The Iron Age 1928-09-06: Vol 122 Iss 10

THE IRON AGE ESTABLISHED 1855 New York, September 1928 Fusion Welds Heavy Plate Swiss Firm Uses Oxy-Acetylene and Electric Weld- ing Important Pressure Joints and Completed Work Tested Continuously MILLER* ELDING was introduced into the shops Sulzer Brothers, Winterthiir, Switzerland, the begin- ning the present century. This firm’s main production has always been the construction steam boil- ers, pressure vessels and sundry apparatus for the chemical and textile trades. Oxy-acetylene welding has changed the working practices such extent that numerous objects, some them very large size, are now constructed welding instead riveting. Shop methods have not yet been fully developed, but judge the stage which both oxy-acetylene and arc welding have now reached, would appear that they are bound supplement rather than compete with each other. some work more advan- tageous adopt one type welding rather than the other; there are course numerous other cases which either method can employed. One essential condition that the design should suitable for the chosen method weld- ing. Types Welding Equipment Installed the equipment: Acetylene made large car- bide-to-water generator (as usual European practice) and, after passing through purification plant, piped various outlets the shops. Oxygen piped through lines, leading from manifold drawing supply from group cylinders. About welders are employed; blow- pipes are the injector type. Fig. shows the interior one the shops, and illustrates the first-rate working Electric welding has been much more recently installed, and the equipment has been means standardized. Direct-current machines with constant voltage, supplying current several workmen simultaneously, require high investment generators and series-resistances, and also are wasteful energy. avoid these drawbacks some individual motor-generator sets are installed. The most economical solution, far initial cost plant and cur- rent consumption concerned, appears adopting *Witten, Ruhr, Germany. 567 VOL. 122, No. Fig. Welded Distributing Piece for Water Wheels. Tested 925 Ib. per sq. in. alternating current for welding. single transformer then sufficient for transforming the supply voltage down the required welding voltage. Experience the Sulzer plant indicates that direct-current welding easier learn, does not need such special welding wire and, many places, easier carry out than alternating-current welding. the other hand, the electric energy required for the latter less. Heavy Pipe Work Gas-Welded Experience years indicates that oxy-acetylene welding yet unrivaled for making pipe connections. instance, Fig. shows steam-distributer which has welded connections the upper side alone. was sub- mitted test pressure 350 per sq. in. can seen that such work can carried out avoid any distortion. Boilers with helical joints have often been built Sul- zer Brothers. utilizing helical weld, the circumferen- tial stresses the welded joint are reduced, and also possible utilize the full length the rolled plates, irre- spective the diameter the boiler. large field for the use oxy-acetylene welding found also the construction piping and sundry other parts for pumping plants and hydroelectric power houses. Examples this class work are shown Fig. and Fig. The former shows part the penstock for Swiss hydro- electric plant. The longitudinal joints are welded with gas, the circumferential joints electrically. The flange rings are electrically welded internally and externally, and the are also used the stiffening pieces. This exam- ple the combination method often adopted. Fig. shows distributing piece before being fitted the pipe line. Two hemispherical pieces were welded together the middle and flanged out for the connections. These pieces suc- cessfully withstood test pressure 925 lb. per sq. in. For such heavy plate, either process welding, the edges the pieces joined together are beveled and the single Vee double Vee thus formed filled with welding rod. This practice quite similar that observed 7 per (at right) Fig. lene Welding Heavy Plate Work Sulzer Brothers Shops, Switzerland Fig. 2—Steam Dis- tributer with Welded Joints. Tested 350 the United States. After the joint material has been deposited this manner, similar quality cast steel the same composition. steel works this improved rolling forging; and Sulzer Brothers obtain the same effect their important gas-welded joints hammering them when red hot. The edges are slightly bent inward, the joint also slightly reinforced externally, and, indi- cated Fig. the reinforced weld obtained practi- cally symmetrical. Thus the joint compensated amply for the lower strength the welding material (because its lower carbon content) compared with the boiler plate used, which unusual quality. Careful annealing after welding finished improves the microstructure the metal the union and, when properly carried out, eliminates any residual stresses due the fabrication process. Tests Completed Work Frequently purchaser disinclined accept welded pipe vessels, basing his refusal the statement that impracticable inspect the work after finished. must admitted that more dependence must frequently put the trustworthiness the welders than workmen engaged most methods construction. Fur- thermore, welding often carried out incompetent per- sons. From the failures which result, observer who knows little about welding inclined blame the welding process itself instead the persons using it. Only because such circumstances and ideas can explained why 568—September 1928, The Iron Age some clients must still supplied with the more expensive hammer-welded joints, even when the tanks must merely leak-proof and are not required withstand pressure. Boilers, high-pressure pipe lines and similar articles, when finished, are submitted severe tests pressures 100 per cent greater than the working pressure, dur- ing which time the welded joints are hammered. After this test both the inner and outer sides all seams are inspected. Quality harder judge when the arrangement the weld such that cannot stressed ordinary test methods. Magnetic and electric tests have been tried the Sulzer organization determine the homogeneity