From critical components in military aircraft to bridge decks to 3D-printed inserts, nanocrystalline steel (NCS) is moving quickly from the laboratory to the manufacturing flooras quickly, at least, as development companies can push qualification trials.
But most involved in NCS have a different definition of exactly what NCS means. By one definition, there are lower-end steels that still qualify even though they are melted at atmospheric pressures: the nanostructure is manipulated in rolling and cooling. Used for structural components in automobiles, appliances and rail cars, those steels sell at 10 to 50 cents per pound. In contrast, vacuum-melted high-performance alloys used for high-stress aircraft components sell for $15 to $25 per pound, or around 100 times as much.
Companies developing NCS tend to be driven by research, and their commonbut not universalbusiness model is to develop a grade to commercial acceptance in a particular market and then license production to an existing mill. Some development companies have been willing to produce commercial quantities themselves in certain cases, but often that is under contract with an existing mill. The revenue stream comes from licensing, with or without royalties depending on the situations. The licensors eschew the capital costs of steelmaking and do not want to compete with their customers, but are willing to baseload a market or specific application.
There are striking performance qualities for some types of NCS, with developers quick to tout their breakthroughs. However, most agree that advanced alloys and finely tuned melting and forming processes have been advancing toward NCS in many mills.
There are already a lot of advanced steels in commercial use in many sectors, said Jeff Grabowski, manager of application development at Evanston, Ill.-based QuesTek Innovations LLC. Some high-grade conventional steels have been developed over 30 or 40 years. They have had their performance optimized over a long time. At the same time, mills and fabricators have adopted their processes to work with them.
That leads to some reticence by steelmakers and fabricators to adopt new materials, Grabowski said. There is little doubt about performance capabilities, but the acceptance process and integration into manufacturing remain a challenge beyond the metallurgy. Nevertheless, developers are pushing aggressively in the laboratory and in the supply chain.
We have been in discussions with multiple major air-melt steel mills, as well as with oil and gas companies that have a major need for NCS in pipe for extreme conditions, Grabowski said. In the case of drill string and casing pipe, the deeper they drill the more the steel needs high-temperature strength. In the North Sea, the challenge is low temperature. And in all applications, there is the need to resist sulfide stress cracking when exposed to sour gas.
A majority of QuesTeks funding has come from the federal government under small-business innovation awards. We are a small company, so we cannot take up manufacturing, Grabowski said. But we always figure scale up into our development. We dont just do the theoretical metallurgy. The NCS grades that QuesTek has available commercially are licensed for manufacture by Wyomissing, Pa.-based specialty mill Carpenter Technology Corp.
The key applications so far for QuesTeks NCS are in military aviation. Its Ferrium S53 replaces 300M in landing gear for Chicago-based Boeing Co.s A-10 Thunderbolt II ground-attack plane (affectionately known as the Warthog); Bethesda, Md.-based Lockheed Martin Corp.s C-5 Galaxy heavy-lift transport; and Falls Church, Va.-based Northrop Grumman Corp.s T-38 Talon trainer. We were asked to develop a steel with the strength of 300M but greater corrosion resistance so it would not need cadmium plating, Grabowski said.
Another NCS, Ferrium C61, is undergoing testing at Boeing for the rotor shaft of the latest generation of the CH-47 Chinook heavy-lift helicopter. We completed component manufacture in May and shipped them to Boeing for rig testing. That is a 12- to 18-month process, Grabowski said. The new shafts will enable them either to reduce weight or increase power at the same weight.
Ferrium M54 is being developed for the Boeing T-45 Goshawk jet trainers arresting hook, with another Navy project evolving in the laboratory. We are working on stainless bearing or gear steel. There is no such thing right now. We are halfway through the program and are still two to four years away, Grabowski said. There is a huge untapped market for nanocrystalline technology in steel and even in other metals. This is going to be a robust market for many years to come.
Steel in building construction conjures images of I-beams, the most elemental application of the metal. But Irvine, Calif.-based MMFX Technologies Corp. is bringing NCS to the job site for key applications where strength and corrosion resistance are important.
