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By A. Gueciouer, A. Akkouche, K. Chalah, A. Benmounah

"Drilling solid waste is a typical industrial solid waste, and it is a major pollutant source to ecological environment. Generally, waste management dewatering systems separate solids and fine particles from the liquid phase of drilling fluid, thereby leaving a clarified aqueous solution and allow the cleaning of waste fluids. Typically, dewatering waste management systems clean drilling fluid through coagulation, flocculation and/or mechanical separation. Chemicals used in dewatering are based on the coagulation-flocculation process, which it facilitate the removal of suspended solids and colloidal particles. The factors which can promote the coagulation-flocculation are velocity gradient, contact time, and PH. The objective of this work is to optimize a formulation adequate for dewatering based on the coagulation-flocculation process used coagulant (Aluminum sulphate), anionic flocculants (Partially Hydrolyzed Polyacrylamide) and anionic polyelectrolytes (in solid form with linear chain with very high molecular weight). The results obtained show the good efficiency of the coagulant and flocculants. INTRODUCTION Rig site dewatering of drilling fluids with recycling of processed water can help an operator to comply with environmental rules by reducing volumes of waste and reducing long term liabilities. It can also reduce disposal costs and provide a cleaner drill site overall. Most of the environmental concerns during the 1980s involved hazardous materials and toxic wastes. Drilling fluids, many of which are chemically benign, have escaped many of the difficult-to-comply-with rules and regulations. During the 1990s, however, operators may be required to submit a written plan for liquid waste reduction for even nonhazardous materials. Many states and local agencies may institute total bans on oil field wastes. Drilling rigs typically produce about 1 bbl of liquid waste for every 1 ft of hole drilled. Thus, a typical drilling operation can produce a large quantity of waste [1]. To improve the dewaterability of sludge, different pretreatment processes have been widely studied and developed including thermal, chemical, magnetic, mechanical, acoustic, electric, electro-acoustic and their hybrid treatment processes [2]. Rig site dewatering (figure 1) is the process of injecting coagulants or flocculating chemicals into the mud entering a large clarifying centrifuge. Coagulation occurs when the solid and allowing it to be attracted to other solids by van der waals forces. Flocculation is the binding of individual solid particles into aggregates of multiple particles. It is physical, rather than electrical, and occurs when one segment of a flocculating polymer chain absorbs simultaneously onto more than one particle [3]."

Jan 1, 2018

By R J. Hill

Blasters are well aware of the problems and expense faced when trying to load in wet bore holes; problems of poor coupling and poor density, as well as the expense of higher priced cartridge product. In answer to these problems, I developed a system for dewatering using nozzles with lay -flat plastic liners which I have used successfully over the last few years. I found the system not only gave me better shots than I could have expected in the circumstances, but also dramatically decreased costs. The system has been adopted by two large roading contractors and a quarry operation in Eastern Canada.

Jan 1, 1986

By Andy Ingriselli, Andrew Famiglietti, John Westland, Greg Landry

Atlas Dewatering was contracted to install and maintain a groundwater control system for the new Bessarion Subway Station and the Tail Track Structure on the Toronto Transit Commission’s new Sheppard Subway Line. Atlas met the challenges presented by the project by closely reviewing the contract documentation provided by the Program Geotechnical Consultant, Golder Associates and by working with the general contractors, Bondfield Construction Company and PCL Constructors Eastern, inc., throughout the duration of both projects. In addition to concerns about soil loss, excessive settlement and seepage, the consultant was concerned about spreading hydrocarbon-contaminated groundwater between the two aquifers present at the Bessarion Station site. By installing a system of multi-level vacuum eductor wells around the perimeter of the excavation, Atlas was not only able to provide a dry excavation for construction, but, due to a unique well design was also able to prevent cross-contamination of the aquifers.

