5 Jul 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. ABSTRACT It is common practice to perform intergranular corrosion testing in accordance with ASTM (1) G28 on solid solution nickel alloys, e.g. UNS N . 13 Apr ASTM G – Designation: G 28 – 02 Standard Test Methods of Detecting Susceptibility to Inter.
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All bend tests require a tensile test machine or similar, with suitable grips and sufficient strength to bend the strongest alloy.
Figure 1 shows a sensitized microstructure, where the darker f28 grain boundaries have a decoration of precipitates. Description of the test.
Selection of g2 Test Method The aatm 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.
ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows: 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. Log in to your subscription Username. The exception to this is ASTM G28 method A, where rates for the onset of intergranular corrosion are described in reference 1. Bend test criteria for several standards.
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 atsm below, in section 4.
Warning statements are given in 5. Mixed Acid-Oxidating Salt Astk. In the case of nickel-rich, chromium-bearing alloys, the test method may be applied to wrought and weldments of products.
Good material should have a corrosion rate substantially less than the threshold value. Some suggested criteria for the listed alloys are shown in Table 2, below. Get in Touch Contact us by Phone or Email to find out how we can help your industry. The most convenient size is asmt a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms.
Applicability of ASTM G28 Testing – OnePetro
More suitable alternatives are offered in Table 5, below. However, there are necessarily limitations in the potential applicability of standard tests because the mechanism of corrosion in the service environment may be different than that targeted in the standard test, due to the difference between the actual service environment and the test solution. Hence, it is normally only used for stainless steels intended for nuclear service, or another application involving nitric acid.
Invia la tua richiesta. Sheriff’s Encyclopedic Dictionary of Applied Geophysics, fourth edition.
Corrosion Materials – ASTM G28 test
The susceptibility to intergranular corrosion in wrought, nickel-rich and chromium-bearing alloys can be detected by measuring the mass loss of the test pieces. SEP also gives guidance on which of its methods apply to which alloys: Proceedings of an international conference Oceanology: These regions will exhibit a lower resistance to the initiation of corrosion in the ASTM tests, and this is where the intergranular corrosion begins. However, the ASTM standards acknowledge that the environments that the material will experience in service are likely to differ from those of the test methods, in which case the corrosion performance could be different.
None of these are identical and cross substitution of results is not possible.
Description of the phenomenon. Make an Enquiry Notice: The effect of post wstm surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water The test method is not applicable to cast products.
ASTM G28 test
Method A requires to immerse aztm specimens in a ferric sulfate-sulfuric acid solution, while the solution described by Method B consists of mixed acid-oxidating salt including sulfuric acid, hydrogen chloride, ferric chloride and copper chloride. The specifications for bend testing are shown in Table 4.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures:.
When a test has been selected, follow the detailed directions in aztm standard for making up the test solution, the preparation of test samples and the finish to be used.
ASTM G28 does not require samples to be heat treated. Nickel-rich, chromium-bearing alloys to intergranular corrosion may be subjected to intergranular corrosion, due to severe service conditions.
This document describes all three of these tests for four common standards, and describes the differences. It does not say what to do about duplex or super austenitic alloys. Conducting the Tests When a test has been selected, follow the detailed directions in that standard for making up the test solution, the g82 of test samples and the finish to be used.
The Tests Table 1 below shows the various methods for four common standards: For many alloys, the onset is at 0.