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By A. E. Bellis

The time effect in reheating certain steels below the critical range is very marked. The increased toughness, shock-resisting power, and machinability of steel subjected to a long, high drawing temperature has been thoroughly demonstrated and is of practical importance, particularly in the manufacture of "smokeless" rifle-barrel steel. The time effect in tempering is most important when a maximum drawing effect is desired, in which case the highest physical properties as well as ease of machining are important considerations. These are the conditions in drilling a rifle barrel. A hole, 0.30 in. in diameter and 24 in. long for the Springfield rifle, and 30 in. long for the Russian military rifle, has to be drilled in the heat-treated material. This barrel-drilling operation is probably the most difficult one in rifle manufacture, and anyone who has been connected with rifle manufacture knows how seriously production is affected when "hard" or non-uniform steel for barrels is encountered. The importance of high physical properties (tensile strength, toughness and resilience) in a rifle barrel is obvious. The physical properties of two different lots of barrel steel are given below. The first lot, No. 1, gave serious trouble in the drilling operation; the second gave no trouble at all.

Jan 2, 1918

By Steven R. Wardwell, Gerald G. Stokes

INTRODUCTION A compaction grouting program to control ground loss, and to minimize surface settlement, was developed for the West Tunnel of the Phoenix Storm Drain Tunnels. The West Tunnel was 4,200 m long, 7.56 m in excavated diameter, and was excavated with shallow cover through the central Phoenix business district. The tunnel could not have been successfully excavated without the compaction grouting program. HISTORY After heated political debate over a ten year period, the Arizona Department of Transportation (ADOT) was granted approval to build the Papago Freeway, an extension of Interstate 10, through central Phoenix. To comply with environmental constraints, a portion of the Freeway was depressed, requiring an excavation 10 meters in depth, thus intersecting surface run-off from the northern section of Phoenix. This required that ADOT and Project Design Consultant, Howard, Needles, Tammen & Bergendoff (HNTB) design a drain system to collect run-off and transport it approximately 4 kilometers to the Salt River through the City of Phoenix. Tunnels were chosen for the main discharge conduits because depth and location of the system made cut and cover construction impractical. A contract for construction of the tunnels was awarded to Shank-Artukovich-Ohbayashi (S-A-O) on May 24, 1984.

Jan 1, 1987

By M. R. Stokes

Over the recent years there has been an increase in the application of retreat mining on longwall faces as mine operators strive for ever greater productivity. The purpose of this paper in then to review current practice as a starting point and then move forward to discuss the future geometry's that a longwall face may take. Single and double production zone three roadway faces are assessed. All possible configurations of three roadway faces are defined. Unsuitable configurations are rejected after analysis of broad ventilation issues. The remaining configurations are then assessed on an operational basis, this includes: limits on retreat synchronisation, structure of centre gate, floor bulging and equipment installation. The remaining viable configurations are then further assessed on ventilation issues, this includes: provision for gas control/gas fringe, face climate and balancing of face flows. Possible face climate is assessed using numerical simulation of the various configurations, the predicted dry/wet bulb temperature and predicted levels of heat stress indices are given and discussed in detail, along with face flow balancing. The necessary conditions required for the successful operation of a double production zone three roadway face system are formulated, together with conclusions as to the possible level of application.

Jan 1, 1997

By ALFRED KAUFFMAN

NO matter what position we hold, workman, foreman, superintendent, manager, president, or what not, let us fail to give or to make good products, then see how quickly we'll be called to account for- our work by the buying public. The waves of progress taught us that millions were wasted in unnecessary strikes-we also learned that many losses were due to neglect on the part of manufacturers to give the same consideration and attention to the human element of their factory as they gave to their machinery. The employees learned also that the employer was their agent who found purchasers for the product of their labor. So between the two we learned that many years of labor were needed in order for a worker to recover his wasted savings, or for the manu¬facturer to replenish his loss. Treat 'em rough, and tell 'em nothing, was not very far from the true relationship between management and employees in manufacturing plants in the early days. Today just exactly the opposite views are held by executives whose function is the handling of employees. Men today want to know what it is all about. They are intelligent enough to comprehend the facts, and to use them constructively, and it is good business to give them the information.

