Hey there, if you’ve ever spent any time buying or working with steel for projects—anything from custom fabrications to structural parts, appliance components, or even automotive trim—you’ve probably heard the term “cold rolled full hard coils” thrown around a lot. And if you’re here, you’re likely asking a question that pops up all the time from new fabricators, DIYers, and even experienced steel folks: What even is the tensile strength of cold rolled full hard coils? Cold Rolled Full Hard Coils
Let me cut to the chase first, because I know you don’t want to sift through a bunch of jargon when you’re trying to spec material for a job. From what we measure every single day in our warehouse and test from every batch of cold rolled full hard coils we sell, the tensile strength usually lands somewhere between 550 MPa and 700 MPa, which translates roughly to 80,000 psi to 101,500 psi. But wait—before you just grab a coil and go, that number isn’t one-size-fits-all. There are a ton of variables that tweak that range, and that’s what I’m here to break down, straight from the perspective of a supplier who’s been doing this for over a decade, not some textbook that’s 20 years old and hasn’t updated for the way we source and process steel today.
First, let’s back up a little so we’re all on the same page, because “cold rolled full hard” means something specific to the steel industry, even if it sounds simple at first. Cold rolling is basically taking hot rolled steel (which comes out of the mill super hot, way too soft for tight bends or sharp edges) and rolling it at room temperature to squeeze it thinner. That process hardens the steel a lot, right? That’s work hardening, for anyone who’s curious about the science. Now, “full hard” is the temper designation—meaning we cold rolled it enough to get that maximum hardness without any additional annealing or tempering steps after rolling. Compare that to things like “standard” cold rolled steel, which is usually annealed to be more formable, or “half hard,” which is a middle ground. Full hard is all about maximum strength, not formability, which is key for parts that need to hold their shape or resist stretching or breaking under load.
Now, why does that tensile strength range vary so much? The biggest factor here is the grade of steel we’re using. Most cold rolled full hard coils we supply are made from either commercial steel grades like AISI 1008 or 1010, or higher-strength grades like AISI 1012 or even 1015 for jobs that need extra oomph. For example, AISI 1008 full hard usually checks in around 550–650 MPa (80–94 ksi), while AISI 1015 full hard can hit 600–700 MPa (87–101 ksi). If you go with a higher-alloy grade, like a low-carbon high-strength (LCHS) cold rolled full hard coil, you might even see tensile strength creep up a little higher, though we stick to the core grades our customers trust for consistent results.
Another big variable is the thickness of the coil. It sounds counterintuitive, but thinner coils (think 0.4 mm to 1 mm, or roughly 16 to 24 gauge) tend to have a slightly higher tensile strength than thicker ones, like 2 mm to 5 mm (10 to 14 gauge). Why? Because thinner steel gets worked more evenly during the cold rolling process—there’s less material, so the compression from the rollers penetrates more uniformly, leading to a more consistent work hardened structure. Thicker coils take a little longer to process, so the work hardening isn’t as uniform across the cross-section, which can pull that tensile strength range down a bit. We always test every coil we ship, though, so we never send out a coil that’s outside our spec range, no matter the thickness.
Wait, let’s talk about what tensile strength actually means, because I get that a lot of people mix it up with yield strength, and that mistake can cost you a job. Tensile strength is the maximum amount of stress a material can take before it breaks, right? Yield strength is the stress it can take before it permanently bends or stretches. For full hard cold rolled steel, the yield strength is usually around 480–620 MPa (70–90 ksi), so the tensile strength is 10–15% higher than yield strength, which makes sense because that extra stretch before breaking is a safety buffer. If you’re using this steel for something like a structural bracket, you care way more about yield strength (you don’t want it bending under normal load) but tensile strength is critical too—you need to make sure it won’t snap under a sudden overload, like a dropped load or a sharp impact.
I’ve seen so many projects go wrong because someone only looked at the yield strength and forgot about tensile. Last year, we had a fabricator come to us with a custom bracket for a delivery van—they used a half hard coil because they thought it was cheaper, and while the yield strength was fine, the tensile strength was too low. When they tested the prototype, it snapped when they loaded it with just a little extra weight, because the half hard is made to bend, not resist breaking. That’s why being clear about tensile strength is non-negotiable for us—we don’t want our customers learning that lesson the hard way.
Now, let’s get into how we test our coils, because not all suppliers test their material, and that’s a red flag. We send every heat of steel we get to an independent lab for tension testing, following ASTM A1008 standards, which is the industry standard for cold rolled steel. The lab cuts out small, standardized samples from each coil, pulls them in a machine until they break, and records the exact tensile strength, yield strength, and elongation (that’s how much the steel stretches before breaking, which is another important number). For full hard coils, elongation is usually pretty low—around 10–15%, compared to 20–30% for annealed cold rolled steel. That low elongation is why full hard isn’t good for parts that need to be bent a lot; if you try to bend it sharply, it’ll crack, because it can’t stretch that much. But that low elongation is also why it’s so strong—all that work hardening makes it rigid and resistant to breaking, even under high stress.
