A redesign of the transition flat (T-flap) hose assembly outfitting the electric arc furnace (EAF) at ArcelorMittal Dofasco, Hamilton, Ontario, has led to significant gains in furnace reliability. Since the implementation of the new design in August 2014, production delays and maintenance costs have plummeted by 90 percent.
The hose provides water cooling to the T-flap, which is used to divert EAF off-gas system suction between the two furnace shells. Repetitive movement of the T-flap back and forth to the active shell had caused multiple failures of the T-flap hose resulting in significant delays and maintenance costs over its 18 years of operation.
To tackle the situation, ArcelorMittal Dofasco formed a cross-functional team to redesign the transition flat hoses to create a more robust design. Taking into account the failure modes as well as the design characteristics that influenced the failures, the team considered several design and material changes and, through in-depth analysis of those designs and materials, came up with the optimal solution a new hose design with two integral steel elbows that allow for the distribution of localized stresses over a larger area. The team also implemented a rigorous inspection and maintenance program to extend the life of the new equipment.
ArcelorMittal Dofascos transition flat hose reliability project was recently awarded the 2016 Association for Iron & Steel Technology (AIST) Silver Reliability Achievement Award (RAA) by AISTs maintenance and reliability technology equipment. The RAA recognizes iron and steel producing companies and their workers who have developed, applied and proved new practices, policies or procedures that have significantly improved North American iron and steelmaking reliability.
Borusan Mannesmann Pipe
Buffeted by and responding to the steep downturn in the oil country tubular goods sector last year, Houston-based Borusan Mannesmann Pipe executed three projects keyed to improve the safety, efficiency and flexibility of its electric resistance welded (ERW) pipe mill in Baytown, Texas.
What proved to deliver the most significant results of the three initiatives implemented between March and June of 2016 ultimately amounted to a complete overhaul of the companys management style. Rather than relegating all decision making to managers, Borusan Mannesmann now empowers each of its employees to be accountable to improve their station, equipment and throughput daily.
As result of its pipe mill project, Borusan Mannesmann reduced work stoppages on the weldline by 57.2 percent. The company also cut scrap generation there by 2.1 percent, increased pipe mill efficiency by 19.2 percent and trimmed yield loss in its slitting process by 0.5 percent.
A second project undertaken at Borusan Mannesmanns quench-and-temper facility led to a 97-percent reduction in material-related delays in addition to an 86.5-percent decrease in the number of tubes requiring restraightening.
The third project mounted by Borusan Mannesmann involved the companys threading operations, where the initiative delivered a 55-percent increase in throughput and dramatically lower defect rates.
The savings achieved through these projects played a pivotal role in enabling Borusan Mannesmann to weather the ravages of 2016, a year when the OCTG market was roiled by fallout from the lowest drill rig count in recorded history. The gains generated by the projects also positioned the company to react to the uptick in demand it is beginning to see in 2017
CSN LLC, Terre Haute, Ind., relies on its temper mill to restore the desired hardness in cold-rolled sheet by elongating the material by up to several percent following the annealing process.
In December 2015, the temper mill control system, originally installed in the late 1990s, failed and could not be restored given its age, conditionwhich was described as a state of extreme obsolescenceand the fact that it wasnt supported by the original vendors.
Prior to the failure, CSN had been investigating alternatives to upgrade the control system since the temper mill had experienced certain operational disruptions. Those efforts were expedited when the system failed.
Fast forward to June 2016 when CSNs temper mill resumed production following the installation of state-of-the-art, Windows-based servers and a touchscreen human machine interface (HMI), Toshiba nV real time controllers and modified, existing I/O drives. The updated system also features diagnostics allowing the operator and maintenance personnel to quickly pinpoint the source of any problem. Add to that web-reporting capabilities that document any temper mill production, quality or mill-delay problems and provide CSN access to a vast amount of real-time information enabling continued optimization of its operations.
CSN credits Implementation of these world-class diagnostics with slicing trouble shooting time by 50 percent. While the previous system required that inspection data for each coil to be entered separately into two systems, only a single entry is now required.
The new control system is said to be more intuitive and easier to operate that its predecessor, giving CSN greater operational flexibility because a wider pool of operators can now run the temper mill.
As part of the update, a high-speed rewind optiondescribed as five-times faster than the previous rewinding methodwas also implemented.
In April, 2016, Outokumpu Oyj announced its intention to become the best value creator in the stainless steel industry by 2020 through a series of customer orientation and efficiency initiatives.
As part of that drive, the companys Outokumpu Americas business unit implemented a standardized operating model ensuring continuous productivity gains across its Calvert, Ala., and San Luis Potosi, Mexico, mills.
In step with that model, Outokumpu Americas last year implemented safety behavior observation processes that required each employee to make and document safe and perceived unsafe behaviors. Also implemented was a green card methodology which provided employees a platform to recommend permanent corrective action to capture what they believed to be an opportunity to improve overall safety. Outokumpu Americas credits the initiatives with leading to a 33-percent reduction in first-aid incidents and total recordable incidents in 2016.
Outokumpu Americas also implemented a program at its Calvert cold rolling works facility keyed to achieve month-on-month improvements in yield, speed and quality. The initiative paid dividends there in the form of a more than 8-percent improvement in yield over the period stretching from the first quarter of 2015 to the fourth quarter of 2016. Cold annealing and pickling line capacity increased by 22 percent while heat sequencing at Calverts melt shop climbed by 15 percent.
Last year, Outokumpu Americas also adopted a program focused on outage optimization, including on-the-job training. The initiative allowed employees to review complex, real-life outage scenarios, enabling them to plan for critical future outages.
Outokumpu Americas credits the outage optimization initiative with improving on-time delivery by 3 percent vs. 2015, reducing overall quality claims to less than 1 percent, and cutting conversion costs by 30 percent.
Steel Dynamics Inc., Columbus Flat-Roll Division
Steel Dynamics, Inc.s focus on operational innovations keyed to increase efficiencies has helped the Fort Wayne, Ind.-based steelmaker differentiate itself from competitors.
One prime example of that strategy at work is a series of energy-efficiency improvement projects Steel Dynamics (SDI) undertook at its Columbus Flat Roll Division in Columbus, Miss., where total plant demand on off-peak is more than 300 megawatts of electricity at full production. A portfolio of projects undertaken at the location enabled Columbus to save 66,190 megawatt hours, or enough energy to supply electricity to 3,700 houses for a full year.
The Columbus facilitys contact cooling water system consists of 15 pumps which supply high-pressure and low-pressure cooling water to the hot strip mill (HSM). Due to the dynamics of the HSM rolling process, the system previously provided more pumping horsepower than was needed when the mill wasnt fully loaded. This imbalance and resulting inefficiency was remedied by installing variable-frequency drives on the larger supply pumps and a process communication exchange between the HSM control system and the Giga water control system, reducing pumping volumes.
Another project increased the efficiency of the baghouse main-draft fan system from under 50 percent to 74-to 76-percent efficiency levels, resulting in a savings of millions of kilowatt hours annually. This was achieved by replacing fan wheels and housings and providing speed control of the wheel through the installation of variable-frequency drive technology.
Additionally, a project replacing high-pressure, compressed-air systems, which require input energy in excess of 1,500 kilowatts, with low-pressure, high- volume supply systems that require an energy input of only 300 kilowatts, has delivered in an average energy savings of 1,200 kilowatts.