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By A. I. Blank, S. E. Maddigan

Many experimental and theoretical investigations have been made on the processes involved in annealing and recrystallization of metals. Most of these, however, have treated the time element as constant and heat-treatments used have been for relatively short times. Aside from the early work by Carpenter and Elam,' the few that have investigated the effect of time on the processes have usually done so for fairly short time periods. During recent years the growing interest in long-time creep properties of metals and alloys under stress has made increasingly important a better knowledge of the recrystallization during prolonged heating. The recrystallization temperature of 70-30 brass given by Clark and White" in 1932 was somewhat above 400°F. (204°C.) but under 500" (260°C.), whereas in our laboratory recrystallization has been observed in creep specimens at 204°C., the lowest temperature of Clark and White's range. Since the creep properties are quite different above and below the recrystallization temperature, erroneous conclusions can readily be drawn by the application of short-time recrystallization data to creep problems. It was thus considered of both practical and theoretical value to make long-time annealing studies near the minimum recrystallization temperature. In this way useful additions could be made to data on recrystallization temperatures and, since the reactions in this range are relatively slow, additional insight could be obtained into the factors involved in annealing. Several comprehensive reviews of recrystallization processes have been written,3-6 therefore only a brief review of the generally accepted facts will be given here. Though the effects of heat-treatment usually are expressed as related to observations with varying temperatures, it is logical to assume that the same order of occurrence will exist with time as a variable. Thus, we may postulate that with increasing time we mill observe the following

Jan 1, 1940

By S. E. Maddigan, A. I. Blank

Many experimental and theoretical investigations have been made on the processes involved in annealing and recrystallization of metals. Most of these, however, have treated the time element as constant and heat-treatments used have been for relatively short times. Aside from the early work by Carpenter and Elam,' the few that have investigated the effect of time on the processes have usually done so for fairly short time periods. During recent years the growing interest in long-time creep properties of metals and alloys under stress has made increasingly important a better knowledge of the recrystallization during prolonged heating. The recrystallization temperature of 70-30 brass given by Clark and White" in 1932 was somewhat above 400°F. (204°C.) but under 500" (260°C.), whereas in our laboratory recrystallization has been observed in creep specimens at 204°C., the lowest temperature of Clark and White's range. Since the creep properties are quite different above and below the recrystallization temperature, erroneous conclusions can readily be drawn by the application of short-time recrystallization data to creep problems. It was thus considered of both practical and theoretical value to make long-time annealing studies near the minimum recrystallization temperature. In this way useful additions could be made to data on recrystallization temperatures and, since the reactions in this range are relatively slow, additional insight could be obtained into the factors involved in annealing. Several comprehensive reviews of recrystallization processes have been written,3-6 therefore only a brief review of the generally accepted facts will be given here. Though the effects of heat-treatment usually are expressed as related to observations with varying temperatures, it is logical to assume that the same order of occurrence will exist with time as a variable. Thus, we may postulate that with increasing time we mill observe the following

Jan 1, 1940

By James F. Kemp

(San Francisco Meeting, September, 1915) THE iron ores of southeastern Cuba present a subject of exceptional geological interest. Their relations to the inclosing rocks are varied and in some cases unusual. The problem of their geological origin is not a simple one and for this reason has occasioned some divergence of views among previous observers. Profiting, however, by. these earlier studies and by more detailed field and laboratory observations as well as by the experience of added years of mining, much more satisfactory descriptions and interpretations can now be prepared. PREVIOUS WORK In 1884, interest in the southeastern coast of Cuba became active among the consumers of iron ore along the Atlantic seaboard of the United States. Active development was undertaken by the Juragua Iron Co., Ltd., a corporation affiliated with the Bethlehem Steel Co., and the Pennsylvania Steel Co. The property of the Juragua company, which is situated about 15 miles east of Santiago, was studied in June and July, 1884, by Dr. James P. Kimball, at the tine Professor of Economic Geology in Lehigh University and one of the best known of American mining geologists. Dr. Kimball published on his return two papers, the first important descriptions which we have of the local geology.1 It is

