Search Back Issues

The Top 25 of Tempering

By on
Growing demand for stay-flat steel has put a spotlight on the small group of processors who have invested in temper mill cut-to-length lines. By Tim Triplett, Editor-in-Chief Manufacturing plants and job shops across the country are adding high-tech cutting machines such as lasers and water jets to improve their productivity and the precision of the parts they produce. To get the optimum output from this computer-controlled equipment, they need to start with steel sheet that is absolutely flat and stays flat when it is cut. This growing demand for stay-flat steel has been a boon for both producers and operators of leveling equipment, notably temper mills, though tempering remains a fairly exclusive club. North America is home to just 25 temper mill cut-to-length lines operated by just 14 companies: SSAB, Steel and Pipe Supply Co., Steel Warehouse Co., Nucor Steel, Cargill (formerly Robinson Steel), State Steel, Norfolk Iron and Metal, Olympic Steel, Central Coil Processing, Feralloy, Ryerson, Nova Steel, Fortacero and Triple S Steel Co. Olympic is now ramping up the nation’s newest temper passing facility in Gary, Ind. (see sidebar), while Steel Warehouse and Triple S Steel Co. are partnering on a new heavy-gauge mill to open in Houston this summer. “We think people are just going to continue to demand better quality steel, and the best steel you can make comes off a temper mill,” says Gary Stein, president of Houston-based Triple S Steel. Norfolk Iron and Metal operates a temper mill at its Norfolk, Neb., headquarters, as well as a line in Rock Island, Ill., also in partnership with Steel Warehouse. “We are seeing greater demand for extremely flat high-strength material. It’s our belief that a temper mill is the best way to handle it,” says Dick Robinson, Norfolk Iron president. “We feel it gives us better quality control than any other means of leveling heavy wide coil. It is the only procedure that helps us meet the quality standards of the future.” Olympic Tempers the Competition Olympic Steel enjoyed one of its most ambitious growth years ever in 2011, from its $156 million acquisition of Chicago Tube & Iron Company to a handful of smaller initiatives across the country. Among its biggest projects was the installation of another temper mill at its newly acquired Gary, Ind., facility. The $30 million mill, located on the west side of U.S. Steel’s Gary Works property, came on line in late 2011. The company has begun accepting orders for temper passed plate as it ramps up to full production later this year. While it is the third temper mill in the company’s portfolio, the new mill differs from previous start-ups in Cleveland and Bettendorf, Iowa. Those were greenfield projects, whereas in Gary Olympic opted to upgrade an older facility purchased from U.S. Steel. The genesis for the project dates back to a 2010 conversation between Olympic’s Chairman Michael Siegal and U.S. Steel’s John Surma. The chairman of the steel company knew Olympic was interested in starting up another temper mill and believed one of a couple sites on the Gary property might work for the project. Olympic ultimately opted for a 177,000-square-foot facility that once housed a U.S. Steel electrogalvanizing line. “We thought this one had the most potential for fitting our needs,” says Raymond Walker, senior vice president of Olympic’s eastern region, who headed up the project. “Tempering in general is driven by people wanting to process higher-strength steels. It’s imperative that the material is flat and stays flat when it gets cut.” Olympic began installation of the temper mill cut-to-length line in June. Designed to handle half-inch plate, 72 inches wide, at grades 50, 80 and 100XL, it includes equipment from I2S, Yalesville, Conn., and Butech Bliss, Salem, Ohio. It is similar to the temper mills at Olympic’s other facilities, but with the very latest systems and controls. The company leveled its first coils on the line in late-December. At full production, the mill will have an annual capacity of 150,000 to 180,000 tons. “We need to work our way through the ramp up and prove the equipment. When we get to the third or fourth quarter, we’ll be running fairly full,” Walker says. Setting up the line in an older building, one that had been idle for three years, had its challenges. Unlike a greenfield site, Olympic had to locate utilities and adapt to existing conditions. “Since this building goes back to the 1960s, there is a lot of history with it. Someone had to find the drawings, dig them out and see who had the institutional memory,” says Walker. On the other hand, the facility paid some unexpected dividends in the form of two 50-ton cranes that came with it. “We thought we were going to have to remove them and start over, but when we fired them up and tested them, we found they were great,” says Terry Rohde, general manager of the facility. “We’re upgrading them, putting remotes controls on them and few other things, but these are million-dollar cranes.” The company will eventually relocate the heavy cranes to the receiving end of the building and install two additional 20-ton cranes for the finished goods side. Olympic is already selling temper passed plate out of the facility, and will eventually add cutting tables for more value-added processing. “In most of our facilities where we have plate products and temper pass, we also have oxyfuel or plasma burning,” Walker