Knowing what equipment you need to produce flat products is half the battle
August 2013 - The anticipation and excitement that accompanies prospective buyers when combing the rows of vehicles at a car dealer can be dampened by an overzealous sales pitch. The pressure of the sale can be overwhelming, leaving buyers unsure of what they want—even if they went in with an idea in mind. “If you think about it, a car dealer is going to sell you what he’s got on the lot, not necessarily what you want to buy,” says Al Waigand, vice president, sales and marketing at Butech Bliss, Salem, Ohio.
The same concept applies when deciding between a roller leveling, temper mill or stretch leveling cut-to-length line. All three processes have applications that they are best suited for, depending on what needs to be achieved. It’s important to match a customer’s expectations with the appropriate solution. “Questions we’ve received make it pretty clear to us that there’s a lot of confusion out there as to which option makes the most sense for a particular set of circumstances,” Waigand says.
Sometimes a customer needs a solution that works with an existing piece of equipment. Butech Bliss worked with a temper mill Bedford Heights, Ohio-based Olympic Steel Inc. had already purchased from I2S in Connecticut. “It’s an integral part of this line,” says Terry Rohde, general manager of the Gary, Ind., division of Olympic Steel. “We placed an order for the I2S temper mill and we placed an order with Butech Bliss for everything else [including coordinating the process].”
This most recent addition to the Gary facility brings Olympic Steel’s temper mill cut-to-length line count to three. However, unlike its two prior acquisitions, which did not involve Butech Bliss, this latest purchase was a collaborative effort between the two companies. “This is a $30 million investment and we have experience with this equipment,” says Ray Walker, senior vice president, eastern region, Olympic Steel. “This latest installation started off better than the other two just in terms of getting it going because of the level of cooperation with Butech Bliss and easy learning curve. The automation component of this unit works well.”
The temper mill cut-to-length line was not the first time Olympic Steel and Butech Bliss collaborated on a project. Olympic Steel worked with Butech Bliss to retrofit a rotary shear into the temper mill cut-to-length line at its Cleveland facility.
Olympic Steel’s Gary facility tempers hot rolled and pickled product, offering CQ up to 100,000 minimum yield products and everything in between. With multiple facilities around the United States, the Gary facility is Olympic Steel’s newest location, positioned to better serve customers in the Midwest.
“This is the first temper mill cut-to-length line we’ve added to our arsenal in 15 years,” Rohde says. “This line with new technology from Butech Bliss has outperformed our expectations with regards to shape, corrective leveling and the overall up time.
“We wanted to start this up in 2011, and Butech Bliss did just that,” he continues. Olympic Steel processed its first coil in December 2011, and the machine has met performance expectations as the company accelerated through 2012.
“When we fired it up, we literally started cutting steel that day and kept producing with very little time spent on conditioning,” Rohde says. “When we put up a coil of 1⁄2-inch-thick, 72-inch-wide, Grade 80, it gives a superior performance. The metal is flat with great shape and no stress.”
The Gary temper mill cut-to-length line also was designed with quick-change technology on wear items. The rolls in the levelers are in a cassette so if a roll is damaged for whatever reason, an operator pulls the cassette out, including bottom and top rolls, and pushes the new cassette in. Once calibration settings are adjusted, the machine is up and running in half an hour—a far cry from older equipment that could take more than two days. “It would take one day to tear the machine apart and one day to put it back together,” Rohde says. “This is much quicker. You’re up and running within a couple of hours max.”
Also designed into the line is a Butech Bliss rotary shear that gives Olympic Steel precise, repeatable cuts. “This shear has a similar feature. If a knife is chipped or simply needs to be replaced due to wear-and-tear, there’s a function that ejects the blade, allowing an operator to insert a new one, and they are off and running again in half an hour,” Rohde says.
Butech Bliss offers all three technologies to customers and recognizes each system has strengths and weaknesses. “The key to selecting the solution that is right for your organization should be driven by your end users’ particular requirements,” Waigand says. (See cut-to-length line comparison chart, above.)
Roller leveling cut-to-length lines have long been the workhorse of the industry. Many of these vintage lines are being upgraded by adding new high-performance levelers or are being replaced with lines that include high-performance levelers. These levelers are designed to withstand higher separating forces and have the horsepower and means to transmit more torque to work more of the half-thicknesses of material to achieve successful performance on many laser cutting applications.
According to Butech Bliss, roller leveler cut-to-length lines have low initial costs and low operating costs compared to temper mill and stretch leveling cut-to-length lines and are a good choice for many service centers. However, roller levelers can’t produce memory-free steel or equalize internal stresses like a temper mill or stretch leveler.
Temper mill cut-to-length lines equalize internal stresses by subjecting material to high compressive forces when the mill elongates the strip during the rolling process. This stress-equalized material performs very well during laser cutting because it remains flat, explains Waigand. Temper mills can improve shape by bending the work rolls and also include a roller leveler. In most cases, two roller levelers help improve shape so the finished product can meet increasingly tighter customer standards. These levelers are necessary because mill rolls are bent symmetrically on the mill centerline and cannot work the material in localized areas across the width of the strip like a roller leveler. Temper mill cut-to-length lines require the highest initial capital investment and the highest operating costs of the three alternative types of lines. However, these costs can be offset by higher levels of productivity.
Stretch leveling cut-to-length lines pull the material by gripping both ends of the strip, applying enough force to one of the gripper mechanisms to move the gripper a predetermined distance so the material exceeds its yield point. This process eliminates internal stresses in the material primarily caused by previous rolling mill processes, resulting in memory-free steel. Because of its memory-free characteristics, material performs well when subjected to laser and plasma cutting applications after stretch leveling.
Stretch levelers also improve the shape of the material by reducing strip camber, eliminating coil set, wavy edges and buckles. Because stretch levelers cannot remove crossbow, these cut-to-length lines typically include a flattener or a roller leveler in the line to precondition the strip and to remove the crossbow shape defect.
Unlike temper mill cut-to-length lines and some roller leveling lines, stretch leveling lines are a start/stop operation and do not achieve as high a level of production. However, these lines work for many service centers when market demand for product is limited and high-quality material is needed. They have relatively lower capital and operating costs compared to a temper mill cut-to-length line.
In Olympic Steel’s case, finding the right solution for its temper mill cut-to-length line has allowed it to welcome additional business. “We’ve created relations with new customers because [the company] they were using before couldn’t get product as stress free as they needed,” Rohde says. Customers sent in trial orders, which were produced to meet their expectations. “And we continue to service them today.” MM
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