How a Steel Producer Improved Yield by 3%

More than 150,000 miles of rail is stretched across the United States, moving more freight than any other system worldwide. Most of the system is managed by private organizations responsible for maintenance and improvement projects that rely on railroad tie plate — a thick, steel panel that sits on the track between the rail and its support. Tie plates help hold rails upright and stabilize their position, extending the lifetime of tracks.

Most North American railroads get their plates from Arkansas Steel Associates. Scrap steel arrives daily at its receiving dock, is melted, casted into a particular length and shape, finished according to the customer’s recipe, then delivered to the customer from the shipping yard.

Each stage of the process relies on heavy-duty industrial equipment — such as the 50-ton per hour arc furnace, 100-million BTU gas-fired reheat furnace, and a 1,000-ton press — that require an operator’s full attention.

Train of Thought

In 1994, Arkansas Steel’s management began to overhaul their plant control systems. Hardwired relay controls were too difficult to maintain and nearly impossible to modify — single changes took a number of hours to complete and were prone to human error. The Allen-Bradley^® family of controllers was selected for their plant. By 2006, Arkansas Steel was running the advanced Allen-Bradley ControlLogix^® controllers from Rockwell Automation.

While updating the plant’s control layer, IT teams began considering additional opportunities to improve operations. They found an issue with workforce utilization: Operators’ attention was divided between the process of creating tie plates and handling data.

“Thousands of hours were lost each year while employees manually created reports for their supervisors’ morning meetings,” says Chet Pinkerton, senior IT manager at Arkansas Steel. “And during the process, attention was split between the steel and collecting data. Everyone needed to drop their pen and paper so they could focus on the task at hand.”

Company leaders began to investigate the impact of this issue across their process, starting with the melt shop. Operators were struggling to accurately track data while simultaneously supervising the melting steel and adjusting for proper chemistry. Too frequently, the quality of the reports suffered.

Another opportunity to improve process was identified around transferring steel from the melt shop to the ladle metallurgy-control system (LMS) and then to the caster area. Reliable, live process data was not available to operators downstream. Taking the time to contact operators in the area preceding their process for information was too slow for the time frame set by molten steel.

Operators at the caster, for instance, lacked real-time insight into the steel’s temperature. At times, this led to the temperature dropping enough that the caster couldn’t use the steel and would send it back for a reheat. Transporting and reheating the steel would take time and energy that could have been spent on the next batch.                     

Tunnel Vision

Once opportunities at the plant’s melt shop, LMS and caster were identified, Arkansas Steel staff selected a manufacturing analytics platform from Rockwell Automation to improve workforce utilization by automating data collection, analysis and reporting. 

“We trusted the data coming from the ControlLogix controllers, so our challenge was to automatically put actionable information into the hands of operators, supervisors and maintenance when it was most useful,” Pinkerton explains. “The services team from Rockwell Automation became an extension of Arkansas Steel, deploying the solution, and integrating the control and information layers.”

Data about each batch is sent directly from the controller to a historian. FactoryTalk^® VantagePoint^® Enterprise Manufacturing Intelligence (EMI) software from Rockwell Automation then transforms the data from disparate sources into digestible information. Freed from handling data, operators now can focus on the process while gaining a real-time view into the batch that arrives next. And each morning, managers automatically receive a heat-sheet report detailing the work that took place the previous day.

The heat-sheet report has been quickly adopted by supervisors as a reliable tool for confirming production quality. The report provides a single view into the melt shop, LMS and caster. By contextualizing multiple data sources, the report provides comprehensive information about the process, and any additions of chemistries and alloys required by specific recipes.

Supervisors quickly realized this manufacturing analytics platform has powerful continuous improvement capabilities. The software’s system-level analytics tools lets users drill down into specific trends, check production data and track batch progress. Customizable dashboards simplify reviewing data from different sources, helping identify solutions to any issue that arose.

“Once we saw the success of operators, supervisors and maintenance teams who used FactoryTalk VantagePoint software, there was no afterthought about applying our learnings to the rest of the plant,” he says. “Productivity gains from automated reporting are important, but the trustworthy, easy-to-access analytics help us meet our real KPI yield.”

Much like the supervisors who were involved early in the process, those in the shipping yard also needed access to the information solution. Their operators were physically taking a bucket full of tie plates and calculating the weight and recording features.

By extending the information solution to the shipping area, managers now can check every piece of information relevant to delivering products at the rate and quality promised to customers. Operators no longer need to manually track data. Each morning, supervisors immediately know the details of tie plates that move through the yard.

Tracking Results

When Arkansas Steel first deployed the manufacturing intelligence platform, annual yield was between 86 to 87%. By reducing the manual collection and reporting of data, and gaining the ability to quickly identify issues, yield has increased to an average of between 89 and 90%.

“Thanks to the VantagePoint software, we’ve been able to focus an operator’s attention on important information and gain insight into our process,” Pinkerton says. “What started out as a workforce utilization platform has transformed into our go-to continuous improvement resource, helping us boost yield by 3% already.”

The morning heat-sheet report has been a major contributor to the improved yield. Managers take the analysis of what happened during the previous day and identify issues or where there is room for improvement. Nearly every week a new opportunity area is identified.

One such opportunity, which ended up saving the company thousands of dollars, was specifying where a batch didn’t meet a customer’s recipe. Casting supervisors found the discrepancy and worked with the quality team to identify precisely where and when chemical additions took the steel off formula. They were able to modify the process by the very next batch to limit scrap. 

Arkansas Steel is also finding that improved communication between operators is reducing downtime. For example, when the caster calls for a batch at a specific temperature, they can easily verify that the steel is at the required temperature. By having access to this information, operators reduce the risk of reheats, and when a reheat is required, it can be requested before the transfer is even complete.

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