says. “Some customers want us to sell them a widget all cut out. That’s the next step.” The Gary mill, a short drive from three interstate highways, will allow Olympic to better serve its existing customers, as well as grow its customer base, Rohde says. Previously, the company served buyers in the Chicago/Northern Indiana region from either its Cleveland or Iowa facilities. “Everyone wants their stuff the next day. If you’re a little closer, you put a little more comfort in your customers’ minds.” The new mill also takes some freight costs out of the equation. “We have a lot of potential new customers who are excited that we’re here,” Rohde adds. “We’re poised for growth in 2012.” Even before they ran the first coil through the new Gary mill, Olympic officials were laying the groundwork for No. 4. The company does not have a specific location picked out yet, although Walker says it will be in the Southeast. It already has an option with equipment manufacturers I2S and Butech Bliss to purchase an identical temper mill for the next location.--By Dan Markham, Senior Editor Paul Labriola at Robinson Steel (now Robinson Laser, East Chicago, Ind.) is widely credited with being the first to temper pass heavy gauge coil into cut-length plate back in the late 1980s. (Cargill acquired Robinson’s temper lines in East Chicago and Granite City, Ill., in late 2009.) Soon to follow Robinson into the market were Steel Warehouse Co., South Bend, Ind., and Feralloy in partnership with U.S. Steel at Burns Harbor, Ind. About a dozen other companies have made the investment in temper mill lines in the two decades since. Why so few? It’s a big commitment. A temper mill cut-to-length line can cost anywhere from $8 million to over $20 million, depending on its features and capabilities, say equipment vendors. Leveling wide high-strength steel in coils up to 1-inch thick calls for tremendous horsepower. Why is it necessary? When hot-rolled steel is rolled, cooled and coiled at the mill, the process introduces undesirable flaws such as coil set, center buckle and edge wave. Such shape imperfections must be removed to produce a high-quality sheet. Conventional roller levelers do a good job of flattening the sheet, but don’t always remove the “coil memory.” Thus when a part is cut from the sheet, it tends to bow or twist as it tries to revert to its original shape. During production, automated cutting heads programmed to travel close to the sheet can actually strike a bent part and damage the equipment. Temper mills level steel by compressing the sheet between two work rolls under enormous pressure with up to 10 million pounds of separating force. Temper passing actually decreases the thickness of the material by 1.5 to 2.0 percent. This process elongates the coil, equalizing its internal stresses, increasing its yield strength and improving its surface finish. Temper pass lines usually incorporate an uncoiler, then a temper mill followed by a roller leveler to produce flat, stress-free material, which is then sheared to the desired length. Roller leveling and temper passing are not the only ways to level steel sheet. Stretch levelers have won many converts in recent years who contend stretchers produce a product comparable to temper passed. Stretch-leveling technology basically works by gripping and stretching the steel with tremendous force to equalize all the internal stresses. At roughly $5 million to $6 million, a stretch level line costs less than half the investment for a typical temper mill, say equipment suppliers. Among the unlikely converts is Steel Warehouse Co., South Bend, Ind., which was an early pioneer in temper leveling and now operates six temper mills. The company is putting a stretch level line in its Milwaukee operation, says CEO Dave Lerman. “Stretchers seem to work well on lighter gauges, not necessarily the super high strengths. The higher the strength, the thicker the material, the more the temper level technology makes a difference.” Which approach is best actually depends on a processor’s customer base. “If you have a market that does not use the super heavy steel, and you don’t have the tonnage to invest in a temper mill cut-to-length line, you do the next best thing. We call it the next best thing because we believe temper mill product is still a bit superior,” Lerman adds. Butech Bliss, a Salem, Ohio, equipment vendor, fabricates all three types of leveling equipment. Like other companies, Butech has run tests comparing the technologies. “The consensus is that temper passed material is the most memory-free. When you put it through a laser burning or punching operation, it stays flat,” says Jock Buta, executive vice president of Butech Bliss. Temper mill lines represent a growth area for Butech and other equipment suppliers. “Part of what’s driving it is a new awareness among users that they can now get this memory-free material, even heavy gauge, which makes their fabrication a lot easier. It’s almost because flatter material is available that more people want it. It’s easier to set up and fixture their parts. It is more predictable, with less variability in cut tolerances,” Buta says. Interest in temper passed material is increasing among users of high-strength or “pipe-grade” steels in particular, Buta says. The stronger the steel, the more difficult it is to level. Another important distinction, he adds: a temper mill produces a smooth, high-quality surface finish, a benefit not achieved