Liquid metal processing - potential for the '90s.

Liquid Metal Processing - Potential for the '90s

Mr. Chairman, ladies and gentlemen, it is a great honor to have been given the opportunity to present this year's Hoyt Memorial Lecture. Like most of my predecessors, I have some ideas to bring to your attention. They concern needed foundry technology and ways to achieve it.

What better forum could there be for a discussion of technological needs than this one, with an audience representing the industry's technological leadership? I will illustrate my ideas regarding foundry technology, using liquid metal processing as the example, hence the title of this talk. I am sure you will have no difficulty in extracting the general message.

Let me preface my remarks by congratulating everyone present. This is the first national foundry meeting of the '90s. That officially makes us all survivors of the '80s.

Looking Ahead

What do the '90s have in store for us? Hopefully, the trends of better times that we have enjoyed for the past few years will continue through improved U.S. foundry competitiveness. Despite the improved health of the U.S. foundry industry, I detect no complacency among foundrymen today. I think we all recognize that our industry remains in a highly competitive situation. In fact, the competitive forces facing us today are more varied and complex than those we faced in the '80s. Markets in some areas continue to decline. There is continued competition from alternate materials and processes. Environmental pressures are escalating and they threaten every aspect of our industry.

There is competition from emerging nations with low labor rates and competition from technologically advanced nations with sophisticated and efficient foundries. There is intensifying competition between iron and aluminum castings for the same markets. And, finally, there still is the traditional competition among foundries for a larger share of the market.

With competitive forces approaching from so many directions, how can we deal with the pressures of the '90s?

It is clear that the tactics that helped us survive the '80s will not be of much use. It is unlikely that the dollar will be devaluated any further, there is little fat left to trim from current foundry operations, and the quality and cost benefits obtained from statistical process control, have mostly been taken. I suggest that the competition is about to shift to the arena of technology because technology has the power to alter the balance in each of the existing areas of competition. * Technology has the power to overcome shrinking markets by creating new and higher value-added products. * Technology has the power to overcome the advantages of competing materials and processes with new and improved cast materials and casting processes. * Technology can help us ward off overseas competition by offering superior products and minimizing costs. * Technology is the only means for solving our environmental and tramp element problems that threaten the manufacture of castings.

It is clear to me that the kind of technology that is developed and the efficiency with which it is applied will determine who will be sitting here 10 years from now, being congratulated for having survived the '90s.

For the foundry industry to grow, progress and innovation are needed in all aspects of founding. If we examine emerging technology, there is good reason for optimism. This suggested the title of this talk, "Potential for the '90s."

Unfortunately, if we measure the rate at which technical change is actually taking place in the foundry, there is also reason for concern. From the standpoint of technology, most U.S. foundries are hardly different today than they were 10 years ago. Granted there is better ventilation and our smoke stacks no longer spew red smoke. However, these were legislated changes, not technical changes designed to improve castings and foundry processes.

Liquid Metal Processing

On a relative scale, liquid metal processing perhaps suffers most from lack of progress. However, this lack of technical progress is a general problem. As evidence, let me remind you of the motto, "Let's return to the basics," that has dominated our industry's efforts for the past decade. The statement clearly indicates the emphasis has been on repairing previous neglect of well-established principles, not the application of new technology.

Unfortunately, time has not stood still. In the decade we spent repairing previous neglects, competing materials and processes have become more sophisticated, environmental constraints have escalated and state-of-the-art foundries have been built throughout the world. As we enter the '90s, a return to the basics will not be enough. Instead, competitive rewards await those who develop and adopt needed new technology.

As George Booth, general manager of Ford Motor Co's Casting Div., recently wrote: "The next decade will be one filled with dramatic changes and opportunities for those that are willing to discard old ways and move progressively into the future...Those who can adapt to these changes will survive. Others, as we have already seen, will not." [1]

What then are the dramatic changes and opportunities that await us in the processing of liquid metal? First, there are opportunities to make dramatic improvements in the productivity and the attendant cost of liquid metal processes.

