The Iron Age 1929-06-27: Vol 123 Iss 26

THE IRON AGE New York, June 27, 1929 ESTABLISHED 1855 VOL. 123, No. Stainless Steel Members R-101 British Airship Record Size Makes Extensive Use Stainless Steel Main Frame—Sister Ship Uses Conventional Duralumin Girders JOHN HARDECKER* the rigid airship built the British Air Minis- try Royal Works, Cardington, England, and her sister ship, R-100, built the Airship Guarantee Co. Howden, England, are now the world’s largest airships, both being 5,000,000 cu. ft. ca- pacity. The R-100 built duralumin, which has been pre- vailing rigid airship practice, tirely new era structural ma- terials with its considerable use stainless has been the contention leading airship designers that the commercial future the airship lay far larger sized ships than those the Zeppelin type. article THE AGE, Jan. shows how this development size has steadily progressed since the first dirigible was built. The lift airship increases the cube its linear dimensions, while the weight increases only the square those dimensions, that only larger sized ships that radically new methods can adopted. impossible use steel for the skeleton small airship, but one like the R-100 R-101 155 tons dis- placement (or the steel framework works out lighter than duralumin for given strength. *Chief draftsman, United States Naval Aircraft Factory, Philadelphia. the R-100, built the same specifications but entirely different design, utilizes duralumin for all its structural members, interesting comparisons will avail- able during the operating life these two airships. The present purpose describe some detail the steel framework the R-101. Some general figures will convey idea the mag- nitude this remarkable structure. The length the R-101 724 ft. in., the maximum diameter 131 ft. in. and the height including the control car about 140 ft. The ratio length diameter 5.5 This ratio was determined give the greatest aerodynamical efficiency from exhaustive tests models the National Physical Laboratory. Each the four fins, including its flap, has area approximately 2200 sq. ft. The longitudinal girders total two miles length and comprise miles booms, 18,000 side and base struts (which absorb miles tubing) and 26,952 tie rods totaling miles length. The tubing all types the girders, struts, fins and other parts the airship totals less than miles, while miles cable are used for bracing. One the most interesting features American in- dustry found the R-101 lies the possibilities for quantity production the fundamentally new type construction which has been used. Whereas the Zeppelin airships have been largely built place (that is, the members brought together their final relationship and then riveted) R-101 has been built sections and erected common bridge steel building. All members the frame were manufactured Boul- ton Paul Norwich; erection was done the large KELETON R-101 Consists Series Circular Frames Separated Longitudinal Girders Ft. Long, the Various Panels Being Cross Braced Steel Cable. Frames require radial ties center ship for stability 1753 Texas-Louisiana se... Fort h, Tex., has arranged for a bond is sue of $1,600,000, part of used for extensions and proceeds to be improveme nts Texas-New Mexico Power Co., and will carry out expal n program in that ter ritory includir transmission line con- tructior Plan property Verry Stave Perry I have |! } juired by new res ed by T. |} Williams, Tre ] cl facture wirebouns Mexik \ tior Brownsville x W M e-president sidiar I An i Airways, I 22 East I ( 1 Str t, New Yor ‘ truct of hangar re ad n hop oil stora we unicip Struc i with 1} ( > \ Ss Building Tac ; } } \ d d 2 tr uton 1ildir I lilding wit] 1ipment I } Ve! e! manutfactu ext ad provement » Claus Ne Co., care | Sterneg 18 Texa Street Pas Tex presider Vv org ait} f $100,000 dt ti il ct nal lis ( Po} 2 East Seventh Street, ge era ipproved final plans i dditior cal refinery for lubr vith macl cor par 117 South Hi Al bama, Inc., Muscle 5 ils, Ala., has plar for xpans neludir tallation dditional equipment production rubber other hard rubber or pat ha arranged for in- cease capital $200,000, part fund to be used for development It has pur- chased Maumee Valle Rubber ¢ T led O ind will opera in affil ited rganization Car ll Du pres lent Toledo Blade, heads Indiana ¥NDIANAPOLIS, June 17 Contract h bee let by Empire Oil & Refining Co Okla., i Building Bartlesville H. B. Olne 1200 East Chicago Avenue East ( cag Ind., for new oil refinery at t t t more than $2,500 ( vith equipment ( Briggs is c