3520 Phenolic Paper-base Laminated Tube are tube products coated with phenolic resin by insulating wound paper and baked by hot rolling. This product has civil performance, suitable for electrical components in the insulation structure, and can be used in transformer oil.
It indicates that it is flat and does not allow defects such as flaking, air bubbles, or ridges, but it does not allow wrinkles and processing correction marks that do not exceed the allowed thickness of the wall thickness.
The surface is allowed to have a small amount of impurities that do not affect the indicated withstand voltage, slight color unevenness, scratches, and glue marks.
The inner wall allows slight wrinkles and bubbles that do not affect the vertical withstand voltage.
The surface should be coated with a moisture- and oil-resistant insulating varnish. Its color should be natural, usually light brown to red brown.
Standard inner diameter, wall thickness range ,and allowable deviation：
|Wall thickness tolerance|
|1. The wall thickness tolerance of the paper tube with a wall thickness of
more than 25mm is determined by both the supplier and the buyer.
2. Specifications other than the standard size can be agreed upon by the supply and demand sides.
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