Coil Processing
Wednesday | 31 October, 2012 | 12:19 pm

Memory-free tension leveling

By Nick Wright

With new lines, steel suppliers expand gauge range, take control of scrap

October 2012 - When processing light- and heavy-gauge steel coils into strips, cutting lead times for just-in-time orders and accounting for all scrap is a one-two punch for efficiency. By addressing those aspects, topped off with integration of multiple features, a company can be reassured it’s running a tight ship.

As of mid-September, service center Del Metals, Brampton, Ontario, was wrapping up the final acceptance tests for the commissioning of its new rotary shear tension leveling cut-to-length line, manufactured by Alcos Machinery Inc., Newmarket, Ontario. Del Metals wanted a North American-sourced line that would expand its range of lighter-gauge products up to 

10 gauge steel with a maximum yield strength of 100,000 psi. Its existing tension leveler processes heavier material, up to 18 gauge, 72 inches wide.

Previously, Del Metals was outsourcing some of its lighter-gauge processing, says Paul LeGendre, vice president of sales and procurement at Del Metals. Del Metals wanted to capture that light-gauge business and bring it in-house. “Alcos had the best solution relative to our needs that we’re looking for, and it helps that they’re local,” LeGendre says.

“We’re a company that believes in reinvesting money on equipment and inventory, and that led to investment in this line,” he says. “We’re letting our customers know we have the capability to be cost competitive on the lighter material.”

Del Metals’ current customer base includes construction, as well as agriculture, mining, light manufacturing and fabrication, and truck transportation. The line will help Del Metals serve those industries and new ones. The procurement and installation goes back about four years because growing in difficult economic times has been challenging, LeGendre says.

Del Metals has an existing stretcher leveler that removes memory from heavy-gauge coil, but it wanted the same capability “so we had stress-free product regardless of gauge,” LeGendre says. “That’s a big selling point. Everything has to be flat and stress free because the end user may laser cut, plasma cut, bend or shear the metal.”

Multiple features

Tension leveling is similar to stretcher leveling in that the strip is stretched beyond its yield point to remove all memory. However, tension leveling lines typically accomplish this faster and run continuously from the uncoiler directly into the stacker.

The line is set up for continuous, high speed, high-output production runs, says Hasan Albulak, president of Alcos. It has a continuous maximum speed of 300 feet per minute. If the shear is cutting 3-foot pieces, Del Metals can complete 100 pieces per minute. “Our line doesn’t stop, so you don’t have any possibility of scratching the material,” Albulak says. “Today’s material is very surface-critical.”  

A normal sheet stacker could not handle volume associated with continuously incoming sheets, Albulak says. To overcome this, Alcos included its four-arm continuous servo stacker, which operates in two different modes depending on the material. When processing the heavier-gauge material, the stacker operates with the high-speed revolving servo-controlled stacker arms. 

For light-gauge material, the stacker assembly rises and works with its integral air flotation system, which floats the sheets onto the stack. The stacker’s damping system protects the sheet edges and discharges a perfect stack out of the line. The stacker is fitted with an automated pallet loading conveyor for seamless pallet changeover.  

Albulak says today’s customer wants memory-free steel. If a processor is using only a leveler as a correctional method, memory will remain. The tension leveler comprises a series of entry and exit bridle rolls, each consisting of four large diameter bridle rolls. The large entry and exit bridle rolls, coated in polyurethane, keep material from slipping while in the multi-stage leveler.

Most importantly, when Del Metals’ customers laser or plasma cut material, it will not spring back due to internal stresses locked away in the strip. The multi-roll corrective leveler consists of three pre-flex work roll sections, each of varying heights and diameters. Each pre-flex roll section tension-levels a specific gauge range. To make roll changes and cleaning fast, the tension leveler top section pops up 180 degrees at the push of a button.  

The line incorporates Alcos’ CNC edge trimmer, ensuring the end product has tight diagonal tolerances. Conventional slitters would require an additional operator for slitter knife changeovers. The edge trimmer is fully automated from the operator station, keeping operators safe. The tension leveling line, fitted with a rotary shear, works continuously, eliminating the need for a looping pit. 

“We make sure that there are no comprises in quality, efficacy or safety. When engineering our lines, this is what we do, and we strive to be the best.” Albulak says.

The line required a new 80,000-square-foot facility, located about two miles 

away. It will complement Del Metals’ 120,000-square-foot facility at its Brampton headquarters near Toronto. Del Metals generally focuses on ferrous material; however, it now will be able to run aluminum and stainless steel, ultimately opening up new customer bases.

“We have state-of-the-art cut-to-length equipment not many can say they have,” LeGendre says.  MM


Atlantic Tube & Steel, Mississauga, Ontario, is benefiting from a custom slitting line it installed last year. The line, made by Alcos Machinery Inc., Newmarket, Ontario, consolidated Atlantic’s workflow for steel that goes into mechanical and structural tubing, says Paul Tassone, one of Atlantic’s plant managers. 

“This line is so versatile,” he says. It can handle 72-inch-wide coil at 60,000 pounds between 0.028 inch and 0.288 inch thick. “Generally a lot of places can’t do what we do because we’ve customized this line so much.”

Atlantic previously contracted outside companies to slit coil. That racked up costs associated with scrap loss, transportation and delivery times. Scrap metal is about 1 percent to 2 percent of all the material Atlantic processes. By working with outside slitters, Atlantic wasn’t able to reclaim its scrap.

“We decided we could manage our own inventory and adapt to our customers’ needs a lot faster if we had an in-house line,” he says. “We found that with the consolidation of steel service centers, delivery time was getting worse and worse. We couldn’t rely on other people to get our material in fast enough.”

Hasan Albulak, president of Alcos, says the line runs heavy-gauge material at about 400 feet per minute and light gauge at 1,000 feet per minute. “This line has roll units for tensioning oily and dry material, which are good for exposed and surface-critical material,” he says.

Alcos specified the slitting line with a proprietary coil tail end clamp. Because the tail end typically is uneven in different gauges, this correctional aspect of the slitter winds the desired strip length automatically without wasting scrap. 

Normally, the tail end would get cropped off, Tassone explains. “But as you’re rolling the coil, the middle is always shorter than the ends. It can be a couple thousandths difference from the crown of the coil in the middle, so as you’re cutting, it relieves that.”

The tail clamp feature eliminates the need for a looping pit. “Instead of dropping the cuts into the looping pit, you can actually hold them,” he says. “It’s really a great added feature with little work.”

Atlantic added 80,000 square feet onto its existing 150,000-square-foot facility to accommodate the line. To handle the coil between its facilities, Atlantic added Alcos’ remote-controlled, automated coil cart, which takes up to three master coils at a total of 100 tons. It’s equipped with sensors and bumpers for safety.

The safety features extend to the slitter, too. Tassone says because of Ontario’s Ministry of Labour’s strict requirements, safety stops need to be easily programmable. The slitter’s entry, slitting and exit zones are protected by laser curtains, or fences, that shut the line down if an operator breaches a beam.

“It’s a great line and does well for us,” Tassone adds. “It makes our business much more flexible and versatile.”


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