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By William Glenn

Early in the last century, Isaac Tyson, Jr., of Baltimore, was a miner of ores of chromium, iron and copper, and a manufacturer of their products. He was first to erect in America, for the reduction of copper-ore, a German blast-furnace, which was copied largely, and the improved successors of which are now universally used in this country. Dying in 1862, he left his manufacture of alkali bichromates to his eldest son, Jesse, while his work in the departments of mining and smelting descended to his second son, James Wood Tyson, the subject of this notice. The father had mined chrome-ores in Maryland and Pennsylvania and manufactured their products at Baltimore; he had mined and reduced copper-ores in both these States; iron-ores at Tyson Furnace in SW. Vermont, and copper-ores in the northern and central parts of that State. Among his holdings was what later became the Ely mine, now called Copperfield. The son extended this work to central Georgia, and carried the family mining interests to the Pacific coast, where he took up chrome-mines in Oregon and elsewhere, as far south as southern California. On December 3, 1900, in the 73d year of his age, James Wood Tyson passed away, in his native city of Baltimore, charging his third son, James Wood Tysou, Jr., with the labors which, 38 years before, his father had resigned to him. Thus was the work of father and son in mining and metallurgy, continuing without interruption through almost

Jan 1, 1902

By E. V. Given

In speaking of the concentration of oxidized lead ores at St. Anthony, I do not wish to infer that we believe all lead ores of a similar grade can be mined and treated at a profit. Our oxidized ore is low grade, and certainly the mine under present economic conditions could not operate on this ore by itself. Because of favorable conditions we can operate the oxide circuit at a small profit although we do not allocate overhead, pumping, and certain other general charges to it. Operations in the oxidized zone were started as an essential part of the development necessary to outline and mine the sulphide ores. Nearly all of our oxidized lead ore comes from the Collins section of the mine, with the transition from oxide to sulphide ore lying between the 600 and 700-ft levels. Production from sulphide ore is much larger than from the oxide, both in tonnage handled and in grade of ore. The oxide and sulphide ores are never mixed either in the mine or the mill. The oxide mill sections have their own ore bins, grinding, and flotation departments. The lead minerals contained in the ore, in the order of their importance are cerussite, wulfenite, galena, anglesite, and vanadinite. The ratios of the different lead minerals change as the ore is pulled from different parts of the mine-total lead being approximately 50% to 60% cerussite, 20% wulfenite, 15% galena, zero to 10% anglesite, and 2% vanadinite. About 3% of the lead was unidentified.

Jan 5, 1950

It was a pleasure listening to this paper. Gary Works' problems were a lot more extensive than the trunnion bearing problems encountered at the Weirton Steel Division. In our two-vessel shop bearing failures are critical in that with a bearing failure on an operating vessel and the second vessel under rebuild, we are down until the vessel rebuild is completed or the bearing is repaired. The first bearing problem at Weirton occurred after we had been operating three years. The failure occurred during the 8th heat following "bum-in" of the vessel. Immediate steps were taken to change the damaged float bearing without an extensive search for the reason the bearing failed. Once the campaign was run out the bearings were inspected and found to be damaged. Field checks revealed that the bearing pedestals were not properly located and as a result the freedom of the float bearing was restricted. The trunnion pin end to end dimension had decreased due to distortion and deflection in the trunnion ring. These dimensions were within tolerances. The damage to our bearing was similar to that in the exhibits from U.S. Steel-Gary Works. Steps taken to correct what was found in the field checks were as follows: 1. The pedestals were relocated to center the bearings. 2. 4" diameter pins were installed to locate the housing in the pedestals. 3. The bearing pedestals were opened up to allow the bearing housing to move slightly in the pedestal. 4. Lubrication fittings for greasing between the bearing housing and the pedestal were installed.

