Wall thickness reduction rate
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I would like to ask everyone how to determine the wall thickness reduction rate for elliptical heads with a nominal diameter of less than 300. Are there any standards? Urgent! ! Thank you!
The minimum thickness after forming is the nominal thickness of the steel plate minus the negative deviation of the steel plate thickness.
For elliptical end caps with a nominal diameter of less than 300, the wall thickness reduction rate can be obtained by consulting the end cap manufacturing company
For elliptical heads with a nominal diameter of less than 300, a wall thickness reduction rate of 10% is generally sufficient; or consult the head manufacturer.
It is generally related to the technical level of the head manufacturing manufacturer; usually, a margin of 2 can be added when cutting the material
The head standard JB/T4746-2002 provides a reference for the thickness reduction amount. I think the values in the book are still quite high. It is best to consult the manufacturer designated by your factory for the end caps, as the manufacturing capabilities vary among different factories.
In the standard for end caps, JB/T4746-2002, there is a standard regarding the amount of thinning; however, no value below 300 is specified. I would appreciate it if those with more experience could share their insights. We calculate this value at 12%. According to section 8.2.4 of SH3408, which outlines the inspection requirements, pipe fittings must not have mechanical scratches or dents whose depth exceeds 12% of the nominal diameter and is also greater than 1.6 mm. ”There is no specific standard
The thinning process varies from one end cap manufacturer to another
The manufacturing capabilities vary among different manufacturers when it comes to heating and pressing heat-pressed end caps; as a result, the amount of thinning that occurs during processing differs. It is best to stay in touch with the manufacturer responsible for the processing to determine this amount together. Following the values specified in the standards will definitely work fine, as there is a high degree of safety built in.
This post was last edited by ONLY_mage on 2009-5-8 23:10. It’s my personal opinion: when DN is less than 300, pipes are generally used for the cylinders. The prominent part acts as an EHB, similar to a pipe outlet. The seamless pipe fittings standards specify a requirement for the thickness reduction after forming of the pipe caps, namely: the thickness after forming shall be no less than 87.5% of the original thickness. Generally, I choose a large forming thinning rate in my designs. For example, 13%, because at 13% the stress level meets the requirements; therefore, if the manufacturer achieves 12%, it will definitely meet those stress requirements as well