Plate-rolling out the weakest links
How North Shore Steel’s plate business transformed
Over the past few years, North Shore Steel has transformed its plate processing division into a provider of highly engineered, precision-cut and rolled components.
When certain customers order a rolled and welded cylinder from North Shore Steel’s plate processing division, they can have their product delivered within not weeks, but about four days. This isn’t common in a sector where workpieces weigh several tons and rolling cycle times are measured in hours, not minutes or seconds. But North Shore Steel isn’t a typical plate processor.
General Manager Byron Cooper is quick to offer a disclaimer: To deliver these cylinders within a few days, the company actually inventories a predetermined number of commonly ordered sizes. And it does this for only a portion of its work, like repeatedly ordered cylinders used in the natural gas compression business, because it has extensive customer data and managers can reasonably predict the ebb and flow of demand.
But even for its made-to-spec work, the heavy plate processor has shortened manufacturing time considerably while expanding its capabilities. According to Cooper, the company made it happen by investing in new equipment and technology, scrutinizing data, and freeing bottlenecks. All of it really boils down to having the right information at the right time, from the initial sales inquiry to the final shipment.
The operation looks little like it did a decade ago, when it was part of Kellogg, Brown & Root’s Greens Bayou Pipe Mill, which used mechanical plate rolls to form large-diameter, thick-walled pipe for offshore oil platforms. Most rolling jobs didn’t use an entire plate, so KBR’s adjacent plate processing operation cut remnant plate sections into flat parts and sold them to heavy industry.
North Shore Steel, a family-owned and -operated steel service center with Houston headquarters just a few miles away, purchased the plate processing operation in 2004. The family also purchased the pipe mill operation, which now operates as a sister company that works closely with North Shore Steel on projects.
For several years the company offered oxyfuel cutting and plate rolling mainly for general fabrication and thin-walled tanks. As business grew steadily during the ensuing years, the shop added more capabilities, including plasma cutting and heavier-duty rolls that could handle thicker plate.
North Shore Steel’s plate business was affected by the Great Recession later than most. The company’s thermally cut parts and rolled cylinders were part of large industrial projects that didn’t halt immediately, but instead slowed gradually throughout 2009 and into 2010. At that point Cooper had just started in his position as GM and as such met with company leadership to discuss a growth strategy.
North Shore Steel operates mainly in the steel service and distribution business. With more than 200 employees, it has more resources than a mom-and-pop, but doesn’t have the bureaucracy of a large, publicly traded steel provider. It has steel distribution facilities in Houston and Beaumont, Texas, that focus on middle-market customers. It also has another Houston facility for distributing fittings and flanges, including long-weld-neck flanges and other components frequently used in pressure vessels, boilers, and general fabrication.
Until the recession, the company’s plate processing operation had focused primarily on basic flat parts and rolled shells. Managers saw the economy in crisis mode; markets were shrinking, not expanding. That also meant purchasing managers were scrutinizing everything to cut costs, which in turn opened the door for plate processors that could offer more value.
North Shore Steel could offer the pressure vessel and offshore market a kind of one-stop shop, with rolled and welded cylinders as well as associated fittings and flanges. Its sister pipe mill, which holds an ASME S-stamp and U-stamp, already employed highly skilled welders certified to the pressure vessel code and had in place a streamlined welding operation.
Adding all these factors, Cooper and North Shore Steel’s board recognized that of all the company’s businesses, the plate processing division had the greatest potential for growth. And with the tax incentives, the time seemed right for equipment investment. All the pieces seemed to be within reach, and the people at North Shore Steel just had to put all the pieces together.
“We decided to get aggressive, to get a bigger piece of a smaller pie,” Cooper said. “So we helped offset the reduction of the overall economy by targeting new markets and new customers to build our business.”
This involved gaining a greater presence in the offshore fabrication and pressure vessel industries. To get there, managers and employees alike scrutinized every process, from the initial sales contact with a prospect to the final delivery. The effort not only helped the company attain its ISO 2001:2008 certification, but also guided the company’s improvement and equipment investment strategy.
