Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 87
Chapter 8 PERCEIVED BOTTLENECKS IN TITANIUM PROCESSING A major task of the panel was to identify bottlenecks in the titanium production operations. Bottlenecks, for the purposes of this discussion are defined as constraints imposed on what might be thought of as an optimized processing procedure that involves time, resources, and costs. Also considered to be bottlenecks are weaknesses in the supply chain that cause expensive delays and that conceivably could become serious obstacles in certain emergency situations. Ore The world titanium ore supply situation was described in Chapter 4. It was noted that: (1) titanium metal comprises only 7 percent of total U.S. titanium demand whereas pigment comprises 93 percent, (2) the United States has ample domestic titanium ore reserves but imported concentrates provide about 55 percent of U.S. consumption because of lower costs, (3) imports conserve U.S. reserves, and (4) concentrates for pigment could provide emergency supplies for metal. Any emergency action, however, would require considerable coordination of facilities and time for conversion. Unlike pigment production that uses considerable domestic ore sources, the United States imports, most if not all, of the ore used for domestic titanium metal production. As far as the panel could determine, the current supply of ore to U.S. plants making titanium tetrachloride has not suffered major interruptions. It is conceivable, however, that supply lines could be interrupted extensively in times of hostilities when long over-the-ocean routes for supply vessels would be vulnerable to interdiction by hostile forces. A more secure and, in that sense, favorable situation would prevail if plans for securing a domestic ore supply for titanium metal production were made before any hostile action created an emergency. Ti tanium minerals are mined in the United States and planning for the emergency utilization of ore from such sources should be implemented. There are no current DOD plans known to the panel for tapping domestic ores in times of a national emergency; the U.S. National Stockpile is the sole source immediately available. Ores for titanium metal production cannot be discussed separately from titanium tetrachloride and titania (TiO2 f or pigment) production. The United States has a large domestic capacity for the production of these commodities, and either could be used as precursor material for the production of titanium metal. A small part of domestic titanium 87
OCR for page 88
88 tetrachloride production already is being used for titanium metal production (after required upgrading from the commonly available commercial product), as shown by its use by three sponge metal producers. Plans need to be draf ted and mechanisms for implementation need to be put in place for the utilization of domestic titanium tetrachloride by the larges t sponge producer, TIMET. TIMET possibly could use titania TiO2 produced f or pigment ~ in it s chlorinators f or the production of titanium tetrachloride within its own facilities in times of an emergency interruption of ores. However, planning for this alternative route has not been worked out. Although several companies in the United States make titanium te trachloride, only one make s a grade suitable f or metal production and actually sells it for this use, i.e., Gulf & Western (G&W) . For making the tetrachloride, this company imports considerable ore and the other part of its ore supply is reported to originate f rom domestic mines. A detailed breakdown of the amounts and the location of the domestic source were not available to the panel. Another company that has a very large capacity to produce titanium tetrachloride and that achieves considerable ore production from domestic mines does not supply titanium tetrachloride to the metal producers. It is understood, however, that tests and negotiations are under way to do this. This company could make a metal grade of titanium tetrachlori de since the company was a metal producer in prior year s . Talks should be conducted and arrangements and plans made for the utilization of the product from this plant for metal production so that its titanium tetrachloride could be made available quickly in times of a national emergency. Considering all of the above, there currently are no bottlenecks in ore supply or processing since that aspect essentially could be bypassed in domestic titanic sponge production. Titanium Tetrachloride The description of titanium tetrachloride production in the United States was covered largely in the previous section on ore. No bottlenecks were described by the major domestic metal producer (TIMET) In its production of titanium tetrachloride for its own use or by the other metal producers who buy t itanium tetrachloride from the current single U.S. supplier. Although an intensive study of the production of this commodity was not conducted by the panel, it has identified some potentially vulnerable areas related to titanium tetrachloride production that meri t study. For example, one must determine how secure TIMET production is with respect to such factors as reserve capacity, dependence on a single source of power from a vulnerable utility (dams and hydroelectric stations being prime candidates for sabotage), and supply of necessary augmenting chemicals to produce titanium tetrachloride (e.g. , petroleum coke).