Jan 1, 1929

By T. J. Driscoll

The effect of coatings on the incendive properties of aluminum alloy 6061-T651 in air-6.4%CH4 was studied for collisions between rusted steel and both uncoated and coated projectiles with incident energies as high as 300 J (220 ft-lb) and velocities as high as 200 m/s (660 fps). These conditions were intended to simulate the rough handling of equipment in coal mines. The ignition probability using uncoated alloy projectiles increased with increasing relative humidity and appeared to be influenced by atmospheric ozone content. The incendive properties of both the uncoated and coated alloy depended on the type of rust used, but the dependence of the coated alloy was very different from that of the uncoated alloy. A number of coatings developed in the last 25 years were found to offer protection from ignition and to remain largely intact for occasional collisions or collisions randomly distributed over the coating surface, but probably not for repetitive collisions at any given point on the coating. These protective coatings utilize a hard anodized aluminum alloy surface coated with one or more layers followed by heat treatment of the coating. Coatings containing Teflon and MoS2 and thicker than 50 µm (2 mils) appear to be most effective.

Jan 1, 1987

Recent developments in engine, transmission and control technology, likely to give rise to improved performance and efficiency of underground mobile equipment, are reviewed. Turbocharging and the electronic control of fuel pumps and injectors can improve diesel engine performance whilst minimizing exhaust emissions. Ceramic materials promise further improvements in engine efficiency. Nevertheless, electrically powered machines, equipped with trailing cables or 'travelling plugs' are expected to find increasing application where there is less need for flexibility and where the cost of ventilation and heating or cooling makes diesel engines unattractive. Voltage to frequency converters and induction motors appear to have a future in mains powered machines. Vehicles employing energy storage in the form of batteries or flywheels will find increasing application, but it is expected that they will remain a minority until there is a significant break-through in battery technology. Hydrostatic transmissions having high power density and efficiency are likely to be used more widely. Electronic control systems are likely to be used to simplify jobs and to improve performance and productivity. Enhancement of remote control systems is to be expected for work in unsafe areas, but true robot operation is considered unlikely for the moment. Attention to ergonomic factors should produce significant productivity gains.

Jan 1, 1985

By R. F. Miller, R. F. Campbell

Sixteen steels containing different combinations of chromium and molybdenum, in amounts up to 5 per cent of each element, were examined for microstructure and hardness after air cooling and after furnace cooling from suitable austenitizing temper- atures. Diagrams summarizing the structnres and hadness resulting from these two cooling rates are presented (Figs. 3, 4, 7).t Data were also obtained on the influence of these two elements, individually and in combination, on the depth of decarburiza-tion observed after furnace cooling (Fig. 8). Composition of Material The chemical composition of the steels investigated is given in Table I. The plain carbon steel was made in a 2 5-ton Heroult electric-are furnace, while the alloy steels were made in a 4.5-ton Ajax-Northrup elec- tric induction furnace. The cast ingots were hot-rolled to 1.75-in. bars. Air-cooled Series The I.75-in. bars were forged to flat plates, 0.25 in. thick, from which specimens 0.5 in. wide by 2 in. long were cut. The specimens were pretreated to improve their homogeneity by heating to 1830°F. (I000°C.) for 20 min. and oil-quenching. They were then reheated to 1740°F. (950°C.) for one hour and air-cooled, after

Jan 1, 1942

By R. F. Campbell, R. F. Miller

Sixteen steels containing different combinations of chromium and molybdenum, in amounts up to 5 per cent of each element, were examined for microstructure and hardness after air cooling and after furnace cooling from suitable austenitizing temper- atures. Diagrams summarizing the structnres and hadness resulting from these two cooling rates are presented (Figs. 3, 4, 7).t Data were also obtained on the influence of these two elements, individually and in combination, on the depth of decarburiza-tion observed after furnace cooling (Fig. 8). Composition of Material The chemical composition of the steels investigated is given in Table I. The plain carbon steel was made in a 2 5-ton Heroult electric-are furnace, while the alloy steels were made in a 4.5-ton Ajax-Northrup elec- tric induction furnace. The cast ingots were hot-rolled to 1.75-in. bars. Air-cooled Series The I.75-in. bars were forged to flat plates, 0.25 in. thick, from which specimens 0.5 in. wide by 2 in. long were cut. The specimens were pretreated to improve their homogeneity by heating to 1830°F. (I000°C.) for 20 min. and oil-quenching. They were then reheated to 1740°F. (950°C.) for one hour and air-cooled, after