Jan 1, 2001

Dewatering tailing slurries by mechanical means is often not possible and gravity and solar driven processes must be used. It has been shown previously that better use of gravity is achieved when the tailing is drained as it settles. Not only are more compact sediments obtained but also the dewatering is faster. From the results of laboratory and field tests reported here, equations were established which describe the evaporation and drainage components of the dewatering. These equations were used to calculate the effects of ponding depth, solids content of the tailing and clim- atic conditions on the time required to dewater the tailing. Since the calculations can be made with and without the drainage component, the advantages to be gained with drainage can be determined. The tailing used in the work was a clay slime from a sand washing operation. However, it is anticipated that this approach will be applicable to other similar tailing.

Jan 1, 1978

By Antonio Zechini, Giuseppe Iorio, Massimo Grisolia

"The new C Line of the Rome Metro runs northwest to southeast across the city center, with 30 new stations and a total length of more than 15.5 mi (25 km). Due to the presence of a dense urban environment, the selected solution for the construction of the stations consists of a cutand- cover excavation, which is retained by multipropped diaphragm walls to minimize settlement and prevent damage to the nearby structures. The bottom of the excavation of the underground stations are about 82 ft to 98 ft (25 m to 30 m) below ground surface, and about 66 ft to 82 ft (20 m to 25 m) below the groundwater table. To ensure dry conditions and to prevent hydraulic base heave instability, deep well systems were designed and used to lower groundwater level and piezometric head during excavation. The dewatering field tests showed how the local stratigraphy strongly affects the dewatering efficiency. Finite element modeling (FEM) of steady state filtration were used to compare the soil permeability with Lefranc in-situ test results and to verify the efficiency of the grouted plugs. The geological sequence along the new C Line consists of a very heterogeneously layered deposit. The base deposit of stiff overconsolidated clay (“APL,” Pliocene age) is overlain by fluvio-palustrine very dense sandy gravels (“SG,” Pleistocene age), which are then overlain by medium stiff clayey silts or dense sandy silts (“AR” or “ST,” Paleotevere units). These deposits are overlain by covered by pyroclastic volcanic soils, tuff, silty sand and sandy silt (Middle to Upper Pleistocene) deriving from the Colli Albani apparatus. A layer of made ground (“R”) of varying thickness covers the stratigraphic sequence and the natural soil profile everywhere.The local hydrogeological framework is very complex and characterized by a double groundwater system. The upper main aquifer is mainly represented by the “pozzolane sequences” (“PR/PN”), while the lower aquifer consists of a deposit of sandy gravel (“SG,” Pleistocene), which is underlain by marine claystone bedrock (“APL,” Pliocene). The pyroclastic deposits (e.g., pozzolane, lithoid and pseudolithoid tuff and clayely tuff) show large variations in permeability due to porosity, compaction processes, sealing and secondary fracturing. Permeability values for each soil type were determined using Lefranc tests at variable head and using pumping tests. The Lefranc tests indicated a wide range of permeability."

Jan 1, 2017

By S R. "Bob" Pilshaw

Productivity is the popular "buzz" word that catches the attention of most managers when it is featured in the more popular mining and construction magazines. Engineering Task Forces and teams are formed to take advantage of productivity opportunities in almost all phases of an operation except the drilling and blasting area.

Jan 1, 1988

By Waterhouse J. D, Harris B. M

This paper briefly describes the construction in 1979/80 of a 70m deep trial open pit coal mine near Bowmans S.A. and describes more fully the hydrogeological aspects of the exercise. The primary purpose of the Trial Pit was to provide a large sample (700 tonnes) of coal for combustion tests to be carried out in West Germany and the United States of America. Consideration was given to obtaining the sample of coal by drilling and by shaft sinking as alternatives to open pit methods. It was expected that economic mining of the deposit on an operational scale could only be achieved by open cut methods and it was recognised that major uncertainties existed in planning such a mine in the deep unconsolidated multi-aquifer deposit. It was therefore elected to obtain the bulk sample by constructing a trial open pit, which would be closely monitored to provide as much data as possible for future planning of a full scale mine. The dewatering of the Trial Pit was achieved using 26 deep pumping wells, assisted in the later stages by several hundred well points. This was probably the largest dewatering project currently in operation in Australia.

