2

Materials Needs for the Industries of the Future

The materials needs of the IOF industries are documented in detail in the technology road maps, and the reader is referred to these road maps for listings and discussions of IOF materials needs. Only a sampling of the most important materials needs of the industries, especially the needs that are common to many industries, are included in this report. Table 2-1 summarizes important materials needs of the IOF industries, shows the relative importance of each crosscutting problem to individual industries, and lists one or two of the major problems facing each industry. The importance of each crosscutting materials problem to each industry is based on the prevalence of the problem in that industry and how well it is being addressed. Oak Ridge National Laboratory (ORNL) has performed an independent analysis of the materials needs of the IOF industries based on the road maps, and the results of their analysis were presented to the committee and included in the committee’s deliberations (Angelini, 1999).

Three things in Table 2-1 stand out immediately. First, many of the industries have some similar, if not identical, needs. Thus, selecting truly crosscutting R&D should not be difficult. Second, many of the important materials needs are in areas that are considered uninteresting, unexciting, or not on the cutting edge of technology. This fact must be considered as OIT project mangers establish the scope and extent of R&D programs. Third, a few areas of materials research are extremely important to ALL of the industries. Progress in these areas would, therefore, have the biggest impact on energy savings and waste reduction. These areas (corrosion, wear, high-temperature materials [including refractories], and materials modeling/database development) are emphasized in this report.

CORROSION RESISTANCE

Corrosion and oxidation are ubiquitous problems in industry, and there are no perfect solutions. Through research, they can be mitigated, however, by the development of materials, procedures, and coatings that can withstand specific process conditions.



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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE 2 Materials Needs for the Industries of the Future The materials needs of the IOF industries are documented in detail in the technology road maps, and the reader is referred to these road maps for listings and discussions of IOF materials needs. Only a sampling of the most important materials needs of the industries, especially the needs that are common to many industries, are included in this report. Table 2-1 summarizes important materials needs of the IOF industries, shows the relative importance of each crosscutting problem to individual industries, and lists one or two of the major problems facing each industry. The importance of each crosscutting materials problem to each industry is based on the prevalence of the problem in that industry and how well it is being addressed. Oak Ridge National Laboratory (ORNL) has performed an independent analysis of the materials needs of the IOF industries based on the road maps, and the results of their analysis were presented to the committee and included in the committee’s deliberations (Angelini, 1999). Three things in Table 2-1 stand out immediately. First, many of the industries have some similar, if not identical, needs. Thus, selecting truly crosscutting R&D should not be difficult. Second, many of the important materials needs are in areas that are considered uninteresting, unexciting, or not on the cutting edge of technology. This fact must be considered as OIT project mangers establish the scope and extent of R&D programs. Third, a few areas of materials research are extremely important to ALL of the industries. Progress in these areas would, therefore, have the biggest impact on energy savings and waste reduction. These areas (corrosion, wear, high-temperature materials [including refractories], and materials modeling/database development) are emphasized in this report. CORROSION RESISTANCE Corrosion and oxidation are ubiquitous problems in industry, and there are no perfect solutions. Through research, they can be mitigated, however, by the development of materials, procedures, and coatings that can withstand specific process conditions.

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE TABLE 2-1 Importance of Selected Materials Needs to IOF Industries   Agriculture Aluminum Chemicals Forest Products Glass Metal Casting Mining Steel Forging Heat Treating Corrosion * ** *** *** ** ** *** ** * * Examples Corrosion by agricultural chemicals Liquid aluminum attack on refractories Corrosion of reaction vessels and pipes Boilers, black liquor Molten glass attack on refractories Molten metal attack on refractories Drilling mud and effluent gases Corrosion of refractories and mill equipment N/A N/A Wear ** * ** *** ** ** *** *** * * Examples Abrasion of earth-moving parts Wear of refractories Liquid/solid abrasion in pipes Wear of raw materials parts and abrasive wear during paper manufacture Wear of refractories in tanks and on handling, molds, and process machinery Wear of dies Wear of drill bits Wear of refractories and equipment for handling hot metal Wear and cracking of dies   High-Temperature Materials (including refractories) * ** ** * *** ** ** *** ** ** Examples   Refractories, anodes, cathodes Containment vessels, refractories Boilers Refractories Dies, refractories Tools and down-hole equipment Better refractories Dies Handling equipment Modeling/Database Development * ** *** ** ** ** *** ** * * Examples   Modeling of castings, modeling of smelter cells Long-term materials response to harsh environments Corrosion modeling Process modeling and refractory response Heat-flow modeling and design of gates and risers Lifetime modeling of down-hole materials Lifetime of materials used in handling Thermo-mechanical response of dies, etc. Thermal response of materials