Jan 1, 1972

THE total crude production from the Dutch East Indies, and the British Protectorates of Sarawak and Brunei for 1932 is given in the following table: BARRELS BARRELS (42 GAL.) (42 GAL.) North Sumatra 4,226,935 Ceram 326,207 South Sumatra 13,956,157 Sarawak 2,739,650 Java 3,845,568 Brunei 1,322,725 Dutch Borneo (main island) . 9,406,733 Dutch Borneo (Island of Tara- kan) 6,579,184 Total 42,403,159 Production, which had shown a rapid increase from 1921 to 1929, has since been reduced. Exploitation drilling in the majority of the larger fields was suspended and existing production kept within predetermined limits by beaning. Most of the smaller fields were shut down entirely. The depth of producing levels varies widely in the different fields. Shallow fields with drilling depths to 500 meters (1650 ft.) are still numer-ous as well as those with depths between 500 and 1000 m. (3300 ft.). A few of the newer fields reach greater drilling depths. up to 1600 m. (5250 ft.). The deepest exploration well drilled to date (Djambi field, South Sumatra) reached a depth of 2332 m. (7650 ft.) before abandon-ment in March, 1930. The specific gravities of the various crude oils produced range between 0.65 (86.2° A.P.I.) and 0.95 (17.5° A.P.I.). The lighter crudes have a high gasoline content and fuel oils are derived from the heavier crudes, which usually are rich in paraffin.

Jan 1, 1933

A group of prominent engineers and contractors of Chicago and vicinity have cooperated in forming a Joint Committee on Military Engineering. The founders are members of all of the leading engineering and contracting organizations of Chicago, including the local branches of the national engineering societies. The purposes of the Committee are to further military preparedness among engineers, contractors and their associates by the following means: (1) Courses of lectures; (2) assigned reading; (3) studies and practical instruction in military engineering;. (4) assisting engineers to qualify as officers in the National Reserve Corps of Civilian Engineers; (5) urging enlistment in and support for engineer troops of the National Guard and such other organizations as the Government may create; (6) furthering instruction in military engineering in training camps and the attendance in them of those qualified; (7) by such other means as from time to time may be deemed advisable. The Joint Committee has already prepared a program covering the vital points outlined. To date the program is practically complete for a period extending from April 20 to July 25. Something of interest will be taken up each week, including lectures by Lieutenant-Colonel W. B. Judson, Engineer Corps, U. S. Army; two lectures by Major P. S. Bond, Engineer Corps, U. S. Army; Lieutenant-Colonel Mason M. Patrick, Engineer Corps, U. S. Army, and several exhibition drills, terrain exercises and inspection trips under the direction and guidance of various officers of the Engineer Troops of the Illinois National Guard. Additions to the program will be made from time to time. '

Jan 5, 1916

By G. Gutierrez, M. C. Fuerstenau, J. D. Miller

The response of pure goethite and two natural iron ores to flotation with potassium octyl hydroxamate is presented. The ores contained 12.5% and 39.7% iron; concentrates containing 69.5% and 61.5% iron, respectively, were obtained with additions of 0.4 lb/ton hydroxamate. Selective flotation of iron oxides from associated gangue minerals has proven difficult in the past with standard collectors, such as sulfonates and fatty acids. As a result, recent work has been directed toward silica flotation with calcium activation after the iron oxide surfaces have been blinded with certain starches.& The results obtained with this technique are encouraging. This method, however, involves depressing a mineral that would normally float under the conditions employed. A preferable method would involve floating the iron oxide because quartz is naturally depressed until activated. Earlier work involved this approach, but in view of the results obtained, collectors that exhibit greater specificity for iron are needed. During an investigation of chrysocolla flotation with potassium octyl hydroxamate, a metal chelate former, it was observed that pyrite floated well with low additions of collector.3 This phenomenon suggests that hydroxamate has a rather strong affinity for iron, and that other iron-bearing minerals should also respond to flotation with octyl hydroxamate. The object of this paper is to determine this response. The experimental work was divided into areas, the first of which involved microflotation experiments with pure goethite with an apparatus described previously.4 Goethite was selected because of the ease