Jan 1, 1981

By Kendall W. T C

This paper provides a brief overview of the history of the Chaffers Dewatering Project which was successfully commissioned in August 1993. Until the end of 1992 the `Superpit' and the deep mines of the Golden Mile had all been dewatered by a staged pumping system from the 28 level in the Lake View Shaft, which was removed at that time when the Lake View Mine was absorbed into the Superpit. Feasibility analysis had indicated that adaptation of oil industry technology offered the greatest potential for a low cost solution to the problem of dewatering the open pit and deep mines. A KCGM engineer and one of the authors visited the Jackson oilfields to look at the deep well pumping technology in use there in early-1991. In the final analysis a new dewatering station was established in the 23 level crushing station of the Chaffers Shaft using conventional plunger pumps, but the rising main was screwed 178 mm OD (7 inch) casing the suspended from the surface to a depth of 686 metres, and was installed using oilfield personnel and methods. Only the second installation of its kind in Australia, the project achieved the dewatering objective at about half of the capital cost of the more conventional approach and at lower operating costs as well.

Jan 1, 1995

By Dudley Walls

In 1974 Amherst, Coal Company disposed of its 28 mesh X O thickener underflow (refuse) by pumping to ponds. Because of the very steep terrain surrounding the plant the pond capacities were limited which necessitated daily cleaning of the ponds on a three (B) shift basis. Needless to say this proved to be a very expensive as well as a very "untidy" operation. Faced with increased pressures from state and federal authorities as well as increased handling problems because of limited pond capacities, Amherst began looking for a different method for the disposal of 28 mesh X O refuse.

Jan 1, 1979

By Wayne Charlie, Joseph P. Martin

INTRODUCTION Typically, uranium mills produce slurred tailings which are transported by pipeline to a tailings impoundment. The slurried tailings contain about 250 solids (75% liquids) by volume and, depending on the milling process, have a high or low ph. Despite decanting water from the tailings pond and losses by evaporation and seepage, Staub (1978) estimates that for lined impoundments over half of the input water is stored in the tailings. As long as the impounded tailings remain in a loose and saturated state, potential hazards exist and include potential for short and long-term seepage from the impoundments and the potential for large scale release and movement of liquified tailings should an embankment fail. The breach of an earthen dam on July 16, 1979 at Church Rock, New Mexico, and the subsequent release of 100 million gallons of water and liquified uranium tailings, underlines the potential hazard. Loose saturated tailings also have a high potential of liquefaction during earthquakes (Charlie and Wardwell, 1979; Martin, Finn and Seed, 1978; and Mittal and Morgenstern, 1976). If the tailings could be dewatered, the liner's integrity would become less critical, longterm seepage and settlements would be greatly reduced. In addition, the potential for tailings liquefaction from an embankment failure or earthquake would be greatly reduced. This paper reviews the concept, criteria, and design of various proposed interior drainage systems to dewater the tailings after deposition. ADVANTAGES OF INTERIOR DRAINAGE The primary purpose of interior drainage systems for uranium mill tailings impoundments is dewatering the tailings as rapidly and as thoroughly as possible. The expected benefits of this new technology are: • Reduction of potential seepage losses by decreasing the hydraulic head. • Reduce earthquake liquefaction potential of the tailings by inducing non-saturated conditions and/or lowering the water pressure. • Reduce the potential for large-scale release and movement of tailings should an embankment fail. • Stabilize the tailings to permit early reclamation. • Recovery and potential recycling of tailings liquid. • Inhibiting long-term seepage out of the impoundment by inducing nonsaturated conditions to provide capillary suction in the tailings.