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE The chemical process industry has long had serious corrosion problems that affect efficiency of production (necessary down time, achievable process rates), product purity (contamination), energy usage, and maintenance costs. The following excerpt from the chemical industry road map will give the reader an idea of the serious needs of this industry. Materials are needed to withstand high temperatures (1000°–3000°F) while retaining superior properties of strength, ductility, corrosion and wear resistance. One of the greatest causes of equipment failure in the chemical process industry is damage due to corrosion and high temperatures. Materials with enhanced resistance to organic acid environments could improve plant operations and maintenance requirements. Improved materials for chlorine based processes are another high opportunity area. Equipment that is more resistant to chlorine and other halogens would reduce the cost of many of the current corrosion problems encountered in dealing with these materials. Refractories and refractory coatings for high temperature furnaces are critical opportunity areas where new materials could have a significant impact on energy and maintenance costs. Development of high temperature non-stick surfaces could potentially improve maintenance of chemical process equipment. Most available non-stick coatings degrade or become volatile at high temperatures, limiting their usefulness in high temperature conditions (MTI, 1998). The glass industry also has serious corrosion problems. In fact, molten glass has been referred to as a universal solvent. Note that materials that can function effectively in very aggressive environments are mentioned in several different connotations. The lack of cost-effective materials that perform adequately in glass furnace environments is another key barrier. In particular, there is a strong need for better refractory materials that can withstand very high temperatures, erosion, and corrosion, but not adversely affect the quality of the glass product. Another materials-related impediment is the performance limits of materials that contact the glass and are exposed to harsh operating environments. Advancement in these areas has been partly limited by a lack of good data on materials properties (Energetics, 1997a). The lack of corrosion resistance has prohibited the use of glass fibers as the reinforcing agent in reinforced concrete. Although the market for this product is potentially large and very lucrative, alkali-resistant glass fibers are not available. Corrosion is also a serious problem in steel plants. Aqueous corrosion occurs wherever water is used for cooling; oxidation occurs whenever steel is exposed to high-temperature oxidizing gases (e.g., in reheat furnaces and caster runout tables). Because all of the IOF industries use or generate heat as part of their processes, refractories are crucial. Oxidation of refractories is mentioned in nine of the eleven IOF road maps listed in Table 1-2 , and the costs of replacing refractories (in terms of materials and down time) are high. Corrosion and oxidation of

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE refractories in the melts in which they are immersed has substantial financial costs and lowers productivity in the steel industry. However, the initial cost and lifetime costs of longer lasting refractories will have to be within the economic constraints of the IOF industries. Because of economic realities in the refractories industry, further improvements are likely to be incremental rather than radical (Freitag and Richerson, 1998). Ceramics, composites, and ceramic coatings are obvious materials for high-temperature applications, but the environmental degradation of these materials is a serious problem. Oxide ceramics are clearly preferable for use in oxidizing conditions but often do not have the necessary mechanical or temperature capability (within the cost restraints of the industry). Silicon carbide and silicon nitride have the high-temperature capability, and silicon carbide is particularly resistant to wear. However, both monolithic and composite materials oxidize and corrode in the severe conditions found in many industrial processes. Many different coatings are used to mitigate corrosion and oxidation problems, but they only delay the inevitable. No universal coating has been developed. The oxidation of coatings is mentioned as a problem in five of the eleven IOF road maps. Clearly, a fruitful area of R&D would be the design, production, and characterization of more effective coatings. WEAR RESISTANCE The wear of materials causes very serious problems in many industries. Equipment that comes in contact with even mildly abrasive substances is subject to wear and requires repair, or even replacement. In the forestry industry, dirt and sand on the incoming logs causes wear on the equipment. In agriculture, equipment that bites into the earth is subject to serious wear problems; the same is true for equipment used in the mining industry. In the most severe conditions, tools with diamond inserts or composite (e.g., tungsten carbide/cobalt) inserts are used to maximize lifetime. In surface mining, as in other industries, wear is a complex problem. Abrasion is the principal problem in the mining industry, but impact, erosion, galling, scuffing, fretting, and rolling contact are also problems. The forging industry would benefit greatly from new materials for dies and die making. The highest priority research for die making and materials is the development of a multi-attribute, heterogeneous die that eliminates the need for lubricants. This would be an engineered die that would have different material characteristics in various parts of the die to match the specific performance requirements of that area. This would provide greater wear resistance in areas that have a lot of material movement across them and would minimize friction and lubrication needs. Another research approach to extend die life is to develop coating and cladding of the die material (Energetics, 1997b).