ee 1 charg Thor & Rodecker 655 Fairfield Aver Ir napol architect hay warded neral contract to Servic ruction ¢ Castle Hall Building, for cost about $100,000 with equipment Indiana State Normal School, Calvert Muncie, L. A rded general contract to A venue, dent, has awa J. Glaser, 610 South Jefferson Street, for 1752—June 20, 1929, The Iron Age Pittenger, presi- two-story vocational training school addi- about with equip- Zabbitt, Hayden Build- Ind., are architects. tion, to $60,000 ment Snyder & g, Columbus, Supreme Oil & Lumber Insurance Co., Building, Indianapolis, special- zing production fuel oil, has plans tract, with for new 35-acre initial refinery on unit to cost about $100,000 with equipment Irving W Lemaux is presi- dent ( ted States Corrugated Fibre Box Co., 1315 Martindale Avenue, Indianapolis, ! iwarded general contract to Shaner Brothers, 1025 Lewis Street, for rebuild- part four-story plant, 100 160 ft., cost over $60,000 with equipment. Nelson Mfg. Noblesville ufacturer of plumbing equipment and supplies planning to rebuild part of plant recently destroyed by fire Head- quarte it Tenth and Chestnut Street St. Pacific Coast Bids will FRANCISCO, June ked early July Port Stock- Claus Spreckles Building, San Francisco, for initial units I mit ll r Sonor Cai... to cost bout $2,000,000 with machinery (Com- iny WwW & zed recently by W. C > mer] connected with Pa- fic Portland Cement Co., and others. A Roberts noted company Hollywood North Orange Drive Hollywood, Cal., has plans r two-stor | t KX x 00 ft.. to cost it $ vitl juipment. Pope & Bur B 1 \ Building, Los Angele re architect I ow & Balk 01 South Market str pal J ] manutacturer ot 1 l bodie have plat fe new e-story plant, t ost about $25,000 with equipment Escondido Union High School District, Escondido, Cal s authorized plans for ‘ high school group, including one- ory manua! art ind shop building, en- projec to « t $125,000 Kist- ner & Co Architects’ Building, Los An- vear Tire Rubber Co., Akror S. EK. Muleock, 1240 Harvard Avenue, Salt Lake City, Utal for one-story factory branch and distributing plant, 100 140 ft., at Salt Lake City, to cost about $80.,- Winburn, Beason Building, Salt Lake City, archi- Austin Co., for hangar, 100 200 ft., with shop and with equipment Zellerbach Paper Co., Sacramento, Cal., planning rebuiid part factory branch and distributing plant at Spokane, Wash., destroyed by fire, June 4 Irrigation & Co., Seattle, has Development applied for from Columbia Grant and ties, for hydroelectric power development permission o use water River near Priest Rapids kima Coun- Project will provide for generating plant of 450,000-hp. capacity, divided into two units, first 200,000-hp. output for service about months steel ine, and will $35,000,000. Aircraft Corporation, Portland, has been organized to take over and oper- ate company with local New com- tower trans- r Work will include a l than mission cost more Breese same name ine manufacturing plant. Columbia Electric pany has arranged for early sale 40,- 000 shares stock, par value, part fund used for general expan- sion. Canada ORONTO, June 17.—Machine fell off during the week, but in- quiries are good volume. Current de- mand confined single tools. Indus- trial building being carried out number large scale and there are a companies with construction ficiently advanced warrant equipment purchases soon. The railroads are also ex- pected into the market within the next two or three months. Small tools come are moving freely. Goodyear Tire Rubber Co. Canada, Ltd., New Toronto, contemplates ad- dition its plant Bowmanville, Ont. Carlisle, 152 Simcoe Street, Toronto, is manager. 3ids are being received, no closing date set, for three-story addition at Stratford, Ont., for Mfg. Co., to cost $40,000. Office Specialty Mfg. Co., Newmarket, Ont., has awarded general contract Herod Construction Co., Mimico, Ont., for three-story addition. factory Kroehler awarded erected at contracts have been $200,000 factory to be Toronto, for the Hartz Co., Ltd. Fegles Port Arthur, Ont., has been awarded general contract Several tor a Construction Co., for addition Sarnia Grain Elevator, Sarnia Ont., to cost $593,050. Western Canada Contracts totalling $2,072,000 have been awarded connection with the $7,250,000 hydroelectric Stave power River at development the Ruskin, for the British Co., Vancouver, The contract for the power plant has not been let. Cater-Halls-Aldinger been awarded Co., Ltd., has for 2,750,000-bu, addition elevator Vancouver, C., for Alberta Wheat