Custom Oil Tempered Springs
Coiling Technologies manufactures custom springs made from oil tempered wire per ASTM A229. It is one of the most common material grades used for large wire spring production, where higher loads and larger springs are required. ASTM A 229 oil tempered wire, also known as “OT,” is commonly used where static applications are required and lower stresses are encountered. While they are commonly referred to as “oil tempered springs," the accurate terminology is oil tempered wire springs. They are commonly used in a myriad of industrial light-duty applications. However, we can manufacture oil tempered springs for any type of application. Contact us today to request a quote!
There are two types of oil tempered wire: Class 1 and Class 2. The Class 2 wire is typically utilized where a higher tensile strength is required. Class 1 material is used for low stress and static applications. It is also more commonly used in applications where electroplating is required and can reduce the risk of hydrogen embrittlement occurring in higher hardness pre-tempered materials like the Class 2 grade or even higher hardness grades like Chrome Silicon ASTM A 401 or high tensile Music Wire ASTM A 228. Oil tempered wire is used across all sectors of industry, from agricultural machinery to transportation. Common in automotive, construction, and heavy machinery applications, oil tempered springs hold their shape under repeated stress in some of the most demanding applications.
CTI produces custom, oil tempered springs in various configurations, including compression, extension, and torsion springs in various shapes and sizes. We can offer shaped oil-tempered wire options that include square, rectangular, and keystone shapes for die springs, wave springs, and wave washer applications. We produce these springs for small businesses and large OEM manufacturers globally. With our advanced cold coiling and wire forming capabilities, we can meet the customers’ exact specifications and tolerances.
Coiling Technologies maintains strict control over material selection and sources the vast majority of its materials domestically. However, our strategic partners include premium material suppliers from the EU, South Korea, and Japan. Our quality management system ensures consistency across all volume levels. Our custom manufacturing process supports tight production timelines without compromising the accuracy or repeatability of the product.
Along with oil tempered wire, Coiling Technologies stocks high-tensile chrome silicon ASTM A 401, ASTM A 1000, ASTM A877, and chrome vanadium ASTM A 231, ASTM A 232 pre-tempered materials to meet high-stress dynamic applications as well as higher temperature demands for specialized applications.
Technical Specifications and ASTM A229 Compliance
Oil tempered ASTM A229 wire is a nominal composition of Carbon 0.55% - 0.85% with a Manganese presence of 0.60% - 1.20%. This specific type of spring wire comes in a pre-hardened state. At the mill, the material is hardened and tempered to produce the desired mechanical properties. It is then typically coated with light oil to prevent corrosion during storage and provides lubricity on the tooling during the coiling process.
The wire diameters range from 0.020” to .625” (1.0 to 16 mm). The wire’s surface is typically dull, mottled gray or black, in contrast to the bright finish you find on fine music wire ASTM A228.
| Technical Specification | Oil Tempered |
|---|---|
| Nominal Composition |
C: 0.55 - 0.85 Mn: 0.30 – 1.2 Fe: 98.29 |
| Density |
0.284 lb./in3 |
| Modulus of Elasticity (E) |
29 x 103 ksi |
| Modulus of Rigidity (G) |
11.6 x 103 ksi |
| Electrical Resistivity |
170 µΩ.cm |
| Thermal Conductivity |
361 Btu/(hr/ft2/in/°F) |
| Min Size |
0.020 in (0.500 mm) |
| Max Temp |
150oC (300oF) |
| Uses |
It can be used for applications that are exposed to constant loads such as garage door springs |
Oil Tempered Torsion Springs, Extension Springs, and More
Coiling Technologies manufactures various types of springs using oil tempered wire. These springs are engineered to control force and movement in industrial equipment. Oil tempered wire is favored for applications with static loads with relatively lower stress levels, but where the ability to withstand fatigue resistance is key. The choice of spring type depends on the specific application and the type of force it needs to handle.
Our different spring types include:
- Torsion springs: primary function is to store and release energy through a twisting motion, generating torque.
- Extension springs: store energy and exert a pulling force between two mechanisms, attempting to bring them back together when separated.
- Compression springs: mechanical device that stores energy when compressed and releases it when the load is removed, returning it to its original shape.
- Suspension and isolation springs: serve to ease the effects of vibration, but they do so in different contexts: suspension springs primarily for ride comfort and vehicle control, and isolation springs for protecting equipment and structures from vibration.
Why Choose Coiling Technologies for Oil Tempered Wire Springs?
Coiling Technologies is a Houston-based Spring manufacturer serving industrial and OEM clients across the US. We engineer and produce custom oil tempered wire springs built to your exact specifications.
Our springs support critical applications across several demanding industries, including oil and gas, aerospace, military, automotive, and heavy equipment.