the weld finished piece work, but none these has yet proved satisfactory. Testing means Roentgen rays has lately been introduced for laboratory study, but still far from shop method. must always remem- bered that the cross-section weld may vary consid- erably, with corresponding variation its transparency the X-rays, that the resulting photograph has light and dark tones even when there fault the work- manship. Photographs must also taken room lined with lead, order save the operators from the rays— conditions difficult fulfill workshop practice. When manufacturing large number boilers, high- pressure pipe lines and similar articles, pieces are chosen random and submitted thorough tests until ruptured. | = make only superficial examination the weld. sin- gle Vee-joint, where the under side easily accessible, inspection can made see the weld has been made right through. double Vee-joint (when the cross-sec- tion X-shaped) this inspection must done after the first side finished. electric welding, opinion the quality the weld formed from the appearance the surface the joint, long the plates are not too thick, i.e., long only one layer the welding wire required. Selection and Test Welders The more difficult control piece welded work, the more necessary exercise particular care select- ing the welders who are carry out. much consider- ation should given their personal character their skill welding. the Sulzer works pieces are always taken from the work under construction and submitted Fig. (Above)—Single Vee Weld Hammered Vigorously While Hot Refine Grain and Pro- duce Slight Reinforcing Effect Under Side Fig. (Below)—Penstock Piping for Swiss Hydro- Electric Project. Longitudinal seams oxy-acetylene welded; circumferential seams and bracing arc welded thorough tests. addition, number special test pieces are constantly welded, either skill welder investigate new welding wire new method welding. certain important contracts, full-sized sec- tions the work are constructed and their behavior studied while being tested rupture. When pieces are cut with the weld extending across the middle and tested tension, the figures obtained for elonga- tion must regarded with caution, since they are greatly affected the position the rupture—whether the weld metal, immediately alongside, some distance back from the joint. much better idea the qualities the Fig. (at Right)— Test Pieces Cut from Electric Are Weld- Metal Heavy Plate. Cold bend two. Hot bend lower left. Tensile test lower right 4 7 2 > § % 4 4 q x 5 ] ' . ®en oo” | | —e 7 The Iron Age, September 7 — deposited joint can obtained from test pieces made solely the filling material. The preparation such test pieces is, course, rather expensive operation and representative conditions only when welding very thick metal. Results such studies are given Table Typi- test specimens are shown Fig. Although the test pieces are porous, the figures quoted for tensile strength and (with one exception) for elongation are fairly Table I Tension Tests of Electric Weld Metal Elastic Ultimate Limit, Strength, Elonga- Electrod Lb. per Sq. In. Lb. per Sq. tion (a) (a) Expressed as a percentage of the gage length, punch- marked half the usual length, i.e., one-half 11.3 times the square root the area the bar. uniform. tions. more simple way evaluating welded joints the bend test. The Swiss practice express the results Tetmajer units, which vary directly with the thickness the piece and inversely the radius curvature the bend. The value this bending unit 100 when both ends lie flat each other, and zero when rupture takes place without any permanent bending; thus the figures cor- respond the percentage elongation the outer fibers. Tetmajer bending units for gas and electric welds, ordi- narily encountered Sulzer’s production, are given Table II. Higher tensile strengths involve lesser elonga- Much importance ascribed the results the deep etch cross-sectioned welds, wherefrom the structure may judged with the naked eye. Places not faultlessly joined together are very clearly recognized. Different tones the joint are caused variations composition. Oxy-Acetylene Welds More Closely Approximate Properties Boiler Plate comparison given Table between the tensile strengths oxy-acetylene and electrically welded joints. These tests were made the Swiss Federal Testing ratories Zurich. The gas welding was done Brothers, and the electric welding leading interest using electrodes its own manufacture. From may observed that the properties the weld material taken from oxy-acetylene welds correspond more closely those the plate than the case electric welding. Table II. Tests Gas and Arc-Welded Joints Elastic Ultimate Contrac- Tetmajer Material Limit Strength tion tion Oxy-acetylene weld 30,000 51,000 16.5 12.0 Oxy-acetylene weld 27,200 50,000 49,0 21.0 a rr 54,500 64,500 13.6 7.0 20 56,000 65,000 13.6 4.2 25.0 100 Unwelded plate.... 30,500 53,000 This also indicates the basis use the Sulzer Brothers’ plant. When the finished work must uni- form throughout possible, oxy-acetylene welding given the preference. only desired that the weld should have high elastic limit high tensile strength without regard toughness ductility, electric welding pre- ferred. New Determination Austenite Boundaries REDETERMINATION two important lines the equilibrium system has been made Prof. Honda and Endo the Imperial Japanese Re- search Institute (147th report). Metal samples were packed magnesia powder double-walled silica container, and heated atmosphere nitrogen; microscopic investi- gation showed decarburization under these conditions. the temperature increased, determinations the mag- netic susceptibility were made frequent intervals, and the results plotted, locating the point where fusion first starts breaks the curve. was located 1600 Borders Aus- tenite Region Equilibrium Dia- gram, Deter- mined Vari- ous Investigators 1928, The Iron Age very slow cooling similar manner. The metal used was Swedish steel. Former investigations steel syn- thesized with electrolytic iron and sugar carbon indicated that the minor impurities Swedish steel not appre- ciably affect the magnetic characteristics. Results are shown the figure. coincided with the curves determined