Pool. Howe Co., Ltd., Port Arthur, Ont., consulting engineer Foreign are being considered Cros Sociedad Anonima, Barcelona, Spain, for new plant near Corunna for produc- tion sulphuric acids, superphosphates and kindred specialties, cost more than $600,000 with machinery. secure phosphate proposed rock from Morocco, and iron pyrites from Huelva district. Samuel Rosoff, head Rosoff Sub- way Construction Co., 461 Ave- nue, New York, has contracted with So- viet Russian Government, construct waterworks that munici- pality to cost $40,000,000, project to be completed within months. will in- clude power equipment, pumping ma- chinery, pipe lines, etc. Amtorg Trading Corporation, 261 Fifth Avenue, New York, official buying agent for Soviet Union. Moscow, Leslie Barlow-Massicks, sales manager, Steel, Peech Tozer, Ltd., Rotherham, England, manufacturer of Iron and steel products, head project estab- lish new plant steel springs. company will formed. part former steel plant John Spencer Son Ltd., Newburn, Newcastle-on- Tyne, has been purchased from Ward & Co., Ltd., Sheffield, which recent- acquired the property. are isO proposed at plant it Lefors, T = : to cost about like sum ’ locate etwe San Benito and = = 000 with equipment. Slack Boeing Airplane Co., Hoge Building, ' Seattle, has awarded general contract —_ THE IRON AGE New York, June 27, 1929 ESTABLISHED 1855 VOL. 123, No. Stainless Steel Members R-101 British Airship Record Size Makes Extensive Use Stainless Steel Main Ship Uses Conventional Duralumin Girders JOHN HARDECKER* the rigid airship the British Air Minis- try Works, Cardington, England, and her sister ship, R-100, built the Airship Guarantee Co. Howden, England, are now the world’s largest airships, both being 5,000,000 cu. ft. ca- duralumin, which has been pre- vailing rigid airship practice, while R-101 ushers en- tirely new era structural ma- terials with its considerable use stainless has been the contention leading airship designers that the commercial future the airship lay far larger sized ships than those the Zeppelin type. article THE IRON AGE, Jan. shows how this development size has steadily progressed since the first dirigible was built. The lift airship increases the cube its linear dimensions, while the weight increases only the square those dimensions, that only larger sized ships that radically new methods can adopted. impossible use steel for the skeleton small airship, but one like the R-100 R-101 155 tons dis- placement (or the steel framework works out lighter than duralumin for given strength. Since *Chief draftsman, United States Naval Aircraft Factory, Philadelphia. the R-100, built the same basic specifications but entirely different design, utilizes duralumin for all its structural members, interesting comparisons will avail- able during the operating life these two airships. The present purpose describe some detail the steel framework the R-101. Some general figures will convey idea the mag- nitude this remarkable structure. The length the R-101 724 ft. in., the maximum diameter 131 ft. in. and the height including the control car about 140 ft. The ratio length diameter 5.5 This ratio was determined give the greatest aerodynamical efficiency from exhaustive tests models the National Physical Laboratory. Each the four fins, including its flap, has area approximately 2200 sq. ft. The longitudinal girders total two miles length and comprise miles booms, 18,000 side and base struts (which absorb miles tubing) and 26,952 tie rods totaling miles length. The tubing all types the girders, struts, fins and other parts the airship totals less than miles, while miles cable are used for bracing. One the most interesting features American in- dustry found the R-101 lies the possibilities for quantity production the fundamentally new type construction which has been used. Whereas the Zeppelin airships have been largely built place (that is, the members brought together their final relationship and then riveted) R-101 has been built sections and erected common bridge steel building. All members the frame were manufactured Boul- ton Paul Norwich; erection was done the large KELETON R-101 Consists Series Circular Frames Separated Longitudinal Girders Ft. Long, the Various Panels Being Cross Braced Steel Cable. Frames require radial ties center ship for stability 1753 \ % hangar Cardington means close fitting bolts. Extreme accuracy the lengths all members and the angles all joints was therefore requisite. Calculations had many cases carried fifteen