The state of the art in microstructure is in rolling and coolingmartensite divided by austenitic layers, MMFX chief executive officer Tom Russo said. We have many patents on high-strength material up to 120,000 kilopounds per square inch (ksi) in yield strength. Triple-phase material can get up to 250,000 ksi.
Two commercial grades are available currently. We have 9 Chrome, with a projected lifespan of 100 years, and 4 Chrome with about a 50-year life cycle, Russo said. We are working on a high-strength 2 Chrome that will be launched at the end of the year. The focus is on construction applications where we can reduce cost and maintain high strength and ductility.
MMFX licenses its technology in two stages: marketing and sales, and manufacturing. We have one licensing agreement in place in China and a separate one in Chile with the Broom Group (SA), responsible for sales and marketing, and CAP (Group) as production partner, Russo said. In North America, we are our own licensor for sales and marketing. Cascade Steel (Rolling Mills Inc., Portland, Ore.) is our domestic production partner.
The Cascade Steel mill has an annual capacity of 800,000 tons of rebar, rounds and flats. One of the advantages of our technology is that it does not require any special equipment, Russo said. Cascade does not have to make a special run. They just integrate our orders into their sequence in the melt shop. They are now up to about 10 heats a month to support our orders.
Mexico is the next target market. Once we have established a marketing partner, we will begin to ship steel from the U.S., Russo said. MMFX will seek a production partner but will support Mexican orders from the United States as necessary.
Beyond the base of construction sales, Russo also has his eye on auto applicationsaxles or support springs, rather than the typical chassis components that traditionally are the market for NCS. Wire is another new area we are exploring, he said. Cascade makes rod, and we are looking for a partner that can draw us into the wire industry. We hope to perform manufacturing trials soon. The target market would be galvanized or epoxy-coated wire and as a low-cost alternative for stainless.
Russo sees NCS growth in every sector over the long term. Look around the industry. Every major mill has its own patents for flat rolled primarily, but also for long products. Flat rolled is more advanced in the market because of the competition in automotive from aluminum, he said. Automobile applications are the most severe, requiring the most ductility. That is not yet required in long products. But as industry moves up the ladder in strength in long products, it will have to look at some microtechnology to meet the needs for high strength and ductility.
The snag, he added, is not in the laboratory. We can have these products. The only question is which mills will be willing to put the investment into both manufacturing and also into educating the market. That is our greatest challenge: to convince the OEMs (original equipment manufacturers) and end-users of the benefits of nano-type steels.
Automakers are focused primarily on the finished cost of vehicles, Russo said. They understand the performance value of nanocrystalline steel, but asking them to change from what they are using now could increase the cost of the finished car, at least in the short term. We are working to change that. We have to understand the position of the mills and the OEMs as much as they have to understand our technology. There is a tremendous education challenge in both directions.
Providence, R.I.-based NanoSteel Co. Inc. (profiled in AMMs March-April 2013 issue) has been focusing on strip casting, thin slab and thick slab. The breakthrough has been that we are no longer dependent on the cooling rate at cast to control the nanocrystalline structure, president and chief executive officer David Paratore said. That means we are no longer limited to strip casting. We are in the midst of trials for both thin and thick slab. We know we can meltwe do it all day long. Recasting is the challenge that we are working on with our partners.
The slab revelation came while preparing for strip casting trials with several auto companies, so NanoSteel is essentially switching on the fly to a parallel development approach. The strip cast trials are carrying on, Paratore said. Its just that they are not the focus of 100 percent of our attention. With that, we are into post-production delivery to customers. Their testing will begin within the next quarter.
As with other NCS pioneers, Paratore is confident in his companys technological capabilities but anxious about market development. The business model in the automotive sector has to change to one of global standardization. The automakers are falling behind other OEMs because they are still using national or regional standards, he said. Automotive is 35 percent of steel demand, but they are the only major sector worldwide that has not reduced the number of distinct platforms. It is already happening in systems like braking and entertainment.
Beyond automotive, NanoSteel is chugging along with an older form of NCS: vapor deposition. For previous generations of NCS there was no ductility, so they had to be used for coatings. We are now working from there on powder metallurgy for laser-additive manufacturing, also known as 3D printing, for small parts and inserts, Paratore said.
Gregory DL Morris