Head thickness
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I have calculated that for DN800, EHA, the thickness of the end cap is 8 mm. So what thickness should be chosen for the steel plate used to manufacture this end cap – 9 mm, 10 mm, or still 8 mm?
Just to be safe, go with 10mm; there will be some thinning during processing!
A thickness can be recommended (taking into account the standard reduction amount), but the manufacturing plant ultimately determines the thickness based on its own manufacturing processes.
If cost is a concern, 9mm or 8mm positive deviation plates can both be manufactured; it depends on your processing techniques and equipment
Choose 10mm to ensure a minimum forming thickness: Note: Steel plates with a thickness of 9mm are generally not available on the market
It is sufficient to indicate the effective thickness or minimum thickness on the drawing. The manufacturer can determine the cutting thickness based on the effective thickness combined with the thinning amount resulting from head pressing. The amount of thinning resulting from spinning and hot pressing for end caps varies, and the degree of thinning achieved by different manufacturers also differs; however, in most cases, adding two millimeters to the effective thickness is sufficient.
It is sufficient to indicate only the nominal thickness and the minimum thickness on the drawings; the actual thickness of the material used is the responsibility of the manufacturer, and it does not need to be considered by the designer. The standard specifies that the machining allowance should be handled by the manufacturer – there is no need for the designer to decide everything; how can a designer know that much? Just like when processing 10 bolts, what thickness of rod to use is the concern of the manufacturing plant; there’s no need to worry about that, as it relates to the production process.
It is sufficient to indicate on the drawing the nominal thickness and the minimum forming thickness of the head.
Mainly, we purchase the steel plates ourselves and process them on our own
The head of DN800 shows virtually no thinning after hot-press forming. When we outsource the fabrication of end caps, as long as the diameter is no more than 1200, they pass the tests after actual measurement (the steel plates used must not have a negative deviation below the specified limit).