significant fig- ures. Accuracy design obviously had accompa- nied equivalent accuracy the manufacture individual components, which naturally called for high standardization and the extensive use precise jigs. The added expense manufacture the individual parts has been more than recovered from the ease with which the R-101 has been erected very few workers very short space time without any fitting the field. There also remains the possibility that additional airships may Fra 77e Fig. Perspective Drawing Few Intersections Be- tween Main Frame Longitudinal Girders Inner Ridge Figs. and 3—Cross Section Closed and Open Tube Used for Booms Girders and Struts Struts tures, particularly their process for continuously heat treating members formed from steel strip. This process was itself the result long experimentation, and enabled stainless steel used airship construction. com- plete transverse frame for the proposed airship was also built and satisfactorily tested. large dirigible necessity complex structure, difficult select any one feature forming the basis the design. its many unusual features, the use rigid transverse rings frames certainly out- standing. Previous practice has been use frames which were like wheels—they had braced radial wires running the center the ship. Elimination these S Girders built speedily and economically with the existing jigs and fixtures. there existed previous standards which per- missible tolerances members this particular class and form could estimated, very close limits were fixed. Main longitudinal girders, ft. long, were required within 0.030 in. absolute length, with permissible variation between individual members the same nomi- nal dimensions 0.020 in. Main radial struts ft. long were required within 0.015 in. absolute length with maximum differences between individually similar members 0.005 in. Frame longitudinal girders ft. long had tolerance 0.020 in., and ridge girders ft. long were allowed 0.025 in. practice, was found pos- sible keep within about one-third all the maximum limits except the 45-ft. longitudinal girders. was this extreme accuracy that assured easy assembly the members into the finished structure. not assumed that the introduction steel into airship construction was merely happy inspiration. There are about equal amounts steel and duralumin used the structure the R-101, and this proposition presents the culmination years painstaking develop- ment. 1924 Boulton Paul designed and constructed two longitudinal girders which embodied several new fea- 27, 1929, The Iron Age wires the R-101, and further simplification main joints the stresses the various members may figured from the principles statics, are most notable items from the designer’s viewpoint. much for the general features the R-101. That one may identify the individual members necessarily condensed description, perspective drawing few panel points printed Fig. Main longitudinals are girders triangular section, number around the complete circle, except over the tail where they are increased sixteen. Each about ft. long, the clear distance between girders the transverse rings. They are made three stainless steel tubular booms with closed joint (cross section shown Fig. 2), and have tubular duralumin struts between booms. Detailed construction shown Fig. Cross bracing swaged rods, similarly arranged the nor- mal wire-braced airplane fuselage, also employed. Transverse frame consists the inner and outer ridge girders, the main and intermediate radial struts and the frame longitudinal (Fig. 1). 14-sided regular polygon, ranging 130 ft. diameter shown Fig. The periphery this polygon triangular crosss-section, about ft. side. Inner and outer ridge girders for the transverse A frames are triangular section about ft. long. They form the sides the above mentioned polygon. Their booms are rolled from stainless steel and are the bulbous type shown Fig. Webs are duralumin sheet double thickness in. wide, with punched and flanged holes for lightness. Radial struts, both main and intermediate, are tri- angular section about ft. long. the loads are smaller, the booms are rolled from duralumin the bulbous section shown Fig. Stamped duralumin webs, in. wide, with punched and flanged lightening holes are used single thickness. Fig. Longitud- inal and Frame Longi- tudinal Consist Stain- less Steel Booms, Tubu- lar Duralumin Struts, and Swaged Rod Cross Bracing simplification the design may best realized com- paring the view joint Zeppelin, taken after crash during the war. Stainless