other authors using ether methods, but trace was found the line a-b, supposed repre- sent the solubility graphite austenite. Quartz for Calibrating Pyrometers Frederick Bates and Frances Phelps, physicists, Bureau Standards, Washington, have studied the changes occurring clear quartz 573.3 deg. When cooling through this temperature the material changes its crystal lattice with liberation much heat that can used fixed point pyrometer calibration. the present temperature scale there are six refer- ence points covering the range from liquid oxygen the freezing point gold. The region from steam, 100 deg. silver, 960.5 deg. C., covered sulphur, 444.60 deg., and antimony, 630.5 deg. The temperature quartz inver- sion (573.3 deg. C.) comes between the boiling point sul- phur and the melting point antimony. view the many advantages connected with the quartz inverson for temperature scale purposes, the authors propose abandoning the antimony point. Use quartz the most convenient and simple method for the calibration and control thermocouples the aver- age laboratory. sufficient select small piece clear crystalline quartz and not convenient drill small hole for the insertion the thermocouple, merely place contact with the quartz. The investigation covered scientific paper No. 557 the bureau. — A2 | | 800 Steering Gear Plant Arranged for Economical Operation Production Lines Start Raw Material Receiving Bay and Extend Assembly Conveyor —Assembly Progressive ARKED economies handling raw material and moving work process have been effected the new plant the Gemmer Mfg. Co., Detroit, maker automobile steering gears. Production has been speeded up, manufacturing costs have been lowered and more uniform product obtained. All these gains are attributed the convenient arrangement the plant, which, with other products than steering gears, highly specialized one. Near the center the plant there 500-ft. receiving bay with monitor-type roof, served overhead electric traveling crane. There room for spotting cars stock the track this bay. Each car delivered point adjoining the department which the material used. After being unloaded, the material in- spected and placed the end the production line along which processed. There ample space between the unloading track and the production lines for the storage sufficient raw stock insure lines material all times. Plant Laid Out for 5000 Units Day brief description the plant layout will make clear the routing material process. The production lines are right angles the receiving bay, and all are located « The Method Handling Raw Material Unusually Convenient and Large Extent Eliminates Trucking. From the railroad cars the track the side the receiving bay, the stock placed the head the production line along which processed. The production lines are the right the Section the Assembly Line Shown the Top the Page, the Steering Gears Are Adjusted and Inspected. The parts are stored the racks the left, which are covered keep out the dust The Iron Age, September ig : 1 / ‘ { 4 tes 4 | one side that bay. These lines extend the side the plant and terminate adjoining assembly conveyor, which travels along the outer wall. Progressive assembly the conveyor feature the plant, which laid out for daily production 5000 steering gears and equipped present for daily output 4000 units. The latter rate production has been attained for extended periods. Each production department has from two nine lines machines, which are practically duplicates,and open spaces are left between the lines each department for the placing additional machine lines, which will permit increase capacity. The lines are arranged and equipped that takes approximately min. for part, except one that heat treated, from first operation until ready for assembly. Inspectors are placed along the lines inspect parts between operations; they also inspect the first pieces that come from the machines when the drills, reamers, taps other tools employed are sharpened changed. All pieces are checked for count and inspected for quality the end the production line before being washed. The departments and production lines are arranged according sequence operations, that completed parts the made principally worm, shaft, column, jacket, hous- ing, cover, adjusting nut and control. The heat-treating department located the center the plant adjacent the departments that make parts requiring heat treatment. There are two 75-kw. electric heat-treating furnaces for normalizing and annealing oper- ations. These were built the George Hagan Co. and are equipped with automatic heat and temperature registering instruments. They are used mostly for heat- treating shafts and ball arms. The furnaces can adjusted for any heat cycle time. They are also equipped with automatic dumping mechanism, which dumps the work through water-sealed chute into water quenching tank, from which power driven conveyor carries the parts. Carburizing done one 280-kw. capacity Hagan coun- terflow regenerative type furnace, which ft. wide and ft. long. Loaded pots are charged into each end alter- ature 1650 deg. Fahr. maintained the heating zone, and the material kept the furnace approximate time cycle hr. Control the furnace entirely automatic and the doors are automatically operated. The time cycle regulated clock. leaving the furnace the car- Parts Are Heat Treated Two Rotary-Hearth Electric Furnaces from Which the Work Dumped Automatically into Quenching Tank steering gears reach the point adjoining the assembly where they are needed for the assembly operations. Stock such rough castings and some forgings, al- though most the latter are produced the plant, are placed steel boxes in. in. high. The boxes are handled the receiving bay the overhead crane, and space conserved stacking loaded boxes one top another. Trucking the plant has been very largely eliminated, material rough stock process, except parts that require heat treating, being trucked. Parts heat treated are carried the furnaces racks. Cars Held Receiving Bay for Disposal Scrap The receiving bay with its railroad track also serves loading bay for turnings. open top car spotted the end the track and remains there until filled, usually about two days, thus serving