During the transition, the plate division’s annual growth increased significantly. Cooper conceded that such rapid expansion didn’t come without some growing pains. Within 36 months his division effectively transformed from a supplier of cut plate and rolled shells for tanks to a provider of highly engineered components, be they for the boiler and pressure vessel industry (which comprises about 60 percent of the division’s revenue) or plate components for offshore platforms and subsea weldments. Today the plate processing division employs 70 people, including seven full-time roll operators.
Processes for engineering and product flow had to be ironed out. “I’ll be honest, it was a shock to the company culture,” Cooper said. “We started targeting fabricators with complicated specifications and stringent processing requirements. We hired new employees, implemented an ISO quality program, and upgraded our equipment. Every step of every job was reviewed, and improvements were made to reduce muda [waste].”
Streamlined Information Flow
No matter how efficient fabrication becomes, none of it matters unless machine technicians receive the correct information. Here, North Shore Steel’s IT department stepped up to the plate (so to speak). “We completely overhauled our front-end systems,” Cooper said. “Our IT manager, George Wynne, had done it before for our distribution business, so we challenged him to customize our company software for our plate processing operation. What he’s done is extraordinary.”
“We’re able to plug in customer requirements, including tolerances, material specifications, origin restrictions, and all the processing steps,” said Scott Shane, sales manager. “It’s really a custom ERP platform that allows us to quote quickly and service the customer.”
During the past year, the company’s salespeople have gained another tool designed to eliminate miscommunication and other “information waste.” The company purchased a CNC plate roll from Davi, and with it came an iPad® with Davi’s iRoll® app.
The app effectively streamlines communication and ensures that whatever is quoted is producible on North Shore’s four-roll Davi machine. A salesperson meeting with a customer can draw a cylinder shape on his iPad, type in the technical detail—including the maximum tensile strength, thickness, and cylinder diameter and length—and the Davi iRoll will show if it’s producible on the machine. It also walks the user through a suggested roll sequence. For reliability, the company ensures any job run through the machine never exceeds 90 percent of its rolling capacity.
A tight diameter calls for more rolling force, as does high material tensile strength. But of all the operations a plate roll performs, the initial prebend often can take the most force to achieve. During prebending, the plate roll bends the leading and trailing edges of the plate, leaving unbent flat sections on each end, giving the plate roll something to grasp during the operation.
Because the app reveals the machine’s true capacity, it also reveals the true amount of unbent flat section required on the cylinder. In the past the amount of unbent flat for prebending was calculated as 1.5 to 2 times the material thickness. There’s a range. However, because the iRoll connects directly with the machine control, it knows the system’s exact capacity levels for a given maximum tensile strength and cylinder diameter (see Figure 1 and Figure 2).
For some jobs, this has allowed North Shore Steel to reduce the length of unbent flat sections, which in turn can shave off a small amount of the plate required to make the cylinder. The amount depends on the cylinder diameter, thickness, and material tensile strength, and it usually seems minute. But over thousands of cylinders, material savings add up considerably.
With the right information, salespeople send work orders to the floor with all the information needed for efficient processing. Technicians don’t need to fight material or push plate roll capacity levels. They don’t worry about how to roll a job; instead, they focus on how that material flows through the shop.
To that end, they’ve analyzed and freed the bottlenecks that can be subtle, at least in the heavy plate rolling world, where cycle times are measured in hours, not seconds. After all, if it takes five hours to roll a large-diameter cylinder, a slow cutting and beveling operation upstream might not seem so slow. Prepping plate for rolling is, at least traditionally, quite labor-intensive, with cut sections being offloaded to stations where workers manually cut K, J, or V bevels into the plate.
The shop’s CNC plate rolling investments have changed the story. This includes the iRoll-connected four-roll Davi system capable of rolling 0.75- to 2.5-in.-thick plate (depending on the cylinder’s tensile strength and diameter). This high-capacity machine has a relatively narrow top roll, custom-machined down to 24 in. diameter, which allows the system to tackle tight-diameter work. The control walks the operator through the process and suggests optimal roll sequences for the job at hand.
