What material are valves designed for low-pressure steam typically made of?

Valves designed for low-pressure steam are typically made of iron due to its strength, durability, and resistance to high temperatures. Iron is capable of withstanding the conditions that low-pressure steam systems create, such as heat and pressure, and provides a reliable barrier to prevent leaks.

In steam applications, the valve needs to maintain integrity against the thermal expansion and contractions that occur with heating and cooling cycles. Iron valves are not only robust but also cost-effective for these types of applications.

Other materials, while they have their uses, are not typically employed for low-pressure steam valves due to various limitations. Plastic, for example, may not withstand the high temperatures and pressures found in steam systems. Brass and copper, while they have some relevant characteristics, are more commonly used in smaller or different applications than what is required for low-pressure steam. Thus, iron remains the preferred choice.