storage bin. The scrap the form turnings put standard scrap boxes, ft. long and ft. deep, which are set alongside each machine the worm department and the turning lathes the shaft department. When the boxes are filled, the overhead crane dumps the scrap into the railroad There production department devoted exclusively the manufacture each part the steering gear, which 572—September 1928, The Iron Age burizing boxes are conveyed overhead hoist roller conveyor the side the furnace and from this conveyor the carburizing compound dumped through grate. The work remains the grate and the compound drawn suction through cleaner storage space, from which fed gravity the point where the pots are loaded. All carburized work hardened two rotating-hearth gas-fired furnaces having electric control. The usual routing the shafts through the normal- izing furnace, prepare the steel for machining, and then through the production line. They are then returned the heat-treating department for carburizing and harden- ing. After quenching, following hardening, parts lead pots for drawing when this required. They are then returned the process departments for finishing opera- tions. Practically all operations except finish grinding the shafts are done before carburizing. The ball arms are heat-treated but not carburized. Electrically Heated Continuous Enameling Oven Feature Finishing the column cover jacket important step the manufacture the unit, the finished appear- ance the column must keeping with the finish a the car which the steering gear used. The jackets are sawed length from steel tubing, burred both ends, given the additional operations that are required some types and then transported gravity conveyor continuous enameling oven. This conveyor-type electrically heated oven, electrically controlled and has sev- eral interesting features. The oven the form inverted “U,” occupying floor space only ft. tric Carburizing Furnace Shown Above. leaving the furnace the carburizing pots are placed the roller conveyor the side and the compound dumped through grate Double Chamber Elec- Steering Column Covers Are Enamelled and Baked the Continuous Type Electric Oven Shown the Right. The oven vertical and oc- cupies small floor space. The work suspended racks and carried through dip coating tank and the baking section the oven The top insulated with 4-in. layer rock wool. The heat flows direction counter the direction the work. The finished work cooled intake air and the incoming work preheated what otherwise would waste heat. Baking heat reached the apex the Fumes are drawn off small fan. The jackets are suspended from racks hooks attached small handling hole the end the jacket. One man feeds the work the conveyor. goes through the dip- ping tank, drains min. and then carried angle temperature 500 deg. Fahr. The entire time cycle min. Approximately 1800 jackets are the conveyor one time. The dipping tank and oven are entirely in- closed and, having the work enter and come out perfectly dry, the necessity dust-proof room eliminated. With more uniform dip, drip and heat secured from the continuous enameling unit, the work comes out with form finish, and stated that rejections have been prac- tically eliminated. The oven was designed and built the Kirk Blum Mfg. Co., Cincinnati, and the conveyor and structural steel the Mechanical Handling Systems, Detroit. Assembly Progressive The assembly line alone the side wall extends the greater part the length the plant. Finished steering columns are placed rollways, from which they pass The Iron Age, September 1928—573 7 d > re | | chain conveyor, 230 ft. long and in. wide, along which the column assembled. Machines for certain work re- quired assembling are located the side the conveyor. The column placed rotating fixture for making the worm thrust adjustment. The assembled column leaving the first conveyor greased the open housing and then placed plate conveyor having special holding fixtures 30-in. centers. this the shaft and cover and minor parts used adjust- ing the gear are assembled. Then the unit taken from the conveyor adjoining individual vises for adjustment and inspection. After inspection the uncompleted assembly goes back the conveyor line and additional minor parts are added complete the unit. the end the second conveyor the steering gear dip-painted and placed third conveyor, which sufficient length allow become dry. From this con- veyor the gears are put standard racks, 100 rack, which they are carried the shipping room, located short distance below the assembly line. They are delivered Detroit customers these racks. Controls, ball arms. jackets and some miscellaneous parts that are not assem- bled until the gear placed automobile are inspected after the finishing operations, boxed and shipped separately from the gear assembly. These from point near the end the assembly line the shipping department, which equipped with depressed track for carload shipments and depressed driveway for local deliveries. Extreme care exercised cleaning finished parts keeping them clean before assembling. the end each department washing machine which the parts are cleaned after final operations. Shafts are washed be- fore heat treatment and washed and oiled after finishing operations. The main parts the gear are placed ered racks the side the assembly line after cleaning order keep them free from dust. Aluminum Alloy Replaces Steel Castings Field Gun Mounts the spring meeting the American Society Me- chanical Engineers, held May Pittsburgh, Brauer the Watertown Arsenal announced that heat- treated aluminum alloys were being installed anti-air- craft mounts. Temperature Fahr Alloy No. 195 Heat Treated “Three four months ago,” Mr. Brauer said, “the Ord- nance Department found metal that was light, yet with physical properties that would permit its use mobile anti- aircraft mounts. After spending considerable time in- vestigations, analyzing numerous tests, and consulting en- gineers and other experts, metal having specifications known No. 195, heat treatment No. was found, which with but few modifications would adaptable. Six per cent elongation, 13,000 Ib. per sq. in. yield point with 28,000 lb. per sq. in. ultimate strength, was established. Further than that, order was placed for this metal used very important components gun carriages. “It may appear singular that the department should in- troduce metal this kind and put into gun carriage; however, there was hesitancy doing, and are firmly convinced that not only these components, but also the near future other parts, will changed over from cast steel having 30,000-lb. yield point and ulti- mate strength aluminum-alloy casting No. 195. Not only are specifications physical properties carefully checked. but also actual test made and each member subjected load equal that which will produce fiber stress per cent the strength the metal the yield point.” From paper presented the same meeting Messrs. 