Valve Materials and Elastomers

Carbon Steel

Carbon steel is commonly used for steam, hot water, condensate, thermal oil and general industrial services. It is suitable for relatively high temperatures, but low-temperature service and corrosive fluids require specific verification.

Stainless Steel

Stainless steels are selected when corrosion resistance, fluid cleanliness or low-temperature operation is required. The choice between 304, 304L, 316 and 316L should consider the fluid, chloride content, temperature and welding requirements.

Cast Iron and Ductile Iron

Cast iron and ductile iron are mainly used in water, HVAC, cooling, heating and general utility networks. Their use in steam, thermal shock or severe mechanical loading applications should be carefully evaluated.

Brass and Bronze

Copper alloys are mainly used in smaller sizes, water, air, utility services and selected marine applications. Chemical compatibility and dezincification resistance should be checked in aggressive waters or corrosive environments.

Elastomers for Butterfly Valves

In butterfly valves, the elastomer seat is often the limiting selection factor. The metallic body may be mechanically suitable, while the elastomer may be unsuitable for the fluid, temperature or operating mode. Chemical compatibility must always be verified.

Practical Material Selection Logic

In real engineering work, material selection should not start from an equivalence table. It should start from the operating conditions. The table is used to confirm standard equivalents and narrow down the acceptable options.

1. Define the fluid: water, steam, condensate, air, natural gas, oil, sea water, chemical or food product.
2. Define pressure and temperature: not only nominal values, but minimum, maximum and start-up conditions.
3. Check material compatibility: body, disc, stem, seat, gaskets and elastomers.
4. Check applicable standards: EN, DIN, ASTM, ASME, pressure-temperature rating, flanged connection, welded ends or threaded connection.
5. Check operating mode: on/off, throttling, operating cycles, water hammer risk, differential pressure and flow velocity.

Important Engineering Notes

• Material temperature limits do not automatically mean that the valve is suitable over the full pressure and temperature range.
• Pressure-temperature ratings from the applicable valve standard and manufacturer data must be checked for pressure equipment.
• Elastomers often have a narrower operating range than the metallic body and may define the actual valve limit.
• Steam, hot water, thermal oil and chemical services require compatibility confirmation before final selection.
• EN / DIN / ASTM equivalence is useful, but should not be considered full interchangeability without checking chemical composition, mechanical properties and the applicable manufacturing standard.

Related Equipment

Philippopoulos S.A. supplies valves and equipment for industrial and marine systems, including butterfly valves, ball valves, globe valves, check valves, control valves, steam traps, pressure reducing valves, safety valves, strainers, separators and boiler house equipment.