Second, there is the opportunity to reduce the cost of consumable materials. These are the metallic charge materials, alloys, inoculants, fuels and refractories that are required to produce castings. Reducing these costs will require new and improved processes.

Automation and computers offer the third major area of opportunity. Just imagine a totally automated foundry. A computer-driven system charges the melting furnace. Sensors automatically control melt composition, while other detectors are constantly on guard to warn of equipment malfunction. In case of problems, computers stand ready to set into motion corrective procedures.

Further down the line, liquid metal is transferred down the chain from melter to mold without human interaction. This includes addition of inoculants and special chemicals that will prevent gases in the mold from entering the liquid metal. Although this is a dream today, many elements of the dream are currently under development. And, it is not farfetched to think that it will be a reality by the end of the decade.

The fourth area of change and challenge relates to the environment. There is no doubt that environmental concerns will be one of the most pressing issues facing foundries in the 1990s. These issues are threatening our traditional processes and, in the long run, environmental issues rather than economic issues might determine the processes we use. Unfortunately, the environmental issue affects competitiveness because, at present, other areas in the world are not faced with the same environmental constraints that we have. It is clear that our foundries need to be made environmentally secure without jeopardizing our competitiveness.

The fifth and last area of change and challenge, like the environment, is a negative factor with which we must deal. This is the issue of tramp elements that threaten our supply of raw material. Today, zinc coated steel is a major problem in ferrous melting. A few years ago aluminum contamination was a problem. The tramp element problem is destined to become more serious for both iron and aluminum castings due to the proliferation of alloyed materials. It is clear that the foundry industry has a big stake in preparing itself for tomorrow's tramp element problems.

Implementing Change

I have outlined the five major areas where technological change will have the greatest impact on liquid metal processing in the '90s. Although we have not discussed the specifics, it should be clear that the areas of need and potential are so broad that no foundry, no matter how large, has the ability or facility to address even a fraction of these issues.

How then can we make needed progress to improve our processes, reduce raw material costs, develop automation, solve environmental issues and prevent harm from tramp elements -- and do it fast enough to have a positive competitive impact? Hans Heine, technical editor of Foundry Management & Technology magazine, made a useful suggestion in a recent talk given to the Detroit AFS Chapter.

The basic idea is that instead of competing with each other on every front, we should "pool resources to generate new technology, and then compete in putting the technology to use." The idea is simple, it makes sense, but judging from our industry's minimal expenditures for cooperative research and development over the years, that is not how we have been doing business. As a result, we are an industry with serious catching up to do.

Today, I would like to get the ball rolling by suggesting a number of programs that we could fund collectively and compete on individually. The ideas concern liquid metal processing. All the programs address important technological issues. All the programs, because of their magnitude, require co-funding if they are ever to reach fruition.

Concerning improvements in the productivity and cost of liquid metal processing, I see major opportunities in the area of melting as a number of new and innovative melting units are now available. These include: the medium-frequency induction furnace, the cokeless cupola, the plasma cupola and the jet melter. Despite the attractiveness of these concepts and genuine industry interest, the rate of their adoption has been slow because many foundries have excess melting capacity that makes it difficult to justify the purchase of new melting units.

Given the excess capacity, a far more attractive option for foundries is improvements to existing melting units. In this respect, there is no better example than the charging of small amounts of metallic aluminum into the iron-melting cupola furnace. The process is simple, requires little or no capital investment and it provides large benefits. [2] For example, the addition of 1-2 weight-percent of aluminum to the cupola charge eliminates the usual oxidation loss of silicon and manganese. It increases the carbon content of iron and raises the iron temperature (Fig. 1).

The remarkable benefits obtained from aluminum arise from its ability to preferentially react with iron oxides that are generated inside the cupola. These oxides ordinarily react with carbon, silicon and manganese to produce the alloy loss associated with cupola operation. The aluminum-iron oxide reaction also generates large quantities of heat, which increases iron temperature and provides a basis for fuel savings.

