The issue of marking the thickness of end caps
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Dear friends, in the design specifications for end caps, there is a minimum forming thickness indicated in parentheses after the nominal thickness. I’m wondering where this value comes from; the design department has different opinions on this, so I’m seeking advice.
The following passage might be helpful to you:
Generally, the thickness is calculated plus a corrosion margin
You can refer to the definition in 3.1.14 of the standard GB150-2011
I still don’t understand. For example, in the specifications for the elliptical head EHA2000X20(18), where does the value 18 come from? Right? The marking that appears on the drawings we have outsourced is not accepted by the personnel on site at present.
For example: when fabricating steel plates by oneself to create an elliptical head with a DN2000 size and a thickness of 10 mm, and there is a reduction in thickness due to processing, how should the numbers in the parentheses be indicated?
What we choose is a thickness that takes into account processing thinning while ensuring strength after molding
The thickness reduction amount for head forming specified in GB/T25198 is too conservative; nowadays, values of around 7% can be achieved. Actually, it’s clearly explained on the second floor: when designing, we usually use the design thickness; if there are openings in the head, we thicken the piping (or add reinforcement rings), as this results in the most economical design drawings. The person on site does not accept the number 18 in EHA2000X20(18); it’s simply that he doesn’t understand it.
EHA2000X20 is the standard head size, but thinning occurs during the spinning process, usually by 10%, in addition to which there is a negative deviation. This value will be written at the end; this notation is specified in the standard
This post was last edited by SDHZZXM on 2017-10-19 at 14:01. A calculated thickness is determined based on the calculated stress, and then a corrosion allowance is added to it to obtain the design thickness, which represents the minimum possible forming thickness...