Jan 1, 1980

The use of rubber-tyred equipment in a decline mining system requires that roadways be kept free of running water. At Renison this is achieved by the use of stage pumping or gravitating to a major pump station and pumping from there directly to the surface. The frequent use of pick-up lines and pump boxes in the decline system provides a method of water control and reduces the amount of slimes in pump lines. The Bassett Fault structure, which lies on the hangingwall of the mine is the major source of ground water. This is encountered in diamond drill holes and exploration develop- ment. Dewatering of this structure is possible by controlling the flow from selected holes. Future pumping requirements may be predicted by analysing changes in the level of the water table and by calculating dewatering rates required to maintain ore reserves available for production.

Jan 1, 1977

By D. J. Gilbert

As a preventive action, the geotechnical department at the mine analyzed the original topography overlying a conveyor tunnel at the mine. Several dewatering drains were installed to intercept water collecting from an old lakebed. Subsequently, 20 steel arches were installed to provide additional support in an area of tunnel where original geological mapping indicated Type IV rock. This project was completed ontime with no loss to production. Construction schedules had to be developed to half hour precision, to accommodate the installation.

Jan 1, 2011

Resolution Copper Mining LLC (RCML) is currently in a Pre-feasibility study evaluating a large and deep copper and molybdenum deposit in the historic mining district east of Superior, Arizona. Work scheduled for the next several years includes dewatering the existing shut-down mine (the Magma Mine) and sinking an exploratory shaft to 2,130 meters (7,000 feet) below the surface. To dewater the Magma Mine and sink the exploratory shaft, RCML must extract and manage about 2 billion gallons of accumulated mine water inventory, as well as about 300 million gallons per year of new inflow. In order to conserve a valuable water resource in a desert environment, RCML worked with the New Magma Irrigation and Drainage District (NMIDD) to provide treated mine water to blend with and supplement the NMIDD?s water supply to approximately 2,000 hectares (5,000 acres) of farmland located east of Phoenix. A 44 km (27-mile) pipeline was needed to convey the treated water. It was essential that a treatment system be used which could reliably meet irrigation water quality goals, produce a non-scaling effluent to maintain pipeline flow capacity, and generate a dense sludge minimizing disposal cost and volume. This paper describes the resulting mine water treatment and recovery system (MWTS) and how the system has performed against objectives.

Jan 1, 2011

By L Grigorov, G J. Jame, A V. Nguyen

The dewetting kinetics between a small air-liquid interface and a silica (negatively charged in water) planar surface in solutions of dodecylammonium chloride (cationic surfactant) has been investigated using the Scheludko cell and digital high-speed video microscopy. The gas-liquid interface was created at the bottom of a small silica capillary of the cell and then was moved towards the silica planar surface. After the rupture of the liquid films between the interfaces, the expansion of the gas-liquid-solid three-phase contact (TPC) line was observed and recorded using a digital high-speed video microscope system, operating at 1000 frames per second. The surface tension of the surfactant solution was measured using the pendant drop technique. The equilibrium contact angle was measured using the Scheludko-Minings method with a silica micro-sphere. The TPC radius was determined as a function of time and compared against the available hydrodynamic and molecular-kinetic models. The experimental data are described very well by the molecular-kinetic model for the TPC line motion. The hydrodynamic model is in agreement with the experimental data only for a short time after inception of the three-phase contact expansion.

Jan 1, 2005

By Gilbert Soler

Page Introduction. By Gilbert Soler.........................657 Deoxidation of Basic Open-hearth Steel. By T. S. Washburn.............658 Slag-metal-oxygen Relationships in the Basic Open-hearth and Electric Processes. By J. S. Marsh. (With discussion)...........................672 The Total Oxygen Content of Plain Carbon Open-hearth Steel during Deoxidation and Teeming. By Michael Tenenbaum and C. C. Brown. (With discussion)......685 The Occurrence of Oxygen in Liquid Open-hearth Steel—Sampling Methods. By T. E. Brower and B. b. Larsen..........................712 Effect of Deoxidation on the Strain-sensitivity of Low-carbon Steels. By H. K. Work and G. H. Enzian. (With discussion)........................723 The Relation among Aluminum, Sulphur, and Grain Size. By C. E. Sims.......734 Some of the papers and discussions that appear on the following pages were presented at the meeting of the Iron and Steel Division in Cleveland, Ohio, on Wednesday, October 18, 1944. with L. F. Reinartz and H. K. Work as Chairmen; the remainder were scheduled for the New York Meeting of the Institute in February 1945, which was canceled.