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE HIGH-TEMPERATURE MATERIALS Because the rates and efficiencies of many processes increase with high temperature, there is always a demand for materials that can operate at higher temperatures. However, the cost of metallic materials increases as the operating temperature increases because the alloying elements necessary to increase temperature limits are themselves expensive. (Refractories are described in greater detail in Chapter 5 as an example of a crosscutting area for the IOF.) Gas turbines operate at the highest temperatures for metallic materials. Several technologies will have to be developed for low-emission, cost-competitive, small gas-turbine power systems for the distributed generation of electricity. The firing temperature will have to be increased substantially without exceeding the low life-cycle cost required by end users. Materials developments will include thermal-barrier coatings, advanced sealing techniques and high-thrust bearings, ceramic-matrix-composite combuster liners, ceramic turbine vanes, and other stationary components. Although the scale-up of single-crystal alloys has been accomplished, they cannot be produced at an acceptable cost for stationary turbines. In addition, users will require durable, long-life barrier coatings for oxidation resistance. An OIT program has developed one successful new material from an intermetallic compound, Ni3Al (NRC, 1997). Research on Ni3Al was begun at ORNL in 1981 and continues even today. A number of other laboratories and universities have also been working with the ORNL team. As this example shows, industries that request the development of new high-temperature materials must be aware of the long timeline for development. Between 1981 and 1996, ORNL spent about $27 million on this program. Trials of Ni3Al began in 1993, and Bethlehem Steel Corporation is now using the material in steel mill rolls and has placed a large order with Sandusky International for more. Other applications are now being evaluated, but the Bethlehem Steel order is the first substantial recognition of the usefulness of Ni3Al-based alloys. The cost for the steel mill rolls is now 50 percent of the cost in 1993. Because no failures have been experienced so far, lifetimes have not been determined. The heat-treatment industry could also benefit from higher temperature operations. This industry requires improved heating-source materials, alternatives to radiant-tube heating for more uniform temperatures, improved furnace-fan materials with increased creep strength, and advanced insulation materials to improve furnace efficiency, cost, and performance. The road map for the heat treating industry identifies a need for a number of new materials that could operate in higher processing temperatures and the development of compositions optimized for specific heat treatments (ASM Heat Treating Society, 1997). General Motors has been evaluating heat-treatment (carburization) fixtures made from the alloys developed at ORNL. Although Ni3Al-base alloys have been

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE shown to be much more resistant to carburization than the usual steels used in this application, as of 1996, no large orders had been placed because no component failures had been experienced so failure mechanisms were not known. Users have been reluctant to proceed until an economic incentive for their use has been demonstrated. MATERIALS MODELS AND DATABASES All of the IOF industries have noted the lack of materials modeling capability. In the metalcasting in/dustry road map, for example, two outstanding problems related to materials properties are cited: (1) a lack of fundamental knowledge of materials properties as a function of chemistry and casting route, and (2) a lack of operating data for the simulation and modeling of properties (CMC, 1998). The combined use of models and sensors would be a powerful tool for controlling processes, preventing failures, lowering costs, and increasing energy efficiency. Materials modeling, linked to materials databases, is important for designing improved materials. Rapid increases in computing power have made possible materials modeling and the design of materials from first principles. Materials modeling, whether for design or for determining the performance of existing materials under operating conditions, requires databases. Even the best materials models will not function properly if the necessary databases are not available. Therefore, the development of materials models must be done in coordination with the development of databases, which could be extremely expensive. Although the need for materials databases is widely recognized, the resources for generating and funding these databases have not been forthcoming. Databases and models are used by the designers, producers, and users of materials and are clearly outside the scope of any individual agency. Therefore, interdisciplinary R&D, with customization for specific industries, will be necessary. ISSUES THAT IMPACT CROSSCUTTING PROGRAMS A number of common issues and emerging technologies will impact crosscutting materials programs. These issues include digital product and process modeling capability; materials producibility and affordability; variation and quality control; pollution prevention technologies; and advanced maintenance technologies.

