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Standards Related to G39 – G G Standard ASTM Standards Related to Corrosion Testing of Metals · Annual Book of ASTM Standards Online: Hello everyone, I am looking for ASTM G39 – 99() Standard Practice for Preparation and Use of Bent-Beam Stress- Corrosion Test Specimens. Please. ASTM G39 – 99() – 弯曲梁应力腐蚀试验试样制备和使用标准规程.

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However, if many cracks are present, a change in shape may not be apparent. Only chemicals appropriate for the given metal or alloy should be used.

ASTM G39 – 99(2016)

asmt The applied stress is determined from the size of the specimen and the bending de? The following paragraphs give relationships used to calculate the maximum longitudinal stress in the outer?

If this condition occurs, either eliminate the crevice or consider a different kind of specimen. This cracking time is used as a measure of the stress-corrosion resistance of the material in the test environment at the stress level utilized.


For instance, the loading bolt can be supplanted by a spring or deadweight arrangement to change the mode of loading. This prototype specimen should have the same dimensions as the test specimens and should be stressed in the same way. In elevated-temperature tests, make arrangements to re? Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress before applying external stress or the total elastic stress after applying external stress should be determined by appropriate nondestructive methods, such as X-ray diffraction 1.

It should also be noted that presence of voluminous corrosion products may obscure cracks, thus making a careful examination mandatory.


ASTM G39 – 99()_图文_百度文库

In alternate immersion, expose the specimen to allow complete drainage and drying of the surface. Once cracking has initiated, the state of wstm at the tip of the crack as well as y39 uncracked areas has changed, and therefore the known or calculated stress or strain values discussed in this method apply only to the state of stress existing before initiation of cracks.

For more specific safety hazard information see Section 8 and Corrosion 14, 11 p. Residual stresses are frequently the more important, primarily because current design satm and close control of processes have kept operational stresses well below the yield strength of the metal in use.

The specimen is most easily made from strip or sheet but can be machined from plate, bar, castings, or weldments; wire specimens may be used also.

Information is available from http: The bent-beam specimen is very well suited for establishing the relative merits of several alloys for the relative severity of several environments.

In these instances metallographic sectioning of the specimen may be necessary to detect cracks. Testing at nominal or design conditions could be misleading.

Although it is possible to stress bent-beam specimens into the plastic range, the stress level cannot be calculated for plastically-stressed three- and four-point loaded specimens as asm as the double-beam specimens.

Since this corrosion site is very close to g3 point of highest tension stress, it may cathodically protect the specimen and prevent possible crack formation or cause hydrogen embrittlement. At stresses above the elastic limit, but below the engineering yield strength 0.

For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens. NOTE 6—The double-beam specimen, described in In immersion tests, arrange the specimens so as to prevent contact with each other.


The actual bending stress there will be greater by a concentration factor dependent on the 3g9 geometry, than the minimal test stress, and generally, may be expected to be in the range of plastic stain. Chemical or electrochemical treatments that produce hydrogen on the specimen surface must not be used on materials that may be subject to embrittlement by hydrogen or that react with hydrogen to form a hydride.

Laboratory test data for carbon and low-alloy steels have been found to correlate with? For plate material the bent-beam specimen is more difficult to use, because more rugged specimen holders must be built to accommodate the specimens.

However, bent-beam Practice G39 or direct tension Practice G49 specimens are normally used to study stress-corrosion cracking g9 strip or sheet under elastic strain only. The inch-pound equivalents in parentheses are provided for information.

Support the specimen at the g9 and bend the specimen by forcing a screw equipped with v39 ball or knife-edge tip against it at the point halfway between the end supports in a fashion shown in Fig. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens.