8 Common Questions About Cor-ten & Weathering Steel

As a trusted provider of cor-ten and weathering steels, we field countless questions from customers about weathering steel, its properties and how it can be used. Below, we answer 8 common questions about corten steel. 

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What is cor-ten steel? 

COR-TEN® is the U.S. Steel’s trade name for atmospheric, corrosion resistant steel while weathering steel and corrosion-resistant steel are the generic terms.  The name is a combination of its two main features: “cor-rosion resistance” and “ten-sile strength.” Today, while the terms “corten” and “weathering steel” are used interchangeably, COR-TEN® remains a trademarked product of U.S. Steel, but is now only produced in Europe under a license agreement with U.S. Steel. Typically, customers are using the ASTM A606-4/A588/A827/A242 grades when referring to “corten” in the U.S.. Read more

Is cor-ten steel rust-proof? 

Cor-ten steel is allowed to rust in order to form the protective patina coating. While this results in a much lower corrosion rate compared to other steels, it does NOT mean corten steel is rust proof. Read more

How long does it take for cor-ten steel to develop its patina?

Cor-ten, or weathering steel, is silver in its original state – just like standard steel. The rate at which the patina forms depends on the environment the steel is in as well as various factors, such as humidity and proximity to bodies of water. In our experience, the patina forms quicker when the steel is exposed to more environmental cycles. Likewise, cold-rolled materials (18 GA sheets or thinner) form the patina quicker than hot-rolled materials (16 GA sheets or thicker). We documented two samples of corten-equivalent weathering steel over the course of 6 months (December -May ) to illustrate how the patina forms and changes color over time. The smaller square is 16 GA hot-rolled sheet and the larger square is 18 GA cold-rolled sheet. Read more

How long does weathering steel last? 

The lifespan of weathering steel depends greatly on the local climate and the conditions the steel is exposed to as well as how it is used and treated. Climate plays an impactful role in the lifespan of weathering steel and how long it takes for the patina to develop. Under ideal circumstances, weathering steel can last for decades. In fact, properly designed weathering steel bridges have achieved lifespans up to 120 years with minimal maintenance. Read more

Can weathering steel be purchased pre-rusted?

The probably more correct answer is no, and yes! Weathering steel is produced and supplied from producing mills “as rolled,” which means just raw steel — not further treated or pre-weathered and left to develop a patina naturally. Treatments can be applied to accelerate the patina process. If you are working on a smaller scale project, you can expedite the process as described below. If you are working on a larger scale project, there are some companies that professionally pre-weather and seal or just pre-weather weathering steel. Read more

Does climate impact the rate in which weathering steels form a patina?

Yes, the rate at which the protective patina forms varies and depends on the climate the steel resides in. In our experience as a high-strength weathering steel distributor, we’ve found that the patina forms quicker when the steel is exposed to more cycles of wet and dry weather. In more consistent (mostly dry or mostly wet) weather environments, it can take longer for the patina to form. Read more

What’s the difference between hot rolled and cold rolled weathering steel? 

The difference lies in how the material is processed. Hot rolled weathering steel is roll-pressed with additional heat at temperatures above 1,700 degrees Fahrenheit. This step makes the steel easier to form and shape and results in a wider size range. Hot-rolled steel can be prone to shrink, and there is less control over its final shape and dimensions. Cold rolled steel starts off by being processed the same way as hot rolled steel; however, once the steel has cooled to room temperature, it is re-rolled at room temperature. This additional processing results in more precise dimensions and enhanced surface qualities. Read more

What type of welding rod or wire should be used to match the color of weathering steels?

For welding on corten/weathering steels, we recommend our Cor-Match™ products. Cor-Match™ is a weathering steel wire and electrode, which features excellent mechanical properties and serves as a weld metal that matches the corrosion resistance and the patina color of weathering steels. Cor-Match™ 80-CW is a composite, metal-cored electrode for FLAT AND HORIZONTAL welding of weathering steels while Cor-Match™ 810-W is a gas-shielded, flux-cored electrode for ALL POSITION welding of weathering steels. Learn more about our Cor-Match™ products here. 

Contact Central Steel Service for answers to questions about cor-ten and weathering steel

Products > Springs

Stainless Steel Springs

Century Spring offers decades of experience designing and manufacturing many types of stainless steel springs and wire-form products for industries ranging from medical devices to aerospace equipment. Unlike ordinary steel springs, stainless steel springs offer superior performance in preventing corrosion and temperature resistance. They offer this chemical resistance without requiring any additional surface treatments or coatings.