OCR for page 89
89 Additional questions can be raised regarding the production by the company that sells titanium tetrachloride to the other metal producers ~ G&W) . Further, it should be of some concern that just two companies provide the entire precursor product for the entire domestic production of titanium metal. Plans for alternative sources should be studied. There is still another area of vulnerability regarding titanium te trachloride supply--that of transporting the product to the users . In the case of TIMET, there is no transportation problem since titanium te trachloride i s made on the s ite where it i s used . trachloride to RMI Similarly, there is no problem in transporting the te trachloride to RMI f rom G&W, the producing company, since it ~ s only one city block removed f ram the user and direct transport is by pipeline. Tank cars are used to ship titanium tetrachloride to D-H Titanium in Freeport, Texas, and to OREMET in Albany, Oregon. These extensive transportation routes are vulnerable. Moreover, the supply system is dependent on a specific type of tank car. As previously stated, no bottlenecks were found in the normal sequence of supplying titanium tetrachloride to metal producers. Even though specific studies to reveal possible bottlenecks were not conducted by the panel, enough is known about the limitations of the titanium tetrachlor~de supply system to cause concern should there be an emergency situation. Studies of the supply adequacy of this commodity should be made and planning should go forward to ensure a reliable supply of this vital precursor material to the metal producers. Titanium Sponge The domestic production of sponge titanium was studied at length. Immediately prior to the NMAB study--and continuing during the early part of its investigation--a sponge shortage resulted from inadequate (albeit probably caused by an "art if icial" shortage due to panic buying and double ordering ~ domestic sponge production capacity . That shortage now has been alleviated. Nevertheless, bottlenecks in the production of sponge should be addressed. For example, the two largest domestic producer s are making sponge with outmoded technology and equipment . The limited expansion and renovation of facilities now in progress by these two companies to improve the production of sponge may be inadequate In case of a national emergency. Other domestic titanium sponge producers are smaller and account for far less quantities of sponge, but they use more modern facilities--in some cases, not yet even In place, however. The fact that the product of the largest domestic producer of titanium sponge (TIMET) is unsuitable and the product of the second largest domestic producer (RMI) is marginal for the ingot melting furnaces of the domestic nonintegr~ted producers, may be considered to be a weakness in the capabilities of the titanium industry. In fact, in a national emergency that involved the stoppage of all imported vacuum-distilled sponge, the situation would be a real bottleneck because
OCR for page 90
go of the elimination of the melting capacity of the nonintegrated producer s . At pre sent, the one small producer of U . S . vacuum-dis t tiled sponge plus the currently planned production of vacuum-distilled sponge by a company now constructing facilities, and a further expansion of domestic electrolytic sponge titanium production should alleviate the problem to some extent, perhaps totally. This would depend on the achieved production from the newer facilities and the timing. Thus, there is a perceived bottleneck in sponge titanium supply. Specific processing bottlenecks identified are that: 1. Reaction pots for titanium sponge production by the major producers are of small capacity and probably too few in number. Excessive time and labor are required to remove sponge from the reactor pots. 3. The leach, wash, and drying time required for "purifying" newly won titanium metal is quite long and results, in some cases, in an environmental handling and disposal problem (exceptions are those cases for RMI and D-H Titanium that generate no disposable by-products). In one case, a sponge-inspection, hand-sorting line is necessary to remove contaminated pieces of sponge (discolored), an expensive and time-consuming operati on. The recycling of pots and by-products is expensive and time-cons~ming. 6. A current weakness, potentially a bottleneck, is the dependence of the nonintegrated ingot melters on imported titanium sponge. Ingot and mill product production from nonintegrated companies would be seriously curtailed in the event of an interruption of imported titanium sponge. These bottlenecks may or may not be subject to alleviation by piecemeal improvement of the specific operations per se. It may be fair to say, however, that the bulk of domestic sponge production facilities are in need of a gross overhaul; outmoded equipment should be replaced and technology updated. Plans have been made to accomplish that objective given the proper incentives. Ingot Melting Specific bottlenecks identified in the conversion of titanium sponge to ingots are that: 1. Sponge lots of various impurity contents must be blended with alloy additions and scrap constituents must be blended to
OCR for page 91
91 2. 3. 5. prepare specific compositional charges for melting. This is a time-consuming limitation associated with the overall melting operations. Also, the need to provide many alloys and grades of alloys is In itself a bottleneck in the production of ingot titanium. In many cases, to prepare consumable electrodes for melting, individual pieces of scrap titanium are hand-welded to construct an electrode shape, which is a time-consuming operation. In all cases, great care must be taken essentially to custom-build the electrodes. Melting-furnace equipment in some melt shops is antiquated. Melting rate is slower than optimum and controls for electrode positioning are inadequate. For some purposes, ingot size limitations are a bottleneck. Larger ingots can be produced with relatively smaller power requirements, thus increasing the unit processing efficiency. 4. Customizing compositions for specific customers, a present common practice, requires the construction of special electrodes f or the f irst melt , then constructing electrodes in a preferred manner to achieve ingot homogeneity in the second melt. Double melting in itself must be considered as a requirement for the industry and is not a bottleneck. However, the practice of triple melting ingots to meet the requirements of some specifications is considered to be a bottleneck. The U.S . ingot-making capacity is reduced by 10 to 15 percent as a result of the requirement to triple melt to meet some specif ications . The claim is that all ingot producers do not have to triple melt to meet the quality standards of triple-melt material. However, those producers claiming triple-melt quality after only double melting are forced to triple-melt to meet the somewhat arbitrary triple-melt specifications. [The claims are dif f icult to prove (i.e., it is difficult to prove a negative) since nondestructive testing techniques are marginal when applied to the problem of seeking proof s, and there is too little statistical history on which referees might pass judgment. ~ Thus, triple melting for premium-quality ingots remains as a requirement and as a bottleneck in terms of reducing melting capacity f rom what it would be without this requirement. There is a lack of adequate personnel who have sufficient background in melting operations to permit capacity expansion of ingot production. Whether or not this perception is general or specific to only a few companies is unknown. Nevertheless, expansion of U. S. melting capacity is slowed by the shortage of proper personnel.
