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 this is done, approximate dimensional proportions shall be preserved. This relationship can be used as a simple check to ensure that the maximum stress does not exceed the proportional limit.

It is most useful for detecting large differences between the stress-corrosion cracking resistance of asm different metals in the same environment, b one metal in atm metallurgical conditions in the same environment, or c one metal in several environments. 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 well as the double-beam specimens.

Relaxation can be estimated from known creep data for the specimen, holder, and insulating materials. Also, it is suggested that specimens be examined for cracks before exposure to the test environment. If it should exceed the proportional limit, the measured de? This practice applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured see Note adtm.

ASTM G39 – 99()_图文_百度文库

Residual stresses are frequently the more important, primarily because current design practices and close control of processes have kept operational stresses well below the yield strength of the metal in use. Once cracking has initiated, the state of stress at the tip of the crack as astn as in uncracked areas has changed, and therefore, the known or calculated stress or strain values discussed in this practice apply only to the state of stress existing before initiation of cracks.


The inch-pound equivalents in parentheses are provided for information. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. NOTE 4—It should be recognized that many plastics tend to creep when subjected to sustained loads. Permission rights to photocopy the sstm may also be secured from the ASTM website www.


However, for meaningful interpretation, comparisons should be made only among tests employing crack detection methods of equivalent sensitivity. It should also be noted that presence of voluminous corrosion products may obscure cracks, thus making a careful examination mandatory. Stress calculations by this practice are not applicable to plastically stressed specimens. To facilitate calculations, a astmm can be used to generate a table for a range of strain?

A specimen thickness of about 0. Support the specimen at the ends and bend the specimen by forcing a screw equipped with a ball or knife-edge tip against it at the point halfway between the end supports in a fashion shown in Fig.

Link to Active This link will always route to the current Active version of the standard. Users of this standard are expressly advised that determination of the validity asm any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.

In sheet-gage bent-beam specimens the de? If stenciling is used for identi? Last previous edition approved in as G39—99 It should be recognized that, at points of contact between specimen and?


Therefore, the use of bent-beam specimens in the plastic range is not recommended for general use.

NOTE 8—If the test is to be conducted in an electrolyte, the spacer shall be made of the same material as the specimen or of an electrically nonconducting material such as glass, ceramic, and so forth to prevent galvanic action between specimen and spacer.

Presence of cracks can be determined with or without optical, mechanical, or electronic aids. This practice is applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured see Note 1.

The advantage of the U-bend specimen is that it is simple and economical to make and use. The inch-pound units in parentheses are provided for information.

All Standards Related to G39

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 xstm or the total elastic stress after applying external stress should be determined by appropriate nondestructive methods, such as X-ray diffraction gg39. Due to high stresses in a specimen, these pieces may leave the specimen at high velocity and can be dangerous. In these instances the critical areas should be packed with a hydrophobic?