Jan 1, 1942

By R. F. Campbell, R. F. Miller

SIXTEEN steels containing different combinations of chromium and molybdenum, in amounts up to 5 per cent of each element, were examined for microstructure and hardness after air cooling and after furnace cooling from suitable austenitizing temper- [ ] atures. Diagrams summarizing the structures and hardness resulting from these two cooling rates are presented (Figs. 3, 4, 7).† Data were also obtained on the influence of these two elements, individually and in combination, on the depth 0f decarburization observed after furnace cooling (Fig. 8). COMPOSITION OF MATERIAL The chemical composition of the steels investigated is given in Table I. The plain carbon steel was made in a 25-ton Heroult electric-arc furnace, while the alloy steels were made in a 4.5-ton Ajax-Northrup elec- [ ] tric induction furnace. The cast ingots were hot-rolled to I.75-in. bars. AIR-COOLED SERIES The I.75-in. bars were forged to flat plates, 0.25 in. thick, from which specimens 0.5 in. wide by 2 in. long were cut. The specimens were pretreated to improve their homogeneity by heating to I830°F. (1000°C.) for 20 min. and oil quenching. They were then reheated to I740°F. (950°C.) for one hour and air-cooled, after

Jan 1, 1941

By R. Priestner, R. F. Krause

Solid, cylindrical crystals of a iron have been fractured at 10°K by the simultaneous application of tension and torsion stresses. Thus, a complex distribution of normal (sN) and shear (ss) stresses existed in a cleavage plane at fracture. In every crystal the clearage-plane normal was inclined to the specimen axis, so that a unique point, M*, in the operative cleavage plane was defined where the quantities sn and s2 N + s2 S) were maximized. It is shown that the maxirrzum resolved normal stress on the cleavage plane at fracture decreased as the resolved shear stress in the cleavage plane at M* increased. Thus, a normal stress la?*! for fracture was not satisfied. A fracture law which takes shear stress into account. and which predicts that (s2 N +s2S) should be constant, is to be preferred. However, the data is best represented by a linear dependence of sN on sS, sS which 110 physical significance can be attached. It is suggested that the fracture-nucleating -mechanism is a short-range one. A critical stress law has not yet been unequivocally established for the propagation of cracks in metals. Measurements of the tensile fracture stresses of variously oriented zinc single crystals1 failed to establish the normal stress law expressed by In Eq. [1], sN is the fracture stress, P, resolved normal to the fracture plane, and 0 is the angle between the fracture -plane normal and the stress axis. Similarly, a comprehensive investigation failed to verify the normal stress law for the tensile fracture of a-iron single crystals.' However, a subsequent investigation,3 using iron from the same ingot, presented fracture data which obeyed the normal stress law. It has been shown previously4,5 that the Griffith criterion for fracture6 does not predict such a normal stress law. This result is of particular significance in considering the fracture of metals, such as zinc and iron, which may fail by cleavage. In these metals fracture propagates in a well-defined "cleavage" plane, whether or not an applied stress is normal to it. When the cleavage-plane normal deviates from the direction of application of a uniaxial stress, for example, the crack propagates under the combined action of normal (sN) and shear (ss) stresses. When the presence of a resolved shear stress in the crack plane is taken into account, the Griffith criterion is expressed by4

Jan 1, 1967

High Pressure Grinding Rolls (HPGR) are said to be a good option in new grinding circuits. Due to their low energy consumption compared to other grinding systems such as SAG milling, there is a strong incentive to check their behaviour for certain ore types. With rising energy prices the operation will become even more beneficial in future. As published in the past, the HPGR is claimed to increase the liberation of the valuable mineral component within an ore. An investigation at the research centre of Polysius was conducted to substantiate the liberation behaviour in finish grinding operations. A pilot scale HPGR test unit (POLYCOM MAGRO) with a roll diameter of 950 mm and processing capacity of 80 t/h was used. Grinding tests were completed with a screen and a two stage drying air separation process (SEPOL). Analysis included standard screen analysis, fractional XRF and modern MLA technology. A technique was developed to oppose the amount of produced slimes (resuming bad flotation) against the positive effect of producing high mass fraction at flotation-easy sizes. The paper shows how effective the use of a dry grinding separation could be in terms of production of mass of liberated metal.