574—September 1928, The Age Templin, Broglio and Marsh the Aluminum Co. Amer- ica, the analysis this alloy follows: 0.57 per cent 4.40 per cent Manganese ....... 0.02 per cent 0.25 per cent Aluminum ........ 94.01 per cent (by difference) Properties developed this alloy after heat treatment and upon being tested room temperatures and elevated 40,000 25,000 > | } a Temperature, Deg Alloy No. 195 Heat Treated and Aged temperatures are given the curves. Heat treatment was not specified. Aging consisted holding one week 400 deg. Fahr. Studies Migration Industry Taking quarter-century range, study the wage earners manufactures the United States, made George Ogden, traffic manager Pennsylvania Railroad, showed gains numbers all nine the sections the United States. These gains, however, varied markedly be- tween sections. New England gained only per cent and the Middle Atlantic States per cent, compared with 237 per cent for the Pacific group and 118 per cent for the East North Central States. Rapidly increasing total population the Pacific States accounted for much the gain that area. numbers its advance was scarcely greater than New England, despite the sharp disparity per- centage gain. 7 7 | | 7 | | | | | | : w | WA | | | | Increasing the Utility the Bend Test Rapid, Accurate and Consistent Quantitative Results Are Obtained Measuring Extension Outer Fibers Failure New Bend Extensometer KINZEL* discovery processes for making the material, and may imagined that the first test the disposal the smelter man was the bend test. The use the bend test still universal and doubt each has some Fig. Welding Society Standard Bending ture Mounted Tension Testing Machine time other seen blacksmith mechanic bend piece iron steel find out whether was “tough.” the field engineering the test also considerable use and practically all specifications for flange plate, rivets, and steels, contain bend test. Moreover, due the ease performance, this test generally carried out the consumer well the manufacturer. However, the fact that the test has not been quantitative has probably restricted its further use. has long been recognized that the bend test gives information which not obtained from the tensile test, because the bend test measures the ductility the material under two-dimen- sional stress. But usually carried out, consistent results are difficult obtain and satisfactory method quan- titative evaluation the performance the material has been developed. spite its age and ease perform- *Union Carbide Carbon Research Laboratories, Long Island City, Chairman, American Society for Testing Materials, sectional committee bend testing. ance, the bend test has probably received less careful thought from metallurgists and engineers than any the other tests, and these facts warranted the development method for quantitative and study the various factors involved. Angle Bend Not True Measure Ductility The original method making bend test was simply bend the piece and note the angle bend. This course varied considerably with the thickness the piece and the tendency bend locally, allowance being made for this the mind the investigator. However, accurate evalu- ation was attempted. The next step bend testing was adopt standard radius about which bend the piece and again note the angle bend. This illustrated two the methods bend testing used today, namely, forcing the piece between two fixed parallels means tup with given radius (Fig. and wiping the piece around pin given diameter (Fig. 2). One great objection these tests that they not give comparative results, simply because the material does not hug the tup the pin. The reason for this that, Fig. Schematic Drawing Bend- ing stationary ta- ble. F,F are fixed blocks table. wedge for hold- ing specimen. movable block rotating about Fig. 3—Rapid Local Elon- gation Kinks Specimen Away from Pin the fibers under greatest stress reach the yield point, they elongate compress very rapidly any fur- ther increase stress and the piece bends locally kinks, leaving the pin tup, indicated Fig. Moreover, there are additional strains introduced the tup pin which probably affect the results, although generally this Study the Bend Test Applied Iron and Steel, Kinzel. Journal, American Society for Steel Treating, November, 1927, page 778. The Iron Age, September 1928—575 | 7 | 7 if effect not serious. The measure the performance— the angle bend—is function both the local effect the kink and the progressive bending either side it. Stresses occurring bending piece are indicated graphically Fig. Compression takes place the in- side and tension the outside the bend, and final failure occurs when the outside fibers are stretched their limit. measure made the actual force necessary this, that obviously the bend test measure ductility only, and not strength any sense. Moreover, the final breaking point determined the ductility elon- gation the outside fibers, this factor, namely, the per- centage elongation the outside fibers, the logical meas- ure the performance bending. bending the piece vise other suitable press, all external stresses except the direct bending moments are constant. such event, the piece takes its own free bend and finally breaks definite outside fiber elongation. evaluating this fiber elongation, quantitative measure the bend perform- ance the piece obtained. This evaluation may af- tected direct measurement measurement the radius curvature and computation. Method Bending Vise Even large bars may readily bent the