Making Steel Last Faster
A new, faster method of bonding wear- and corrosion-resistant materials onto steel got a major nod by The Wall Street Journal last year.
MesoCoat, Inc., a start-up company based in Euclid, Ohio, won a 2012 innovation award for its new process that has the potential to reduce the lead time for cladding from between six and 24 months to just six to 10 weeks, depending on capacity and demand.
Metal cladding accounted for about $1.7 billion of the $1 trillion international steel market last year, and could top $2.3 billion in 2018, according to Wellesley, Massachusetts-based BCC Research, a market research firm that analyzes global technology trends.
CermaClad competes with roll cladding, explosion cladding and weld overlay. Roll cladding, especially, requires large capital investment. “Roll cladding and explosion cladding are fairly expensive and [have a] long lead time,” says Andrew Sherman, president and CEO of MesoCoat.
By contrast, a CermaClad plant’s capital investment is smaller, more similar to the cost of a painting or welding plant. “But one CermaClad machine can do what about 40 [laser] welders can,” Sherman says. A laser welder scans a small spot across the surface; the CermaClad machine scans with a line, covering up to 40 times the area in the same amount of time. “Instead of a point moving over the surface, we’re at the same speed doing a 12-inch-wide scan,” Sherman says. “What takes 100 hours in a laser cladding cell takes us a couple of hours.”
This level of productivity could be a game-changer. Six or eight CermaClad machines could clad the entire output of a rolling mill, says Anupam Ghildyal, manager of strategy and finance at MesoCoat. While the cost of CermaClad material depends on many factors, steel clad in stainless steel may be 30% to 40% of the cost of using solid stainless, Ghildyal says. Besides the cost savings, there are also welding and fabrication savings because the base metal is a lot easier to weld than stainless.
Sherman founded MesoCoat in 2008 as a spin-off of his other company, Powdermet, Inc., a nanotechnology and advanced materials research and development organization, also based in Euclid.
Innovation in Action
Several years ago, Sherman was working on a contract with the U.S. Navy to develop a metallic nonskid surface coating for the decks of ships. The new surface needed to stand up to environmental and mechanical wear, as well as high-temperature jet exhaust on aircraft carrier decks. Sherman had come up with a solution, he says, but applying it turned out to be a problem. Laser-weld overlay and other available processes were too slow to process the large areas involved.
At the heart of the CermaClad technology is a super-high-powered plasma arc lamp developed at Oak Ridge National Laboratory in Oak Ridge, Tennessee. The plasma arc mimics the conditions on the surface of the sun, providing the intense heat the CermaClad system uses to rapidly melt powdered metal and fuse it to steel substrates. The lamp provides this intense heat over a much larger area than conventional technologies, enabling much faster cladding than was previously possible.
A professor at the University of Cincinnati put Sherman in touch with a researcher at Oak Ridge National Laboratory who had been investigating the use of a super-high-powered radiant plasma lamp as a heat source for fusing wear-resistant coatings to metal. Sherman saw the potential.
The NASA Glenn Research Center in Cleveland, Ohio, had a prototype plasma lamp, which was used to demonstrate and develop the CermaClad technology concept. In 2009, MesoCoat acquired an exclusive international license for the lamp technology. Then, MesoCoat proceeded to create, refine and integrate the necessary supporting technologies.
In 2011 and 2012 MesoCoat built prototype CermaClad machines and started construction of a dedicated CermaClad manufacturing facility in Euclid, scheduled to open in the second quarter of 2013. The plant will house one CermaClad machine that will apply corrosion-resistant cladding to the inside of pipe, 8 to 36 inches in diameter, for use in the oil and gas industry. It will have a capacity of 66,000 feet of pipe per year, Sherman says. When in full production, the plant will be among the largest pipe-cladding facilities in the United States, according to company literature.
Meanwhile, that original surface coating for decks was developed and is currently doing well in the long and stringent qualification process for military applications.