Jan 1, 2012

By Paul G. Dunn

Safe rapid drift development results principally in reducing exposure of underground workers to the working face. This reduction in exposure is not achieved until either the rock walls have been suitably scaled or sufficient support has been put in place. Rapid drifting enables quicker access to orebodies (increasing returns), higher production rates and a resultant lower cost of mining. The Mining Innovation, Rehabilitation And Applied Research Corporation (MIRARCO) has been developing technology and a methodology for safe rapid drift development within the underground metalliferous mining industry. In terms of rock scaling for underground metal mines, there is still considerable use of manual and mechanical impact rock scaling techniques. Two main issues result from this approach. The first is that in highly stressed or highly fractured ground, a decision has to be made as to when sufficient scaling has taken place. This is not always easy to do and hence operator judgment is a crucial element in this approach. During a baseline study of current rock scaling practices, a wide range of scaling practices were observed within five different underground mining operations; this demonstrates the difficulty inherent in the rock scaling quality decision making process. The second issue is related to the exposure of workers to freshly created rock surfaces. In manual scaling techniques this is unavoidable and despite the best scaling practices, accidents still occur. In an attempt to provide an alternative scaling technology, MIRARCO has been investigating highpressure water jet scaling for removing loose rock as part of the drift advance process. This technology not only provides a means by which scaling practices can be engineered (remove the loose material you want to in a given rock mass condition), it is also quicker and easily automated. Automating the scaling process removes workers from exposure to freshly created rock surfaces and also enhances the application of spray-on liners through improved adhesion of these support types to the rock surface. This paper describes the water jet scaling technology research and methodology for safe rapid drifting within the underground metaliferous mining industry and highlights the key issues and major drivers behind their continued development at MIRARCO.

May 1, 2004

By A. L. Mular

"On behalf of Bob Bruce and myself I would like to begin by stressing some key points.First, most of us know that the Canadian Mineral Processors was formed in 1969 and is an offshoot of the Canadian Gold Metallurgists. I attended that first meeting in 1969, and I haven't missed a meeting since! Pretty obvious that CMP serves the best booze! At any rate, we know that our meetings are supported by CANMET. Camsell Hall is always at our disposal; Bob Bruce acts as permanent secretary pretty much free of charge; we receive a financial grant from CANMET. This brings me to a second point.Second the Canadian Mineral Processors do not enjoy a free ride in this relationship. CMP provides a genuine service to the mining industry, to government, and to universities. For the industry, CMP serves as a forum for the rapid dissemination of new ideas and new technology developed at remote locations throughout Canada. New developments outside Canada are introduced by invited speakers at our meetings. The effect is to help reduce operating costs and increase efficiency.For government, problem areas and research priorities can be isolated through mutual discussions. Direct communication at our meetings can help CANMET to temper its goals and modify its national priorities.For universities, CMP provides a wealth of operating experience and practical know how. The yearly proceedings are a major current reference source fo1· those of us who teach mineral processing. Admittedly, the proceedings are publ-shed from CMP coffers. However, I note that our fees are up this year, which brings me to a third point.Third, we face some potential problems of a financial and political nature. From a financial view, we may lose our CANMET grant and other financial good will simply because of spending constraints. Our fees are expected to climb each year thereafter.From a political view, we know that the metallurgical society of CIM is anxious to incorporate CMP as a section. The pros and cons of such a merger have been described in a recent mailing. In th2 final analysis, the political and financial problems are interrelated. There are several alternative solutions to both problems, which brings me to a fourth point"