Jan 1, 1968

A group of prominent engineers and contractors of Chicago and vicinity have cooperated in forming a Joint Committee on Military Engineering. The founders are members of all of the leading engineering and contracting organizations of Chicago, including the local branches of the national engineering societies. The purposes of the Committee are to further military preparedness among engineers, contractors and their associates by the following means: (1) Courses of lectures; (2) assigned reading; (3) studies and practical instruction in military engineering;. (4) assisting engineers to qualify as officers in the National Reserve Corps of Civilian Engineers; (5) urging enlistment in and support for engineer troops of the National Guard and such other organizations as the Government may create; (6) furthering instruction in military engineering in training camps and the attendance in them of those qualified; (7) by such other means as from time to time may be deemed advisable. The Joint Committee has already prepared a program covering the vital points outlined. To date the program is practically complete for a period extending from April 20 to July 25. Something of interest will be taken up each week, including lectures by Lieutenant-Colonel W. B. Judson, Engineer Corps, U. S. Army; two lectures by Major P. S. Bond, Engineer Corps, U. S. Army; Lieutenant-Colonel Mason M. Patrick, Engineer Corps, U. S. Army, and several exhibition drills, terrain exercises and inspection trips under the direction and guidance of various officers of the Engineer Troops of the Illinois National Guard. Additions to the program will be made from time to time.

Jan 5, 1916

By R. S. Sandhu, L. E. Baker, W. Y. Shieh

The finite element method of analysis was introduced by Clough.1 Within a short period, it has developed into a powerful solution technique in structural and continuum mechanics. It has been used to solve boundary value problems in two and three-dimensional elasticity.2-5 Anisotropy and heterogeneity of materials were allowed for at the earliest stages. 1,4 Its application has been extended to allow for cracks,5 creep and viscoelasticity, 6,7 incremental construction,6-8 nonlinear elasticity3,9 effect of joints in rock,10 and to materials with different behavior in tension and compression.7 Because of its versatility, the finite element method has found increasing application in the field of rock mechanics. In fact, several of the more significant developments have been motivated by problems in this field. Elasto-plastic material behavior based on the incremental or rate-type theory of plasticity rather than the deformation theory was considered by Reyes and Deere11 A material law based on a generalization 12 of the Mohr-Coulomb criterion was used. In this chapter, the formulation of material laws developed by Reyes and Deere 11 is used. An efficient analysis procedure, incorporating recent developments in finite element analysis, is developed for plane-strain conditions. To demonstrate its effectiveness, the procedure is applied to three cases, one for which an exact solution is available, another for which field observations had been made, and a third one for which a parallel study was made, using an accepted limit-equilibrium method.

Jan 1, 1970

By F. Weinberg

WHEN impure Zn (< 99.99 pct)&apos;&apos;Z or Zn-Cd alloys3 are progressively solidified, a cell or "corrugation" substructure4 is produced in the solid, with a high impurity or solute concentration along the cell walls. When these materials are polished and suitably etched, etch pits are often observed along the cell walls. For the Zn-Cd alloys these etch pits have been associated with decorated dislocations, present in the corrugation boundaries to accommodate the lattice strain. In the course of an investigation of Zn-2 pct Au alloy, molten metal of this alloy was poured into cold water and the resultant solid pieces were sectioned, polished and etched with a Cr0 ethant. An extremely regular cell pattern was observed on the etched surface, similar in general to the corrugation structure previously reported for impure zinc and Zn-Cd alloys. At higher magnification, regularly spaced pits were observed along the cell boundaries. An example of the regular cell pattern at the center of a specimen is shown in the center and lower portions of Fig. 1; the top of the figure shows the pattern near the specimen surface. Typical etch pits in the cell walls are shown in Fig. 2. It was surprising that a cell pattern as regular as that shown in the center of Fig. 1 was produced at the very rapid solidification rates used (estimated as > 1 cm per sec). In addition, the distribution coefficient for the Zn-Au system is greater than 1. Accordingly, the center of the cells should be rich in solute and should etch