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE Digital Product and Process Modeling As competitive pressures force shorter product development and realization cycles, every decision in product and process synthesis requires high-fidelity modeling and simulation to validate physics-based or behavior-based design attributes. The effective use of modeling tools for dynamics, thermal, mechanics, material, and behavioral systems are the prerequisites of tomorrow’s digital manufacturing. These models and the knowledge base will have to be shared in a networked and collaborative environment. The most recent work stations are capable of solving intensive engineering problems in hours, sometimes even minutes. For example, with ProCast finite element modeling and simulation tools, engineers can visualize possible cracks in casting parts caused by thermal variations in the manufacturing process. The manufacturer can then use these simulation models to assist suppliers in changing mold designs and delivering near-zero-defect casting parts that minimize reworking and defects. Materials Producibility and Affordability The affordable fabrication of materials is a challenge to all manufacturing sectors, especially the aerospace industry. As environmental regulations and performance requirements become more stringent (i.e., buy-and-fly ratio), companies are looking for better superalloy high-temperature materials and near-net-shape processing technologies to reduce the costs of raw materials and manufacturing operations. Currently, most research tools and process models in the research community are inadequate for predicting and validating material properties in manufacturing processes. For example, the casting of titanium-based aerospace parts requires labor-intensive, repetitive monitoring of material properties in the production process to ensure quality and reliability. Research focused on measuring on-line, residual stress in materials during the manufacturing process would help the industry. The research should expand the monitoring focus from dimensional accuracy to materials performance to provide a better understanding of the quality of processes, machines, and parts. This research could eventually lead to interdisciplinary research on integrated materials, manufacturing, physics, and computation, which would advance the fundamental understanding of manufacturing science and would benefit all industries. Variation and Quality Control Smart production systems could monitor process variations and lead to higher quality, less expensive operations. Research could focus on the development of

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE adaptable, reliable, intelligent process-control software that includes real-time, onboard models of machine, process, material, and environment. The objective would be to guarantee process and product quality globally through an integrated engineering regulating point system. To control process variations, process industries need reconfigurable, reusable, self-learning, and knowledge-transferable systems that can be added to sensors and process-control systems. Green Products and Processes Better integrated sensors and process-control technologies would improve energy efficiency and reduce waste generation, while lowering development and installation costs. A green manufacturing system (i.e., a green factory) would enable plants to monitor process parameters and would provide accurate information directly and quickly. Another pollution-prevention technology, alternative chemical-based coatings, would promote chemical-free manufacturing processes. Innovative sensors could monitor and control chemically corrosive environments. Emerging technologies, such as microelectromechanical system (MEMS)-based process sensors and wireless communications, would help in the development of environmentally benign technologies. Advanced Maintenance Technologies for Product and Process Performance Service and maintenance are important to maintaining product and process quality and customer satisfaction. The recent rush to embrace computer-integrated technologies in manufacturing industries has increased the use of relatively unknown and untested technologies. The difficulty in identifying the causes of system failures that use these technologies has been attributed to several factors, including system complexity, uncertainties, and lack of troubleshooting tools. Currently, service and maintenance in many manufacturing industries are still reactive. The problem arises from an incomplete understanding of the day-by-day behavior of manufacturing machines and equipment. We simply do not know how to measure the performance degradation of components and machines, and we lack validated models and tools to predict what would happen when process parameters take on specified values. Research should be focused on determining the factors involved in product and machine breakdown and on developing smart, reconfigurable monitoring tools to reduce or eliminate production down time and reduce dimensional variations caused by process degradation. Achieving these goals will require intelligent reasoning agents in process controllers to provide proactive maintenance capabilities, such as measurements of performance degradation, fault recovery, self-maintenance, and remote diagnostics. Manufacturing and process

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MATERIALS TECHNOLOGIES FOR THE PROCESS INDUSTRIES OF THE FUTURE industries could then develop proactive maintenance strategies to guarantee the quality of process performance and ultimately minimize system breakdowns.

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