How CermaClad Works
At its core, the high-powered lamp has a plasma arc that stretches between two tungsten electrodes to a length of 8 to 12 inches, Sherman says. The light energy from the lamp is captured and focused using water-cooled copper reflectors. The resulting line of intense heat/light then scans over the powdered cladding material on the surface, melting it and fusing it with the base metal.
The lamp system is also capable of supplying hundreds of kilowatts at the scan line. For comparison, a typical laser-welding cell is in the 2- to 10-kilowatt range.
To clad the inside of a pipe, first the surface is grit-blasted. Then the cladding precursor material is applied in a layer a few millimeters thick.
It consists of the desired cladding material—powdered metal, such as stainless steel or Inconel, or a cermet, such as ceramic or metal composite—mixed with binders to make a slurry that is similar to a very thick paint.
The pipe is rotated and the lamp system passes through lengthwise, scanning the interior in a continuous path. The heat from the lamp rapidly melts the cladding material, which fuses with the base metal, forming a strong metallurgical bond.
From Concept to Commercial Production
The Oak Ridge Lab demonstrated the feasibility of using the plasma lamp to fuse metal coatings. MesoCoat then had to make it work in a commercial manufacturing setting. Many aspects of the process needed development.
To ensure the cladding precursor material stayed in place after applied, MesoCoat had to formulate binders that would not affect the properties of the cladding metal and could hold the powdered metal in place without sagging or dripping, even when the pipe is moved or rotated. Also, since the plasma lamp heats the work extremely fast, “the binders have a tendency of turning to gas,” Sherman says. “[Heating] has to be done under very controlled conditions, or things just pop.” In addition, the process binds together two unlike materials that have different coefficients of thermal expansion.
“It takes a lot of thermo-mechanical understanding to get it all to work together,” Sherman continues. “Every time we work with a new material, a new heat input, a new substrate, we have to make sure the metallurgy is right.”
MesoCoat has cooperative agreements and collaborations with several major companies, primarily in the oil and gas and large-equipment industries. “Those relationships are helping us perfect [CermaClad] and investing in it,” Sherman says. “We have two multimillion-dollar investments from Fortune 50 companies.”
In addition to the new plant in Ohio, MesoCoat’s expansion plans include pipe-cladding plants in South America and South Asia. In the first quarter of 2014, a four-line plant in Brazil is slated to open, supporting the oil industry’s needs for clad riser pipe and flow lines. An eight-line facility in Indonesia to clad pipe for the natural gas industry is planned for later in 2014.
“Right now we’re pretty focused on market entry in clad pipe,” Sherman says. “The next factory we build will be doing clad plate for fabricating reactor vessels” for industries such as nuclear power, petrochemical and water desalination.
MesoCoat also has a robust research and development pipeline for the energy business, working toward such offerings as nickel-chrome cladding for boiler tubes. Eventually, the company will move into additional markets, such as sheet and bar steel.
“It’s too early to make predictions, but [MesoCoat] has shown the ability to meet milestones and secure potentially significant strategic partnerships,” says Ross Kozarsky, senior analyst at Lux Research in Boston, Massachusetts. MesoCoat has obtained qualification to American Petroleum Institute standards and has entered joint development agreements with a number of companies, including Brazilian energy company Petrobras and a major heavy-equipment manufacturer.
Part of a Bigger Picture
Worldwide, the annual direct cost of corrosion is $2.2 trillion, according to a paper by George F. Hays, director general of the World Corrosion Organization in New York, New York. According to Hayes, the only major attention to corrosion is around the aircraft and oil industries where personal and environmental safety are clearly at stake. CermaClad technology is designed to enable practical options for preventing corrosion in a broad range of metals applications as MesoCoat’s cladding capacity grows and the demand increases for steel protected with corrosion-resistant alloys.
Barbara Donohue is a freelance writer and editor who turns technology into English for companies and publications. She is also a mechanical engineer with 15 years of industry experience.