OCR for page 92
92 Primary Fabrication Ingot Surf ace Conditioning Prior to ingot-breakdown forging operations, some companies perform extensive surface conditioning whereas other companies do not. Those that do not pert arm conditioning have found that bloom yields are essentially the same whether or not ingot surfaces are conditioned. Thus, a question is raised with respect to the need for this operation. Perhaps it is necessary for a few companies that, for one reason or another, do not produce acceptable surfaces on ingots during melting. The question needs to be resolved, however, so that the surface conditioning step can be bypassed if it is not needed, which would decrease processing time and increase production. In this sense, surface conditioning may be a bottleneck for some companies. Bloom Forging Bottlenecks in this operation are related to inadequate soaking furnace capacity, inadequate press capacity, and inadequate manipulators. As important as these equipment def iciencies is the inadequate number of professionally trained personnel who are trained to monitor metallurgically the breakdown forging operation and to operate the f orging equipment . All these def iciencies are not always prevalent at each plant pert arming breakdown forging . However, on an industry-wide basis, the inadequacies do constitute a bottleneck in the f low of titanium mill products to the market. Bloom Conditioning Almost without exception, rather extensive grinding and cropping operations are performed on ingot blooms to remove breakdown forging defects. These operations are responsible for reducing the yield from ingot and, of course, for increasing processing time . Techniques are available to reduce the grinding and cropping loss. For example, larger f orging equipment would permit larger, faster reductions at temperatures closer to the design-deformation temperature, and optimizing the fabrication of ingots to bloom would reduce losses. Another possibility, at least for some companies, would be to permit yttrium additions to the titanium materials (at the ingot-making stage). It has been shown that yields are increased markedly for yttrium-containing mater' als. Thus, the losses from ingot to bloom, ascribed to the ingot-bloom-conditioning operations, constitute a bottleneck in the processing of titanium. Although the conditioning operations may not be eliminated completely with improved fabrication (and alloying) practices, they may be reduced considerably. Planning for such improvements should be undertaken.
OCR for page 93
93 Billet and Bar Mo st of the billet and bar currently produced is processed through GEM rotary forging machines. Some bar is produced in rolling mills. Because the GEM machines are getting old and, in many cases, are undersized for the fabrications expected of them, production is considerably slower than would be the case on better equipment. This lack of adequate equipment for some fabrications may be considered a bottleneck. Almost as important as the reduction machinery for making billet and bar, the furnacing associated with those operations also has been reported as lagging. Many operations are plagued by slowdowns due to the need for furnace maintenance and to inadequate temperature control even when the furnaces are working. Therefore, this inadequacy of furnacing for billet and bar manufacturing is considered a bottleneck. Lack of sufficient trained personnel to schedule and monitor billet and bar manufacturing and to pert arm the subsequent inspection operations can be cited as another reason f or extended lead times in the procurement of these mill products. Such a personnel bottleneck can be corrected only after a rather lengthy training program is in place. Flat-Rolled Products Except for the larger plate products that are produced on a toll basis in steel mill equipment, about the same problems can be cited with respect to fabrication equipment, furnace ng, and personnel as were cited f or the billet and bar operations . The spotty production delays that are encountered are bottlenecks in the production of f lat-rolled products. Little is known about bottlenecks in the production of large plates of titanium at steel mills. One statement made is that titanium blooms sometimes are given a low priority for fabrications at steel mills and take a lower position in the fabrication schedule than is merited. One reason cited is that the steel mill operators and crew are paid on a weight throughput basis and, since a titanium bloom is light compared to a steel bloom, they postpone titanium rolling to a time of their own choosing. A relatively simple correction would be to develop a labor-management agreement to pay toll on a rolling-time basis or to otherwise adjust operator and crew wages to afford proper compensation commensurate with their steel-rolling wage scale (a weight ratio factor). Until remedied, this ridiculous situation remains as a bottleneck in the production of titanium plate. Other semi-products also are rolled in steel mill equipment on a toll basis. For example, hot band is produced on Steckel mills as precursor material for hand-mill sheet product in some company operations. A considerable amount of unalloyed titanium strip also is rolled in steel