Jan 1, 1963

By J. PARK

Discussion of the paper of J. PARSE CHANNING, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 529 to 538. FRED H. RINDGE, JR., * New York, N. Y.-It is interesting to note that although this movement was started only seven years ago at Yale, it has spread in that brief time to 200 colleges and technical schools, anti thousands of men are interested in it. There are 3,000 graduates who became acquainted with the movement in college days anti are now promoting the industrial betterment idea all over the country. Some of these men are employed entirely in this work, and the number of such workers is constantly increasing. We feel we are really doing a very fundamental thing in getting so many coming engineers and prospective employers of labor to interest themselves in these things which we have been discussing this morning; these things which are so vital to efficiency and success in any line of business or engineering to-clay. Of course the institutions located in our large industrial centers have the greatest opportunity for practical service. But I have just returned from one college, Pennsylvania State College, where 300 engineering students in three clays signed up as interested in this movement and as anxious to take active part in the work this summer. That is one of a number of colleges situated in towns where there are 110 industrial opportunities. Therefore, their field of service must be where they work

Jan 5, 1915

By Clarence Linville

IN an article published in the Iron. Trade Review 1 I gave a convenient arrangement for the installation of wet and dry bulb thermometers for use in making moisture determinations in the air being blown into a blast furnace, and also gave a chart for use in obtaining moisture values from the thermometer readings. The data from which this chart was prepared were obtained from the tables in use by the U. S. Weather Bureau.2 The work of Carrier 3 has shown that these tables are somewhat in error. He has recalculated the values for moisture as referred to, wet and dry bulb thermometer readings, and he has prepared a psychrometric chart from the values thus obtained. This work has priced the subject of psychrometry upon a correct scientific basis. I think it is proper that we should recognize the importance of his work and give him credit for one of the most interesting and valuable researches that have been published in recent years. Blast-furnace men are not ready to use, as he suggests 4 a value expressed in grains of water accompanying a pound of dry air. However convenient this may be for heating and ventilating work and other engineering problems, there are several reasons for preferring the use of a value expressed in grains of water in a. cubic foot of mixed air and water vapor, in connection with combustion phenomena and the effects of moisture on blast-furnace operation. Previous papers presented to the Institute have used such values and we have

Jan 10, 1913

By Felix E. Wormser

REGISTRATION started bright and early Monday morning in the Silver Corridor at the Waldorf-Astoria with Mrs. W. H. Bassett as chairman. What a registration-over 200 ladies! Several joined us from as far away as California and Washington State. Apparently they enjoy our meetings so much that present travel inconveniences didn&apos;t discourage their coming. At noon the ladies joined the men at the All-Institute Luncheon and Monday evening we had our informal dance, which is separately reported. Tuesday morning was devoted to our annual meeting at which all Section annual reports were read. At noon we were all the guests of the W.A.A.I.M.E. at a luncheon at the Port Arthur Restaurant on Mott St. in Chinatown. Many of us rode down on the old 3d Ave. elevated railway-the last of four. It, too, is soon to be torn down. The luncheon was delightfully unusual, with huge dishes of delicious Chinese food on each table. Our chairman, Mrs. Read, who lived in China in her youth chose our menu, and she chose it well, for most of us indulged so heartily that as we arose from the table we felt we couldn&apos;t eat again for 24 hours. Someone donated sherry wine, and boxes of Chinese pencils as favors. We wonder who? All owe a big vote of thanks for this lovely party to Mrs. T. T. Read and Mrs. H. A. Prosser, chairmen, and Mrs. H. W. Hardinge, Mrs. R. Hursh, and Mrs. R. L. Lloyd, vice-chairmen.

Jan 1, 1944

The failure of finely-divided sulfide particles to respond to flotation has resulted in a significant loss of our natural resources. As mentioned by Professor Arbiter, the overall recovery of copper from porphyry copper ores is generally between 80 and 85 percent. The recovery of copper sulfides from these ores is about 90 percent, the difference in these recoveries being due to failure of oxide copper minerals to respond to flotation. The 10-percent loss of sulfide copper has not been studied. Losses are known to be in the fractions finer than 74 microns, but the sizes that are not responding to flotation have not been established. In the case of molybdenite, however, it is known that particles finer than about five microns are not recovered. Work in other systems, notably the hematite-quartz system, has shown that good flotation of very fine particles from natural ores is possible (1, 2). The size distribution of one ore that was researched is given in Table 1, and as shown, approximately 50 percent of the ore was finer than 10 microns. Flotation experiments were conducted with this ore, which contained 45 percent iron, utilizing octyl hydroxamate as collector and without any desliming (1). The results of these experiments are presented in Table 2. From the standpoint of mechanisms of collector adsorption, similarities exist between those occurring in the hydroxamate-hematite system and many xanthate-sulfide systems. .This is, multilayers of ferric hydroxamate are present on hematite under flotation conditions (1,3).

