A case study about a multinational steel company that protects its most valuable steel production assets from corrosion.
By EonCoat*
After the recent slowdown in the global steel industry, caused by oversupply, falling prices and rising raw material costs, Posco, one of the world's largest multinational steelmakers, headquartered in South Korea, needed a strategy to address these challenges while continuing to protect its assets and continue to innovate in the sector.
Focusing on high value-added products, reducing costs and innovating in its products and processes POSCO recorded double-digit operating margin and a share price increase of more than 50 percent in 2016, according to its annual report.
Now the company, which earned the title of the world's most competitive steelmaker for the eighth consecutive year in 2017, world steel industry research agency announced, is poised to make bigger profits with innovative products and processes that will transform the industry.
A fundamental initiative of POSCO has to do with a unique approach it is taking to protect its mass carbon steel production and infrastructure from corrosion. This is an ongoing challenge for steel companies around the world, particularly in coastal areas exposed to high humidity and salty air.
The company is using an innovative coating that provides a long-term solution to combat corrosion and atmospheric corrosion under insulation (CUI). The coating not only helps to minimize the necessary maintenance and production downtime, but also promotes health and environmental safety, which is one of the company's main missions.
Protect the most valuable steel assets from corrosion
Because steel mills must have enough raw material to produce, they are usually located near maritime terminals where both the raw material and the finished product are easy to transport.
Therefore, the equipment and processing infrastructure of steel mills must be coated to resist atmospheric corrosion produced by high humidity and salty air. They must also resist corrosion under insulation, which can occur from exposure to moisture from sources such as steam, pressure washing, sprinkler systems, or frequent condensation and evaporation of atmospheric moisture.
However, when it is necessary to apply traditional barrier liners from time to time in such coastal areas, this can increase the cost of maintenance and the time of interruption of production.
To protect its steel assets from corrosion for several decades, as well as to improve health and environmental safety, POSCO turned to EonCoat, an aerosol-applied inorganic coating manufactured by the Raleigh, North Carolina-based company of the same name.
This coating provides two layers of protection for POSCO's steel assets. First of all, unlike conventional barrier coatings, which only physically cover the surface, this coating forms an alloy layer that chemically adheres to the surface of the steel. This effectively prevents the entry of moisture and other corrosion promoters. It also forms an outer layer of ceramic that further resists corrosion, water, abrasion, impact, chemicals and high temperatures.
According to Sungjun Ahn, senior manager of Dong Buk Chemical, the company in charge of the coating application process at POSCO, the EonCoat was selected to extend the life of the equipment, in accordance with POSCO's sustainability and environmental management policies.
"POSCO's stakeholders, including its investors, benefit when they can safely extend the life of their steel assets with less maintenance," Ahn said. "By eliminating the need for frequent repainting, they can invest more productively in product and process innovation."
At the Pohang steel plant, aerosol applied inorganic coating is used to protect a wide variety of equipment, such as storage tanks, boiler dust collectors and spring piles (including the splash zone and below the waterline).
Due to the high temperature resistance of the coating, up to 500 degrees Celsius, it is also used in high-temperature areas of the steelmaking process, such as at the ends of steel rollers and for pipe insulation.
Due to the unique inorganic properties of the coating, it is very effective in stopping atmospheric corrosion under insulation, which can affect pipes or ships under insulation due to water penetration.
Because the coating is also resistant to chemicals, it is also being considered to be used as a primer for equipment that comes into contact with sulfur dioxide (SOx) and nitrogen dioxide (NOx) gases, which are produced in the burning of fossil fuels and the smelting of minerals.
More innovative processes
While it is taking a proactive approach to preventing corrosion, POSCO already uses a number of advanced steel production technologies at its two South Korean plants, Pohang and Gwangyang, among others:
Finex: This eco-friendly iron manufacturing process allows the direct use of cheap iron ore fines and non-coking coal as raw material. Compared to a conventional blast furnace process, this significantly reduces operating costs and emissions, as well as drastically reducing overall construction costs by eliminating the need for sintering and coke plants.
Belt casting: This method eliminates the slab manufacturing process to produce hot flat products directly from cast iron. Compared to traditional slab manufacturing, this technique reduces costs, energy use, production time and pollution.
Endless hot rolling: This solid-state bonding method is a rolling technology that binds bars made of slabs, the material for hot-rolled products, to endless rolling. Compared to previous rolling processes, this method radically reduces production time while allowing for firmer and thinner steel plates.
Revolutionary products
With these advanced steel production technologies, backed by a corrosion prevention approach, the company recently introduced some innovative products. Among others, the giga Steel (giga steel) of high strength, which can withstand more than 100 kg of load per 1 mm2 with a tensile strength of 1.5 gigabytes, produced in its steel mill in Gwangyang (Korea).
Since the tensile strength of the product, measured by pulling the steel plate from both ends until it breaks, is greater than 1 gigapascal (GPa), a unit of force, it was called Giga Steel. That is to say that a piece of Giga Steel the size of the palm of the hand (10 cm X 15 cm) can support the weight of 1,500 medium carts of 1 ton. The exclusive material will allow to build significantly lighter and more resistant vehicles, since it is three times stronger than aluminum and has excellent formability.
At the company's global research and development center located in Songdo, Korea, a new steel forming laboratory will evaluate the formability of newly developed steel products such as Giga Steel, and will include the use of a 2,000-ton hydraulic press to assess the formability of large components such as the sides of automobiles. An existing steel forming laboratory will also evaluate the basic physical properties of the steel required by customers (forming, welding, coating, corrosion and fatigue) and provide support, such as quality certification.
Health, safety and environmental protection
In addition to meeting the challenges of the steel industry with product and process innovation, the company also takes seriously its commitment to the health and safety of its workers and the environment.
According to Merrick Alpert, President of EonCoat, "our company takes great pride in helping POSCO promote eco-friendly processes and products that contribute to sustainable global development." As part of its environmental management process, POSCO has sought to improve air quality near steel mills and surrounding areas, reducing the total emission of air pollutants, including dust, NOx, SOx and VOCs.
Because the coating is inorganic and non-toxic, there are no volatile organic compounds or hazardous air pollutants (PAHs) or odor. This improves health and safety and helps mitigate the negative effects of air pollution.
The coating is made up of two non-hazardous components that do not interact until they are applied by a standard industrial plural spray system such as the one commonly used to apply polyurethane foam or polyurea coatings. This means that inorganic and non-flammable coatings can be applied safely even in enclosed spaces.
"POSCO's use of inorganic coating is part of its effort to innovate in the steel market," concludes Ahn. "It is helping the company deliver on its commitment to benefit all stakeholders, including investors, customers, employees, as well as the local and global community."
