Custom Maraging Steel Springs

Coiling Technologies is a certified custom industrial spring manufacturer. We create custom sizes for a variety of springs with applications in heavier industries, such as military or oil & gas. Our springs have proven to be effective and high-quality through years of usage in harsh conditions.

Whatever the demand, Coiling Technologies will meet it with the highest performance parts, made from the best materials, such as Maraging C300 and C350. We produce products for industrial use, so we make sure our springs are reliable and durable.

Maraging Steel Spring Features & Benefits

Maraging steel springs are carbon-free iron-nickel alloys with the addition of cobalt strengthen steel (C-type), molybdenum, titanium, and aluminum. Maraging steels belong to the category of ultra-high-strength materials which have excellent toughness properties. C300 grade has tensile strength properties up to 300 Ksi and C350 is up to 350 Ksi while still retaining excellent ductility.

The main benefit of this material is that it is an easily shaped hard steel containing many other useful properties.

Technical Specification Maraging C300 Maraging C350
Nominal Composition  

Ni:18.0 - 19.0
Co: 8.5 - 9.5

Mo: 4.6 - 5.20

Fe: Balance

Ni:18.0 - 19.0
Co: 11.5 - 12.5

Mo: 4.6 - 5.20


0.289 lb./in3, (8.0 g/cm3)

0.292 lb./in3, (8.1 g/cm3)

Modulus of Elasticity (E)

27.5 x 106 psi

29 x 106 psi

Modulus of Rigidity (G)

10.6 x106 psi

11.2 x 106 psi

Coefficient of Expansion

5.6 µin/in.-°F (70°F to 900°F)

6.3 µin/in.-°F (70°F to 900°F)

Electrical Resistivity

68.5 µΩ.in, (174 µΩ.cm)

68.5 µΩ.in, (174 µΩ.cm)

Thermal Conductivity

176Btu-in/ft2hr-°F, (25.3 W/m-K)

176Btu-in/ft2hr-°F, (25.3 W/m-K)

Min Size



Max Temp

482oC (900oF)

482oC (900oF)

Uses of Maraging Steel Springs

It is resistant to crack propagation and used in aircraft or high-performance racing springs

C350 alloy is heavier and harder than C300 due to higher amounts of Cobalt. Used in high end military applications, such as, recoil springs for heavy guns.

Maraging C300 & C350 Spring Applications

Maraging steel is commonly used in military defense applications and high-performance gears and shafting. Our springs are used as valve springs in oil pumps, firearms parts, and torsion springs in aerospace equipment. Maraging steel springs are used frequently when there is a need for a high strength-to-weight ratio. Applicable standards for Maraging Steels are MIL-S-46850D,

Applications for these springs include:

Industries Using Maraging C300 & C350 Springs

Coiling technologies springs are used in many industries from military defense to the automotive aftermarket. Nearly any industry with heavy equipment or large applications can benefit greatly from our high strength, temperature resistance springs.

Some other common industries we serve:

Types of Springs Coiling Technologies Offers:

What Sets Coiling Technologies Apart?

Coiling Technologies works to create custom springs to meet every demand in your industry. From custom small and large coils, to a wide variety of materials and options to choose from, we can help you create the exact springs you are looking for!

Coiling Tech’s experienced team will be happy to help, contact us today.