steel strip, used for the closed joint tubes the main longitudinals and for the booms the ridge girders, has the following composition and properties: 0.16 0.22 per cent per cent (maximum) 1.0 per cent (maximum) After hardening from temperature 960 1000 deg. C., and tempering suitable temperature, this strip Fig. 5—Ridge Girders Have Stainless Steel Booms (Open Type) With Webs Doubled Duralumin Sheet, Punched and Flanged Frame longitudinals are relatively short lengths fore-and-aft girder placed over the outside each frame corner. Since the main longitudinals must sections, the transverse frames are the logical dividing points, and this member really part the transverse frame. Frame longitudinals are about ft. long and similar construction and material the main longitudi- nals. Stranded wire cable used for cross bracing. single cable larger than strands was used, duplicate cables being installed for greater loads. Exhaustive tests the cables with end fittings showed that after once loading half the nominal breaking load the cable, successive loadings below that point caused permanent set. Young’s modulus ranged between 22,000,000 and 25,- 000,000 per sq. in. Intermediate these main members are often many smaller ones used meet special conditions arising specific points. The detailed fittings the joints are themselves interesting study, but are described best reference the photographs (copyrighted views pub- lished permission the British Air Ministry). The has the following physical properties: Proof stress:* 145,000 154,000 Ib. per sq. in. Ultimate stress: 198,000 210,000 per sq. in. Cold bend without cracking, about radius three times the thickness. Stainless sheets and plates for making the fit- tings and wiring plates are austenitic steel. This depends somewhat cold working for its required phys- ical properties; worked the quenched condition. Typical composition and physical properties follow: 0.36 per cent Proof stress:* 112,500 per sq. in. Ultimate stress: 131,200 per sq. in. Elongation in.: 28.5 per cent. Drawn steel tubes, hardened and tempered, the com- *Proof stress British term, essentially representing the elastic limit the material. the case stainless steel strip defined “that stress which the stress-strain diagram departs from the straight line proportionality 0.1 per cent the gage length.’’ For stainless steel sheet, the definition “that stress which the stress-strain diagram departs from line proportionality 0.5 per cent the gage The Iron Age, June 27, position employed for axle tubes, are also used some places. These are usually large diameter and thin gage in. and in. predominate) and are difficult heat treat without distortion. Nevertheless these tubes have been heat treated give values corre- sponding approximately those the closed-joint tubes stainless steel strip, namely: Proof stress: 136,000 Ib n Ultimate stress: 180,000 202,000 Ib. per. sq. Cold bend about a radius five time the thickne without cracking. Steel stampings are all high-tensile, heat-treated steel having minimum tensile strength 125,000 Ib. per sq. in. These are used for shackles for the bracing wires the main longitudinals and for other similar pur- poses. Duralumin the booms the radial girders have the same section the steel the ridge girders. Closed- joint tubes duralumin similar the booms the main longitudinals are also used. Stamped sheets form the girder webs. Before forming, this material heated 480 deg. C., quenched, and then all cold work completed during the next two hours. Duralumin die stampings are employed for the end joints between ridge girders and longitudinals. Thousands aluminum-silicon alloy die castings—(10 per cent silicon) are used, cast with great dimen- sional accuracy, sound and with very good ductility. The specified mechanical properties chill-cast 1-in. test pieces are: Ultimate tensile strength: 27,000 per sq. in. Elongation in.: per cent (minimum) solder another important material used the structure R-101. Bracing cables are pro- vided with adjustable end fitting which houses the end the cable cone-shaped socket. Solder used form solid cone with the splayed-out ends the strands 1756—June 27, 1929, The Iron Age Figs. and 7—Simplicity Joint Lower Ridge Girder Contrasted with Similar Intersection Photo- graphed from Wrecked Zeppelin the cable, strong enough prevent the cable from pulling through. The cadmium-zine eutectic has low melting point well sufficient shear strength. Its chemical composition cadmium 82.6 per cent and zinc 17.4 per cent. The melting