Despite the obvious benefits of the process, it has been implemented in only a few foundries because there is residual aluminum in the liquid iron, which raises fears about gas defects.

Solutions to the residual aluminum problem are needed. Despite its terrible reputation, the aluminum problem is not insurmountable. When a solution is found, aluminum additions will provide major benefits in lower costs and more consistent iron composition.

Reducing Consumables' Cost

The second major area of technological change is concerned with reducing the cost of the consumables used in liquid metal processing. Since a significant fraction of the cost of a casting is the cost of raw materials, it is clear that savings in this area would make important contributions to foundry competitiveness. Reducing raw material costs is not easily accomplished, however.

It is an unfortunate fact that when a means for utilizing a low-cost material is found, the demand for the material increases and so does the price. The best way to circumvent this dilemma is to utilize a material with a source of supply that is so large that the foundry application will have little effect on the total demand.

A material that meets this criterion is a pellet containing iron ore and carbon which can be converted to metallic iron in the cupola. Today, the commercial reduction of ore to iron is carried out in blast furnaces, where carbon monoxide and hydrogen in the blast steam diffuse into iron ore pellets, and over a period of hours, reduce the oxide to the metal (Fig. 2). The exciting thing is that this process can be accelerated, with the reduction completed in minutes, if carbon monoxide is generated inside the ore pellet [3]. This is accomplished by including carbon in the pellet (Fig. 3). The process for production of iron from carbon-ore pellets has been carried out successfully in cupolas. Further, silicon and manganese have been produced in cupolas in similar fashion.

It would seem the next logical step is to produce cast iron, to specification, by using appropriate mixtures of iron, silicon and manganese pellets. The estimated cost of liquid iron produced by ore reduction is very low, about $100/ton.

It should not be overlooked that the iron and alloy elements produced in this manner are free of tramp elements. In this respect, the metal product is equivalent in quality to high-cost pig iron.

Two processes for cupola smelting of ore have been developed [3,4]. Because of the limited resources available to the developers, the processes need further optimization. The available evidence suggests that an investment today in needed optimization studies would yield a valuable new foundry process to produce low-cost, tramp element-free, cast iron or ferroalloy.

The third area of opportunity is automation and computers. There is no doubt that computers will help to revolutionize the foundry. However, for liquid metal processing, the field is still in its infancy. A major impediment to the application of the computer's full power is our lack of understanding of foundry process fundamentals. Simply put, if you don't understand how it works, how can you teach the computer? I believe it is inevitable that the availability of computers will create a very large driving force for the development of fundamental knowledge of foundry systems.

To illustrate what can be done, I would like to describe the work in progress to develop a user-friendly, process model of a cupola operation. The goal of the program is to be able to accurately describe cupola performance in real time. This will enable a foundry to instantly diagnose cupola performance and it will suggest changes that are needed to achieve a desired operation. The model will also run off-line studies to establish the cost and operating consequences of intended changes in the process. In the long run, the model will automate cupola operation using information obtained from a variety of sensors.

Unlike any previous model, the current model describes the processes that take place inside the cupola in order to determine the state of operation. The project is nine months old, and already effective heat transfer, fluid flow and chemical models have been developed. As anticipated, the modeling effort has identified areas where fundamental information is needed to improve computation. Studies to secure this information will be carried out in the next phase of the program.

It is clear that few foundries have the resources to accomplish this modeling effort alone. Indeed, the program is being funded by the American Foundrymen's Society, the U.S. Department of Energy and 19 foundry and supplier corporations, who, together, have committed $1.5 million to a three-year program. I am convinced that when this program is completed, we will be able to facilitate and optimize cupola operation to a degree that few have ever conceived as possible.

