The maximum temperature for non-special alloy steel valves generally depends on the specific grade of steel used and the valve's design and application. For most carbon steels commonly used in valve manufacturing, the maximum service temperature typically ranges from about 400°F to 800°F (approximately 200°C to 425°C).
However, it's essential to refer to the specific material specifications (such as ASTM standards), valve manufacturer data, and design parameters because some carbon steels can withstand higher temperatures, while others may not. For applications requiring higher temperatures, special alloys or stainless steel valves may be recommended. Always ensure that the choice of valve material is compatible with both the temperature and the fluid being handled.