point 263 deg. C., and the shear strength solder 15,700 per sq. in. Methods used Boulton Paul for working the stain- less steel have been successful that one may regard the manufacture special sections stainless steel having been put into mass production. Essentially the process consists forming the sections from annealed strip, and then carrying out the hardening and temper- ing continuous process which assures uniform phys- ical properties and close tolerances. For instance, the corrugations which later form the closed joint the tube (Fig. are formed along the edges the strip drawing the strip through dies. Then the strip with its curled edges curved circular section passing through other forming dies. The final seaming done pulling the section through circular die and over mandrel which shaped fold the corrugated edges over one another. reinforcing liner can also formed inside the main tube for special mem- bers carrying greater loads for short distances. This entire operation forming the closed-joint tube done continuous pass through several dies set one draw bench. This formed section then pulled through electric furnace for the hardening heat. die set the entering side the furnace such section cause reasonable amount friction. This assures that the tube shall kept straight under the pull. the furnace raised about 1050 deg. C., and emerges through hollow circular die which cold water kept circulating. This constitutes the quench. Tempering done very similar manner, except that the temperature about 420 450 deg. Tubes ft. long are produced ‘ (minimum) Fig. 9—Beardmore 650-Hp. Engine, Burn Heavy Oil ing the contents emer- gency. Tanks are installed the passenger deck supply compensating weight when the full passenger complement not carried, provide extra ca- pacity for long demonstration without passengers. Without using special tanks, tons heavy fuel oil can carried. Passenger accommodations are located two decks inside the ship near the bottom. The upper deck (exclusive the promenade) has area 5500 sq. ft. The lower deck has area 1730 sq. ft., which can increased later, found nec- essary, approximately 4000 sq. ft. means side wing decks. the upper deck lounge with either side, from which the pas- sengers may obtain outward view. This deck also carries separate dining room for per- this closed-joint section the draw-benches installed. sons, number two-berth sleeping abins and necessary Cutting length after hardening and tempering done toilet facilities. thin mild steel disk run high speed. The lower deck carries the captain’s control room, The greater part the steel used the airship and beneath this control car projects outside the en- stainless. Other minor steel members are zinc-coated velope. The kitchen with its electrical cooking arrange- modified Sherardizing process. All duralumin parts are ments located the lower deck. The lower deck also given anodic treatment and then coated with lanoline. carries smoking room and quarters for the crew. The The aluminum-silicon alloy die cast- ings possess excellent inherent anti- corrosion properties and require special treatment. Since cadmium very closely related zinc chem- ically, the solder introduces risk corrosion. action with the zinc-plated fittings and galvanized wire. There are five engine cars, each attached two points only, they can readily detached entire, when Each car contains one Beardmore 650-hp. water-cooled engine, built burn heavy oil. Use heavy oil dictated safety measure, since the heavy fuel oil when poured gasoline fire will put out. The en- gine also shows per cent saving fuel, compared with gasoline engine; while weighs per horsepower, believed that future refinements design will cut this half. The engine arranged the car that there ample room remove cylinder head, piston connecting rod while the ship flight. Fuel oil tanks each hold 224 gal- lons (equivalent 1870 Fuel from any these tanks can run into special pressure tanks from whence can blown compressed air any reservoir the ship. This new feature facilitates feeding the engines and trimming the ship. Certain tanks are fitted with special disks and circular cutters for dump- Fig. 8—General Assembly Five Main Frames with One Gas Cell Position The Iron Age, June 27, | x rrr crew consists captain, three officers and men. The ultimate installation will provide accommodations and berths for 100 passengers. Many points interest must omitted this brief description such tremendous airship R-101. When looking upon the world’s largest airship, one