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.
|Published (Last):||17 September 2016|
|PDF File Size:||15.7 Mb|
|ePub File Size:||14.15 Mb|
|Price:||Free* [*Free Regsitration Required]|
Sheriff’s Encyclopedic Dictionary of Applied Geophysics, fourth edition.
ASTM G28 test
Both of these tests should be followed by water quenching. Description of the test Description of the phenomenon Test methods Pictures Request a quote. This document also points out which alloys the tests are intended for, and recommends the most appropriate test when none is specified.
Advanced search Show search help. ISO is the most rigorous in terms of defining test methods, and says which alloys should use which test methods as follows:.
This test should be avoided for most CRAs, except in the circumstances described below, in section 4. The test solutions and exposures for some common intergranular corrosion tests.
The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N, N, N, and N 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.
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.
R Baboian, Corrosion Tests and Standards: 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. ISO is specifically for duplex and all austenitic stainless steels, and recommends ageing at two different temperatures:.
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. The ASTM G28 test methods A and B are utilized in many industries as quality control tests in order to assess the resistance to intergranular corrosion of various stainless steels and nickel-based alloys, such as Alloy and Alloy Corrosion, caused by grain boundary precipitation phenomena, could be related to the chemical composition or the thermomechanical processing of the material.
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. Nickel-rich, chromium-bearing alloys to intergranular corrosion may be subjected to intergranular corrosion, due to severe service conditions. ASTM G28 lists alloys and specifies the test exposure for each.
Some standards require the test sample to be aged prior to testing, to simulate the precipitation that might occur during welding. 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 queried.
For many alloys, the onset is at zstm. The most convenient size is often a cylinder 10mm diameter by mm long, but other dimensions are possible to suit particular product forms.
Rock Mechanics Symposium and 5th U. The effect of post weld surface treatments on the corrosion resistance of super duplex stainless steel welds in sea water The precipitation of such chromium-rich or molybdenum-rich particles often carbides usually also leads to regions depleted of Cr or Mo surrounding the precipitates. Method A requires to immerse the 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.
Intergranular Attack Testing – ASTM G28 – Colorado-Metallurgical-Services
SEP method 3 is a special environment only suitable for the Ni-Mo alloys, as described below, in section 4.