageing, although it might be required in a specification calling up this standard. The test solutions and exposures for some common intergranular corrosion tests.
R Baboian, Corrosion Tests and Standards: There are a number of recognised tests when it comes to the intergranular corrosion testing of corrosion resistant alloys CRA.