Jan 1, 1945

By T. S. Washburn

Deoxidation is one of the most complex metallurgical operations in the basic open-hearth process. The necessity for deoxidation arises from the fact that the refining operations that precede it require the oxidation of the steel bath. when the refining is completed and the desired composition of the bath has been obtained with respect to the elements subject to control by 'oxidation. there is usually an excess of oxygen present in the bath from the standpoint of the amount desired in the finished steel. The objectives of deoxidation are to control the amount and type of oxides and, although not directly ilnp1it.d by the term or always considered as a Part of the process, to control the amounts of gases such as hydrogen or nitrogen that will be present in the finished steel. There are other aspects to be consideretl in connection with deoxidizing procedures. In addition to the primary objectives of oxide and gas control. the composition of the steel is affected by the elements introduced during the deoxidizing process. Factors in furnace operations are likewise involved, such as slag composition, temperature control. arid heat time. .ill of these should be considered in establishing the most satisfactory deoxidizing procedure for each grade of steel. The purpose of this paper is to outline the objectives of deoxidation as related to steel characteristics, and to summarize the factors in furnace practice and the economic aspects to be considered in connection with deoxidation procedures. Objectives of Deoxidation The primary objectives of deoxidation are the formation and elimination of oxides. The amount of oxygen present in the bath prior to deoxidation is an important factor, since it is the basis of any deoxidation procedure. The oxygen content of the bath is primarily a function of the carbon content, although it is affected also by the temperature, the oxidation of the slag, and transient conditions within the furnace. The relation of oxygen to carbon in the bath is shown in Table I. Table I shows that under actual operating conditions, the amount of oxygen present in the bath is higher than the theoretical amount. This relation would be expected, since the bath is in a state of metastablc equilibrium during the period that the carbon is being eliminated. The most important feature demonstrated by this table, however, is the rapid increase

Jan 1, 1945

By H. K. Work, G. H. Enzian

In the manufacture of steel for commercial purposes, the deoxidation practice used, i.e., the method and degree of deoxidation, is an important factor affecting the structure and mechanical properties of the finished steel. Deoxidation practice exerts a pronounced influence not only on the soundness of the ingots but also on the reaction of the steel to a number of mechanical and thermal treatments. The first mentioned effect of deoxidation is more or less obvious and was first demonstrated, though perhaps not fully appreciated, by Robert Mushet when, in 1856, he added speigeleisen to low-carbon bessemer blown metal. In 1861. Bessemer patented the addition of one pound per ton of silicon to his blown metal to "cause the metal to lie quietly in the mold." The second effect of deoxidation-—that is, the effect on the properties and behavior of the steel—is, one might say, more subtle, and certainly not as well understood as the first, although in many cases it is the more important consideration. This paper is limited to a discussion of only the second effect of deoxidation and: in particular, to the effect on the strain-sensitivity of low-carbon steels. General Discussion Originally it was thought that the function of a deoxidizer was to combine with the oxygen present in the steel as iron oxide and prevent its subsequent evolution as a gas. -More recently it has been realized that a deoxidizer does more than this. Frequent reference has been made to the effect of deoxidizers on the nitrogen in the steel, and some attention has also been paid to hydrogen. As a consequence of the above situation any study of deoxidation must be concerned with the gas content of the steel and the effect of the deoxidizer on the gases involved. The term "gas content" as used here refers to gases extracted from steel during melting in vacuum rather than to elements present in steel in the gaseous state. The extracted gases, at least in the case of oxygen and nitrogen, are generally accepted to be products of decomposition of oxides, nitrides, or other more complex compounds. The manner in which deoxidation affects the gas content of steel and the significance of gases in steel have been and still are subjects of considerable speculation. No attempt will be made here to give a complete discussion of the literature on this subject but a few references will be cited for purposes of illustration. N. Hamilton1 found a correlation between the oxygen content of alloy steel and the behavior of the steel during tube piercing. Davenport, Bain, and others associated oxygen with aging properties of steel while Köster5 and a number of others6-lo made similar claims for nitrogen. Daniloff, Mehl, and Hertyll stated that "deoxidation decreases the susceptibility of steels to aging directly

