ASTM G_Laboratory Immersion Corrosion Testing of Metals. August 18, | Author: Description. Designation: G 31 – 72 (Reapproved ). Buy ASTM G() Standard Practice for Laboratory Immersion Corrosion Testing of Metals from SAI Global. Offering ASTM G31 corrosion testing + modified tests to fit your needs and budget . Rapid, high-quality service by experts.
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The reporting of nonuniform corrosion is discussed below.
If the influence of heat transfer effects is specifically of interest, specialized procedures in which the corrosion specimen serves as a heat transfer agent must be employed 1. Any necessary distortion of the test conditions must be considered when interpreting the results.
ASTM NACE / ASTMG31 – 12a Standard Guide for Laboratory Immersion Corrosion Testing of Metals
If metallic contamination of the stamped area may influence the corrosion behavior, chemical cleaning must be employed to remove any traces of foreign particles from the surface of the coupon for example, by immersion of stainless steel coupons in asym nitric acid following stamping with steel dies. Molarity and normality are also helpful in defining the concentration of chemicals in some test solutions.
The degree of lateral spreading of pits may also be noted. With a thickness of approximately 3 mm 0. Current edition approved May 1, The values given in parentheses are for information only. Originally approved in The behavior of the specimens in this galvanic couple are compared with that of insulated specimens exposed on the same holder and the galvanic effects noted.
A method of electrolytic cleaning is described in Practice G 1. This cracking occurs under conditions of applied or residual tensile stress, and it may or may not be visible to the unaided eye aastm upon casual inspection. Close attention and a more sophisticated evaluation than a simple mass loss measurement are required to detect this phenomenon. The most common testing periods are 48 to h 2 to 7 days. If there are qstm pits, the average and maximum depths of pits are determined with a pit gage or a calibrated microscope which can be focused first on the edges and then on the bottoms of the pits.
Link to Active This link will always route to the current Active version of the standard. Zstm for chemical cleaning after testing of specific metals and alloys are described in Practice G 1. ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. Therefore, at least duplicate specimens should normally be exposed in each test.
There are a number of other special types of phenomena of which one must be aware in the design and interpretation of corrosion tests. Constant K in Corrosion Rate Equation 3. Masking may also be used to achieve the desired area ratios but may cause crevice corrosion axtm. If clad alloy specimens are to be used, special attention must be given to ensure that excessive metal is not removed. We are a non-profit group that run this website to share documents. A distinction should be made between those occurring underneath the supporting devices concentration cells and those on the surfaces that were freely exposed to the test solution see Guide G Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
However, the calculations must not be based on mass loss except in qualification tests such as Practices Awhich is usually small but on microsections which show depth of attack. A superscript epsilon e indicates an editorial change since the last revision t31-72 reapproval. However, the absence of cracking should not be interpreted as indicating resistance see 4.
Determination of Metal Corrosion Rate by ASTM G31-72. Canadian Laboratory
Preferably, the use of a reflux condenser ordinarily precludes the necessity of adding to the original kettle charge. It is impractical to propose an inflexible standard laboratory corrosion testing procedure for general atsm, except for material qualification tests where standardization is obviously required.
The mechanical property commonly used for comparison is the tensile strength. Excellent references for the use of statistics in corrosion studies include Ref. Care should be used to avoid the removal of sound metal.
ASTM G31-72_Laboratory Immersion Corrosion Testing of Metals
A large surface-to-mass ratio and a small ratio of edge area to total area are desirable. The density in the constant K cancels out the density in the corrosion rate equation. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the astmm of regulatory limitations prior to use. For proper interpretation of the results obtained, the specific influence of certain variables must be considered.