Problems with on-site metallographic testing of containers
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For the high-temperature container, on-site metallographic testing is planned to check whether the microstructure has deteriorated. The material is Alloy 625, and the operating temperature is 400 degrees. Should the testing be done on the side in contact with the medium, or can both the inner and outer surfaces be tested? If it is difficult to access the container for operation, is metallographic inspection of the outer surface effective? Thank you!
I have never seen regular inspections of containers being carried out on their inner surfaces.
If there is enough time (for example, 3 to 5 years), the outer surface will become fairly representative~~~~~
Could you explain it in more detail? After all, the medium does not come into contact with the outer surface, and time elapsed is not necessarily a relevant factor; sometimes it’s not just temperature that plays a role.
That is because the inspectors do not take corrosion into account. There are cracks, but they are not visible on the outer surface.
Generally, inspections should be carried out on the welds inside the container; in cases where such conditions are not available, inspections can be done on the outside as well. However, if defects occur inside the container at an early stage, they are difficult to detect. Some of our equipment cannot be stopped, so ultrasonic emission testing is used for non-destructive inspection on the outside of the container
It seems that your organization places a great deal of emphasis on and follows strict standards in testing.
Metallography should be examined not only on the inner surface but also at the areas with the highest temperatures.