Unlike mass-production suppliers, we focus on engineered solutions tailored to each client’s design, material, and performance goals.
Request a Quote for Custom Oil Tempered Springs Today
If you need custom oil tempered springs built to meet complex dimensions, Coiling Technologies is ready to deliver. Our team works directly with engineers and procurement professionals to manufacture large, high-performance springs for critical applications.
Use the form on this page to submit your requests, or request a quote to get started. For immediate questions or consultation, contact us here.
Custom Oil Tempered Springs FAQs
What is oil tempered spring wire?
Oil tempered wire, shortened to OT in the trade, is a carbon steel spring wire supplied in a pre-hardened state. The mill hardens and tempers the material to the required mechanical properties before it ships, then coats it in light oil to prevent corrosion during storage and to lubricate the tooling during coiling. CTI manufactures oil tempered springs per ASTM A229. The published composition is 0.55 to 0.85 percent carbon with manganese from 0.30 to 1.2 percent and iron at 98.29 percent. Surface appearance is a dull, mottled gray or black rather than the bright finish of music wire.
What are oil tempered springs used for?
Oil tempered wire is one of the most common material grades for large wire spring production, where higher loads and larger springs are required. It suits static applications at relatively lower stress, and the published use example is components exposed to constant loads such as garage door springs. Industry use covers agricultural machinery, transportation, automotive, construction, and heavy machinery. CTI produces compression, extension, torsion, and suspension and isolation springs in oil tempered wire, plus shaped wire in square, rectangular, and keystone profiles for die springs, wave springs, and wave washer applications.
What is the difference between Class 1 and Class 2 oil tempered wire?
Class 2 wire carries higher tensile strength and is used where stress levels demand it. Class 1 serves low stress and static applications. Class 1 is also the preferred grade where electroplating is required, because it reduces the risk of hydrogen embrittlement compared with higher hardness pre-tempered materials such as Class 2, chrome silicon ASTM A401, or high tensile music wire ASTM A228. If your part will be plated, name the class and the plating process on the drawing so material selection and the post plate bake get planned together.
What is the maximum service temperature of an oil tempered spring?
The specification table lists 150 degrees C (300 degrees F). That sits above plain carbon 1050 at 200 degrees F but well below the 425 degrees F published for chrome vanadium and the 500 degrees F published for AISI 4161. Oil tempered wire is a pre-tempered carbon steel with no alloy addition to resist softening, so sustained service near the top of its range shows up as load loss on a spring held at fixed deflection. For warmer service, chrome vanadium or chrome silicon is the next material step.
What wire sizes are available in oil tempered material?
Minimum size in the specification table is 0.020 in (0.500 mm), and the published wire diameter range runs 0.020 in to 0.625 in (1.0 to 16 mm). Above 0.625 in the material changes character entirely, moving to grades such as 5160H, 4161, 6150, and 51CrV4, which arrive without a mill temper and must be heat treated after forming to reach optimum tensile strength. That crossover point is worth identifying at design time, since it changes the process route, the achievable tolerances, and the inspection plan for your part.
Does oil tempered wire need heat treatment after coiling?
A full quench and temper is not required, because the mill already hardened and tempered the wire to its mechanical properties. What the spring does need is a stress relief after coiling to reduce the residual tensile stress that cold forming leaves on the outer wire surface, stabilize free length, and limit set on first loading. Fatigue sensitive parts benefit further from shot peening after stress relief. CTI performs heat treating and shot peen in house with advanced cold coiling and wire forming capability, so both operations stay under one ISO 9001:2015 quality management system.
How should an oil tempered spring be protected from corrosion?
The mill oil on the wire prevents corrosion in storage only, not in service. Oil tempered wire is plain carbon steel with no corrosion resistance, so a spring going into humid, outdoor, or washdown conditions needs a coating, a metallic conversion process, or electroplating. Powder coating is available in house at CTI. Where plating is the requirement, Class 1 material lowers the hydrogen embrittlement risk and prompt baking after plating is still necessary. Springs facing genuinely corrosive environments, extreme temperature, or repeated dynamic shock loading belong in a different material class.
Where does CTI source oil tempered wire?
Coiling Technologies maintains strict control over material selection and sources the vast majority of its material domestically, with strategic partners among premium suppliers in the EU, South Korea, and Japan. Alongside ASTM A229 oil tempered wire, CTI stocks high tensile chrome silicon ASTM A401, ASTM A1000, and ASTM A877, plus chrome vanadium ASTM A231 and ASTM A232 pre-tempered material for high stress dynamic and higher temperature work. The quality management system holds consistency across volume levels, and material certifications with chemistry and mechanical property data are available with the order.