OCR for page 94
94 company strip mills. The bottlenecks that might exist In this steel mill toll processing are unknown. It is known, however, that long scheduling delays have been experienced. Reportedly, some of these delays result from too little rolling-mill capacity to afford short-time, turn-around service in the strip rolling of titanium. Hence, because of scheduling difficulties, the toll rolling of strip may be considered to be a bottleneck. The hand-mill pack rolling of titanium alloy sheet products may be considered a technological bottleneck, albeit that the hand-mill processing of thin plates to sheet gauges in packs (within steel envelopes) is the accepted way to do it. The development of alloys amenable to strip rolling is one solution; direct powder rolling described in Chapter 11 is another, and perhaps there are other solutions. Meanwhile, the hand-m~lling of alloy titanium to sheet remains a rather slow production operation and is technically a bottleneck. Most flat-rolled product is surface-finished after the rolling operation. Mill scale and contaminated-skin layers must be removed, flattening often is called for, and inspections are made f or the detection of defects. The procedures outlined are necessary; however, it is questionable if the procedures are optimized technically. Therefore, they possibly constitute a bottleneck in comparison with improved operations. The real bottleneck exists, however, when the company lacks specif ic equipment to do a particular job and consequently must send the product out f or toll services. The transportation time and the toll shop scheduling for services constitute bottlenecks. Ro 11-and-Weld Tubing Titanium tubing most commonly produced is prepared from precursor strip (unalloyed titanium) by the roll-and-weld (longitudinal-weld) technique. The strip, after surface conditioning to finish gauge and final inspection, is slit to width. The strips are coiled and fed into the tube lines where automatic roll dies and welding turn the strip into continuous tubing which is cut to length. Lengths of tubing are individually inspected . Perhaps the processing speed of thi s tube-line equipment is optimum but it does appear slow. If research and development could improve the production speed of tube lines, this technical bottleneck would be alleviated. Extrusions A study of an extrusion facility having a high-volume production of titanium extrusions was not conducted. Bottlenecks in the production of extrusions, if they exist, were not identified within the segments of the titanium industry studied by the panel.
OCR for page 95
95 Conventional Powder Metallurgy The ready availability of sizable quantities of high-purity, reasonably priced titanium powder, especially titanium alloy powder, i s not yet. a reality. This powder availability problem represents a bottleneck to the more extensive use of powder. Quite possibly, thi s supply problem has resulted in some delays in expanding existing applications for the limited quantities of powder now available. The technical requirements for powder handling, consolidation, hot Ecstatic pressing (HIP), and heat treatment (if needed in addition to HIP treatments) may be thought of as a bottleneck because of the extensive scheduling and operations time needed. Castings The production of titanium castings also was not extensively studied. However, in the limited investigation conducted, it was found that the availability of electrodes from which castings are derived via the consumable-electrode process is a bottleneck, at least for some companies. It appears reasonable that this bottleneck could be reduced by some action determinable by a separate study of the problem. One solution is suggested in Chapter 11. The technical problems associated with producing sound, high-strength, high-ductil~ty, tough castings constitute a bottleneck in the application of castings. For example, castings for critical components require 100 percent inspection. Further, castings from some manufacturers require extensive weld repair. These production shortcomings constitute a major problem in the appli cation of castings and may be considered a bottleneck. Although investigated several time s without success, the development of an optimized titanium casting alloy might alleviate some of the problems. Specialty Products Some of the high-technology products (e.g., rolled shapes, alloy foi 1, wire, and seamless tubing) fall into the specialty products category. The production of these items was not studied; therefore, bottlenecks in their production are unknowns. General Comments to Bottleneck Custom-Job-Shop Status The titanium industry is largely a custom-job-shop metal operation. As such, by definition and practice, it is inherently a production of end products by starts and stops with the accumulation of ~n-process and
OCR for page 96
