Nickel-based steel alloys have high resistance to corrosion, and Hastelloy C22 springs are the best. In addition to outstanding resistance to all manner of pitting and cracking, they are good for chemical environments that might otherwise oxidize the metal.
Copper Beryllium Springs.
Copper beryllium is a precipitation hardened alloy adding 1.6% to 2.0% beryllium into Cu. While maintaining characteristics and corrosion resistance which Cu possesses, copper beryllium shows mechanical properties, fatigue characteristics, and wear resistance comparable to steel.
Development of copper beryllium started in the early part of the 20th century. Used a great deal in computers, copper beryllium has been used for the essential parts of communication equipment, aircraft, cars and cell phones.
Stronger than phosphor bronze for springs, copper beryllium has been applied to switches and connectors for lightweight electronics.
Base alloy containing approximately 4% beryllium is used as the basis of copper beryllium.
Copper beryllium sheet and strip are made into a billet through the vertical type semi-continuous casting process.
Then the billet is hot worked, and then, after removal of the surface oxide layer generated at the hot-working process, is cold-worked repeatedly into coils.
High Modulus Springs.
High modulus spring material is Co base alloy containing 35% to 45% Co or Co-Ni base alloy. Used in spiral springs, superalloys for high modulus springs like elgiloy springs which are cobalt alloy based were originally developed as watch springs. Their chemical composition makes these high elastic springs.
Ni-Ti Shape Memory Alloy Springs and Super-Elasticity.
Shape memory alloys are mainly used for their superelasticity.
Normally strain returns to zero or the original point after unloading. When sufficient stresses are applied to reach tensile yield strength, permanent deformation called plastic strain occurs.
When straining shape memory alloy, elastic deformation occurs at first, then yielding and plastic deformation follows. Shape memory alloy springs can vary their spring constant, provide recovery stress (shape memory effect), or be designed with a high damping capacity, which may be useful in adaptive vibration control.
Titanium Alloy Springs.
The term “Titanium” comes from “Titan” in Greek mythology. Titanium sheet dates from as early as the end of 18th Century but wasn’t used commercially until 1948. Although titanium has a short history as an industrial material, it has excellent strength, lightness and corrosion resistant. Titanium alloy has been widely used for aerospace components.