Jan 1, 1945

By J. S. Marsh

The student of steelmaking is all too well acquainted with the fact that in many instances he must deal with data that in graphical representation exhibit the property most desirable in bird shot. This is scarcely mystifying, since the effort to establish one variable as a function of another is usually hampered by the simultaneous operativeness of two or three other factors that may be important. A large part of arriving at relationships that have the pleasing self-consistency of, say, precise measurements of thermal expansion, consists of determining what factors must be held constant-—an even larger part usually consists of collecting data for which those factors have been so maintained. It is not intended to imply that functional relationships in the physical chemistry of steelmaking are hopelessly obscure; on the contrary, it is merely necessary to be undisturbed by marked deviation of some points from a curve that otherwise makes sense. A reaction mechanism suggested by such a curve may call attention to hitherto unsuspected factors operative in the origin of the deviating points, and thus permit another step to be taken in the direction of fuller understanding. It is proposed, therefore, to suggest several empirical relationships. Even though the approach is not always rigorous, deviations caused by simplifying assumptions appear to be too small to obscure a provisional It has been appreciated for some time that the carbon-oxygen reaction in liquid steel is highly important. For example, Körber et al.,' in introducing a summary of their extensive work on steelmaking reactions, said: "... the far-reaching and truly dominating action of carbon upon the metallurgical reactions will be especially stressed ..." In "Basic Open Hearth Steelmaking"2 (hereafter BOHS, for simplicity), it is accepted repeatedly that the various slag-metal interactions are nearly always controlled by the carbon-oxygen reaction. Before further discussion of this reaction, however, it will be worth while to consider briefly the carbon-oxygen equilibrium. In BOHS (p. 483) it is stated that: When liquid iron is brought into contact with gases containing carbon monoxide it absorhs carbon and oxygen. Conversely the carbon and oxygen in the metal unite to form carbon monoxide which is evolved from the bath during the open-hearth boil or while rimming ingots are solidifying. . . . When the equilibrium pressure is one atmosphere the equilibrium-constant equation simplifies, on the assumption that the activity of each element is equal to its percentage, to a constant which has been so much used that it has acquired a special symbol m. where m = %C X %O