Perhaps most significant, Cooper said, is the system’s effect on material movement. The roll works with a fair number of thin, large-diameter cylinders. Left unsupported during rolling, these workpieces tend to bow downward under their own weight. Working with a previous system, technicians had to hold the workpiece in place with an overhead crane, tying up valuable material handling resources for hours. In fact, larger cylinders could take as long as five hours to process.
Now that same cylinder can be formed on a CNC rolling machine in a little more than two hours without a crane. The plate roll has an overhead support and two side supports that keep thinner cylinders on track throughout the rolling process. This frees the crane to move material for other rolls, including one three-roll, variable-axis system known to North Shore Steel workers as “the Big Davi.” With a 40-in.-diameter top roll that can be interchanged with a 30-in. roll, the mammoth machine (most of which is hidden in a pit below the floor) can cold-roll plate up to 6 in. thick (see Figure 2). At its sister company, Greens Bayou Pipe Mill, a system with a 44-in. top roll diameter—workers call it the “Bertsch 44”—can hot-roll plate up to 10 in. thick.
“When you get into the extreme thicknesses, your market sandbox becomes a lot smaller, which fits nicely with our investment strategy,” Cooper said.
Upstream and Downstream Improvement
A rail spur runs right by the facility, adjacent to a truck lane. Obviously, the place was designed with transportation in mind.
Historically, a large fork truck offloaded material, not the easiest feat when moving large plate. This restricted where material could be stored—in low stacks across a wide area, with room for the fork truck to maneuver. Handling plate recently became a lot more efficient and safer with a magnetic crane (see Figure 3).
“Not only is material offloaded faster, but by not using a fork truck, we’re able to utilize more square footage of the stockyard and minimize wear and tear on our own equipment,” said Scott Lambert, operations manager.
Next, plate is sent to the company’s oxyfuel and plasma cutting area, which includes a cutting bed 160 feet long. One machine, from Kinetic Cutting Systems, is a combination system that offers plasma, oxyfuel, and, perhaps most significant, drilling and milling—all at one work station. The system can drill deep holes, mill pockets, and thermally cut complex profiles and bevels, without transferring products to multiple machines. As Cooper explained, this effectively brings the done-in-one approach to plate processing (see Figure 4).
The company uses a collection of automated cutting and beveling technologies that have reduced plate preparation time dramatically, be it a V, K, J bevel or anything else. The speed of the weld preparations has improved product flow before the plate rolls, while the precision ensures optimal weld quality, critical for such code-level work (see Figure 5 and Figure 6 and Figure 7).
Best Use of Talent
To get a rolling job at North Shore Steel, managers set the bar very high. When a job candidate arrives, managers take him to the plate roll area, position some scrap plate at the machine, and ask the job candidate to roll a cylinder.
Consider one technician nicknamed “King Kong,” who already had a good amount of rolling experience when he came to North Shore.. During his job interview, he rolled a high-quality cylinder on the first try, confidently and without hesitation. King Kong was hired on the spot.
These experienced techs have given North Shore Steel a good reputation. “We’ve gotten good feedback on the roundness of our cylinders,” Cooper said. “We’re regularly able to produce cylinders within half the roundness tolerance window of ASME requirements. This means our customers don’t need to struggle with the fit-up process, saving them time and money.
“Given the competitiveness of this industry, we are focused on doing things that can’t easily be replicated by others,” Cooper explained. That strategy is what guides the company’s investment decisions, which, according to sources, are not made lightly. “The owners of North Shore Steel offer a balanced approach—on the one hand risk-averse and conservative, but on the other hand committed and aggressive. It all depends on the specific investment opportunity. If the target market is identified and the payback is reasonable, the owners have demonstrated a real willingness to invest in our business.”
Like any manufacturer, North Shore Steel is trying to make life easier for its customers, be it with automated cutting or more efficient rolling and welding. Managers emphasized that they do not look at any process in isolation. From sales to final shipment—and all the steps in between—each process directly affects the others, and the manufacturing value chain is only as strong as its weakest link.
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