Presented in this report are the results of stress corrosion cracking testing per ASTM G36 (Standard Practice for Performing Stress-Corrosion Cracking Tests in a. austenitic stainless steel was studied in accordance with the ASTM G The samples were unidirectional cold-rolled up to 60 and 90 percent reduction in. Revised ASTM G36 apparatus. This client had been testing stress corrosion- cracking in metal welds by clamping a QVF 2″ glass pipe fitting to his samples.
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Deepest crack found on longitudinal cross-section of bare tube. Quality Assurance Return to Corrosion Testing.
Circumferential cracking of the bare tube test specimen was apparent within the first 8 hours of testing even while the test specimen was on test.
Careful examination is recommended for correct diagnosis of the cause of failure. 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. Crack characteristics were investigated by preparing metallographic sections of the test specimens. The boiling points of aqueous magnesium chloride solutions at one atmosphere pressure as a function of concentration are shown graphically in Fig.
The weld and HAZ of the finned tube appeared to have more cracks than the base metal, and the cracks appear to nearly connect from fin to fin. The boiling points of aqueous magnesium chloride solutions at one atmosphere pressure as a function of concentration are shown graphically in Fig. Materials that normally provide acceptable resistance in hot chloride service may crack in this test.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Photographs of typical appearance of the cracks on both tubes are shown in Figures 1 and 2. It is a method for detecting the effects of composition, heat treatment, surface finish, microstructure, and stress on the susceptibility of these materials to chloride stress corrosion cracking. Historical Version s – view previous versions of standard.
Black lines indicate the approximate location of the outer surface of the tube. See Section 7 for specific ast precautions. No preparation other than deburring and degreasing was performed on the test specimens prior to testing.
ASTM G36 – 94(2013)
Although this test may be performed using various concentrations of magnesium chloride, this procedure covers a test solution held at a constant boiling temperature of It is a method for detecting the effects of composition, heat treatment, surface finish, microstructure, and stress on the susceptibility of these materials to chloride stress corrosion cracking. Corrosion Testing Laboratories, Inc. Referenced Documents purchase separately The asstm listed below are referenced within the subject standard but are not provided as part of the standard.
See Section 7 for specific safety precautions. It is the astmm of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Link to Active This link will always route to the current Active version of the standard. Newark, Delaware USA Accompanying paperwork states that both types of tube were fabricated from the same heat lot of material.
Both test specimens were taken off test at 8 hours for examination at low magnification. This danger is particularly great when small cross section samples, high applied stress levels, long exposure periods, stress-corrosion resistant alloys, or a combination thereof are being used.
A suggested test apparatus capable of maintaining solution concentration and temperature within the prescribed limits for extended periods of time is also described herein. Microphotographs of the deepest cracks found on the mounted sections are shown in Figures 3 and 4.
Revised ASTM G36 apparatus
The aatm may not be relevant to stress-corrosion cracking in polythionic acid or caustic environments. On the finned test specimen, cracks extended down the fins from the outer edge to the tube wall in a direction roughly normal to the tube wall; at the tube wall the cracks extended in a short arc both longitudinally and circumferentially, the arcs stopping before the next fin was encountered.
Return to Corrosion Testing. Two 2 1-foot long pieces of 0. Test procedures conformed to the referenced ASTM test method.
CTL-ASTM G36 – STRESS CORROSION CRACKING in a BOILING MAGNESIUM CHLORIDE SOLUTION
Circumferential cracks with connecting longitudinal b36 in base metal of bare tube. Although this test may be performed using various concentrations of magnesium chloride, this procedure covers a test solution held at a constant boiling temperature of Deepest cracks found on transverse cross-section of finned tube.
However, such correlations may not always be possible. Active view current version of standard. Etching both sections did not reveal any additional crack depth as sometimes occurs in metallographic studies of stress-corrosion cracking.
Link to Active This link will always route to the current Active version of the standard. Regular examination periods for test specimen cracking were scheduled. The test specimens were immersed in the boiling solution and supported using the suggested ladder-back cradles.
It was decided that cracks in the bare tube could be best examined using g336 longitudinal cross-section, while the cracks in the finned tube could be best examined using a transverse cross-section. Cracking of both test specimens was observed, and the tests were terminated.
This leads to the possibility of confusing stress-corrosion failures with mechanical failures induced by corrosion-reduced net cross sections.