manner out- lined above first kinking the ends and then placing the specimen vise press. Such test gives information the limit fiber elongation the material. This absolute figure and independent the thickness c - - f=) Compression Beyon Gravity Fig. 4—Graphical Representation Stress Distribution Across Bent Bar the piece when the specimen tested least three times wide thick. (This minimum width necessary eliminate the edge effect and bring into play the full two-dimensional stress.) certain bars—particularly round rods—it not practical have the required widths. Such specimen may bent and the test applied ex- actly the same way, but the results will comparative rather than absolute. might appear first thought that there would some difficulty noting when the incipient failure takes place. Actually there difficulty, for the failure takes place shear across the outside plane and the instant failure decided slip occurs which readily visible. few tests will suffice show the ease determining this point. From the foregoing obvious that certain precau- tions the actual performance the bend test are advis- able. First, the piece bent should least three times wide thick, remarked above. Second, bending the piece care should taken avoid tensile forces. recommended that the piece bent vise press, although the use the usual wiping machine tup should satisfactory provided the fiber elongation measured evaluate the performance the piece. the direct measurement fiber elongation, given gage length laid off the specimen include the final point fracture. The piece bent and the length 576—September 1928. The Iron Age which the material first shows signs incipient fractur. measured. The ratio the increase length original length the percentage fiber elongation. This method open the objection that measures average elongation over the gage length chosen, rat! than the actual elongation the point failure. Due the nature the bending moments, which increase central point the bend point failure approach: there often decided discrepancy between the the average values. Moreover, the gage marks are apt affect the results, although with care this can avoid Direct Reading Bend Extensometer The author has developed bend extensometer for the rapid evaluation tests, shown Fig. consists es- sentially two fixed points with movable point between them. The movable point actuates needle, the position which may read the dial. simply applying the fixed points the outside surface the bent specimen, shown, reading obtained the outside scale the dial. This reading multiplied the thickness the piece and converted from the inside the outside scale gives the percentage fiber elongation the specimen the place where the instrument applied. For example, the photo- graph the dial reads 45, the bent specimen being in. thick. The product and gives 39, and the inside dial opposite the outside dial. Thus, there per cent elongation the outside fiber the specimen. The instrument may used regardless the degree curvature, within practical limits, demonstrated the mathematics given the appendix. However, should not applied ductile sheet material which causes the needle rotate more than one revolution the dial, because the approximations involved the derived for- mula are then not sufficiently accurate. general, accuracy better than per cent.of the final figure ob- tained when using the extensometer. This has been checked against carefully measured short-gage lengths number specimens, may appear that the bend extensometer open the same objection the use length. This not true for two reasons. First, the gage length used may made very much shorter than would practical Fig. tensometer for Read- ing Stretch Outside Bent Speci- men direct measurements (0.322 in. for the present instru- ment), and second, moving the points along the arc, the rate change the radius may noted and the exact = — 7 7 | « the point failure obtained extrapolation. However, the latter method usually not necessary, the gage length the meter short that gives satis- factory practical results. may made shorter occa- sion demands. number tests have been made with the bend exten- someter and has been found give consistent, accurate results. For comprehensive discussion the bend test- Chrome-vanadium bar The test has been applied various types steels American Welding Society, September, 192 Material with wide range thicknesses and characteristics. The following list gives some the results obtained: Per Cent Bend per cent nickel steel plate.......... Chrome-vanadium bar (hard)...... Miller. Journal, Supplement Giving Mathematical Basis evaluating fiber elongation from measurement the radius curvature necessary consider the geometry the bent specimen. Fig. longitudinal cross-section From the similar triangles the figure, t from which may deduced that the ratio elongation unit length, where the bar bent almost com- pletely upon itself, shift the neu- tral axis occurs from the center gravity toward the inside surface. Surface 2 Ne Surtace | | Fig. 6—Longi- tudinal Sec- Bar + This modifies the above formula, but most cases this modification may neglected. (For discussion this point, those interested are re- ferred the author’s previously men- tioned Thus, measuring the thickness the piece and the ra- dius curvature the outside sur- face the point failure, the elon- gation may evaluated. The meas- urement the radius curvature presents some difficulties. may accomplished tracing the arc and applying compasses the section un- der discussion constructing circle match the arc the usual geometric way. Both methods are comparatively laborious. The bend extensometer based the principle the usual dioptometer, used oculists measure curvature Introduction quantitative evaluation bend per- formance, together with easy method obtaining this figure, should give impetus the use the bend test, par- ticularly cases where ductility important factor. Dial Graduation lenses. The motion the central point measures the distance from the top the the chord between the fixed points. The rela- tion between the radius curvature are, its chord and the maximum normal distance from the chord the given the following equa- tion: H = - sa(-S 4 where the distance from chord