Select the corresponding valve disc based on the medium's acidity/alkalinity, temperature, and other characteristics. Marine butterfly valves primarily use aluminum bronze or stainless steel for their valve discs.

Aluminum bronze discs offer heat resistance and corrosion resistance; suitable for freshwater, seawater, oils, etc.

Stainless steel discs provide high-temperature resistance and corrosion resistance; suitable for freshwater, weak acids, natural gas, steam, etc

Al Bronze Disc	Stainless Steel Disc

Metal seals are mainly suitable for high-temperature and high-pressure environments; under normal operating conditions, soft-seal butterfly valves ensure both fluid flow and sealing integrity.

The following are four commonly used soft seals:

Sealing Material	NBR	EPDM	FKM	PTFE
Operating Temperature	-40℃-93℃	-50℃-135℃	-23℃-200℃	-200℃-180℃
Applicable Media	Freshwater, seawater, weakly alkaline , natural gas, oils	Freshwater, seawater, strong alkali, weak acid, air	Freshwater, seawater, natural gas, steam, oils	Freshwater, seawater, strong alkalis, strong acids, alcohols, steam, oils
Key Features	Oil-resistant	Aging-resistant	High-temperature resistant	Corrosion-resistant, high-temperature resistant
Image Reference

The fit between the valve disc and seal directly impacts fluid sealing performance. When selecting stainless steel or aluminum bronze valve discs, choose based on the medium's properties, temperature, and pressure. Regarding sealing: Metal seals withstand high temperatures and pressures, making them suitable for more demanding operating conditions. Elastic seals have greater temperature limitations but offer more stable sealing performance.