Regarding the thickness of wound gaskets during compression
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Recently, while setting up the database for the PDMS software, it was necessary to specify the thickness of the graphite wound gasket. According to the standard GB/T 4622.2 \"Wound gaskets – Dimensions of gaskets for pipe flanges\", the thickness of gaskets used for flat and raised face flanges is 4.5 mm or 6.5 mm. By default in the software, the gaskets are all assumed to be 3 mm thick. In actual use, after the graphite wound gasket is compressed, will 4.5 mm be reduced to 3 mm? Or will the thickness remain basically at 4.5mm? Thank you.
A compression rate of around 30% will suffice; it’s basically 3 mm.
Additionally, it can go up to 3mm at most; it cannot be less, as the thickness of both the inner and outer rings is 3mm.
The gasket can only compress the protruding wound part; the remaining inner and outer rings cannot be compressed. However, in practical use, this 1.5mm or even smaller error can generally be eliminated through other methods.
For a gasket with an original thickness of 4.5 mm and inner/outer ring thicknesses of 3.0 mm each, an examination of its structure reveals the following: 1. After the flanges are tightened, the thickness of the gasket approaches 3.0 mm or even exceeds it, with the degree of approach depending on the amount of pre-tensioning force. 2. Due to the presence of inner and outer rings, as long as the gasket’s specifications are not excessively large, the likelihood of these rings being compressed is very low; when the pre-tensioning force is sufficient, the inner ring gets embedded in the V-shaped metal strip, and at this location the minimum thickness of the gasket is approximately the sum of the thickness of the inner ring and the thickness of the metal strip； On the outer ring side, it may reach 3.0 mm due to flange deformation and V-belt compression
First of all, the thickness certainly won’t remain unchanged; there is usually some compression. However, it’s hard to say exactly how much, as different manufacturers use different levels of compression. Still, the difference is generally not significant. What the people above said is all correct