Another thing that affects tensile strength is the mill we source from. We work with two mills that we’ve trusted for over 8 years now, and they both follow strict quality control. If we ever get a batch that’s even a little outside the spec range, we send it back immediately—we don’t mess around with subpar material. Last year, we had a bad batch from a new mill we tried to source from, and their tensile strength was 10% lower than it should have been. We caught it before it went to any of our customers, but that’s exactly why we test every single coil. You don’t want to end up with a coil that’s labeled full hard but is actually just standard cold rolled, because that’ll fail on your job.
Wait, let’s talk about some common use cases for full hard cold rolled coils, so you can see why tensile strength matters for each. If you’re making appliance parts, like the outer shell of a washing machine or a fridge door, full hard is perfect because it needs to hold its shape, resist dents, and not stretch when you apply pressure. The tensile strength here is key because if it’s too low, a dent will cause the metal to stretch and eventually crack. For automotive trim, like the metal strips along a car’s window or body, you need something that’s strong enough to not bend out of shape during manufacturing or use, and full hard delivers that. Even for things like metal signs or industrial shelving brackets—you need that tensile strength to hold heavy loads without breaking.
A lot of new customers ask us, “Can I get higher tensile strength than 700 MPa?” And the answer is technically yes, but it comes with trade-offs. If you go with a higher-grade cold rolled full hard coil, you might get up to 750 MPa or even 800 MPa, but that steel is much more brittle. Brittle steel is bad because it can crack suddenly under impact, without warning. For most applications, 550–700 MPa is the sweet spot for full hard cold rolled—it’s strong enough for most jobs, not so brittle that it’s dangerous, and easy to work with if you’re using the right equipment (though you do need sharp tools for cutting, since it’s harder than standard steel).
Let me also bust a common myth here: some people think cold rolled full hard is just as strong as hot rolled full hard, but that’s not true. Hot rolled full hard is usually around 450–550 MPa, which is lower than cold rolled. Cold rolling adds that work hardening step that makes it stronger. That’s why cold rolled is preferred for most applications that need high strength and a smooth finish, by the way—hot rolled has that scaled, rough surface, while cold rolled is smooth and has a consistent thickness, which makes it easier to machine or form if you’re careful.
Now, if you’re planning a project and you’re not sure what tensile strength you need, here’s a quick tip for figuring it out. If you’re using the steel for parts that will see a lot of load or need to resist breaking, aim for the higher end of the range—650–700 MPa. If you’re just making small parts that don’t need to hold heavy loads, like thin metal signs or small brackets, 550–600 MPa is more than enough. If you’re working on a custom project, send us your specs, and we can help you pick the right grade. We don’t just sell coils—we help our customers pick the right material, because we know that a good material makes a good project.
Wait, let’s circle back to the original question, because I know some of you skipped to the end for the number. So the short answer: cold rolled full hard coils have a tensile strength of roughly 550 MPa to 700 MPa (80 ksi to 101.5 ksi), depending on the steel grade, thickness, and processing. But the longer answer is that this range is consistent across high-quality coils, and you can’t just take that number at face value—you need to make sure the coil is tested, from a trusted source, and matches your application needs.
I’ve been in this industry long enough to know that buying steel can be overwhelming, especially if you’re new. There are so many terms, grades, and numbers that it’s easy to get confused. That’s why we make it our job to be transparent with every customer. We send along test certificates for every coil so you can verify the tensile strength and other specs, we’re happy to answer any questions you have, no matter how small, and we don’t pressure you to buy more than you need. Whether you’re a small fabricator needing one coil for a custom job or a large manufacturer that orders full truckloads every month, we treat every customer the same.
If you’re ready to talk about your project, need samples, or have more questions about tensile strength, steel grades, or anything else related to cold rolled full hard coils, just reach out. We’re here to help you get the right material for your job, at a fair price, with the consistency you can count on. No hidden fees, no surprise specs, just good steel and good service.
So to recap, the key takeaways: tensile strength of cold rolled full hard coils is 550–700 MPa, that number varies based on grade and thickness, always ask for test certificates, and pick a supplier that actually tests their material (not just guesses). If you keep those things in mind, you’ll never have a failed project because of the wrong steel.
Looking forward to hearing about what you’re working on. Shoot us a message to get the process started.
Hot Rolled Products References:
- ASTM A1008 / A1008M – 21, Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability, and Ultra-High Strength, ASTM International, 2021.
- Kalpakjian, S., & Schmid, S. R. (2014). Manufacturing Processes for Engineering Materials (7th ed.). Pearson Education.
- Cold Rolled Steel Specification and Application Guide, American Iron and Steel Institute, 2019.
Kennen Steel International Co., Ltd.
Address: No. 10, South Road, Area C2, Lecong Iron & Steel World, Shunde District, Foshan City, Guangdong Province
E-mail: info@kennensteelco.com
WebSite: https://www.kennensteelco.com/