Jan 1, 1945

By B. M. Larsen, T. E. Brower

For some years we have been carrying on a rather comprehensive investigation of the occurrence of oxygen in liquid open-hearth steel. This investigation was interrupted by the war emergency and is therefore incomplete, with many questions still answered only partially, if at all; yet it seemed worth while to present a report of progress on this difficult field of research, if for no other reason than to promote discussion and further investigation of this important problem. The significance of such studies depends in large measure upon the accuracy of measurements of oxygen content in liquid steel while it is still in the furnace or as it flows into the ladle, or thence into the mold and there is, as we shall show, good reason for believing that the main source of uncertainty is in the sampling, not in the analytical method as such. The difficulty arises from the fact that any method of sampling is of itself apt to alter the amount of oxygen in solution in the liquid steel, because this oxygen is in a readily reactive condition. On the one hand, being usually present at a concentration appreciably in excess of that corresponding to equilibrium with the carbon then present, it may decrease rapidly in percentage by reaction with carbon and evolution of CO, especially if the liquid metal is in any way shaken or brought in contact with a cooler solid surface. On the other hand, it may increase rapidly by ab- sorption of oxygen from a slag, a furnace atmosphere, or from air. These circumstances, which are inherent in the problem, as well as our conclusion that, despite the considerable amount of careful work already done, there is still no method of sampling liquid steel acceptable as an unquestioned standard, ed us to undertake systematic comparisons of oxygen content of large numbers of samples taken: (I) by a single method at different positions and levels in the bath; (2) at the same place by different sampling methods; and (3) from bath, tapping stream and pouring stream. The different sampling methods yield somewhat different values and there is as yet no way to tell with certainty which is the most accurate. But the general reproducibility and consistency of the results give us some confidence in certain inferences we draw from them: namely, that the "spoon" method of sampling, properly carried out, gives somewhat more consistent results than the "bomb" method, as it has usually been practiced; that, in the bomb method, an aluminum cap is preferable to a steel cap; that the oxygen content of liquid steel in a finished heat is substantially the same all over the bath at the same level, and tends to decrease at lower levels further from the slag interface; also that it tends to decrease, and to decrease erratically, from furnace bath to tapping stream entering the ladle. Accordingly it seemed desirable to report these observations in detail as a first step, so that the reader may judge their significance as a contribution towards solution of the main problem, which is to find a means of pre-2

Jan 1, 1945

By C. E. Sims

In some experimental work conducted several years ago, it was noted that sulphur seemed to have a distinct influence on grain size of carbon steels. 111 order to check this observation, a series of S..A.E. 1040 steels was made with the normal composition held as nearly constant as possible. The steels were made with three sulphur levels, which were 0.012, 0.024 and 0.038 per cent sulphur, respectively. For each of the sulphur levels, steels were made with only silicon deoxidization and with aluminum additions of 0.1015, 0.025, 0.050 and 0.10 per cent. The melting medium was an acid-lined high-frequency induction furnace. These steels were forged and rolled and differentiall!. quenched from temperaturcs in the range of 1500O to 1800°F. After this, the A.S.T.M. grain size was determined and plotted as in Fig. I. It will be noted, first of all, that the aluminum-free steels had filler grain size with higher sulphur when heated to 1500, but that this condition was reversed at 1700°. When aluminum was added to produce fine grain size, the steels in the lowest sulphur level were fine-grained only to 1600°. and then only with an addition of one pound of aluminum per ton. The medium sulphur steels werc fine-grained to 1600' with a wider range of aluminum addition. The steels in the highest sulphur level were fine-grained at 1600° over a still wider range of aluminum additions and fine- grained at 1700° with an addition of one pound per ton. Fig. 2 shows curves of the grain-coarsening temperature for these steels and illustrates how sulphur and aluminum combine to give greater inhibition to grain growth than aluminum alone. Only the highest sulphur steels have a grain-coarsening temperaturc above 1700°.. At 1650°, the low sulphur steel is fine-grained only at its peak, while the highest sulphur steel is fine-grained over a wide range. In these tests, one pound of aluminum per ton gave the best results; this is equivalent to about 1 1/2 lb. per ton for commercial condition. IllcQuaid-Ehn tests made on these steels showed the same trend but to a lesser degree. The tests were repeated on a series of S.A.E:. 1015 steels with sulphur levels of 0.02 and 0.03j per cent. Aluminum additions were made in the range from 0.025 to 0.15 per cent. These steels were forged and rolled, normalized at 2000°F. to put them all in the same starting condition, then reheated to various temperatures from 1600" to 1800" and cooled at rates that would allow ferrite precipitation in the austenitic grain boundaries. The results of these tests arc shown in Fig. 3. It will be noted that. up to the temperature of 1650°, there is very little difference in the grain size obtained from the two levels of sulphur. .At temperatures of 1700° and 1750°, however, the lower sulphur steel was fine-grained only with an aluminum addition of 1 1/2 lb, per ton;

Jan 1, 1945