Historically the most widely used material for bellows manufacturing. Good for temperatures up to approximately 300°F (150°C). Usually soft soldered to end fittings.
Somewhat more corrosion resistant than brass. Has slightly greater tensile strength. Usually soft soldered to end fittings. With proper care, may be brazed or arc welded. An excellent choice for many higher volume applications.
Heat treatable. Widely used where maximum stability and life expectancy are necessary. May be brazed and heat-treated after assembly for greatest stability. Maximum operating temperatures should not exceed about 400°F (204°C).
Monel 400 / 404
A copper-nickel alloys with higher corrosion resistance than brass, bronze and beryllium copper. High strength and excellent corrosion resistance in a range of acidic and alkaline environments. Maximum operating temperature about 400°F (204°C). May be brazed, arc or laser welded. Good for applications such as steam traps.
Alloys used for bellows manufacturing include types 316, 316L, 321, 347 and A-286. Excellent tensile strength and corrosion resistance. May be soldered, brazed and welded.
Inconel 600 / 625
High nickel alloys with superior corrosion resistance. Higher tensile strength at elevated temperatures accommodates higher bellows stress change. Not age hardenable. May be brazed, arc or laser welded.
Inconel X-750 / 718
High nickel alloys with excellent corrosion resistance to most media. Has highest tensile strength at elevated temperatures of all bellows materials fabricated by Fulton. May be age hardened before or after assembly. May be brazed, arc or laser welded.
A nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments. May be brazed, arc or laser welded.
Ni-Span C Alloy 902
A nickel-iron-chromium alloy that is precipitation hardenable due to aluminum and titanium additions. The titanium also provided a controllable thermo-elastic coefficient, the alloy’s outstanding characteristic. May be processed to have a constant modulus of elasticity at temperatures from -50 to 150°F (-45 to 65°C). Thorough cleaning of surfaces is necessary for welding, brazing or soldering. Parts are best joined in the heat-treatable condition.
Bellows have been formed successfully from many other materials in small quantities for experimental applications. Included are silver, titanium, and low carbon steel. Experimental work also is continuously being done on new materials.
Fulton’s engineers should be consulted before specifying any special materials.