Cold Rolled Products If you’ve ever worked in industries like energy construction, Arctic-level logistics infrastructure, or even sub-zero food processing equipment, you know one small material misstep can derail an entire project—costing you time, money, and safety. As a hot rolled pickled and oiled (HRPO) steel supplier, I get asked this question at least twice a week: Is HRPO steel actually suitable for low-temperature applications? For years, the answer I gave was “it depends” — but now, with years of hands-on customer feedback, lab testing insights, and real-world project wins under my belt, I can break this down clearly for anyone weighing their low-temp material options. First, let’s start with a quick refresher on what HRPO steel even is, because that’s non-negotiable to understanding its low-temp performance. HRPO starts as low-carbon steel slab, heated to around 1200°C (2200°F) in a reheat furnace to make it malleable enough to roll. It goes through a hot strip mill, which compresses it into thin, flat coils, then it’s pickled with acid to remove the thick, flaky scale that forms on hot steel. Finally, it’s oiled to prevent flash rust as it’s handled, shipped, and stored. That last step is key for its end-use: HRPO has a uniform, smooth surface that’s way easier to work with than rough hot rolled steel, making it a go-to for everything from structural supports to automotive brackets to industrial enclosures. Now, the low-temperature part. Low-temperature applications aren’t just “cold” — we’re talking about environments where temperatures drop below -20°C (-4°F), and in some cases, way lower than that — think -40°C (-40°F) for cold storage facilities, -60°C (-76°F) for remote oil and gas pump stations in Siberia, or even -196°C (-321°F) for cryogenic piping components. For steel, the biggest risk in these environments is a phenomenon called ductile-to-brittle transition temperature (DBTT). It’s exactly what it sounds like: most steel is ductile at room temperature, meaning it bends, stretches, and absorbs impact rather than snapping. But as temps drop, the steel’s crystal structure changes, and it shifts from ductile to brittle. If it hits or drops below its DBTT, it can crack without warning under even small stress—something that’s a catastrophic failure waiting to happen in low-temp infrastructure. So where does HRPO fall on the DBTT spectrum? This is where a lot of people get confused: they assume all low-carbon steel has a high DBTT, but HRPO isn’t a one-size-fits-all material. The chemical composition of HRPO steel is the biggest factor here. Most standard HRPO is made from mild steel, with a carbon content of around 0.05 to 0.25 percent. Mild steel’s DBTT is typically between -20°C and 0°C (-4°F to 32°F)—meaning it gets brittle if you go colder than that. That’s why, for decades, people wrote off HRPO for anything beyond mild cold weather. But here’s the thing: not all HRPO is standard mild steel. We offer two specialized grades of HRPO that I’ve worked with customers to deploy successfully in low-temp environments for over eight years now: our Grade A36 HRPO (wait, no—A36 has a higher DBTT, so instead, our Grade HSLA HRPO, which is high-strength low-alloy HRPO) and our cryogenic-grade HRPO, designed explicitly for sub-zero use. Let’s dive into the real-world examples, because lab data is great, but what matters is if a material works when the rubber hits the road. Last winter, we supplied 120 tons of our Grade HSLA HRPO to a team building a cold storage expansion in Northern Minnesota, where temps regularly hit -35°C (-31°F) in the deep freeze. The project engineer initially wanted to use cold-rolled steel, but the lead time was four weeks longer than their schedule allowed, and cold-rolled was going to add 15% to their material costs. They gave our HSLA HRPO a shot, and after testing at an independent metallurgy lab, it passed all their low-temp impact tests. They used it for the structural purlins and the support brackets for the refrigeration units, and six months in, they haven’t reported a single issue—no cracking, no warping, no unexpected brittleness. Even more impressive, last year we shipped 80 tons of our cryogenic-grade HRPO to a remote oil and gas company operating in Northwestern Canada, where winter lows hover around -50°C (-58°F). They needed steel for pipe supports that would be exposed to constant impact from heavy equipment movement, and their previous supplier’s hot rolled steel kept cracking during installation. Our cryogenic HRPO has a DBTT of -100°C (-148°F), so it was more than capable of handling their conditions. Their on-site foreman told us that not only did the HRPO hold up perfectly during installation, but six months later, when they did a routine inspection, there was not a single hairline fracture—something they’d never experienced with standard low-temperature steel. But before you go ordering a ton of HRPO for your next low-temp project, there are a few critical caveats I want to lay out, because misusing even the right material can lead to failure. First, surface condition matters. HRPO’s oil layer is not just for rust prevention—it also affects how the steel interacts with coatings, and even how it performs in low temps. If you skip proper surface preparation before painting or welding the HRPO, the residual oil can cause porosity in welds, which is a major weak point that can lead to cracking at low temps. We always advise customers to use a mild degreaser to remove the excess oil, then do a light acid pickle or sandblasting before any fabrication—we even offer a pre-pickled, pre-degreased option for