Our vast inventory of in-stock springs and standard parts is available for same-day shipping to deliver your needed parts as quickly as possible. Additionally, our dedicated custom spring development and customer support teams understand the needs of various industries and applications. They can help you navigate design criteria such as spring size, materials, surface finishes, and end types to find your application's optimal spring solution.

Whether you need a small stainless steel spring for a dishwasher or a high-performance, large stainless steel spring for oil and gas drilling equipment, discover how our expansive spring inventories and custom spring design expertise can best serve you today!

Request a QuoteRequest a Custom Quote

We are ready to collaborate directly with you to design stainless steel springs to fit unique applications. Stock stainless steel springs can easily be adapted to suit many customized applications.

We understand that quality and engineering excellence are prerequisites when designing and manufacturing stainless steel springs in critical safety systems. Our manufacturing and quality control systems are fully ISO and AS certified, and all custom products undergo a rigorous first-article, in-process, and final inspection process.

Our state-of-the-art manufacturing technologies feature CAD and CAM tools, allowing us to quickly create digital CAD designs and transfer them to our CNC spring coiling and forming machines for production runs. Our automated production machines and robotics can quickly perform complex multi-axis manufacturing techniques such as spring coiling and forming operations. These capabilities allow us to serve industries that need large volumes of customized stainless steel springs in accelerated development programs.

Custom Stainless Steel Spring Manufacturing Capabilities

We offer customization options for a custom stainless steel spring that includes outer diameters, wire diameters, free length, spring rate, end types, or tighter tolerances. We can even offer custom options to fit your application's load and deflection requirements.

While a 300 series stainless steel spring can meet the corrosion resistance requirements of most applications, we also offer additional stainless steel alloys, such as 17-7PH, as custom options to provide protection in the most demanding environments, such as marine applications and within oil and gas drilling equipment.

Furthermore, we proudly offer exotic, high-performance stainless steel alloys as customization options, including 316LVM, Duplex, and super Duplex stainless steel alloys. Duplex alloys derive their name because they comprise two metallurgical phases- austenite and ferrite while super duplex contains higher quantities of chromium, nickel, and molybdenum. Furthermore, 316LVM is a type of 316 stainless steel alloy that has undergone a secondary melting process during ingot production that provides a microstructure that provides additional crevice corrosion and pitting resistance. All three of these exotic, custom stainless steel spring alloys offer superior corrosion resistance and strength compared to 300-series stainless steel springs.

No matter your custom spring needs, we are ready to partner directly with you today to bring your custom springs to life. We are committed to minimizing total development time on every custom project, passing the time savings on to you as reduced procurement lead times.

Request a Custom Quote

Stainless Steel Springs Characteristics

In general, stainless steel springs are known for their corrosion resistance compared to carbon steel springs. They provide all the benefits of carbon steel springs, such as elasticity, strength, and excellent corrosion resistance. They also have excellent fatigue resistance under repeated cyclic loading. Together, these properties make stainless steel springs durable and low-maintenance spring options, even when exposed to moisture and corrosive fluids.

Furthermore, stainless steel springs feature a smooth, nonporous surface finish, making them easy to clean and not requiring frequent surface cleanings. They do not accumulate bacteria or other pathogens and are biocompatible, meaning they do not react with bodily tissues. These advantages make them popular choices for medical and food processing equipment applications.

Stainless steel springs are highly cost-effective and are not significantly more expensive than comparable carbon steel springs.

How to Select a Stainless Steel Spring

In general, selecting a stainless steel spring starts with determining whether you need a spring with additional corrosion resistance. Next, you should evaluate the level of corrosion resistance you need and choose 316-alloy stainless steel if you need further protection. Lastly, consider whether you need a custom high-strength stainless steel alloy, such as 17-7 PH or Duplex.

You should then consider your stainless steel spring's geometric properties and how they fit your design requirements. For example, stainless steel compression springs are defined by the following critical geometric properties: Free Length, Outer Diameter (OD), Wire Diameter, and Spring Rate.

