Processing expert becomes the first to install an in-line leveler in a pickling line
Above: With eDrive, Bradbury split the gearbox into two independent drive sections, increasing both plunge and the ability to level through the entire thickness of the strip.
Processing expert becomes the first to install an in-line leveler in a pickling line
July 2019 - During the American Iron and Steel Institute’s annual meeting in June, members of the leadership team noted that 75 percent of the grades in use today were developed in the past 20 years. Heidtman Steel has been at the forefront of figuring out the most efficient and cost-effective ways to process carbon flat-rolled steels. Heidtman has transitioned from marketing high-strength steels to acquiring the equipment needed to process them. One example is its recent pickling line upgrades.
The Toledo-based company operates six direct and four joint venture processing operations in Illinois, Indiana, Michigan, Ohio and Mexico. Heidtman was the first processor to adopt a mill-adjacent model, eliminating or minimizing inbound freight. Its Butler location shares a rail system with Steel Dynamics Inc., where coils are shipped within the campus directly into the Heidtman plant, according to Jamie Geiger, Heidtman’s marketing specialist. Five of the plants offer pickling capability, complemented by slitting, stretcher leveling, blanking and coil coating capabilities.
Heidtman installed two Bradbury hydraulic levelers on its pickling lines in Granite City and Butler last year. The selected pickling lines had to be re-engineered to include Bradbury’s 17-roll hydraulic levelers with eDrive technology.
The pickler at Heidtman’s Butler, Indiana, plant can pickle coils from 0.375 inch thick by 72 inches wide. The pickler in Granite City, Illinois, can pickle coils from 0.5 inch thick by 72 inches wide.
Configurations
“The capital investment of $1.5 million enabled us to statically upgrade these pickling lines,” says Ben Shinkle, Heidtman’s corporate engineer. “Because each pickling line is configured differently, we had to install the units at different positions. Granite City necessitated post-acid tank positioning, while Butler installed a pre-acid tank configuration. Among the benefits we have realized are improved shape and surface, more efficient line speeds and less cropping scrap,” he adds.
At the Butler plant, says Geiger, “It’s been easier for us to level, get shape correction and break up the surface scale before the coil goes to the pickler. Because both lines are more efficient, we are able to run at faster line speeds. It’s also much more cost effective than adding operations for shape correction.” Orders for the two new levelers were placed in 2017, with deliveries and installations occurring in early and mid-2018, according to Steve Baker, sales manager with the Bradbury Group.
The levelers can process materials from 0.059-inch through 0.21-inch thick with tensile strengths reaching up to 120,000 psi. Processing speeds can reach up to 400 feet per minute.
Both left and right are before and after examples of coils run by Heidtman through its pickling lines. Corrections include straightening and leveling, which removes edge wave and other defects.
eDrive
Bradbury developed its patented eDrive technology after discovering the mismatch of roll speeds as material makes its way through a leveler. This phenomenon was noticed when torque limiters on the drive shafts of the exit rolls were showing excessive wear as compared to the entry shafts. Further testing revealed that material was actually being forced through levelers from the front. With all leveler rolls of equal diameter and geared the same, material was “bunching up” internally, reducing the stretching process required to equalize material shape.
The plunge of the entry rolls helps to yield the material to a plastic state. Yet when the plunge was increased, the bunching would worsen, and horsepower consumption would increase with little improvement in material condition.
To remediate that, Bradbury split the gearbox into two independent drive sections, increasing plunge and increasing the ability to level through the entire thickness of the strip. The machinery builder focuses on specific horsepower to the material at the point of plastification, while the exit side of the gearbox is more concentrated on “returning the material to flat” and pulling the material out of the leveler, says Baker.
Results
Bradbury has monitored the performance of the in-line levelers and the quality reports from Heidtman since the equipment was ramped up, says Baker.
He says Heidtman has described improved shape and surface and the ability to bypass the downstream shape improvement process. “This saves processing cost and internal transportation costs and reduces the quality issues since handling time is reduced,” he says.
Less scale has to be removed during the pickling process due to leveling. “This improves process speeds and reduces acid consumption.”
Heidtman reports experiencing increased line speeds, both feed-up and line-run speeds, of between 25 and 40 percent compared with the previous process.
There has been at least a 1 percent reduction in downstream scrap. “Since the shape is better, downstream processes can run with less edge trim and cropping of damaged leads and tails,” Baker explains.
The totality of more efficient pickling operations—including acid consumption, water consumption and the reduction of maintenance in the pickling section because correct strip shape prevents damage to rolls—reduces process costs and improves efficiency, he says.
Heidtman also eliminated claims from customers for scratches by 95 percent. This again, was due to the reduction of anomalies in strip shape. There was an improvement in energy usage, too, because leveling raises coil temperature of the strip before it enters the pickler, allowing faster process speeds. MM