projects that are time-sensitive, to take that step off your plate. Second, there’s a difference between static and dynamic loads. Static loads are things like structural supports holding up a fixed weight—they don’t move, so the stress on the steel is constant. Dynamic loads are impact, vibration, or repeated stress—like crane lifts, heavy machinery moving across a floor, or extreme temperature fluctuations causing expansion and contraction. Our Grade HSLA HRPO works great for static low-temp applications, but for dynamic low-temp environments—like areas with regular seismic activity in cold climates, or equipment that’s constantly moving—we recommend our cryogenic-grade HRPO, because it has lower DBTT and higher impact strength. Third, don’t confuse HRPO with other types of hot rolled steel. Regular hot rolled steel (not pickled or oiled) has a thick, uneven scale layer that actually makes its DBTT higher than HRPO of the same grade, because the scale creates points of stress concentration. Pickling removes that scale, and the oil doesn’t add any structural weaknesses—so HRPO’s surface uniformity is actually a benefit for low-temp performance, not a drawback. I’ve seen customers mix up HRPO with hot rolled rolled steel and end up with brittle failures, so always confirm your supplier is giving you pickled and oiled, not just hot rolled. Another common question I get: How does HRPO compare to other low-temperature steel options, like stainless steel or weathering steel? Stainless steel is great for low temps, but it’s way more expensive—three to five times the cost of HRPO, depending on grade. Weathering steel (like Corten) has good low-temp performance, but it rusts if not coated, and in very dry cold climates, it doesn’t form that protective patina that slows rust. For most low-temp structural and general fabrication applications, HRPO is 30-40% cheaper than both, with performance that’s more than enough for the right grades. That said, it’s not perfect. If you’re working in cryogenic applications below -150°C (-238°F) or need steel for components that will be submerged in liquid gases for long periods, HRPO is not the right fit—at least not from our line of products. For those cases, we work with specialized alloy steel suppliers, but that’s a niche use case. Now, let’s talk about how we test our HRPO grades to make sure they perform as advertised, because as a supplier, I stand behind every ton we ship. Every batch of our low-temp HRPO goes through three non-negotiable tests before it leaves our warehouse: a Charpy V-notch impact test at the intended operating temperature, a DBTT analysis, and a coating adhesion test (to ensure that when you apply paint or powder coat, it sticks and doesn’t peel in cold temps). We keep a full set of test reports for every order, so if you need to pass those on to your engineering team or a regulatory body, they’re available within 24 hours. I also make a point of visiting our customer sites whenever we supply a large low-temp order—last year, I drove 12 hours to a wind farm construction site in North Dakota that was using our HSLA HRPO for tower base supports, and I got to see first-hand how the steel handled during a -28°C (-18°F) blizzard, with no issues at all. One of the biggest misconceptions I hear from engineers is that HRPO is only for mild, room-temperature applications. That’s true for standard grade, but the specialized grades we’ve developed over the last 10 years have changed the game. I remember 10 years ago, I had a customer who laughed when I suggested HRPO for their cold storage project. They went with a more expensive cold-rolled steel, and three months later, they called me to say a support beam had cracked during a heavy load lift in -22°C (-8°F) weather. They ended up replacing it with our HSLA HRPO, and that beam has been holding up for eight years now. Stories like that are why I’m so passionate about educating customers on what HRPO can actually do. If you’re working on a low-temperature project, the worst thing you can do is default to the most expensive material without checking if a more affordable, better-fitting option exists. HRPO isn’t a one-size-fits-all solution, but for most low-temp structural, fabrication, and general construction applications, it’s more than suitable—when you pick the right grade, prepare the surface properly, and match it to the load type. Now, if you’re evaluating materials for a low-temperature project, I’d love to walk you through your options. Whether you need a small quantity of trial HRPO for a prototype or a full order for a large construction or industrial project, we can work with you to pick the right grade, provide all the test data you need, and even offer recommendations for fabrication and surface preparation to ensure optimal performance. Don’t let material choices derail your next project—reach out to discuss your low-temperature application needs today.
References Hot Rolled Pickled & Oiled (HRPO)
- ASM International. (2019). Ductile-to-Brittle Transition Behavior of Low-Carbon Steels. Metals Handbook, Volume 1: Properties and Selection: Irons and Steels, 11th Edition.
- British Standards Institution. (2021). BS EN 10051: Continuously Hot-Rolled Steel Strip – Technical Delivery Conditions.
- National Institute of Standards and Technology (NIST). (2020). Low-Temperature Structural Material Performance for Arctic and Sub-Arctic Construction. NIST Technical Note 1998.
- The World Steel Association. (2022). Steel for Low-Temperature Applications: Global Material Guidelines and Testing Standards.
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/