Jan 1, 1979

By T. M. Gurr

It is estimated that in excess of one-half million chemicals are used throughout the American workplace. Hundreds of new chemicals are also being introduced into the workplace annually. Exposure to some of these chemicals can be harmful to workers and to the environment. The Occupational Safety and Health Administration (OSHA) estimates that approximately 25% of the U. S. labor force or approximately 25 million workers are exposed to one or more chemical hazards each year. OSHA has determined that this poses a serious problem for workers exposed to such chemicals. Chemical exposure may cause safety and health problems. Health problems can include a cause or contribution to heart ailments, kidney and lung damage, sterility, cancer, burns, and rashes. Safety hazards can include the potential to cause fires and explosions and other serious accidents.

Jan 1, 1989

By W. F. Holbrook

In a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO. In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 per cent MgO slags over the range 1475' to 1525' C. is included. The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple. Twelve-gram charges of 0.8 per cent sulphur-metal and 5-gram charges of slag were subjected to heating for 30 min. at a prescribed temperature. The charges were analyzed for sulphur content. For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal. Six slag and metal charges were made coincidentally in 5/8in. holes in a section of an electrode graphite rod. One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors. For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant. Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO. Slags with Magnesium Oxide Constant 15 Per cent Mg0.—The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SiO2, 5 to 27 per cent A1203 and 24 to 53 per cent CaO. Variation in composition has been in steps of 2 per cent over much of the area. Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered in steps of 4 per cent and even

Jan 1, 1938

By L. H. Cadoff, L. M. Adelsberg

The layer growth method has been used to investigate the reaction kinetics of liquid titanium and hafnium with carbon and the [liq] - [liq + TiC] and [liq] - [liq + HfC] phase boundaries at temperatures above 1800°C. The equipment and experimental procedures used in this investigation are basically identical to those described in an earlier paper' on the Zr-C reaction. Temperature control, however, was improved significantly by connecting a Latronics Colo-Ratio automatic pyrometer and a controller to the power source. The subsequent temperature variations were ±10°C; previously ±20°C was obtained using manual controls. The absolute accuracy of the pyrometer, however, must be considered to be only ±40°C.* The spectrographic analyses of the materials used in this study are listed in Table I. The isothermal reactions of titanium (1800° to 2700°C) and hafnium (2300" to 3000°C) with carbon (graphite crucibles) resulted in the formation of carbon-saturated liquid metal and layers of Tic and HfC, respectively. The thicknesses of the carbide layers, determined from metallographic measurements at 100 times, as a function of carburization time and temperature are given in Figs. 1 and 2. At each temperature, parabolic growth behavior for these reactions was observed and could be expressed as x2 =Kpt, where X is scale thickness (corrected for heating and coolingL), Kp the parabolic growth constant, and t the isothermal carburization time. Values of Kp as a function of temperature for the carbides are shown in Fig. 3 and listed in Table 11. The growth constants are expressible as: kpTiC = 0.2 exp(-61,800/RT) sq cm per sec for Tic and Kp HfC = 2.62 exp(-95,300/RT) sq cm per sec for HfC. The liquidus phase boundaries were determined from metal samples treated in graphite crucibles for different times ranging from 4 to 100 min at each of the temperatures indicated in Table 11. Metallographic examination revealed that the carbide precipitates were distributed uniformly throughout the frozen metal matrices. This is attributed to the rapid cooling rates (800°C per min) and the small difference in density between the precipitated carbide and the liquid metal.

Jan 1, 1968

By W. F. Holbrook

In a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO. In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 per cent MgO slags over the range 1475' to 1525' C. is included. The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple. Twelve-gram charges of 0.8 per cent sulphur-metal and 5-gram charges of slag were subjected to heating for 30 min. at a prescribed temperature. The charges were analyzed for sulphur content. For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal. Six slag and metal charges were made coincidentally in 5/8in. holes in a section of an electrode graphite rod. One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors. For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant. Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO. Slags with Magnesium Oxide Constant 15 Per cent Mg0.—The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SiO2, 5 to 27 per cent A1203 and 24 to 53 per cent CaO. Variation in composition has been in steps of 2 per cent over much of the area. Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered in steps of 4 per cent and even

