Anodizing of aluminium and aluminium alloys-Assessment of resistance of anodic oxide coatings to cracking by deformation

GB/T 12967.5-1991 Deformation method for evaluating the crack resistance of anodic oxide films on aluminum and aluminum alloys. GB/T12967.5-1991 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Anodizing of aluminium and aluminium alloysAssessment ofresistance of anodic oxide coatings to cracking by deformation
Anodizing of aluminium and aluminium alloysAssessment ofresistance of anodic oxide coatings to cracking by deformationGB/T 12967. 5--91
This standard is equivalent to the international standard IS03211-1977 "Assessment ofresistance of anodic oxide coatings to cracking by deformation for anodizing of aluminium and aluminium alloys".
1 Subject content and scope of application
This standard specifies the empirical method for testing the crack resistance of anodic oxide films by deformation. This standard is mainly applicable to the inspection of thin anodic oxide films with a thickness of less than 5 um on the surface of the plate. 2 Principle of the method
The specimen is bent on a simple device with a certain spiral. The device should have a certain radius of curvature and a scale value. Determine the maximum radius of curvature when the oxide film of the sample shows rupture during the bending process, and use this value to calculate the percentage curvature of the sample. 3 Device
The test device is shown in the figure below.
Approved by the State Administration of Technical Supervision on June 4, 1991 and implemented on March 1, 1992
Example 1:1.7
12967.5-91
Clamping Butterfly
Rubber Frame
Figure 1 Measuring Instrument Structure
Note: 1. Two screws are used to fix the end points of the sample; 2. The steel model is spirally installed on the wooden platform and has a scale value of 1 to 18. Each scale value corresponds to a radius of curvature. The conversion formula is: R=21-E
Where: .-·Radius of curvature,
F—scale value.
The relationship between the radius of curvature and the scale value is shown in the following table: e
English tightening screw
Scale value
Test steps
4.1 Sample
GB/T 12967.5--- 91
Radius of curvature R
Scale value E
Dimensions of the anodized sample × b × h, mm: 250 × 20 × 5 (maximum thickness). 4.2 MeasurementbZxz.net
Fix one end of the sample at the position of the scale value of 18 with the clamping screw, and the effective surface of the sample faces outward. 4.2.1
Radius of curvature R
4.2.2 Bend the sample gradually along the spiral direction. The sample should be bent in a manner close to the measuring instrument. Finally, fix the other end of the sample with the second screw.
4.2.3 Mark the minimum scale value corresponding to the position where the crack appears on the anodized sample. 4.2.4 During measurement, if the crack is difficult to observe, the sample can be immersed in 20g of copper sulfate pentahydrate (CuSO·5H.0) at a temperature of 20℃, hydrochloric acid (p1.18g/mL) and distilled water 1000mL for 5 minutes, and then re-installed on the device to record the minimum scale value corresponding to the position where the crack begins to appear.
Result expression
The percentage curvature of the anodized sample is represented by A, and the calculation formula is as follows: A
Where: sample thickness, cm;
radius of curvature, cm.
Test report
The test report should include the following contents:
This standard number;
Results and the expression method used;
Some abnormal phenomena encountered during the test;100a
Operation methods and other issues not included in this standard, (2)
Additional remarks:
GB/T12967.5—91
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by Northeast Light Alloy Processing Plant. The main drafters of this standard are Gao Kangzhi and Wang Ziyi. 468
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