Jan 9, 1915

By J. P. Murphy, T. E. Leontis

DURING the last few years, the trend in the aircraft and automotive industries has been toward higher and higher operating engine temperatures. This has created considerable interest in the effect of temperature on the properties of alloys. In the magnesium field, it has been recognized for many years that the addition of cerium imparts high strength and good resistance to creep at elevated temperatures. Beck,1 in his treatise on-magnesium, has summarized the work of German investigators. This includes the unpublished data of Menking, showing the increase in strength and hardness of extruded alloys containing 2 to 20 per cent Ce at temperatures from 200 to 300°C. (68° to 572°F.) and the results of Vosskühler, who demonstrated the improved resistance to creep of alloys containing 6 per cent Ce plus 2 per cent Mn and 0.5 per cent Ce plus 2 per cent Mn at 150°C. (302°F.). Wellinger and Keil2 have also reported the creep properties of a forged magnesium-cerium-manganese alloy at 200° and 250°C. (392° and 482°F.). Haughton and Prytherch have determined the tensile properties of various forged magnesium alloys containing cerium, cerium plus manganese, cerium plus calcium, cerium plus nickel, cerium plus nickel plus manganese, and cerium plus cobalt plus manganese at temperatures up to 290°C. (554°F.). Magnesium-cerium alloys have been used in some commercial applications. It is reported that an alloy containing 3 per cent Ce plus 0.5 per cent Mn plus 0.5 per cent Ca is being used on a forged impeller in Great Britain. Two forged parts made from an alloy with a nominal composition of 5 per cent Ce and 2 percent Mn have been found on the German .BMW-801D aircraft engine. These two forgings consist of a supercharger impeller and a rear cam-follower guide. In this country, several types of pistons have been made experimentally in both .the cast and the forged conditions from an alloy containing 6 per cent Ce plus 2 per, cent Mn and in the cast condition from an alloy of magnesium plus 10 per cent Ce. The cast pistons have been tested in various types of internal-combustion engines, with promising results. This paper presents the results of an extensive investigation on the properties of various cerium-containing magnesium alloys in both the cast and the forged conditions. Data are presented to show the beneficial effects of increasing amounts of cerium on the mechanical properties of magnesium at elevated temperatures. The effects of heat-treatment on the properties of these alloys and the attendant changes in the microstructure are discussed. The

Jan 1, 1946

By AIME AIME

THE Hazleton district of the Pennsylvania Anthracite Region will be the scene Oct. 14 and 15 of the fall meeting of the Coal Division and the Pennsylvania Anthracite Section. Here, coal mining has been active for more than 100 years and hereabouts industrial necessity inspired the numerous inventions of the Pardees, Eckley B. Coxe, a former A.I.M.E. president, and the Marltles, who contributed much to the success of the Institute in its early days, as well as to the upbuilding of modern methods in the anthracite and bituminous industries. Headquarters will be the Altamont Hotel, Hazleton, Pa. There will be two technical sessions Friday, registration preceding the first which is scheduled for 11 a.m. to 1 p. m. The second will be called at 2:30 p.m. Saturday is reserved for mine and plant visits, with golf and tennis after luncheon for those so inclined. The ladies are cordially invited to the meeting and arrangements have been made for their participation in much of the program. The chairmen of the committees preparing for the meeting are: Donald Markle, president, Jeddo-Highland Coal Co., General Committee; R. E. Hobart, mechanical superintendent, Lehigh Navigation Coal. Co., Committee on Visits and Inspections; H. D. Kynor, general manager, Northumberland Mining Co., Committee on Programs and Papers; B. H. Stockett, general manager, Weston; Dodson, Inc., Reception Committee.

Jan 1, 1932

E. D. Peters, Jr., Dorchester, Mass.: This paper of Mr. Keller's seems to me a step in a direction that has been very little exploited, and iff likely to lead to valuable practical re-

Jan 1, 1899

By A. H. Geisler, J. H. Keeler

Preferred orientations in rolled and annealed titanium sheets were determined by the Geiger counter spectrometer X-ray diffraction technique. Five annealing textures dependent upon the temperature range of annealing were found, and in order of increasing annealing temperature pendent upon the temperature range are: 1—a deformation like texture, 2—a rotated inorder a-recrystallization temperature texture, 3-a retained u-recrysraIlization texture, on annealing at lower temperatures of the ß-region, 4—a transformation texture based on recrystallized a and predicted by the Burgers' relationship, and 5—a ,ß-cube texture. These results are examined in terms of current theories of recrystallization textures. UMEROUS investigators have described the tex- ture obtained by cold rolling the hexagonal metals, titanium, zirconium, and beryllium, which have c/a ratios less than that of ideal packing, 1.633. The basal planes are rotated out of the rolling plane, about the rolling direction, so that the basal poles are tilted toward the transverse direction as shown schematically in Fig. la. In all instances but one,' it was also reported that the [1010] direction was parallel to the rolling direction (see Fig. lb). Hot rolling has been reported as causing a similar tilt of the basal poles in the transverse direction (see Fig. la) and causing the [1010] direction also to be parallel to the rolling direction as shown schematically in Fig. lb. Annealing after deformation does not appreciably change the tilt of the basal poles in the transverse direction." Beryllium2-7 continues to have the [1010] direction in the rolling direction after annealing, and similar observations for titanium and zirconium' . have been reported for annealing at fairly low temperatures, again as in Fig. lb. At higher annealing temperatures, however, the recrystallized grains of titanium" and zirconium have an orientation such that the [1120] direction is approximately in the rolling direction, although the basal poles are still inclined in the transverse direction. Figs. la and lc show the resulting orientations schematically. This change in orientation has been described as a nominally ±30° rotation of the hexagonal crystallites about the basal poles of the cold rolled texture and is apparent from the results which are summarized in Table I for investigations with the X-ray diffraction technique employing film. The angles y, , and ß are indicated in Fig. 2 which represents the stereographic projection of (1070) poles for the mean orientation of a pole figure. Texture determinations for titanium using the Geiger counter spectrometer have provided similar results except that in some instances additional components of the texture were proposed, as shown by the summary of data in the upper half of Table 11. On the other hand, the spectrometer technique, when applied to zirconium,* has revealed a splitting Recently completed studies of the textures of annealed zirconium", show zirconium to possess textures very similar to those reported here for titanium. Therefore, much of this discussion will include zirconium by virtue of its close similarity to titanium in pref erred orientations. of the intense areas of the pole figure for samples annealed at 600°C. This splitting could be described by a 7" rotation of the tilt axis about the normal to the rolling plane. Such a splitting for the annealed texture relative to the cold rolled texture was not observed in other determinations for either zirconium or titanium using the less sensitive film X-ray methoe and makes the relationship between the two types of texture more complex than the simple rotation about the (0001) pole based on film work. The more precise investigations on zirconium permit the descriptions in the lower part of Table 11, which show that the texture depends quantitatively on the temperature of annealing. When zirconium is annealed at temperatures up to 400°C, the texture is similar to the cold rolled texture, while annealing in the range 500" to 900°C produces a texture which is only approximately described as [11%] in the rolling direction. More precisely described results for zirconium show that the two types of splitting ( 1—about an axis in the rolling plane through an angle given in the second column in Table II and 2—about the normal to the rolling plane through an angle given in the third column of Table 11) depend on annealing temperature. The [1120 is the rolling direction only when the annealing temperature is in the vicinity of 900°C

Jan 1, 1957

June was the month in which AIME was founded in the year of 1871. For some reason, February was selected as the month for the legal Annual Meeting. One can't help thinking wistfully of Annual Meetings in June but of course this is not the reality. Because the Centennial Ceremonies are taking place in February, that month has been chosen as the one in which MINING ENGINEERING, the monthly magazine of the Society of Mining Engineers, a constituent society of AIME, is publishing its Commemorative is- sue to celebrate the event. SME and ME take a proprietary air about AIME. This is mostly because AIME started as the American Institute of Mining Engineers. Metallurgy was added to the name in 1919 and Petroleum in 1956. The official abbreviation of "AIME" has been retained, however.

Jan 1, 1971

Discussion of the paper of A. P. WATT, presented at the St. Louis meeting, October, 1917, and printed in Bulletin No. 130, October, 1917, pp. 1476 to 1563. THE CHAIRMAN (0. M. _BILHARZ, Miami, Okla.).-Mr. Watt's reference to sorting or hand-picking of the ore in the lead district, which is being introduced at Mine La Motte, is especially interesting. I believe, from my former experience in the district, that hand-picking should be practised to some extent by all the companies in the Lead Belt. I know that a great many thousand tons containing only very small amounts of lead are passed through the mills, which, of course, is not to the advantage of milling machinery. That procedure may be Warranted at times of high prices, but I think that hand-picking should ordinarily be adopted to some extent: ERNEST GAYFORD, Salt Lake City, Utah.-On page 1525, speaking of the settling of slime previous to treatment either on slime tables or by flotation, Mr. Watt states: "The settling area allowed per ton of dry slime varies from 11 to 16 sq. ft.-an average for the district would be about 13 sq. ft. of settling area per ton of dry slime. This figure applies when the, discharge contains 20 per cent. solids." Mr. Ramsey, of the Dorr company, is here and I would like to ask him whether a settling area of 13 sq. ft. per ton of dry slime per 24 hr. is not considerably above the average area of Dorr settling tanks, and whether 20 per cent. solids is not above the general dilution for that' capacity? I should also like to know what is the general average on slimes of that character. E. R. RAMSEY, Denver, Colo.-An allowance of 13 sq. ft. per ton does seem rather large. I am not familiar with the settling characteristics of the dolomitic gangue, but as an average over the country, I should say that 6 or 7 sq. ft. would be nearer correct for discharge at that consistency. L. A. DELANO, Bowie Terre, Mo.-We have had an opportunity to try our tanks at the highest capacity, and-find that by thickening the slime to 30 per cent. solids we average 12 sq. ft. per ton of dry slime. ERNEST GAYFORD.-DO you find any definite ratio between the thickness of the discharge and the settling capacity of the tank? Do you consider that the tank has a larger capacity if the discharge is 3 to 1 than if it is 50 per cent. solids? L. A. DELANO.-I think it has greater capacity with the thinner discharge. It depends a good deal on the density of feed to the tanks; in our case the feed contains 2.5 per cent. solids.

Jan 1, 1918

Jan 1, 1890

Jan 1, 1929

By H. E. Elliott, R. S. Busk, A. T. Peters

One of the problems of the fabricator of metals and alloys is the propensity of some composition rarnges toward abnoermal grain growth during certain stages of fabrication. In this respect magnesium alloys are no exception among alloys. Fortunately, convenient foundry control methods have been developed by which the abnormal grain growth possible in certain magnesium-alloy castings can be suppressed. An unusual characteristic of magnesium alloys, however, is that castings of some composition ranges are subject to local grain growth during heat-treatment without the necessity of intentional mechanical stressing of the part prior to heat-treatment. This effect occurs only under certain critical casting conditions, and only in certain alloys of greater than about 8.5 per cent aluminum content, such as C alloy (Mg, 9 per cent A1, 2 Per cent Zn, 0.2 Per cent Mn) and G alloy (Mg, 10 per cent Al, 0.2 per cent Mn). The first observation of this phenomenon in cast magnesium alloys occasioned much surprise, since it is not observed in other meta1s- Jeffries and Archer1 have stated that "the grain size of cast metals, provided they have not been plastically deformed, cannot be changed by heating below the melting point." The study of the conditions leading to abnormal grain growth in cast magnesium alloys, and of the mechanism of this phenomenon, has led to some very interesting observations. Perhaps the most significant of these was the observation that stresses originating from cooling contraction in magnesium-alloy castings are the only stresses necessary, under certain conditions, to cause local recrystallization and subsequent grain growth in the casting during heat-treatment. Before recent developments, this phenomenon of abnormal local grain growth Was a definite problem in the production foundry on C alloy sand castings. Illustrated (Fig. I) is a picture of a casting scrapped because of this defect. A mottled effect is produced in coarse-grained areas by suitable etching solutions. The properties of metal in the affected area are much impaired by such grain coarsening. Ultimate tensile strengths of half the normal value have been measured in metal of this nature. In this paper are described the techniques that have been developed by The DOW Chemical Co. for studying, and in large measure solving, this production problem. Also discussed are studies of the mechanism by which excessive grain coarsening occurs, and the fundamental conditions that produce this effect. The abnormal grain growth discussed in this paper will be referred to as "germinasium since this term has been definedl as any process leading to an abnormally coarse grain size. This paper deals only with abnormal local grain growth that may occur during the solution heat-treatment of certain magnesium-alloy castings, as dis-

Jan 1, 1945

T. W. ROBINSON, Pueblo, Colo.: Mr. Potter's review is a striking testimony to the important part played by science in this branch of practice. But, the question arises, In which department has science effected most ? The available raw material, the size of furnaces, the general design and equipment of the plant, and the daily management, are particulars, each of which contributes to the general result, while the effect of each merges into that of the others. The following notes concerning the operations of the furnace-plant of the Colorado Fuel and Iron Company (formerly the Colorado Coal and Iron Company), at Pueblo, may throw some light upon the question of their relative importance. This company operates three stacks, and when the plant first came under my observation, about nine months ago, the furnaces were constructed, equipped,and run as stated below: Raw Materials.—The main sources of ore-supply were, as they still are, the Orient and Calumet mines of the company. The Brecce and Morning Glory ores, mentioned below, were formerly brought from Leadville, but are practically now no longer used. The Orient ore is a porous brown hematite, easily reducible in the furnace. The Calumet is a magnetite, very refractory in character, requiring preliminary roasting. Both are fairly uniform in composition. The Breece and Morning Glory are red hematites, resembling in appearance the soft ores of the Vermilion range, Lake Superior. The coke here used is made of coal from the company's mines in southern Colorado, and is distinct from that produced by the company in the western part of the State. The structure is similar to that of Alabama coke. The limestone employed is a calcite. The analyses are given in Table I. I would note, parenthetically, that I know of no section of the country presenting harder conditions for furnace-practice than these materials impose. Results cannot be measured by the more

Jan 1, 1894

By AIME AIME

THE Coal Division holds its fall meeting in the Pocahontas coal field, at the West Virginian Hotel, Bluefield, W. Va., Oct. 9 and 10. The first day will be a busy one-two sessions for the presentation of papers and a dinner in the evening. Hon. E. Fudge, Assistant Undersecretary, Mines Department, and R. V. Wheeler, head of the Mines Research Board of Great Britain, will be the guests of the Division. Mr. Wheeler will discuss the British Mining Act as relates to the coal industry. George S. Rice, Chief Mining Engineer, U. S. Bureau of Mines, will present an account of the recent meeting at Buxton in England, of representatives of England, Germany, France, Belgium and the United States to formulate a plan and to correlate research work now in progress in the various countries. The second day the members will be the guests of the operators on a trip through the Pocahontas field. The work of preparation for the meeting is being actively pushed by committees headed by T. H. Clagett, R. M. Lambie and H. D. Smith, and a good attendance, both local and from the general membership of the Division, is anticipated. Because many will make the trip by car the principal automobile as well as rail-road connections to Bluefield are given here. The program for Friday, Oct. 9, follows:

Jan 1, 1931

By Kalervo Rankama

UNTIL a few years ago, geological mapping, the study of ore boulders, and different geophysical methods were the principal means used in the systematic search for mineral deposits covered by a layer of disintegration products or soil. These methods have been developed to a high stage of perfection as far as the geometrical definition of the conductor is considered. Use of geophysical methods in prospecting is based on the fact that an ore body differs from the country rock not only geologically but also in its physical properties. The general drawbacks and complications included in the use of geophysical methods are well known to everyone who has been using them, so need not be entered into here in detail. One of the more important ones is the fact that geophysical methods are unable to furnish information concerning the chemical composition of the ore bodies responsible for the indications. Further, the ores of many metals, such as silver, gold, beryllium, zinc, mercury, tin, lead, vanadium, antimony, chromium. molybdenum, tungsten, manganese, cobalt, nickel, and the platinum metals cannot be directly located by known geophysical methods, owing to lack of physical characteristics suitable for distinguishing them from the country rock. Thus it is quite natural that efforts have been made to develop direct methods for prospecting and locating ore bodies of the elements named. Known as chemical, biogeo-chemical, and geobotanical methods of prospecting, these have been much improved during recent years. A brief review of these methods and of some results obtained with them will be presented in the following, on the basis of available information and my own experience.

Jan 1, 1947

By Charles R. Fettke

BefoRe the Drake well on Watson Flats below Titusville, Pa, inaugurated the modern petroleum industry on Aug. 28, 1859, a considerable industry, based on the manufacture of mineral oils through the destructive distillation at relatively low temperatures (750' to 800' F.) of cannel coals and shales in closed, air-tight retorts, had already sprung up in Europe and America because of the increasing cost of animal and vegetable oils and fats and the growing demand for illuminating and lubricating oils. In 1860, eight out of 55 such coal-oil companies in the United States had plants located in Pennsylvania.' Of these, the Lucesco Works, costing $120,000, situated near Kiskiminetas Junction, was the largest operating in the country. It was equipped with 10 revolving 2.5-ton retorts and 16 stills for rectifying the oil, each holding 2000 gal. The total output of crude oil was almost 6000 gal. per day.2 The discovery of an abundant supply of natural petroleum by the Drake and other wells stopped the distillation of coal oil in America. Most of the smaller plants were closed and others were converted into petroleum refineries. At present, in spite of the temporary over-production of petroleum, the coal and oil-shale carbonization industries are again attracting the attention of far-sighted oil companies who realize that the gradual exhaustion of the American petrol-

Jan 1, 1923

By Charles R. Fettke

BefoRe the Drake well on Watson Flats below Titusville, Pa, inaugurated the modern petroleum industry on Aug. 28, 1859, a considerable industry, based on the manufacture of mineral oils through the destructive distillation at relatively low temperatures (750' to 800' F.) of cannel coals and shales in closed, air-tight retorts, had already sprung up in Europe and America because of the increasing cost of animal and vegetable oils and fats and the growing demand for illuminating and lubricating oils. In 1860, eight out of 55 such coal-oil companies in the United States had plants located in Pennsylvania.' Of these, the Lucesco Works, costing $120,000, situated near Kiskiminetas Junction, was the largest operating in the country. It was equipped with 10 revolving 2.5-ton retorts and 16 stills for rectifying the oil, each holding 2000 gal. The total output of crude oil was almost 6000 gal. per day.2 The discovery of an abundant supply of natural petroleum by the Drake and other wells stopped the distillation of coal oil in America. Most of the smaller plants were closed and others were converted into petroleum refineries. At present, in spite of the temporary over-production of petroleum, the coal and oil-shale carbonization industries are again attracting the attention of far-sighted oil companies who realize that the gradual exhaustion of the American petrol-

Jan 1, 1923

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Jan 1, 1938

By AIME AIME

IN accordance with the custom of recent years, the Institute joined with the Western Division of the American Mining Congress in holding a joint meeting at Joplin on Sept. 28, 29 and 30. Actually the meeting might be said to have begun on the 27th, since the Engineering Education Committee held two sessions on that day, which are reported on another page. In addition to these sessions there were informal gatherings in the Hotel Conner, which was the headquarters, on the golf links and elsewhere of all those who had arrived by Sunday morning. The technical sessions were formally opened on Monday morning by Robert E. Tally who, after suitable preliminary remarks, introduced A. Scott Thompson, of Miami, Okla. Mr. Thompson in welcoming the visitors to the Tri-State district said that it had come to be known as a poor man's country and at the present price of zinc did not find it difficult to live up to its name. He also referred to the work Mr. Tally had done for the stabilization of the mineral industry. H. Foster Bain, in responding to this address for the Institute, said that mining men generally felt at home in Joplin, that the solutions of their problems and the general practice that had been developed in the district were not only of great interest to them, but that visitors could learn much

Jan 1, 1931

By Joseph Pogue

THE writer visited the Muzo emerald mines in July, 1915, and spent six days in their study. This paper embodies the results of his observations, plus information personally communicated by Robert Scheibe, FIG. 1.-SKETCH MAP SHOWING APPROXIMATE LOCATIONS OF ALL IMPORTANT EMERALD MINES AND PROSPECTS IN COLOMBIA. (Data in part supplied by Robert Scheibe, July, 1915.) Professor of Geology in the Mining Academy of Berlin, who at the time of the visit was completing a detailed field investigation of nearly a year's duration of the emerald deposits of Colombia. An elaborate account of this valuable work may be expected at a future date from the pen of Professor Scheibe.

Jan 5, 1916