Jan 1, 1938

By Diler Katircioglu-Bayel, Oner Yusuf Toraman, Safak Gokhan Ozkan

Calcite has found many applications in the industrialized countries recently, such as filler for paper, paint, plastics, rubber and food. Furthermore, calcite separates many toxic elements, and thus it is used in water treatment, and it is also used to raise the pH of drinking water. Due to its special features, calcite has been characterized as a useful coating and reinforcement filler for applications. Finer particle size of calcite has been determined to provide improved features for all of these applications. For submicron particle production, wet milling is selected over dry milling to produce finer particle sizes. Wet stirred media mills are also used in many industries. For that reason, this study investigated the effects of operating parameters on particle size reduction in the wet grinding process. The knowledge acquired by this study will allow the finding of optimal operating parameters for a stirred media mill to optimize specific energy consumption and reduce particle size.

Several years ago, North American mining companies began to realize they needed to expand their spheres to remain viable. This strategy has been successful, according to Robert W. Schafer. Today, companies from other continents have also recognized the need for an international view for long-term growth and viability, he said. Schafer is vice president for exploration with Kinross Gold. He was the program chairman and moderator of the keynote session at the 1997 SME annual meeting, held in Denver, CO, Feb. 23-27. The theme of the meeting was "Minerals - Serving the Global Community." A record attendance of more than 6,000 people participated in the meeting, which featured 415 exhibitors occupying 582 booths. The title of the keynote session was "Corporate Perspectives on a Global Minerals Industry." Each of the three keynote speakers discussed a different perspective of a global minerals industry.

Jan 1, 1997

By M. K. Yen, W. R. Hibbard

Previous studies of plastic deformation of metals have emphasized the important role of bending and constraints during strain under relatively pure stresses.1"5 Some new phenomena such as early conjugate slip6 and polygonization7 are intimately concerned with the relief of bending stresses, the former by slip and the latter by a process analogous to re-crystallization. However, few analyses of the bending deformation of single crystals were found in the literature, and those8,9 are sufficiently previous to the modern interpretations of slip to invite further investigation in this area. The transverse bending mode of testing, using the two-point loading method, was selected because the center portion of the specimen may be considered as under a theoretically pure bending stress with a uniform bending moment. Considerable attention was given to both the lattice distortion and flow characteristics of the crystals during deformation. Experimental Proeedare A specimen under the action of equal and opposite couples at both ends is said to undergo pure bending. The shear and moment diagrams of a specimen under the two-point loading method of transverse bending are shown in Fig 1. The moment over the middle-third of the span is equal to PL/6, and the vertical shear is zero. Fig 2 (A) illustrates the stress distribution in the elastic range on a plane across the middle of the specimen. It can be seen that the normal stress has a maximum value at the extreme surfaces on the tension and compression sides, and decreases proportionately to zero as it approaches the neutral plane. However, when the plastic range is reached, the stress distribution is no longer a straight line relation, but changes in a manner which can be best illustrated as shown in Fig 2(B). The following calculation and stress analysis are mainly in accordance with the works reported by Timoshenkol0 and Kochendörfer.9 From the simple beam formula, the maximum normal stress will occur at the surface of the specimen. For a round specimen with a radius r and for a rectangular specimen with a height 2h and width 2b, the maximum normal stress, Sp, will be given by the following formulas: For round specimen: 2PL Sp = 3pr3 [1] For rectangular specimen: Sn = 8bh2 [2] Since it is reasonable to consider that slip takes place under the same conditions as in uniaxial loading, the resolved shear stress S?, along the operative slip direction will be as follows: For round specimen: 2PL sin x cos ? Sp = 3pr3 sin x cos ? [3] For rectangular specimen: PL S8 = 8bh2 sin x cos ? [4] where X is the angle between the specimen axis and the slip direction and X, the angle between the specimen axis and the major axis of the glide ellipse. It was also reported by Kochenclorfer9 that the critical bending moment, that is, the bending moment exerted on the specimen to initiate slip, should be higher than the value given by the equations stated above. Based

Jan 1, 1950