What are the valve body, valve core, and valve seat of a valve? What are the materials? How to choose materials

Generally speaking, I’ll provide a simple selection method for our company: 1. The valve body is usually coated with nylon or paint. 2. The valve disc is made of stainless steel, while the valve seat is made of EPDM (ethylene propylene diene monomer rubber); it can be used with media such as water and alkalis. This mainly depends on the corrosivity to stainless steel; however, in the case of hot water – such as condensate – a valve seat that can withstand high temperatures is required. 3. The valve disc is made of stainless steel coated with EPDM, while the valve seat is made of EPDM; it can be used in applications requiring corrosion resistance, such as those where stainless steel would be susceptible to corrosion. 4. The valve disc is either TFL-coated or made of TFL material, while the valve seat is also made of TFL; it is suitable for use in highly corrosive environments such as those with hydrochloric acid. In China, people usually opt for direct TFL treatment, which involves a head-on approach and results in a shorter lifespan. Rubber spraying offers better results, but it’s expensive and subject to import restrictions, such as the case with Keystone products. It depends specifically on the medium used by your company.