ASTM G39 PDF

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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To facilitate calculations, a computer can be used to generate a table for a range of strain? Only chemicals appropriate for the given metal or alloy should be used. This procedure is recommended when it is desired to include the effect of surface condition in the test. Hold them in this position by welding the ends together as shown in Fig. 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 1.

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In elevated-temperature tests, make arrangements to re? Thus, the use of the elastically stressed bent-beam specimens for materials evaluation is of limited value.

The inch-pound values in parentheses are provided for information. Once cracking has initiated, the state of stress at the tip of the crack as well 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.

On the other hand, magnitude and direction of residual stresses frequently are difficult to predict and also difficult to measure. The prototype specimen should have the same dimensions as the test specimens and should be stressed in the same way. It is recommended that grinding or machining to a surface? The inch-pound values in parentheses are provided for information. Last previous edition approved in as G39—99 NOTE 2—The double-beam specimen, more fully described in Bend the strips against each other over a centrally located spacer until both ends of the specimens touch.

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A convenient stressing jig is shown in Fig. 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 Note 1.

Since this corrosion site is very close to the point of highest tension stress, it may cathodically protect the specimen and prevent possible crack formation or cause hydrogen embrittlement. This can be accomplished by mounting the specimen holders on appropriate racks and exposing the entire rack to the environment.

Residual stresses are frequently the y39 important, primarily because current design practices and close control of processes have kept operational stresses well below the yield strength of qstm metal in use. From the inner supports the stress decreases linearly toward zero at the outer supports. A specimen thickness of about 0. This prototype should have the same dimensions as the test specimens and should be stressed in the same way. The inch-pound equivalents in parentheses are provided for information.

In these instances metallographic sectioning of the specimen may be necessary to detect cracks. Your comments are invited either for revision of this standard qstm for additional standards and should be addressed to ASTM International Headquarters.

The thickness g9 the specimen is usually dictated by the mechanical properties of the material and the product form available. However, for meaningful interpretation, comparisons should be made only among tests employing crack detection methods of equivalent sensitivity.

Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. The common parameter in these equations is the modulus k of the elliptic integrals.

A double-beam modification of a four-point loaded specimen to utilize heavier materials is described in The awtm is therefore unsuitable for studying the effects of different applied stresses on stress-corrosion cracking or for studying variables which have only a minor effect on cracking.

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It is desirable to remove the required amount of metal in several steps by alternately grinding opposite surfaces. The specimens shall be approximately 25 by mm 1- by in.

Stressed Coupons

In choosing a set of test conditions, it is important that they environment and qstm be well de? 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. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.

A description of such a specimen is given by Wilson and Spier 5. 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.

The stressed specimens then are exposed to the test environment and the time required for cracks to develop is determined. To protect personnel and to prevent specimen loss, drill holes in specimen ends and holders and secure the specimens by wires to their holders.

Stress calculations by this practice are not applicable to plastically stressed specimens. 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.

Inspection of Specimens Permission rights to photocopy the standard may also be secured from the ASTM website www.

Information is available from http: The inch-pound units in parentheses are provided for information. From the contact with the spacer the stress decreases linearly toward zero at the ends of specimens. This excludes corrosion-reduced sections that fail by fast fracture.