For more information on how to select springs, including stainless steel springs, that fit your application, check out our dedicated guides for each spring type:

Compression Springs Extension Springs Torsion Springs

The company is the world’s best Spring Flat Steel supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Typical Tolerances

Stainless Steel spring tolerances depend heavily on the exact spring type and geometry. As such, we have performed extensive empirical studies, which we have used to develop tolerance equations for different manufacturing techniques. We have combined these with the best industry standards to create general tolerance ranges for stainless steel spring types and geometry, which can be seen below.

Typical Tolerances:

• Wire diameter +/- 0.-0.001"
• Body diameter +/- 3-10%
• Free Length +/- 2-5%
• Loads and Rates +/- 10%

- Block tolerances do not apply to spring manufacturing

However, spring-specific tolerance calculations are complex and, as such, are fully integrated into our design and manufacturing automation software.

If you contact our design team today, we will gladly walk through spring-specific tolerance values with you to provide general tolerance values for your spring type and geometry!

Dimensions Measurement Guide

Using compression springs as an example, you can quickly obtain all of the relevant dimensional properties of your stainless steel spring by measuring it with calipers at the following locations.

1. Outside Diameter: Hold the spring on the outer surfaces between your fingers and use calipers to measure the outside of the coil to measure the compression spring's Outside Diameter (O.D.).

2. Wire Diameter: Use your calipers to measure the wire that forms the spring's helical shape to find the Wire Diameter. To be sure of the measurement, you should measure the wire diameter at both ends of the spring.

3. Free Length: Place the entire length of the uncompressed spring between your calipers to measure its Free Length.

4. Total Number of Coils: Place the spring flat on its side and count the total number of coils on the spring. Be sure to include even coil portions in your total count. (See the diagram for an example).

For more information about the Dimensional properties of all kinds of springs, check out our dedicated guides, tailored to each spring type:

How to Measure a Torsion SpringHow to Measure a Compression Spring

Where Stainless Steel Springs Are Used

If you know where to look, you can find stainless steel springs almost anywhere.

As detailed previously, they are prevalent in applications that demand a spring to be chemically inert with surrounding environments and materials, such as Medical Devices, surgical instrumentation, auto-injector syringes, and biomedical implants. For this reason, they are also used in food-grade processing equipment and machinery.

They can be found in dozens of critical Aerospace Safety Systems, the most recognizable being control surface actuation systems, which are the movable parts of the aircraft’s wings and tail that allow the pilot to maneuver the plane.

They are also used in numerous Automotive Components, such as engine valve springs, which facilitate the precise timing required for internal combustion engines.

Finally, stainless steel springs are also integrated into many springs are integrated into many household appliances and consumer products, such as dishwashers, door locks, and air conditioners.

FAQs About Stainless Steel Springs

Are stainless steel springs magnetic?

All stainless steel springs have a small degree of magnetism, imparted during the cold-forming processes used to wind the coils. However, the magnetism of stainless steel springs is far less than that of other spring steel alloys.

What are the primary advantages of passivated stainless steel springs?

The chromium oxide surface layer is the chemical mechanism that provides corrosion resistance. This surface layer prevents additional oxygen from reacting with the iron below. Passivating is a secondary chemical process that increases this surface layer to ensure it is sufficiently thick and unbroken. As such, it is strongly recommended for springs that will be subjected to highly corrosive mediums.

What is the difference between stainless steel alloys (300/302 and 316)?

Alloy 300/302 is a general-purpose stainless steel with good corrosion resistance in applications with light exposure to water or mildly corrosive mediums. In contrast, 316 stainless steel has more corrosion resistance against a wide range of fluid medium applications, which is why it is the favored alloy for medical and food-grade applications.

How else are stainless steel springs different from carbon springs?

It’s important to note that all 300 series stainless spring steels generally have slightly lower tensile strengths than high-carbon spring steels. The difference may not be consequential, but the designer should know the differences during the early phases of spring design.

Contact Information

Contact us directly today, and allow our experts to resolve all your questions and guide you to one of our in-stock stainless steel springs that will fit your application.

If you need immediate assistance, you can always reach us at our dedicated line to speak directly with our team: 800-237-.

We are ready to provide comprehensive engineering support from your earliest design stages to final product approval.

Request a Quote and Consultation

We can also help you shop many different custom spring types and configurations commonly available used in stainless steel springs and determine whether a custom design would better suit your application.

Simply Request a Custom Quotation so we can partner with you to customize a stainless steel spring for your unique application.

Once we hear from you, our design team will follow up with a quote for a custom solution and be happy to answer any follow-up questions you may have.

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