Regarding corrosion allowance
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This post was last edited by Zhang Junli on 2018-3-30 at 16:08. The set of container drawings indicates a thickness of 10.0 mm and a corrosion allowance of 1.0 mm. But it is 8.8 mm at the time of leaving the factory, with the head and cylinder exceeding the corrosion allowance. Yet the quality certificate states that it is qualified. The supervision and inspection also confirmed it. After making some adjustments, it’s true that the design thickness is no longer visible. How should clause 8.3.11 of the large-diameter standards be understood regarding \"corrosion (and erosion) exceeding the corrosion allowance\"?
The calculated thicknesses for the cylinder and the head are different; the 8.8 you mentioned refers to the head, right?
It seems the question wasn’t explained clearly. The design thickness you mentioned of 10 mm – is that the calculated thickness plus a corrosion margin?
It is recommended to post the calculation sheet for a look
It wasn’t explained clearly. 10mm should be the nominal thickness. 8.8mm should be the thickness after the head is thinned. The marking on the head in the diagram should be 10 (8.8). The most important thing is to carry out calculations: calculated thickness + corrosion allowance + reduction due to plate thinning = design thickness. As long as the design thickness is less than 8.8, then there is no problem.
The thickness indicated on the diagram cannot strictly be called the design thickness; it should rather be referred to as the nominal thickness. In layman’s terms, it is the thickness chosen for the material or the thickness specified in the material selection. Check the design thickness given in the calculation documents to find out its value
This post was last edited by letitbe on 2018-3-28 at 14:42. It was in its pre-corrosion state at the time of production, not after corrosion; what’s unreasonable about a forming thickness of 8.8mm? Has it corroded away before it even started to be used?
Not clear? The design thickness on the drawing is 10.0 mm, and there is no calculation sheet. The factory measurement value stated in the data is 8.8mm
This post was last edited by wanlirn on 2018-3-29 at 15:36. Take a look – what’s mentioned in posts 5 and 6 is quite detailed. The values indicated in your diagram aren’t the design thicknesses as you understand them; without calculation sheets, it’s impossible to determine whether the thickness of 8.8 mentioned in the material specifications for that container is problematic or not. . No, it’s not the design thickness. No, it’s not the design thickness. No, it’s not the design thickness. No, it’s not the design thickness. No, it’s not the design thickness
The question isn’t stated clearly. Does the design thickness you mentioned refer to the same thing as the design thickness specified in GB150? Or the thickness indicated on the diagram? “How should we understand the phrase “in particular, the head will exceed the corrosion margin”? Do you mean that 8.8 refers to the minimum thickness of the head after forming, as specified in the drawings?