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Posco #3 Retrofit Latest in Long Line of Successful Upgrades for Morgan
Ever since the first rod mill was built, retrofits have been instrumental in keeping existing mills competitive in a moving market place, constantly demanding reductions in conversion cost and improved product quality.
A major player in providing these types of upgrades has been Morgan Construction Company, which since it was founded in 1888, has completed hundreds of retrofits.
Although new technology is a key element to any mill modernization, history shows that the most successful revamp projects have resulted from a number of additional factors, among them extensive pre-planning and training, factors that are important to the mill builders as well.
We understand and as a result of carrying out these factors, along with the installation of new technology, mill operators are able to enjoy smoother startups with minimal impact on production planning. Further, new mills yield higher levels of profitability and improved return on investment.
"New technology is a major factor of any retrofit," said Mark Shore, Director of Rolling Mill Sales and Proposal. "But it also takes extensive pre-planning to make sure the mills, faced with squeezed profit margins and tight labor markets, complete their retrofits on time, on target, and on budget.
"Making a retrofit profitable is the result of careful up-front work performed by the mill builder that is carried out in combination with the addition of new equipment and technology. To this end, Morgan covers all bases to make sure everything is done correctly." He added, "It is important, that there are no surprises while building the mill, so there won’t be any surprises after the mill is completed."
A case in point is a major retrofit completed early in 2002 when Morgan completed the modernization of the No.3 mill at Pohang Iron and Steel Company (Posco) Ltd., in Pohang, Korea. Commissioned in February, the two-strand mill, which is the largest of Posco ‘s three mills, was initially built by Morgan in 1988.
He said that the mill is capable of producing rod at temperatures as low as 750 degrees C, at speeds of up to 110 meters per second, adding, "Output for both strands, which previously totaled 700,000 metric tonnes per year, has increased to an annual rate of 820,000 metric tonnes."
Morgan’s involvement in the two-year project began even before was awarded the contract in October 2000. To eliminate the chance of surprise, said Shore, the Morgan conducted a preliminary audit of Posco’s mill.
The audit, which is also a service that is available from the Morgan Field Service department, is designed to discover possible mill obstructions that could hinder the installation or subsequent operations. In this case, as noted, a preliminary audit was performed by Morgan prior to receipt of the contract.
Brian Allen, Director of Field Service, and a member of the auditing team at Posco, explained, "We wanted to make sure the system would do what the client wanted it to do, and that the site would be able to take full advantage of the company’s latest technology and engineering. "
Potential Problem Eliminated
The audit, he said, discovered a potential problem existed with the lubrication system. "Due to the fact that the equipment was allowing cooling water to enter Posco’s lubrication system from the existing mill, we felt this would definitely be a potential problem to the upgraded mill.
"Our solution was," he continued, "that as part of the retrofit, an independent lubrication system for the RSM be considered. Although this involved additional routing of pipe work and the system cost extra, the decision, we felt, would definitely eliminate the risk of water contamination to the newly installed equipment."
As a result of the preliminary audit and proper planning, and the subsequent changes, the problem was eliminated and the mill is able to experience less downtime and improved production.
The upgrade itself was based on using the rod TEKISUNTM Reducing/Sizing Mill (RSM) philosophy. According to Foley, "The upgrade was designed to provide significant operation benefits including increased finishing speeds, single-family rolling, free-size rolling and product tolerances of +/-0. 1 mrn."
He pointed out that the RSM is located between the No- Twist® Mill (NTM) and pinch roll and laying head. "This was done," he explained to provide Posco with ultimate flexibility in mill operation with reduced downtime due to the ease of changing between finished rod sizes."
The installation also includes an off-line quick-change RSM, pinch roll, laying head, traversing water boxes, ring distributor, and shear modification for each strand.
Other innovations at the mill include three of the company’s proprietary systems:
(1) The Morgan Clevite Bearing Monitor System (MCBM), which continuously monitors temperature of bearings for No- Twist® Mills, RSMs, pinch rolls or laying heads. This equipment alarms the operator when an abnormal condition occurs to prevent the damage of the bearings;
(2) The Morgan Vibration Monitoring System (MVMS) that continuously monitors vibration levels of selected components of No- Twist® Mills, RSMs, laying head pinch rolls or laying heads. Its purpose is to detect the onset of failure in bearings and gears and to warn the operator of the unsatisfactory conditions; and
(3) The Morgan Enhanced Temperature Control System (METCS), which maintains the required level and uniformity of tensile and microstructures for all products requiring precise temperature control. Uniformity and repeatability is maximized by accurate control of temperature during rolling.
METCS, which provides uniform strand-to-strand, billet-to-billet, and heat-to-heat temperature profiles to maximize the uniformity of tensile and consistency of metallurgical properties, increases yield by attaining laying head temperature more quickly at order changes. It also provides a standard operating practice through the use of stored schedules, all the while guaranteeing +.1O °C accuracy of product at the exit of the laying head without operator intervention.
To complete the upgrade with minimum disruption of the mill’s production, the installation was performed in two phases. Phase I, which took place in November 2001,
consisted of an eight (8)-day line stop whereby the existing No.2 water boxes were removed and replaced with static troughs. Piping to existing water boxes No. 1 was modified to independent (separate) water box operation.
As a result of the extra effort put into completing this retrofit, from start to finish, the mill is providing the company with what it is supposed to provide... one that is efficient and profitable.q