Jan 1, 1979

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute&apos;s treasury; and these appropriations should be as large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character of meetings held and " the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A standing Committee on Local Section Appropriations, consisting of one past chairman of a Local Section, one member of the Institute&apos;s Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active Sections to the welfare of the Institute as a whole. 6. According to Article XI, Section 2 of the Bylaws, requests for appropriations shall be signed by the Chairman, Secretary and Treasurer of the Section. 7. Requests for appropriations must be in the hands of the Secretary of the Institute by February 15 of the year for which they are desired.

Jan 1, 1940

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute&apos;s treasury; and these appropriations should be as. large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character of meetings held and the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A standing Committee on Local Section Appropriations, consisting of one past Chairman of a Local Section, one member of the Institute&apos;s Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active Sections to the, welfare of the Institute as a whole. 6. According to Article XI, Section 2 of the Bylaws, requests for appropriations shall be signed by the Chairman, Secretary and Treasurer of the Section. 7. Requests for appropriations must be in the hands of the Secretary of the Institute by February 15 of the year for which they are desired.

Jan 1, 1946

1. Healthy and active Local Section organizations are vital factors in promoting the vigor and growth of the Institute. 2. Activity on the part of Local Sections should be recognized and stimulated by appropriation of funds from the Institute&apos;s treasury; and these appropriations should be as large as is consistent with the relative needs for other activities. 3. As between different Sections, the amount of such appropriations should be based primarily on the extent of activities as reflected in the number and character of meetings held and the attendance of the members at such meetings. 4. In making a request for funds for any year, the officers of a Local Section should submit a report on the printed form approved by the Directors at their meeting on November 19, 1937. 5. A standing Committee on Local Section Appropriations, consisting of one past Chairman of a Local Section, one member of the Institute&apos;s Executive Committee, and one member of the Finance Committee, shall be appointed by the President and shall pass upon requests for appropriations and authorize payments within bounds of the budget. The committee will be guided by the principles herein outlined, always having in mind the vital importance of healthy, active Sections to the welfare of the Institute as a whole. 6: According to Article XI, Section 2 of the Bylaws, requests for appropriations shall be signed by the Chairman, Secretary and Treasurer of the Section. 7. Requests for appropriations must be in the hands of the Secretary of the Institute by February 15 of the year for which they are desired.

Jan 1, 1946

By Haim Chiswik

IN recent years considerable attention has been devoted to the devel-opment of new commercial uses for silver, chiefly because of lowered prices and large stocks of the metal. This has led to increased interest in the phase diagrams of silver alloys. The silver-lead diagram is reported&apos; to be of the simple eutectic type, but no measurements of the solubility of lead in silver have been made. The solubility of silver in lead has been estimated2 from diffusion experiments and resistance measurements to vary with temperature from 0.09 to 0.18 atomic per cent (0.05 to 0.10 weight per cent). Silver-rich silver-lead alloys have recently been recommended as high-strength bearing metals.3 The silver-bismuth diagram is similar.&apos; The solubility of bismuth in silver has been estimated to be about 5.5 weight per cent on the basis of X-ray work.4 Matthiessen5 found a solubility of silver in bismuth from 0.25 to 0.50 per cent by conductivity measurements. Silver and thallium form the same type of diagram,1 with no data on their mutual miscibilities. We have studied the first two of these diagrams by X-ray methods, verifying their main features and determining the solubilities of lead and bismuth in silver at several temperatures. We also determined the solubility of thallium in silver at one temperature. The solubilities of silver in lead and in bismuth were found to be too low to be detectable.