arc, the length the chord, and the radius curvature. The meter constructed that always very small compared with that the term minor im- portance. the chord length dis- tance between the outside points, 0.322 in., that for practical pur- poses may dropped when the Elongation Dial Reading for Any with the Dial Reading Fig. (Above)—Chart Convert Mid- dle Ordinates (Dial Readings) into Fi- ber Elongations Fig. (At Chart Plate Thickness. Method straight line corresponding required thickness. From the | dial reading hand the thick- ness line, then the line, then across the left-hand scale for percentage elongation then across the line, See footnote 1, page 575. The Iron Age, September 100 greater, and the formula becomes very sharp bends where the radius less than the correction should applied another bend ex- tensometer should used which the distance between the fixed points less than the present meter. This will apply only thin material with high ductility. the fiber elongation, based the final length rather than the original length, designated then from Fig. the relation 100 ensues, and from the above formula 400 om The factor 100 introduced for percentage basis. The dial the meter calibrated that the factor Standardize Finished Bars and Shafts Several new standardization pro- jects have been proposed the Amer- ican Engineering Standards Commit- tee, including bars, shafts, studs and gages. The American Society Me- chanical Engineers has become spon- sor for these four projects. Com- ments requests for information should sent the first-mentioned organization West Thirty-ninth Street, New York. developing standards for iron and steel bars the following items would considered: stock shapes and lengths for iron and steel bars, including flats, squares, rounds and other shapes. The standardiza- tion Woodruff keys, project now under way under American Engineer- ing Standards Committee auspices, has convinced that body the neces- sity standardizing the sizes and shapes iron and steel bars, particu- larly with reference the dimensions and tolerances hot and cold-finished bars. Under subject splined shafts and splines, recommended that study made the relations be- tween keys and shafting various kinds; square and flat keys, both parallel and taper; splines and double keys. Both solid and hollow shafting would considered. Standardization dimensions stud bolts, including thread dimen- sions and working tolerances, also contemplated. matter some interest the metal fabrication industries project for organizing committee technical experts undertake the work gage standardization. expected that the work will benefit manufacturers and purchasers gages replacing the great number sizes and types now being manu- factured comparatively small number sizes and types. The United States Navy has done much 578—September 1923, The Iron seen from Fig. that there definite relation between and the true fiber elongation, the relation be- ing has been shown, the dial reading times the thickness the piece and the value may then obtained this equation. order simplify this process for actual use, the writer has pre- pared Fig. simply obtaining the dial reading the bend extensom- eter the bent specimen, the fiber elongation may read from the curve the chart corresponding the thickness the specimen hand. The curves are given for usual thick- nesses. However, conceivable that some particular thickness may desired, for example, shop testing 13/32-in. plate regularly would need the corresponding curve. The follow- ing shows how the curve may graphically obtained. important work establishing gage standards for naval use, and several private concerns, such the Fire- stone Tire Rubber Co., the General Electric Co. and the Pennsylvania Railroad, have established specifica- tions. These and other specifications will studied and coordinated national way. Gray Iron Institute Makes Cleveland Its Headquarters The Gray Iron Institute, recently organized, has established permanent headquarters the Terminal Tower Building, Cleveland. announce- ment issued Arthur Tuscany, manager the institute, stated that the executive committee had picked Cleveland its headquarters because its central location, making pos- sible reach overnight from that city most the important foundry cen- ters the country. The Terminal Tower Building adjoins the site the new Union Station that now being erected Cleveland. Details the organization the institute and its objects were printed AGE May 24, 1928, page 1476. Booklet Iron Ore Considerable statistical and other data the Lake Superior iron ore industry included annual booklet issued the Lake Superior Iron Ore Association, Union Trust Building, Cleveland. The mining com- panies, the mines they operate and their sales agents are listed, well the individual mines grouped ranges and their shipments for the past years. Total annual ship- ments are given ranges for years. Included also are receipts Lake Erie ports, shipments from mines other States outside the Lake Superior district and imports countries. the nomographic chart (Fig. 8), going from the dial leading the straight line corresponding the thickness automatically performs the multiplication, that value for results. Now the correction factor from for any given value independent the thickness, that adding the requisite amount any case, the final value ob- tained. Thus, the chart would used noted the caption. doing this for number dial readings, special curve may readily plotted. special cases where great deal work being done with one thick- ness material, special dial for that thickness may easily con- structed changing the figures the dial correspond with the per- centage fiber elongation, shown the curve just indicated. The bend extensometer scales have been worked out that all charts are elimi- nated for usual conditions. Program Metals Section Safety Council Industrial safety steel plants will receive particular emphasis meeting the metals section the National Safety Council held accidents and progress the steel industry will given Dr. Chaney, Bureau Labor Statistics, Department Commerce. Voss, safety director Central Alloy Steel Corporation, Canton, Ohio, and Mike Grady, president Stark County, Ohio, Foremen’s