96 expensive inventories, and we th seemingly end, ess checks and inspections that of ten require ad justments in scheduling with frequent decision-making interruptions. Thus, the entire system--the nature of the business- way be considered a bottleneck-prone production system compared with the production of mass-produced standard products. Some relief of this condition might be found in the development of a more standard line of products acceptable to a broad base of less discriminating users. Although not studied in any depth, it is believed that the excessive transport of in-process products both wl thin plants (cross-hauling) and between plants ( someti mes by the distance of half a continent ) constitutes a bottleneck to the efficient production of titanium products. This problem might be alleviated by consolidating the production facilities at single sites, by acquiring the equipment and facilities now used on a toll basis, and by restructuring production lines within plants (to reduce cross-hauling). Ti tanium Tonnage Powder Metallurgy The titanium production system described above is like a Gordian knot--unravelable except by the stroke of a sword. For titanium mill processing, the sword may be tonnage powder metallurgy (TPM), not for complex powder metallurgical shapes weighing ounces or pounds but for mill products weighing tons. However, the TPM solution is by no means certai n; this is discussed in Chapter 11. Summary Perceived bottlenecks and weaknesses at the various titanium processing stages are summarized below (comments on their poSsi ble alleviation were of f e red in the preceding text ~ . Proce ss Stage Ore Titanium Tetrachloride Bottlenecks or Weaknesses Foreign source is a weakness. Long overwater transport is vulnerable. Only two plants as sources for the entire domestic sponge titanium production is a weakness. (A third has now come on-stream.) Long ~ overland ~ ral1 transport of titanium tetrachloride to three producers of titanium, in special rail cars, is a weakness.
OCR for page 97
97 Titanium Sponge Inadequate capacity was a bottleneck that appears to have been alleviated. Inadequate quality of sponge to serve all melters is a weakness. Reaction pots of small size is a bottleneck. Method of removing sponge f ram pots is a bottlenec k. Methods of post-winning purification of sponge may be a bottleneck. Di sposal of by-product acid-leaching wastes is uneconomic and environmentally undesirable. Auxiliary processes may be bottleneck. Batch, rather than continuous, winning is a bottleneck. Dependence of the nonintegrated melter s on imported sponge is currently a weakness. Ingot Melti ng The customizing of alloys and grades of titanium product for customers is a bottleneck. The necessity for blending sponge and scrap grades to prepare ingot compositions is a bottleneck. The construction of consumable electrodes f or melting i s a bottleneck. Insufficient numbers and sizes of melt furnaces are bott lenecks . The necessity for triple melting some ingots to meet special specifications is a bottleneck. The size limitations on ingots may be considered a bottleneck. A shortage of adequately trained personnel may be considered a bottleneck.
OCR for page 98
98 Primary Fabrication Bloom Forging The necessity of surf ace conditioning ingots may be a bottleneck. Inadequate furnace pert ordnance and capacity is a bottleneck. Inadequate press function is a bottleneck. Inadequate manipulator equipment ~ s a bottleneck. A shortage of personnel properly trained f or conducting and monitoring the bloom forging operations is a bottleneck. Bloom Conditioning The necessity for extensive bloom conditioning is a bottleneck. Billet and Bar Inadequate def ormation equipment i s a bottleneck. Flat-Ro lied Products Ro 11-and-Weld Tubing Inadequate furnace pert ormance and capacity ~ s a bottleneck. A shortage of personnel properly trained f or conducting and monitoring def ormation operations is a bottleneck. Furnacing and handling equipment and personnel inadequacies may be considered as bottlenecks for selec ted operas ions . The necessity to toll out fabrication, surface finishing, and inspection operations ~ s a bottleneck. The technological requirements f or producing alloy sheet s are bottlenecks . The low production rate of the tube lines is a bottleneck. Produc Lion not studied; bat tlenecks unknown. Powder Metallurgy The unavailability of low-cost, high-qualit>- titanium powder is a bottleneck. The necessity for multiple, technically precise operations in making complex-shape PM titanium products may be considered a bottleneck.
OCR for page 99
99 Castings The ready availability of consumable elec bodes for cast products is a bottleneck in some cases. The necessity f or extensive weld repair and 100 percent inspection is a bottleneck. Specialty Products Production was not studied; bottlenecks unknown. General The custom-job-shop nature of the titanium metal industry may be considered as a bottleneck to the more ef f icient production of ti tanium product s . The excessive cross-hauling of materials within plants and the extensive transportation of products between plants ~ including transportation of products to be serviced on a toll basis) constitutes a bottleneck to the more expedient production of titanium products .
OCR for page 100
Representative terms from entire chapter: