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By M. A. Roche

AST fall over half a million tons of ore and rock were broken in one blast at the open pit of the Hudson Bay Mining & Smelting Company's operation, at Flin Flon, Manitoba. The following particulars of the blast, and details of the preparatory work, indicate how an operation of this scope is carried out. The data given, in essentially the present form, were first published by The Canadian Mining Journal. The area blasted was 150 ft. wide and about 700 ft. long. A total of 123 tons of 50 per cent forcite gelatin, in 5 by 16-in. cartridges, was used for the charge. Drilling for the blast was started on May 29, and was completed late in August, requiring 1297 machine shifts for drilling only. Total footage drilled for the shot was over 5 miles of 6-in. hole. The main blast consisted of 232 holes spaced on 17.5-ft.

Jan 1, 1934

By George S. Rice

ARIAL maps of prospective mineral-bearing territory have become almost indispensable in all the branches of exploration, and have proved particularly useful in the great oil area of the Southwest. About nine years ago aerial photographic mapping in this area was begun. The early product was lacking in scale accuracy and other control features, which limited its effective use. Since then, the evolution of the technique of such mapping has been steady, with several mapping companies collaborating with five of the leading oil companies, and aerial maps have been prepared covering practically the entire area.Improvements in cameras, film, and developing equipment and practice have resulted in more uniform and clearer photographs, but the outstanding development has been the accuracy obtained with respect to scale and all other control features. Maps are no

Jan 1, 1936

By L. W. WALLACE

IN an engineering fashion we have made an assay of the engineering profession, using as a. sample the engineers listed in "Who's Who in America" (1928-1929). We are aware that some will say it is an unfair sample; that it came from the best mine. This is readily admitted, with this qualification: that all engineers and architects by virtue of their training and experience have been freed of most of the dross to which mankind is heir. They are -a selected group to begin with, having all the potentialities those in the sample possess. We are also aware that some will say a part of those included in the sample are not engineers. Our answer to that criticism is this: An engineer is no less an engineer because for the time being he is president of a bank, a university, an opera company, or a hotel company. Moreover, he is no less an engineer because he is a governor of a commonwealth, a United States senator, a member of the Cabinet, or the President of the United States.

Jan 1, 1929

By PERCY E. BARBOUR

TWO YEARS after its organization, the Institute issued its first volume of TRANSACTIONS, covering activities that began in May, 1871, and continued through February, 1873. The preface of this first volume reads: The present volume contains the rules of the Institute, a list of members and associates, an abstract of the proceedings of the-first two years, and a number of papers selected from those proceedings. There is, therefore, nothing new in it. The papers have all been published, according to the custom of the Institute, in the Engineering and Mining Journal, and many of them have been copied into other periodicals. They are republished here, solely to enable members and associates to preserve them in convenient form. Various considerations have determined the selection of papers for this purpose. Some have been omitted at the request of the authors who, having modified the views expressed in them, naturally deprecated a republication of those views. Others have been omitted, in order not to devote too large a proportion of space to single topics, or single branches of mining or metal¬lurgy, in view of the fact that the membership of the Institute extends throughout the whole country, and represents numerous departments of these industries. Some, on the other hand, have been chosen, although not laying claim to special originality, because they contained information of importance, not easily accessible elsewhere, the presentation of which, in a form convenient for reference, was generally desired.

Jan 1, 1921

By E. H. Griswold

PETROLEUM production engineering is essentially the application of the laws of 'physics and mechanics to the production of oil. A true production engineer is one who can apply the principles of mechanics, hydraulics, thermodynamics, and other physical arts so as to facilitate' the efficient and economical recovery of oil. To this end he must have wide knowledge of practical field operations and a working knowledge of geology, with a thorough understanding of the underground state of the fluids which he seeks to control. Generally speaking, there have been two schools of production engineering, the California development and the Mid-Continent development. In California the preliminary production engineering was done by representatives of the U. S. Bureau of Mines and the State Mining Bureau, and was essentially subsurface work in regard to casing patterns, water shut-offs, and completion procedure, inasmuch as these were problems of the utmost immediate importance to the California industry. The oil companies were impressed with the value of such work and placed engineers, or more strictly speaking, engineering geologists on their field staffs. These men, realizing the need of further technical study in the mechanical phases of producing operations, added mechanical and mining engineers, and out of the blend developed what is now known as a production engineer.

Jan 1, 1932

By Basil B. Zavoico

ALTHOUGH the American petroleum industry was affected by the Second World War from its early beginning it was not until Dec. 7, 1941- that the industry was placed on full war footing. Even throughout most of 1942 the American overseas operations were limited and not until late in the year did expansion of military activities, more particularly the offensive in North Africa, affect the domestic supplies to such an extent that critical deficiencies developed locally in this country, particularly along the East Coast. The definite outlook for greatly expanded offensive operations by the United States on both Atlantic and Pacific fronts makes certain that during 1943 the domestic situation will. not be alleviated; rather it may become even more critical even though additional transportation facilities, now being built and planned. will be completed from the southwestern producing states to the East Coast.

Jan 1, 1943

By J. P. Sheehan, W. R. Hibbard, M. Baeyertz

This paper deals with molybdenum modifications of 5140 steel that have the same hardenability but a better tolerance for phosphorus than the AISI-SAE 5140 grade. Lack of toughness in steels with higher than normal phosphorus contents is well known to metallurgists. This problem is troublesome even within normal phosphorus ranges, if the heat treatment or the design of the part or the service is critical. Under such unfavorable conditions and also in the case of phosphorus contents toward the upper side of the commercial range, the use of molybdenum to replace a part of the chromium in 5140 steel provides a factor of safety. The toughness of steel is variously exhibited in different mechanical tests; broadly the term is applied to the capacity of the steel to deform prior to fracture. Defined in this way, toughness is considered to be an inherent quality that depends upon the composition and structure of the steel, and also upon its temperature during deformation and fracture in the test. In the present state of our knowledge, the type of mechanical test needs to be included in any discussion of toughness, because the revelation of this quality in steel depends on the stress state and rate of stressing imposed by the test. In comparing the toughness of one steel with another by laboratory testing, it has long been customary to use notched tests that impose severe constmint to deformation, and then to test over a range of temperatures to obtain the so-called transition. At temperatures above the transition, the steel fails after considerable deformation and absorption of energy. Below the transition, less energy is absorbed as the steel fails largely by cleavage. The transition range itself is characterized by a more or less abrupt change in energy absorption and type of fracture. The conventional V-notch Charpy impact test has been used exclusively in the work covered by this report. For the steels under study, rather sharp transitions are obtained with this test, at testing temperatures that are easily obtained in the laboratory. The position of the transition on the testing temperature scale provides a rather sensitive index of the toughness of the steel, when the steels under study are similar in character as they are in this work. Turning to the metallurgical reasons for the greater toughness of one steel as compared to another, the authors propose to limit the discussion to the small field under study. Only one structural state is considered, tempered martensite of a hardness of about 28 Rockwell C or 269 Brinell. The study deals first with the loss of toughness in AISI-SAE 5140 steel caused by increasing the phosphorus content from about 0.020 to 0.040 pct. A second part of the work deals with counteracting this loss in toughness by replacing a part of the chromium by molybdenum. A series of molybdenum modifications was studied, in each of which the chromium was reduced sufficiently to duplicate the hardenability of 5140 steel. Phosphorus affects the toughness of steel in two ways. An inherent lack of toughness of phosphorus-bearing ferrite as compared to low phosphorus ferrite has often been noted. Jolivet and Vidall have shown that phosphorus has the same effect in tempered martensite in chromium steels. The other well known effect of phosphorus is to make steel susceptible to temper embrittlement. Temper brittleness is a loss in toughness brought about by tempering steel within a limited temperature interval somewhat below the A1 temperature. In most of the standard AISI-SAE alloy steels, this temperature interval is approximately 850-1100°F. Either of these types of loss in toughness is easily followed by the shift in the transition temperature obtained with the notched-bar impact test. The data to be presented show the beneficial effect of substituting molybdenum for a part of the chromium in 5140 steel with either moderate (0.020 pct) or high (0.040 pct) phosphorus contents. Both the inherent lack of toughness of phosphorus-bearing steel and temper brittleness are counteracted by this use of molybdenum. The work of Jolivet and Vidal mentioned above shows the detrimental effect of phosphorus on the toughness of tempered martensite in the absence of temper embrittlement, as well as the temper brittleness caused by phosphorus. They used two steels, essentially 0.25 pct C-1.4 pct Cr, with 0.044 and 0.013 pct P, respectively. The nonembrittled state was obtained by quenching in oil from 1610°F, then tempering for one hour at 1200°F and quenching in water. In this state the transition temperature range of the low phosphorus steel in the notched-bar impact test was below that of the steel with 0.044 pct P. An additional treatment of 24 hr at 975°F (that is, in the embrittling range) caused both steels to lose toughness, but the high phosphorus steel showed the greater embrittlement. Recently Hollomon2 has published a comprehensive survey and bibliography of the literature on temper brittleness, to which the reader is re-

Jan 1, 1950

By W. C. Clarke

An empirical study of the nature of the embrittle-ment which occurs in martensitic and semiaustenitic precipitation hardening stainless steels upon exposure at temperatures of from about 550" to 875°F has been undertaken. This work was aimed at determining cazusation and means of controlling this phenomenon. A commercial copper bearing precipitation hardening alloy was used as a basic material for study. The effect of heat treatment variables was studied as was the effect of variations in analysis. It is concluded from the evidence that martensitic and semiaustenitic precipitation hardening stainless steels are subject to 885°F ernbrittlement similar to that observed in the straight chromium stainless steels. A characteristic of precipitation hardening stainless steels which has limited their use in certain applications is that they embrittle when held at temperatures in the range of from about 550" to 900°F. This is true to a more or less degree in all currently available alloys, either the basically martensitic type or the semiaustenitic type. The rate of embrittlement varies markedly with exposure temperature, being low at 550" to 600°F and in-creasing as the temperature increases. In spite of this embrittlement, these alloys with their unique combination of high mechanical strength, reasonable toughness, and good corrosion resistance are used in many hundreds of applications. Nevertheless, there are potential applications where the embrittle-ment described is a limiting factor. The purpose of this investigation was to study the embrittlement of these alloys and to find a way to control or eliminate it. GUIDELINES USED IN PRESENT WORK The work reported in this paper is based on a study of 17-4 PH*, a very widely used alloy. It has been used *Trademark of Armco Steel Corp., licensor. in pressurized water and boiling water atomic reactors operating at about 550°F for a number of years. As the life of such equipment is extended or operating temperatures are raised, the possibility of embrit-tlement becomes of increasing concern to materials engineers. Much investigation work was done with respect to the use of 17-4 PH at 550°F. K. C. Antony' states "Such estimation" (of an activation energy for the diffusion of chromium in iron) "would indicate W. C. CLARKE, Jr. is Senior Research Engineer, Advanced Materials Division, Armco Steel Corp., Baltimore. Md. This manuscript is based on a talk presented at the symposium on New Developments in Stainless Steel, sponsored by the IMD Corrosion Resistant Metals Committee, Detroit, Mich., October 14-15, 1968. significant secondary aging is improbable at temperatures less than 700°F within normal component service life". This statement is modified however by the recognition of the accelerating tendencies of applied stress and internal stress as well as the possible effect of irradiation. In this investigation of 17-4 PH, the H 1100 (1900°F-1 hr oil quench or air cool + 1100°F-4 hr-air cool) condition was used, partly because this condition is normally used in atomic reactors. As shown later, the precipitation hardening temperature has no real bearing on the rate of embrittlement. An exposure temperature of 800°F was selected since embrittlement at 800°F is rapid, permitting development of relative data in time periods of 400 to 500 hr. For those not familiar, a nominal present day analysis of 17-4 PH is: C Mn P S SiCrNiCuCbN 0.04 0.30 0.015 0.015 0.60 16.00 4.30 3.25 0.23 0.030 TYPICAL BEHAVIOR OF 17-4 PH Figs. 1 and 2 show the behavior of a commercial heat of 17-4 PH under the conditions defined. Characteristically, 800°F exposure causes a rapid drop in Charpy V-notch impact strength. Tensile and yield strengths gradually increase and a gradual loss of elongation and reduction of area occur, accompanied by an increase in hardness. Notched tensile strength increases to 125 hr exposure and then sharply decreases after exposure for 500 hr. The notched vs un-notched tensile ratio remains virtually constant to exposure for 125 hr (1.67 to 1.56) but drops to 1.15 after 500 hr. Tensile ductility is not alarmingly affected even after much longer exposure times than these. For example, samples aged at 1100°F for 1 hr exposed at 800°F for 4000 hr showed a drop in elonga-tion of from 13 to 11 pct and in reduction of area of from 58 to 37 pct. Notched impact is the property SmIgth KSI 3JJ[/__________^UTS-Nrteh 260 ;/- 240 —^ 200 UTS-Smooth________._, o ioo mo Sob" m Too Hours Exposure Fig. 1—Effect of exposure at 800°F for various times on notched tensile strength and smooth tensile and 0.2 pct yield strength of 17-4 PH in the H 1100 condition.

Jan 1, 1970

By W. A. Backofen, D. L. Holt

Push-pull fatigue tests have been carried out at 4.2°K, 77oK, and room temperature on two poly crystalline materials of widely different stacking-fault energy (?): pure copper (? - 70 ergs per sq cm) and the Cu-8 wt pct A1 alloy (? - 2.8 ergs per sq cm). Constant stress-amplilude was imposed and measurement was made of the plastic-strain amplitude (ep) at saturation. Lives extended from 104 to 106 cycles. Designating lives at the various temperatures by NRT, N77, and N4.2. the ratios N77/NNT and N4.2/N77 ranged from 3.5 to 18 under the condition of common Ep . Metallo-graphic examination revealed different crack morphology in Cu-8 Al fatigued at room temperature, and at 77" and 4.2oK. At room temperature, cracks lay in or near grain and lain boundavies; at 77o and 4.2oK. cvacks were transcrystalline. Tests on single crystals of Cu-8 A1 showed that such a change in the cracking mode in polycrystallitle material accounted for a factor of- about 3.25 in N77/NRT . The longer life at lower tewperatztre (conslant cp) has heels attributed to two deuelopinents: a reduced production of the dislocation tangles and subgrain boundaries which serve as paths of rapid cracking, and suppression of oxygen chetni-sorption at the crack tip It was concluded that in both materials the luller accounted for an extension of the life at 4.2oK beyond that at room temperature by a factor of 15. XV ECENT experiments on the fatigue of Cu-A1 alloys in the so-called high-cycle range (greater than lo4 cycles) have emphasized the importance of stacking-fault energy (y) as a quantity affecting crack propagation rate and fatigue life.1,2 It was found in comparisons at essentially fixed plastic-strain amplitude that crack growth rate decreased by a factor of about 5 over the composition range from copper (? - 70 ergs per sq cm) to Cu-8 wt pct Al (? - 2.8 ergs per sq cm). The argument was made that, when stacking-fault energy is high, cross slip and climb are favored, so that dislocation tangles and/or subgrain boundaries form more readily under cyclic loading. Since the boundaries and tangles act as paths of rapid crack propagation ,3, 4 life is shortened as a result. However, when stacking-fault energy is reduced (as by alloying), cross slip and climb become more difficult, with the result that substructure formation is retarded and growth rate is also reduced. A purpose of the present work was to investigate the substructure effect in relation to temperature. As temperature is lowered, ? is varied only slightly (if at all), but decreased thermal activation can interfere with cross slip and climb. Thus substructure formation could be curtailed and life increased. Fatigue life in the high-cycle range is also known to be strongly influenced by environment. Working with copper, Wadsworth and Hutchings observed that life in a vacuum of 10-8 mm Hg exceeded life in air by a factor of 20.5 They isolated oxygen as the agent that furthered cracking. While the details are still unclear, a requirement in any mechanism of oxygen-accelerated cracking is that there be chemisorption at the crack tip. That could prevent welding on the compression half cycle,= interfere with reversal of slip,1, 6 or aid in breaking metal-metal bonds at the crack tip.5'7 In the work being reported here, temperature was lowered by immersion in liquid nitrogen and helium, which also served to reduce both the oxygen concentration and chemisorption rate. A possible effect upon life, i.e., a lengthening, had to be recognized. Several researchers have determined fatigue lives at low temperatures presenting their results in the form of stress amplitude (S) vs cycles in life (N) curves.8-11 Such curves reflect, primarily, the fact that metal is strengthened by lowering temperature; effects of substructure and changing environment tend to be masked. The difficulty can be overcome by comparisons based on identical plastic-strain amplitudes, and in the present work the dependence of life on both plastic strain and stress amplitude was established. EXPERIMENTAL Materials. The principal materials were polycrystal-line copper (? - 70 ergs per sq cm)" and the Cu-8 wt pct Al alloy (? - 2.8 ergs per sq cm),I3 the latter being near the limit of solubility of aluminum in copper and having, therefore, the lowest stacking-fault energy in the CU-Al system. Specimens were machined from 0.118-in.-diam cold-swaged rods of high-purity (99.999 pct) copper and the Cu-8 Al alloy, the latter produced initially in a graphite boat by induction vacuum melting a mixture of 99.999 pct Cu and 99.99 pct Al. The machined specimens were annealed to produce mean grain diameters of about 0.070 mm in copper and 0.190 mm in the alloy. Specimen dimensions are given in Fig. 1. Values of the tensile yield stress, ultimate strength, uniform strain (determined by the Considgre construction), and reduction of area, for both materials at 4.2oK, 77oK, and room temperature, are listed in Table I. The tensile apparatus in which these results were obtained has already been described.14 Apparatus. Specimens were fatigued in push-pull with a machine that is illustrated schematically in Fig. 2. The specimen is first soldered into the top grip (1) with Woods metal, and the grip is then screwed into the inner tube (2) which is connected to the drive rod of the Goodmans vibration genera-

Jan 1, 1968

By Henry Louis

IN the discussion on the paper on subsidence by R. V. Norris and H. W. Montz (Teohnical Publication No. 153), H. N. Eavenson has been good enough to quote some of my views regarding the phenomena of subsidence; he has, of course, only mentioned these briefly, and as he has not represented them quite correctly, it is evident that I have failed to make them clear. Seeing that he, and apparently some of the others who took part in the discussion, appear to hold views different from my own, I think it advisable to put my opinions down as definitely and as clearly as possible, because it appears to me at least possible that some of the differences above referred to may be differences of language and definition rather than of fact. The statements I propose to submit refer to the simplest cases, namely where an area in a practically horizontal bed has been entirely worked out. My experience has been confined to beds of bituminous coal and of ironstone, but D I do not at the moment see why there should be any difference in principle between the working of a bed of anthracite and one of bituminous coal, provided that the other conditions are the same. I wish to emphasize that I am considering the conditions of complete working out of the mineral bed with the roof allowed to come down and form goaf in accordance with the general British practice; 1 am excluding, therefore, methods of hydraulic, pneumatic, and hand stowage where extraneous material is brought in to hold up the roof. I am also excluding the case of bord and pillar working where pillars of small size are deliberately left in, apparently with the idea that these will subsequently crush and let the roof down gradually. Such a method of mining has long been discontinued in this country, indeed in Europe generally, and I venture to predict that the time will come when such a recklessly wasteful method will no longer be tolerated even in the United States. Further, I am referring entirely td static conditions after the mineral bed has been worked out and the ground has come to rest; the phenomena that occur during the course of extraction are much more complicated, and these I am not discussing here. Under these conditions, I have

Jan 1, 1929

By W. H. Bassett

IN the commercial annealing of cartridge brass there are four points regarding which definite data are essential. They have to do with the correct interpretation of grain count in its relation to annealing temperature and, incidentally, to Brinell hardness. These points are: 1. The comparison of the grain sizes of two cartridge-brass mixtures: 69 copper, 31 zinc, 0.376-in. (9.5-min.) gage; and 68 copper, 32 zinc, 0.130-in. (3.3-mm.) gage. 2. The comparison of the grain sizes of annealed metal that had previously been reduced by rolling varying amounts; for instance, 20.0, 36.6, 50.9, and 59.1 per cent. 3. The determination of standards for grain sizes on annealed brass of the composition 68 per cent. copper, 32 per cent. zinc and 69 copper, 31 zinc. 4. The comparison of grain size with Brinell hardness on identical samples of annealed metal. In their comprehensive and thorough investigation of the recrystallization of cold-worked alpha brass on annealing,1 Mathewson and Phillips have discussed the relations between temperature of anneal, degree of deformation, and structural alteration in alpha brass. They have also shown certain comparisons between the ordinary physical properties and the grain size of annealed brass. The purpose of the present investigation is mainly concerned with the grain size of cartridge brass, its relation to Brinell hardness, and the publication of sufficient data to enable those engaged in the inspection of such material to have a correct foundation upon which to work.

Jan 1, 1919

By H. C. Fiedler

X HE development of the cube-on edge secondary re-crystallization texture in Si-Fe strip requires that normal grain growth be restrained. It has been shown that the degree of restraint and hence the completeness of secondary recrystallization depends upon the size and number of second-phase particles, which in turn is dependent upon the prior processing history.1y2 The purpose of this note is to show that, for heats in which manganese sulfide particles are providing the restraint to grain growth, the choice of hot rolling temperature depends upon the manganese content. The making and processing of the heats to the final gage of 0.012 in. has been described.3 The compositions are given in Table I. Apparent in Fig. 1 is the decrease in the ability of strips hot-rolled from 1175°C to undergo secondary recrystallization as the manganese content increases. It has been shown that 1175°C is below the solubility temperature of 0.014 pet S in even the 0.038 pct Mn alloy: and the observed behavior is attributed to an increasing fraction of the sulfur forming large manganese sulfide particles at the heating temperature for hot rolling. This fraction of the sulfur is thus unavailable to subsequently form the small, uniformly dispersed particles which are needed to restrain normal grain growth. Since the sulfur is completely in solution at 1325°C,3 strips from all three alloys show strong secondary recrystallization behavior when hot-rolled from that temperature.

Jan 1, 1969

By George E. Beavers

Under the title used for this paper, the converter practice of the Tennessee Copper Co. is described in the TRansactions of the Institute.l That article contains the following statement: "The limit in capacity of the Peirce-Smith converter in terms of concentrate has not been reached but approximately as high as one ton of concentrate has been handled for each ton of liquid matte charged and good working conditions have been maintained." It is not the intention of the writer to review the conditions leading up to the introduction of a Peirce-Smith converter at Copperhill, but, instead, to offer later data to show how satisfactory the installation has been. Converter Campaign, June 15, 1930 to August 23, 1931 Blowing time (converter days)............... 349.90 Number of blows........................... 427.00 Tons matte charged........................ 38,335.00 Copper assay of matte, per cent.............. 13.67 Tons blister copper made.................... 9,246.00 Time to blow one ton of copper, minutes...... 54.50 Air used per minute, cu. ft................... 12,500.00 Blast pressure, lb........................... 12.80 Air per ton copper, cu. ft.................... 681,330.00 Air per ton iron, cu. ft....................... 199,040.00 Tons flux used............................. 11,845.00 Tons flux per ton matte..................... 0.31 Tons flux per ton copper.................... 1.28 Tons flux per ton iron....................... 0.37 Tons concentrate treated.................... 28,960.00 Copper assay of concentrate, per cent......... 17.13 Tons concentrate per ton matte.............. 0.76 Tons material charged per converter day...... 235.70

Jan 1, 1934

By R. P. Smith, L. S. Darken

FOR a high-purity iron-carbon alloy, the phases existing at equilibrium at temperatures slightly above the temperature of the metastable eutectoid are austenite and cementite (hyper-eutectoid) or austenite and ferrite (hypo-eutectoid) and those below the eutectoid temperature (carbdn content > 0.02 pct) are ferrite and cementite. Such an alloy, held in a carefully controlled and measured temperature gradient (about 1 cm per deg) which includes the eutectoid temperature, then quenched and examined metallographicall.y, provides a precise measure of the eutectoid temperature. The samples were hollow cylinders approximately 1.3 cm OD, 0.63 cm ID, and 2.5 cm long, which had been carburized to the desired carbon content at 1000°C with an appropriate hydrogen-methane mixture. In order to cool the samples to room temperature with a minimum change of carbon content and absence of cracks they were quenched in a Cerro Bend bath at 480°C, followed by a water quench to room temperature. Three cylinders were suspended in the furnace1 in a purified helium atmosphere, by a closed end, thin wall, silica tube which also served as a thermocouple well. The top and bottom cylinders served only as a means of making the temperature gradient along the center cylinder more uniform. The temperature was determined with a platinum-platinrhodium thermel calibrated by comparison with a thermel certified (* 0.5OC) by the National Bureau of Standards. After holding in the temperature gradient for 24 to 72 hr the samples were quenched in Cerro Bend at 480°C, followed by

Jan 1, 1960

By Valentine Garfias

THE various phases of the Mexican oil industry have received so much publicity that there is little to add to the discussion of present and future production, extent and importance of prospective fields, and status of petroleum legislation, to mention but a few of the angles of the Mexican oil problem. However, out of this wealth of information, which is generally of contradictory nature, the average petroleum man is at a loss to know something definite regarding the various questions involved so, keeping the foregoing in mind, it has been the writer's aim to record in a concise form the most reliable and up-to-date information regarding the salient features of the Mexican oil situation. PRESENT STATUS OF MEXICAN OIL INDUSTRY Production During 1921 The Mexican oil fields, during 1921, produced in round numbers 203,000,000 bbl. of which 176,000,000 bbl., or 86 per cent., were exported, the bulk of -these exports, or about 73.3 per cent., going to the United States. The Mexican exports were divided by grades as follows: Light crude, 47.0 per cent.; heavy crude, 22.0 per cent.; tops, 3.5 per cent.; fuel oil from light crude, 24.0 per cent. The balance, or 3 1/2 per cent., includes the bunker fuel shipments and the coastwise trade in Mexico, which is not classified as to grades. The figures show that, in importance, the light-oil fields from about 755 per cent. of the Mexican petroleum industry.

Jan 4, 1922

The Hurghada field is still the major producing field in Egypt. There was almost no activity in the Abu Durba field during 1936 and no new evidence is available. The following table summarizes the information on the Hurghada field for the year 1936. Hurghada Field Age of field to end of 1936, years.................... 23 Producing area for gas and oil, acres................. 1,050 Barbels Total oil production to end of 1936.................. 29,046,572 Total oil production during 1935.................... 1,212,182 Total oil production during 1936.................... 1,218,708 Daily average during November, 1936............... 3,249 MillionB CU. Ft. Total gas production (Aug. 1925 to end of 1936)...... 3,966 Total gas production during 1935................... 278 Total gas production during 1936................... 280 Maximum daily in 1936............................ 0.9 Number of producing wells completed to end of 1936... 94 Number of producing wells completed during 1936. ... 3 Number of wells abandoned during 1936............. 3 Producing wells at end of 1936...................... 768 Average depth of bottom of producing wells, ft....... 1,720 Average depth of top of producing horizon, ft......... 1,598 Character of oil, approx. average during 1936: Gravity at 60' F., 0.900; base mixed. Character of gas, approx. average during 1936: gallons gasoline per 1,000 CU. ft., 6.2. Producing rock (main): Nubian sands, Cretaceous; character, sand rock and sandy shales. 1 The figures given by the author were in tons. A conversion factor of 6.98. based on 0.900 sp. gr., was used to obtain the number of barrels.—Ed. 2 All pumping.

Jan 1, 1937

By M. G. Benz, J. F. Elliott

The austenite solidus of the iron-carbon system has been determined using a series of diffusion couples, each of which consisted of a specimen of austenite held in contact with a melt saturated with austenite. After the equilibrium distribution of carbon had been established by diffusion at a specified temperature, i.e. the austenite specimen had become austenite of the solidus conzposition, the diffusion couple was cooled, sectioned and anazlyzed for carbon. The solidus was found to be a straight line: A revised iron-carbon temperature-composition diagram is presented, COMPOSITION has a marked effect on the temperature at which austenite begins to melt and the austenite solidus of the iron-carbon system describing this effect has been the subject of many investigations.1-10 The significant results of these investigations are presented in Fig. 1. The experimental methods and purity of the materials used in them are summarized in Table I. In plotting the data in Fig. 1 no attempt has been made to convert these results to the International Temperature Scale of 1948," except for the data of Adcock,5 as this conversion would do little to reduce the uncertainty that exists as to the position and shape of the solidus. A point of major concern in evaluating these data is that the alloys studied, except those used by Adcock, were not binary alloys of iron and carbon, Table I. Also, it would appear that several of the methods did not permit equilibrium to be established through the system being studied. All that can be said for the results of these investigations is that they indicate only approximately the location of the solidus with the uncertainty as to its location at 1 pct C being approximately 100°C. The current investigation was undertaken to provide reliable data by which the austenite solidus could be established. It was hoped that information on the liquidus also could be developed at the same time, but experimental limitations prevented this as austenite segregated from the liquid on cooling. After a careful study of possible experimental methods and extensive laboratory tests, it was decided that the use of a series of austenite-liquid diffusion couples would provide the most reliable results. This paper describes the method and its results and also includes a complete iron-carbon temperature-composition diagram based on what are considered to be the best available data. EXPERTMENTAL METHOD The diffusion couple used for this investigation consisted of a small cylindrical pellet of austenite held in contact, at a specified temperature, with a melt saturated with austenite. The composition of the cylindrical austenite pellet was chosen to be approximately 0.1 wt pct C less than the estimated

Jan 1, 1962

By J. W. Hickman, E. A Gulbransen

The physical and chemical structure of the oxide films formed on metals and alloys is of interest in our understanding of their protective properties. According to Pilling and Bedworth,¹ if the specific volume of the oxide is equal to or greater than that of the metal, a compact or continuous structure results; if the volume of the oxide is less, a cellular or porous structure forms. With the cellular type of coating the surface layer of oxide offers no impedance to oxidation; at a given temperature the rate of oxidation is quite constant. On the other hand, the compact type of coating acts as an effective barrier to oxygen and the rate of oxidation will follow a parabolic law. The recent work of Gulbransen2 and of Leontis and Rhines3 on the oxidation of magnesium indicates that it is not necessary for the volume of the oxide to be greater than that of the metal in order that the oxidation may follow a parabolic rate law. One exception to the rule of Pilling and Bedworth¹ is noted by Scheil;4 namely, tungsten. At 500° and 700°C long-time oxidations indicate a linear rate law with time. However, Dunn's6 0xidation measurements from 700°to 1000°C indicate that a parabolic rate law is followed. The oxide is mainly yellow WO a with a thin layer of the blue oxide. Preliminary results on the oxidation of tungsten6 in the temperature range 400° to 500°C indicate that the oxidation does proceed according to a parabolic rate law. Irrespective of the actual rate law that tungsten may obey, it is of interest to compare the results obtained on the oxidation of tungsten in the thin film region with those found when the metal is scaling. A time-temperature study of the oxides formed on both molybdenum and tungsten may indicate whether there exist any peculiarities in the oxide structures of the thin film region compared with those of the scaling region of oxidation. In a recent paper the authors7 presented an investigation of the structures of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper. The results of these studies are presented in graphical form as existence diagrams of the oxides on a time-temperature scale. The existence diagrams of the oxides occurring on some of the metals are simple and show few chemical transitions, but there are many cases in which the physical state of the oxide surface changes as a function of time and temperature, as evidenced by the appearance or disappearance of orientation effects and sharpness of patterns. In general an increase in temperature results in an increase in

Jan 1, 1947

By E. A. Gulbransen, J. W. Hickman

The physical and chemical structure of the oxide films formed on metals and alloys is of interest in our understanding of their protective properties. According to Pilling and Bedworth,¹ if the specific volume of the oxide is equal to or greater than that of the metal, a compact or continuous structure results; if the volume of the oxide is less, a cellular or porous structure forms. With the cellular type of coating the surface layer of oxide offers no impedance to oxidation; at a given temperature the rate of oxidation is quite constant. On the other hand, the compact type of coating acts as an effective barrier to oxygen and the rate of oxidation will follow a parabolic law. The recent work of Gulbransen2 and of Leontis and Rhines3 on the oxidation of magnesium indicates that it is not necessary for the volume of the oxide to be greater than that of the metal in order that the oxidation may follow a parabolic rate law. One exception to the rule of Pilling and Bedworth¹ is noted by Scheil;4 namely, tungsten. At 500° and 700°C long-time oxidations indicate a linear rate law with time. However, Dunn's6 0xidation measurements from 700°to 1000°C indicate that a parabolic rate law is followed. The oxide is mainly yellow WO a with a thin layer of the blue oxide. Preliminary results on the oxidation of tungsten6 in the temperature range 400° to 500°C indicate that the oxidation does proceed according to a parabolic rate law. Irrespective of the actual rate law that tungsten may obey, it is of interest to compare the results obtained on the oxidation of tungsten in the thin film region with those found when the metal is scaling. A time-temperature study of the oxides formed on both molybdenum and tungsten may indicate whether there exist any peculiarities in the oxide structures of the thin film region compared with those of the scaling region of oxidation. In a recent paper the authors7 presented an investigation of the structures of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper. The results of these studies are presented in graphical form as existence diagrams of the oxides on a time-temperature scale. The existence diagrams of the oxides occurring on some of the metals are simple and show few chemical transitions, but there are many cases in which the physical state of the oxide surface changes as a function of time and temperature, as evidenced by the appearance or disappearance of orientation effects and sharpness of patterns. In general an increase in temperature results in an increase in

Jan 1, 1947

By J. B. Cheatham

An analysis of indexing is given for an idealized plastic rock. Indexing refers to chipping from a bit tooth to a previously formed crater. A method is indicated for computing the dependence of chip size and shape as well as force on the tooth for various tooth shapes as a function of crater configuration and distance to the previous crater. Pressure on the tooth is found to vary with depth of penetration after a critical depth has been reached. Damp sand model experiments indicate that simple solutions using linear and logarithmic spiral slip-line fields for Coulomb plastic materials give reasonable approximations to the failure patterns. Both idealized roller cone bits and fixed blade or drag bits are considered, and methods are presented for approximating the force on the bit and the chip volume when the rock is subjected to sufficiently high pressure to behave plastically. One of the primary objectives of drilling research investigations is to develop theoretical equations which can be used to predict the behavior of rock under drilling loading conditions. Since rocks usually fail in a brittle manner at atmospheric conditions, much current research is directed to studies of the brittle failure of rock under the action of drilling too1s. 1,2 The results of triaxial test on rocks indicate that both rock strength and ductility increase at high confining pressures.3 Recent results from single bit-tooth indentation experiments on dry rocks indicate that the transition from brittle to ductile failure under a bit tooth can occur at pressures sufficiently low to be of interest in oil well drilling.4 Single bit tooth experiments and analyses are not directly applicable to the drilling process since one of the important facets in drilling is the interaction between a bit-tooth and the previously formed crater. This interaction is referred to as indexing.' The purpose of the present paper is to indicate how plasticity theory can be applied to the analysis of indexing for plastic rock. Drag bit or fixed-blade drilling is considered and a discussion is given of the drilling action of an idealized roller cone bit. Results of simple experimental studies using a damp sand model are given as a method of visualizing the failure patterns in rocks under high confining pressures. These results are compared with plasticity theory using simple solutions based on linear and logarithmic spiral slip-lines. Discontinuous stress fields are proposed for drag bit drilling based upon the soil mechanics analysis of Shields. SINGLE BIT TOOTH RESULTS Single bit tooth indentation experiments using dry rocks under pressures from 0 to 5000 psi have indicated a correlation between the shape of a force-displacement curve and the nature of the rock failure beneath the tool.4 Continuous linear curves are in-

Jan 1, 1965