Hello, everyone! How to compare the performance of expanded PTFE gaskets?
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Hello, everyone! How to compare the performance of expanded PTFE gaskets? We use this type of gasket for aerospace polysilicon production; two manufacturers have submitted bids, namely AIG and one company from Shenyang. It’s not possible to tell the difference between these products based on their appearance. Apart from comparing their performance (HG20592 and 4707), what methods can be used to compare their compression ratio and rebound rate? Are there any other ways to make such comparisons? Please give us some advice. We, as manufacturers of these devices, only know how to choose them according to standards; we don’t have any other references. Thank you for your help. Also, the quotes from these two companies differ by 500,000 per ton.
If there are significant differences in the internal quality of such gaskets, they can be distinguished by feel; however, when the differences in internal quality are minor, it is almost impossible to tell them apart based on appearance alone； As LZ mentioned, the difference between the quotes from the two suppliers mainly depends on the source of the material (polytetrafluoroethylene) used by the suppliers, as well as the production scale of the gaskets, among other factors ； It is recommended that LZ find another supplier and get a quote for comparison – after all, it’s better to compare several options! I recommend Zhejiang Guotai Sealing Materials Co., Ltd., a factory that is a member of Sinopec’s Materials and Equipment Department’s resource market (this is not an advertisement! ), the winning bidder for our company’s tender procurement!
Thank you for the answer from above. We had the two gaskets tested at Xi’an University of Technology, and their physical structure and chemical properties are exactly the same. I’m not sure whether this indicates that their mechanical properties are also identical; please give me some advice.
Similar chemical properties do not necessarily mean identical mechanical properties; even if the molecular formula is the same, their chemical structures and arrangements may vary, and mechanical property tests are still required to determine this.
For mechanical properties, you can compare the data on expanded PTFE from other brands. When choosing gaskets, mechanical properties such as compression rate and rebound rate are important to consider; for PTFE, however, what’s most crucial is its creep relaxation (cold flow), as this is the main issue that leads to the failure of PTFE products
I have a question: the expanded PTFE gaskets we purchased for use in saline pipelines leak not from the flange surfaces during pressure testing at 0.4 MPa, but rather from the middle of the gaskets. Is this a characteristic of this type of material? Is it still the issue of substandard material quality?
More experiments can be conducted on the products from these two manufacturers, such as compression ratio, recovery rate, stress relaxation rate, tensile strength, sealing performance, maximum temperature, and maximum pressure. Also, the prices of foreign products are definitely a bit higher than those in domestic markets; they can’t be exorbitant either. In short: as long as it offers good value for money and meets the sealing requirements of the equipment itself, that’s fine!