Environmental Issues

Concerning environmental issues, I don't think there is a single foundryman in the U.S. who doubts that environmental issues will force changes in the foundry of the '90s. No process, no matter how important, is exempt from scrutiny. We are all aware, for instance, of the attempts being made to classify silica as a carcinogen and the potential impact it could have on the foundry industry.

To a large extent, our industry has taken a "bury your head in the sand" approach in dealing with environmental problems, hoping that it would all go away. To the contrary, environmental regulations are becoming more stringent. In order to develop a rational defense, we need to identify the key issues and problems. Once determined, we need to apportion resources so we are prepared for what lies ahead.

One of the most serious consequences of not doing so is the inability to plan major investments in foundry plants and processes without taking major environmental risks. In this respect, managers always have one sure option for avoiding the risk: locate the plant offshore.

As you probably know, there are a number of potential environmental problems that affect the processing of liquid metal. I would like to suggest one of these for study. It concerns the availability of foundry coke and the long-term future of the cupola.

In the steel industry, the environmental problems related to cokemaking were one of the key issues in the decision to abandon the blast furnace and cokemaking in favor of new processes based on coal and oxygen. These processes are not attractive for the manufacture of cast iron. Although the foundry coke industry is in a much better position environmentally, there is no guarantee that the current safe status will not suddenly change.

Just three weeks ago, major changes were made in the emissions standards for coke ovens which the steel industry claims it cannot meet.

With perhaps 70% of cast iron produced in cupolas and with environmental regulations becoming ever more stringent, wouldn't you agree that foundries with cupola melting should consider what would happen if coke became unavailable? I believe if it would happen, it would not signal the demise of the cupola because the counter-current shaft furnace concept has too many virtues to be abandoned.

In my opinion, if coke becomes unavailable, alternate fuels will come into use. The most likely fuel is formed coke, which is coke produced by a more environmentally acceptable process. The second choice fuel is natural gas or a similar gas synthesized from recycled plastic.

None of these systems is sufficiently developed for us to feel assured that an alternative is available. Good business practice would dictate that we eliminate our vulnerability by developing needed formed coke and cokeless cupola technology. As added incentive, formed coke and the cokeless cupola could prove to be superior concepts in their own right.

Gas Defects

The final area that will see changes in the '90s concerns tramp elements. Although there is a need for processes to help us combat the effects of an increasingly contaminated scrap stream, I would like to consider a more immediate problem. This is the problem of gas defects, which to my mind is a tramp element problem.

Gas defects remain a serious problem, and the trend to thinner-wall castings and higher strength alloys will intensify the problem. The literally hundreds of papers written on the subject of gas defects are filled with contradictory information, which suggests that solutions to the new problems will not be easily found. Clearly, further understanding is needed.

I really became convinced that further work was needed in this area just two years ago, when I attended the CMI-sponsored symposium "Gases in Cast Iron," with the industry's most prominent experts there to discuss the subject. The first thing I noticed was that the auditorium was packed. From that I inferred that gas defects were still a problem.

I then noted that most of the papers being discussed were more than 20 years old. When I asked the speaker why there weren't any more recent papers in the packet we got, he replied that there were no more recent papers. Why?" I asked. "Because it is impossible to get research money," was the answer.

Despite the amount of information published about gas defects, it's plain to see that the subject is still not well enough understood to consistently solve the foundryman's problems. Today, gas defects often present only cosmetic problems. With thinner-wall castings and higher-strength alloys on their way, the problems will not be cosmetic. Do we wait, as usual, until the situation becomes desperate? Or, can we trust our judgment that there is a need to establish programs in this area right now?

The list of projects I have described could have been longer but you have been spared by the time limitation placed on this talk. Similar lists of projects can be made for the cast materials and molding segments of the industry. Clearly, if the composite list of projects were judiciously screened for relevance and impact, I expect a relatively long and impressive list of programs would survive.

How then do we implement these programs? As I indicated earlier, by pooling resources to fund and conduct needed research and development.