Club will debate the subject, “The Foreman Responsible for the Accidents That Occur His Department.” The debate will lowed presentation slides John Oartel, chief the safety bu- reau, Carnegie Steel Co., Pittsburgh. “The Placement Men, What the Surgeon Can Do,” will the sub- plant surgeon Clairton works, Car- negie Steel Co., and further informa- tion derived from experience the steel plant will offered ad- dress “Safety from the Viewpoint Supervision,” Dominic Samuels, foreman Youngstown Sheet Tube Co., Youngstown. Roosevelt, vice-president Eagle-Picher Lead Co., New York, will talk “Safety from the View- point Management,” and accident prevention the foundry will Unsafe Practices Foundries,” Nelson Kyser, safety engineer Studebaker Corporation, South Bend, Ind., and another paper “De- veloping Safe Human Factor Our Industries,” Hartley, direc- tor the educational department, National Founders Association, Chi- cago. new 13-in. skelp mill in- stalled the National works, Na- tional Tube Co., McKeesport, Pa., four-high roller-bearing mill. . — 7 | Automatic Furnace Control for Hardening Rotating Hearth With Speed Varied Suit Requirements—Gas Fuel Used for Two Heating Zones nace lined with in. firebrick, which reinforced with in. insulating calcined brick and in. natural brick. steel plate cas- ing in. thick forms the exterior shell. The furnace sand-sealed hardening gears and pinions has been obtained the Automotive Gear Works, Inc., Richmond, Ind., the installation its heat-treating department gas- fired rotary furnace (by Holcroft Co., Detroit) capable handling 900 lb. hour. The furnace has two heating zones the temperatures which are held within plus minus deg. Fahr. means Leeds Northrup automatic recorder con- troller and Dixon control valve. Heat supplied McKee burn- ers spaced ft. in. apart. addition there are two manifolds, one for each zone. Three outer flues lo- deg. apart have been pro- vided. The hearth nickel chrome alloy, the inside diameter measuring ft. the revolving type and operated %-hp. 3-phase 60- motor running 1200 r.p.m. and equipped with Reeves variable speed transmission. The time re- quired for complete revolution the hearth ranges from min. hr. The hearth pan made cast iron and has bearing brackets. structural steel base, the fur- y JA \ \ \ nnular Burner Nozzles = | Reducer Half Section Through the Furnace Vertically (Right) Shows Support and Rotating Elements the Rotating Hearth. shown the relative loca- tion one the gas burners. The horizontal section (left) gives details the great speed reduction from 1200 r.p.m. the motor revolution 143 min. Insulation and firebrick are shown sectioned. Reproduction the pho- tograph shows gears being fed into the furnace for hardening prevent infiltration air into it. Since reducing atmosphere can maintained all times the use gas, the gears and pinions are free from scale when they are removed from the hearth. maintain the temperature within the furnace 1600 deg. Fahr., 1.2 cu. ft. 570 B.t.u gas suffices for each pound work. Equipment in- cludes Ingersoll-Rand vertical re- ciprocating gas compressor with cylinder in. diameter, operat- ing 375 r.p.m. The compres- sor produces 2820 cu. ft. gas hour, delivered lb. pres- sure. Tinting Metal Fence Beautifies Fountain Setting | The coloring tinting ex- terior metal work has been car- ried out successfully the heavy rod fence which surrounds the Buckingham Memorial Fountain Chicago. Interior metal work has long been colored har- monize with its surroundings, and effect the desired color the fence was built copperweld rod. This steel cored metal having heavy layer pure copper molten welded the original ingot. special solution was applied brush, and suc- cessive applications were made until the desired tint was reached and the greenish color has be- come part the copper, with tendency flake scale. The Age, September q | | greater, and the formula becomes very sharp bends where the radius less than %-in. the correction should applied another bend ex- tensometer should used which the distance between the fixed points less than the present meter. This will apply only thin material with high ductility. the fiber elongation, based the final length rather than the original length, designated then from Fig. the relation 100 ensues, and from the above formula 400 The factor 100 introduced for percentage basis. The dial the meter calibrated that the factor Standardize Finished Bars and Shafts Several new standardization pro- jects have been proposed the Amer- ican Engineering Standards Commit- tee, including bars, shafts, studs and gages. The American Society Me- chanical Engine’ has become spon- sor for these projects. Com- ments requests for information should sent the first-mentioned organization West Thirty-ninth Street, New York. developing standards for iron and steel bars the following items would considered: stock sizes, shapes and lengths for iron and steel bars, including flats, squares, rounds and other shapes. The standardiza- tion Woodruff keys, project now under way under American Engineer- ing Standards Committee auspices, has convinced that body the neces- sity standardizing the sizes and shapes iron and steel bars, particu- larly with reference the dimensions and tolerances hot and bars. Under the subject splined shafts and splines, recommended that study made the relations be- tween keys and shafting various kinds; square and flat keys, both parallel and taper; splines and double keys. Both solid and hollow shafting would considered. Standardization dimensions stud bolts, including thread dimen- sions and working tolerances, also contemplated. matter some interest the metal fabrication industries project for organizing committee technical experts undertake the work gage standardization. expected that the work will benefit manufacturers and purchasers gages replacing the great number sizes and types now being manu- factured comparatively small number sizes and types. The United States Navy has done much 400 read directly. will seen from Fig. that there definite relation between and the true fiber elongation, the relation be- ing has been shown, the dial reading times the thickness the piece and the value may then obtained this