Problems with asbestos gaskets or metal wound gaskets! ?
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We often use these two types of gaskets, but disputes arose during their use. Have asbestos pads been phased out? And when we use metal wound gaskets, testing for leaks with soapy water results in leaks occurring quite often. And when asbestos gaskets are used, there is less leakage. Some people say that when using metal wound gaskets, one shouldn’t tighten the screws too much, as this can cause leaks! Will this situation occur? How should this gasket be used to reduce the chance of leakage?
You can check the relevant specifications. These two types of gaskets are generally used under different conditions; the main difference lies in their cost. Metal wound gaskets are more expensive. Here we usually use them for media such as steam, as they provide good sealing performance and it’s possible to tighten them further in case of leaks. Asbestos gaskets are typically used for water, low-pressure applications, and certain types of oils; they are cheaper, and metal is used in their production
These days, metal wound gaskets or graphite gaskets are generally used instead; asbestos gaskets have been largely phased out. They might still be used in low-pressure water systems, but asbestos gaskets are too troublesome to repair
The only advantage of graphite gaskets over metal gaskets is their lower cost; however, they are not recommended for use. Even in industrial water pipelines, leaks occur after just a short period of time (after 2 years), and it is very difficult to prepare the flange surfaces when replacing them. In our factory, a new employee once spent an hour cleaning a flange surface while replacing an asbestos gasket of DN25 size during a major maintenance task； As mentioned by the original poster, if a metal wound gasket leaks during testing, this issue can be resolved by tightening the bolts to prevent leakage.
Due to their different applications, metal gaskets are more commonly used in steam pipes.
We also use more metal wound gaskets; replacing asbestos gaskets is too troublesome. The advantage is their lower cost