High temperature valve selection

Valve operating temperature is 425 ~ 550 ℃ for high temperature Ⅰ (referred to as PI level). The main material of the PI-class valve is the CF8-based "High Temperature Class I Medium Carbon Chromium-Nickel Rare Earth Titanium High-Quality Heat-Resistant Steel" in ASTMA351 standard. As PI is a special designation, the concept of high temperature stainless steel (P) is included here. Therefore, if the working medium is water or steam, the high-temperature steel C5 (ZG1Cr5Mo) may be used for the sulfur-containing oil although the high-temperature steel WC6 (t≤540 ℃) or WC9 (t≤570 ℃) Here we can not call them PI level.