Solutions

There were three key phrases in that last statement. The first was pooling resources. Pooling provides a vast return on investment for foundries. A good illustration is the cupola modeling project. The program costs individual foundries only about $5000 a year, which is only 1% of the project cost. In this case, the tangible interest demonstrated by the foundry contributions attracted 80% of the needed funds from non-foundry sources.

The second key word was fund. As I just indicated, foundry interest demonstrated by the willingness to partially fund programs is a key factor to obtain participation by large contributors, such as government agencies and industrial institutes.

Obtaining funds from the foundry industry has been a problem in the past. In this respect, a quote from AFS past president Tim Hitchcock is appropriate. [5] It concerns institutionalized errors, which certainly is an apt description for the lack of funding of research and development. He said: "No one is going to change until management does."

I believe management's attitude toward industrywide R&D is the biggest uncertainty in our technological future. Hopefully, the painful experience of the '80s, the determination to maintain a powerful U.S. foundry industry and the understanding that technology is the next competitive frontier have changed this attitude.

The third key phrase was conduct needed research and development. This will require a new type of partnership -- a partnership between industry and academia. The growing complexity of technology is making it evermore difficult for foundries to carry out major research projects. This is illustrated by an examination of AFS Transactions.

In 1955, almost 90% of the entries in the AFS Transactions were contributions from industry or industrial laboratories. By 1989 this number had shrunk to 40%.

The cupola modeling program demonstrates the type of cooperation that is currently needed to carry out highly technical programs. In this case, two universities are working on the laboratory and mathematical modeling aspects of the problem, with industry converting their output to practice.

The U.S. foundry industry is fortunate to have a wide range of expertise among academics who are interested in foundry science and technology. Many have been struggling to maintain their foundry interests. This academic base is a vital asset to the U.S. foundry industry if we are to make the needed technological strides.

Today's academics, as a group, are very conscious of industry's needs, and in most cases, make excellent partners. A byproduct of the partnership will be the education of professionals with backgrounds that are sorely needed by the foundry industry.

It seems to me that the U.S. foundry industry is potentially well positioned to take on the challenges of the '90s. Whether we succeed depends on whether we take up the mantle of technological leadership.

My feelings in this regard are best expressed by a recent statement made by J.R. Stover, chairman of Eaton Corp, regarding revival of U.S. manufacturing after the near disaster of the early '80s. He said: "Our task is to see (to it) that we don't waste this second chance for leadership in the new, consolidated world markets that are now taking shape." [6]

Ladies and gentlemen, I hope you agree!

References

[1.] G.N. Booth, "Foundry Technology in the 1990s,"

modern casting, December 1989, p 15. [2.] S. Katz and V.R. Spironello, "Effect of Aluminum

on Iron Temperature, Silicon Recovery, and

Desulfurization in an Iron-Producing Cupola,"

AFS Transactions, vol 92 (1984), p 161. [3.] F.J. Weiss, A. Goksel and F.T. Kaiser, "Production

of Hot Metal from Carbon-Bearing

Iron Oxide Pellets by the Pelle Tech (PTC)

Process," Iron and Steel Engineer, February

1986, p 34. [4.] J.E. Rehder, "Hot Metal from Ore and Coal Fines,"

Iron and Steel Engineer, May 1980, p 31. [5.] D.P. Kanicki, "Back to School on Quality,"

modern casting, May 1989, p 7. [6.] J.R. Stover, "Second Chance for Manufacturing,"

33 Metal Producing, February 1990, p 9.

Mr. Katz, who is principal research scientist, Metallurgy Dept, General Motors Research Labs, delivered this address April 23, 1990 during the 94th AFS Casting Congress and CastExpo in Detroit.

PHOTO : Fig. 1. Advantages of aluminum addition to the cupola charge.

PHOTO : Fig. 2. Schematic representation of ore reduction in the blast furnace.

PHOTO : Fig. 3. Schematic representation of ore reduction in the cupola using carbon-ore pellets.