by stretcher or roller leveling. Delta Steel Technologies (formerly DBI), an Irving, Texas, supplier of temper mill equipment, also has compared the flatness of temper passed steel to other processes. “We have measured the springback, and the temper passed material was by far flatter,” claims Joe Savariego, Delta president. However, suppliers of stretch leveling equipment, such as Leveltek International, Benwood, W. Va., and Red Bud Industries, Red Bud, Ill., argue that their technology is just as effective at a much lower cost. Dean Linders, RBI’s vice president of sales and marketing, says stretchers and temper mills basically accomplish the same goal: they both apply force that exceeds the steel’s yield through all of the material, top to bottom, relieving the internal stresses. “As long as you can exceed the yield on 100 percent of the material, it doesn’t really matter whether you use a temper mill or a stretcher. They both do a good job,” he says. Most temper mill cut-to-length lines also include a roller leveler to help get the material flat. A temper mill compresses and lengthens the material proportionally, Linders explains, so a coil that starts out with a wavy edge may still have edge wave even after it is tempered. “A temper mill does not necessarily do a fantastic job of getting material flat. That’s why you see a roller leveler after the temper mill to address the side-to-side length differential that produces edge wave or center buckle.” A stretcher, on the other hand, accomplishes both feats at the same time by stretching the material top to bottom and side to side. Linders acknowledges that a temper mill produces a smoother surface. A temper line with a rotary shear also is a faster, more continuous process, whereas stretchers must stop and start as they regrip the material. But he disputes the common belief that stretch levelers cannot handle high-strength heavy-gauge steels. “It just comes down to how big you can build it. It is not a matter of the technology as far as the process goes. If you can build one big enough, there is no limitation.” Red Bud has installed over 30 stretcher level lines since 2003, designed for sheet ranging from 10-gauge all the way to three-quarter inch. “The results are just as good whether we are stretching 10-gauge or three-quarter,” he claims. Today, the company is getting inquiries from customers that want to stretch level metal up to an inch thick. “With hydraulic cylinders, it’s not that hard to produce the stretching force. The trick is being able to grip the material without marking it or slipping when we apply the types of forces we need to stretch it. That’s the challenge,” Linders says. So, what is a service center to do as more and more customers demand flatter memory-free steel? Sourcing it from a competitor with a temper mill is one option. Installing a stretch leveler is another. Or they can bite the bullet and invest in a temper mill cut-to-length line of their own, Savariego says. “These temper mill lines are more obtainable than people think,” he adds. Cleveland-based Olympic Steel is now ramping up its third temper pass line in Gary, Ind. Ray Walker, senior vice president for Olympic’s eastern region, says the latest temper mill equipment can handle high-strength heavy-gauge sheets up to 110,000 min yield, once thought impossible to truly level. Uses for such material include construction and agricultural equipment, cement mixer drums, crane booms, aerial work platforms and other critical applications. Olympic usually temper passes material to fill a particular order, rather than stocking temper-passed plate. It makes more sense to inventory the material in coil form, Walker explains. “For us to turn a coil into a cut-length sheet, it is just a matter of the next day. When it is sitting there in coil form, you can make it any length you need. That provides more flexibility for the customer.” While he declined to discuss the price of temper-passed plate, he noted that sophisticated applications call for sophisticated steel, and customers are willing to pay a premium. A temper mill is a major competitive advantage for its owner, he says. “There are fewer people who can process wide, heavy-gauge, ultra-high-strength steel, have the inventory, and can deliver it on time.” How many temper mills does the market in North America need? No one really knows. Processors say they are taking it one regional market at a time. Some lines are full, others have excess capacity. “A temper mill is a giant investment, probably five to eight times the cost of a regular high-end cut-to-length line, so you have to put tons through it,” Lerman says. “You can’t be in this business in a casual way. If you are not running them pretty hard, you won’t make money with them.” Investing in a temper mill is not for everyone, agrees Robinson at Norfolk. “A temper mill is a significant investment and it demands that you do significant tonnage to make it pay. Right now if you have material you want temper passed, there is plenty of capacity to get it done. Our economy needs to grow a bit.” But demand for temper passed material is on the upswing all over the world, adds Savariego at Delta. “Users need to know that when they put a sheet of steel on that laser, it will produce a true finished part. The only way to do that is with true stay-flat steel,” he says. “It’s an evolution of technology. Eventually it will be a must-have. End customers will come to expect it.”