Introduction to Spring Materials
Often overlooked by designers and end-users, spring material sometimes takes a backseat to other design considerations. However, spring material is a critical design consideration because it defines many spring properties, such as the behavior of the spring under loading and within operational environments. Today, we will discuss the differences and uses of steel springs, such as high-carbon, stainless steel, and alloy steel. We will also profile other metallic spring materials, such as nickel and copper alloy spring steels, which offer unique advantages tailored to demanding applications.
If you can grasp the specific uses of each spring material, you will understand how to select a spring that meets your application's unique requirements at the right price. Let’s dive in further and discover the nuances of spring material.
High-Carbon Spring Steels: Versatile and Cost-Effective
High-carbon spring steels derive their name because they have a relatively high percentage of carbon (approximately 0.6%-1.0%) used as alloying ingredients compared to ordinary low-carbon steel. The additional carbon increases the strength and durability of the spring when compared to low-carbon steel spring counterparts.
Common High-Carbon Steel Springs
High-carbon steel is commonly called music wire in the spring industry. Music wire springs are fabricated from high-carbon, tempered steel. Tempering steel is a process where the metal is heated up to half its melting point and then cooled in ambient air in a controlled process. Tempering increases the ductility of the spring steel, allowing high-carbon springs to operate under heavy loads for extended periods of operation.
Another important high-carbon spring steel is oil-tempered high-carbon steel. Similar to ambient air tempering, oil tempering involves heating the steel. Next, the steel is rapidly quenched in oil, as the name denotes. This fast, cost-effective heat treatment adds fatigue resistance and allows the spring steel to maintain strength at elevated temperatures.
Where High-Carbon Steel Spring Can be Found
High-carbon steel springs can be found in many automotive mechanisms, such as the compression springs used in suspension systems. High-carbon steel springs are excellent value springs that can be specified to fit a wide range of general-purpose mechanical applications and offer reliable performance.
Stainless Steel Springs: Strength and Corrosion Resistance
Stainless steels contain additional alloying elements in higher concentrations than carbon. Chromium, Nickel, and sometimes Molybdenum are added to achieve excellent corrosion resistance under the most extreme operating environments because the chromium forms a protective oxide layer on the surface of the stainless steel.
Common Stainless Steel Spring Materials
Most stainless steel springs are fabricated from 302, 304, 316, or 17-7 PH alloys, which are differentiated by varying Nickel, Chromium, and Molybdenum compositions. Furthermore, 17-7 PH alloy stainless spring steel undergoes a precipitation-hardening heat treatment to achieve additional strength and hardness.
Stainless steel springs offer superior performance in preventing corrosion compared to ordinary steel springs. As a bonus, they offer this chemical resistance without requiring additional surface treatments. Stainless steel springs also maintain strength at elevated temperatures.
Where Stainless Steel Spring Can be Found
Stainless steel springs can be found in applications that still demand a spring to be chemically inert with surrounding environments and materials. As such, they are commonly used in medical devices. For example, compression springs are found in surgical instrumentation, auto-injector syringes for drug delivery, and even biomedical implants.
Alloy Spring Steels: Enhanced Durability for High Stress
Alloy Steels get their name simply because they are alloyed with more than one element. You may see other terms like “low” or “high” alloy steels. High alloy spring steel contains total alloying ingredients that comprise more than 8% of the steel’s composition. In contrast, low-alloy steel contains small concentrations of total alloying elements (typically around 5%).
Common Alloy Steel Spring Materials
Chrome Silicon spring steel contains Chromate and Silicon as alloying ingredients. During the processing of this alloy, the spring steel is cold-drawn into a wire and heat-treated to achieve excellent strength and resistance to high temperatures. Additionally, alloy steel springs like chrome silicon spring steel are excellent at resisting shock loading and cyclic fatigue failure.
Where Alloy Springs can be Found
Alloy spring steels are widely used in aerospace components because they possess excellent fatigue resistance against cyclic loading. For example, alloy steel torsion springs are engineered into dozens of safety-critical systems, including various aerodynamic control surfaces such as ailerons and wing flaps that maintain aircraft stability during flight.
Copper-Based Alloys: Electrical Conductivity and Flexibility
Copper spring steel properties are valued because of properties that set them apart from the other steel springs mentioned here. They are valued for their electrical conductivity, non-magnetism, and good corrosion and wear resistance properties.
Common Copper Alloy Spring Materials
As the name indicates, Beryllium Copper springs are fabricated from a copper-beryllium alloy. It is a standout high-strength copper-alloy spring material because it is a good electrical conductor and is corrosion-resistant.
Phosphor Bronze springs are copper alloyed with tin and small amounts of phosphorous. The tin increases the corrosion resistance and strength of the bronze, while the phosphorus adds additional wear resistance. This way, phosphor bronze and beryllium copper springs are highly corrosion and wear-resistant.
Where Copper Alloy Springs can be Found
Copper springs are used in many electrical applications, such as battery contacts, switches, and relays. Specifically, the tapered barrel compression springs are great copper-based springs used in electrical switches. The barrel shape adds stability, making them great for electrical buttons and switches.
Nickel-Based Alloys: Advanced Applications and High Resistance
Nickel-based alloy spring materials contain nickel as the base element and large quantities of other elements such as chromium, molybdenum, or even titanium.
They have high strengths and are heat-resistant, meaning they can maintain strength at extremely high temperatures. They are also corrosion-resistant, even in the most severe chemical environments. As such, they are the highest-performing spring material for performing in the most demanding mechanical environments.
Common Nickel-Alloy Spring Materials
Eligiloy (common name: Phynox) is an age-hardened nickel-based alloy that contains cobalt. Monel is a common nickel-based alloy spring material that contains a large percentage of copper as an alloying ingredient. Inconel is another notable nickel-based alloy comprised of over 50% nickel and around 25% Chromium. Hastelloy is another notable nickel-based note alloy containing additional molybdenum as an alloying ingredient. All nickel-based spring materials have high strengths under extremely high temperatures and pressures.
Where Nickel-Alloy Springs can be Found
Nickel-based spring materials are commonly found in the engines of heavy machinery used for excavation and construction. They are typically custom-specified for valve springs within large machinery engines. They are used in mechanical components within nuclear power generation equipment.
Century Spring’s Expertise in Material Selection and Custom Solutions
Century Spring specializes in stock and custom springs as a quality-first manufacturer, and we have springs available in the spring materials detailed above. We offer rapid turnaround, shipping, and delivery on over 40,000+ in-stock designs available to ship today!
Don’t see the spring you need in stock? Century Spring offers custom design and fabrication services for advanced materials such as alloy and nickel springs. Our team of highly skilled engineers is ready to help you design the perfect spring and help you select spring material that will meet the unique challenges of your application.
We always work quickly to minimize total development time so you can move on to tackling the next design challenge. Don’t waste any more of your valuable design time today; let our spring design experts take the lead!
At Century Spring, you always get the spring you need when needed! Century Spring is ISO 9001 certified, and all parts are always Made in the USA.