Jan 1, 1940

By Bashir Ahmed, Fred D. Wright

Numerous investigators have studied the various factors that influence the ultimate strength of model mine pillars, such as ratio of height-to-least width; restraint or friction on the top and bottom; 1,2 the effect of stress distribution in pillars on their strength;3 and the scaling factors involved in applying the results of model pillars to full-scale pillars. However, the load-bearing capacity of pillars after initial failure does not appear to have been investigated. Yet many mines employ methods in which small pillars or pillar remnants are left systematically; these pillars crush as mining progresses and, of necessity, affect the behavior of surrounding rock even after initial failure. The effect of such crushed or crushing pillars depends largely on their load-deformation characteristics. This chapter presents the results of a preliminary investigation to determine the load-deformation characteristics of a few model mine pillars to and beyond initial failure. Various investigators have also studied the elastic and viscoelastic behavior of mine structures. In such studies, computers are frequently employed to obtain numerical results by the finite difference or finite element methods. It would be entirely feasible to write a program that would approximate the load-deformation characteristics of pillars to and beyond the crushing stage if these characteristics were known. More accurate information on the induced stresses and deformations in overlying strata and on surface subsidence could be obtained, information which should result in better strata control by enabling the engineer to calculate more accurately the effects of changes in pillar spacing, size, and shape.

Jan 1, 1972

By F. S. McNicholas, M. S. Walker, V. C. Rogers

During the year of 1944 and the first half of 1945, the Climax Molybdenum Co. made a study of some of the problems in block and panel caving, with the use of a scale model. The experiments dealt essentially with the type of rock and conditions at Climax, but some experiments were carried out to simulate conditions found in other mines. Most of the previous experiments on the caving characteristics of rock have dealt with sedimentary or broken igneous material. The series of experiments described here was designed to show the caving action of unbroken igneous rock. Con- siderable difficulty was experienced in duplicating unbroken material in the model. The results obtained are believed to be relatively correct, but verification must necessarily come from future mine operation. Observations in the mine and glory hole, together with statistical data, were used as criteria for creating similar conditions in the model. In 1913, George R. Lehman&apos; experimented with broken material in a model for the Inspiration Consolidated Copper Co. and, more recently, P. B. Bucky2 experimented with broken material with a capping of mill tailings. Mr. Lehman&apos;s model represented a maximum ore height of 70 ft. capped by 55 ft. of waste. He varied the draw-hole spacing from 6¼ ft. to 8? ft. and 12½ ft. The material used graduated from fines to 30-in. maximum size. Some of his conclusions were: "(I) The less the distance between chute centers, the greater the extraction (Fig. I); (2) the higher the ore column, the greater the extraction; (3) the less the amount drawn at a time from each chute, uniformly, the greater the extraction of clean ore before the capping appeared, but not the greater the total extraction to a I per cent copper final product." (Fig. 2.) Professor Bucky concluded, in part: "(I) Drawing of ore may take place at any time from any finger and in any amount without affecting materially: (a)

Jan 1, 1946

By E. V. Crane

A TREMENDOUS volume of the metal rolled annually into sheets, strips and coil stock finds its way to a host of stamping and manufacturing plants which are the quantity production units of the country. Considerable in volume, too, are the rolled and extruded rods which go into forging and manufacturing plants for conversion into the same general line: those widely sold metallic necessities and luxuries of the household, the office, transportation, farming and building construction. Yet, in spite of its age and its importance, the stamping trade has been doing its "engineering" largely by trial and error. Its distinctive method is shearing out and plastically working metal to finished shape in a few quick strokes with high loads and expensive tools which are warranted only by large quantities to be produced. The principal operations have many features in common with rolling and wire-drawing methods. Combinations of stresses are different, however, and details of operations are infinite in variety. An engineering study of the subject begins with stress analysis, but must go back to metallurgy for its foundation. A grouping of pressed-metal working operations according to whether the metal is (1) sheared, (2) bent, (3) drawn or (4) squeezed has proved useful. All of these groups include instances of both hot and cold operations. For discussions of metal working properties, the division between hot and cold working is taken as the recrystallization range of temperature. This, of course, brings tin, lead and often zinc into the hot-work range at or near room temperature. The outstanding hot-working press field is in forging: particularly of brass; all of which is included in the squeezing group.

Jan 1, 1931