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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Typical U-bend configurations showing several different methods of maintaining the applied stress are shown in Fig. In addition to the cracking time the following data shall be reported: Depending on the degree of restraint, residual stresses may even exceed the initial yield strength of the material.
3 & 4 POINT BEND FIXTURES – Cortest
Therefore, the use of bent-beam specimens in the plastic range is not recommended for general use. To facilitate calculations, a computer can be used to generate a table for a range of strain?
This equation can be solved by computer, by trial and error, or by using a series expansion of the sine function. It is recommended that grinding or machining to a surface? As noted in 7. In these instances the critical areas should be packed with a hydrophobic? A number in parentheses indicates the year of last reapproval. The specimens shall be approximately 25 by mm 1- by in. Personnel installing and examining specimens should be cognizant of this possibility and be protected against injury.
The applied stress is determined from the size of the specimen and the bending de?
It is most useful for detecting large differences between the stress-corrosion cracking resistance of a different metals in the same environment, b one metal in different metallurgical conditions in the same environment, or c one metal in several environments. Relaxation can be estimated from known creep data for the specimen, holder, and insulating materials. The asmt in an engineering structure can be varied between operational design stresses and residual stresses from heat treatment or fabrication.
Permission rights to photocopy the standard may also be secured from the ASTM website www. A typical atmospheric exposure rack is shown in Fig. In alternate immersion, expose the specimen to allow complete drainage and drying of the surface.
This can be accomplished by mounting the specimen holders on appropriate racks and exposing the entire rack to the environment. At stresses above the elastic limit, but below the engineering yield strength 0.
ASTM G39 – 99(2016)
In elevated-temperature tests, make arrangements to re? To protect personnel and to prevent specimen loss, drill holes in specimen ends and holders and secure the specimens by wires to their holders. By proper choice of holder and insulator materials, however, many plastics can be used, especially in short-time asmt.
These intervals are usually increased as the test progresses because the logarithms of observed cracking times are often normally distributed as described by Loginow 6 and by Booth et al 8. 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. The thickness of the specimen is usually dictated by the mechanical properties of the material and the product form available.
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. An engineering structure, because of residual stresses, is expected to be stressed to its yield strength at some points even if the design stress for that structure is appreciably below yield strength. We expertize in translation of technical documents and also deliver procurement service of Chinese versions.
Calculations for transverse stress or edge-to-edge variation of longitudinal stress are not given; the specimen dimensions are chosen to minimize these stresses consistent with convenient 3 FIG.
3 & 4 POINT BEND FIXTURES
The calculated stress applies only to the state of stress before initiation of cracks. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Due to high stresses in a specimen, these pieces may leave the specimen at high velocity and can adtm dangerous.
For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens. The other quantities are given in It also excludes intercrystalline or transcrystalline corrosion which can disintegrate an alloy without either applied or residual stress.
NOTE 5—In atmospheres gas galvanic action between specimen and holder either does not exist or is con? Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
This prototype specimen should have the same dimensions as the test specimens and should be stressed in the same way.
A detailed discussion is given by Loginow 6. Historical Version s – view previous versions of standard. A specimen thickness of about 0.
The inch-pound values in parentheses are provided for information. A convenient stressing jig is 3g9 in Fig. Advantages of such a notched specimen include the probable localized cracking in the notch and an acceleration of failure.
Although it is possible to stress bent-beam specimens into the plastic range, the astj level cannot be calculated for plastically-stressed three- and four-point loaded specimens as well as the double-beam specimens. For plate material the bent-beam specimen is more difficult to use, because more rugged specimen holders must be built to accommodate the specimens.