must not swept away enthusiasm for mere size; repre- sents much more than just larger airship. The builders have gone back the basic principles, utilizing all that has been learned from past airship construction, operation and maintenance, and started anew plan which takes full view the necessity for maximum safety well the modern demand for comfort and for fabrication methods that are directly applicable production. Some the basic developments materials, particularly steels, represent more than mere applications airship con- struction, for they undoubtedly open fields for steel devel- opment other industries. Endurance Laminated Springs extended series tests being made the springs research committee the British Department Scientific and Industrial Research, determine the en- durance spring steel plates under repetition re- versed bending stress, the displacement vehicle springs under road-running conditions, and the effect the mechanical properties laminated springs produced the “nip” which they are subjected the process assembly. From these tests Batson and Bradley the National Physical Laboratory conclude that the Pivot Vertical Two Grank Throw. Testing Machine Designed Alternate Bending Stresses Spring (Test Piece) Studying Endur- ance Laminated Springs. Alloy steel seems little better than carbon steel explanation the unexpected spring fractures now found service may lie effect due the skin the leaves the spring. special testing machine has been devised, the elements which are sketched Engineering, Jan. 11, 1929. The test piece (ordinarily heat treated spring the ends arms and Pivot can raised that any desired initial stress can imposed the sample. Alternate bending during the test induced the angular motion and which transmitted from the crank shaft through the arms and made aluminum alloy. The amount bending con- trolled locating the fixed points and appro- priate points circular slot indicated the dotted arcs. The machine driven 500 1500 r.p.m. variable-speed motor. The amount stress measured the bending arm the radius curvature the test piece. The automatic cutout consists arm parallel the test piece and just above it. This arm carries six screws, adjusted just not touch the test piece its position maximum strain. When the piece cracks, its contour changes sufficiently foul one more 1758—June 27, 1929, The Iron Age the screws, and open switch the motor circuit. The screws are usually set close the test piece that the insertion piece paper will cause stop. Endurance limits polished specimens determined this machine agree with those determined the rotating beam method. However, the leaves are tested the same surface condition when put into com- mercial springs, the endurance limit only per cent high. Six-leaf springs, designed for working load 392 lb., and made carbon and alloy steels various com- positions and heat treatments are being studied exten- sively. Some surprise felt the fact that the alloy steel springs, when tested this way, gave little any better results than those carbon steel. Recovery Secondary Metals Important Industry Collection waste material established branch industry has been given consideration United States Bureau Mines. There are more than 3000 scrap iron and steel yards the United States, many which have extensive equipment. data are collected the Bureau Mines showing the quantity secondary ferrous metals recovered, but estimated that, exclusive the scrap available steel mills, railroads and large manufacturing plants, more than 5,000,000 tons miscellaneous ferrous scrap collected and sold annually. This estimate does not include rails, pipe, machinery and other equipment renovated and sold for original use. This use old ma- terial very extensive all parts the country. Nearly 500,000 net tons secondary copper récov- ered annually the United States. This recovered from copper metal, brass scrap and other copper alloys. Nearly 300,000 tons secondary lead are recovered an- nually. The main sources supply secondary lead are old pipe, lead cable, battery plates and lead lining acid tanks, although large quantity derived from babbitt, solder, terne metal, type metal, brass and white metal drosses. Large quantities secondary zinc are recov- ered redistillation, sweating, remelting, etc. Enormous quantities secondary tin are recovered an- nually. Nearly all detinning done the United States the electrolytic process the chlorine process. Pro- duction secondary antimony mainly from alloys. The recovery secondary aluminum pig aluminum alloys amounts nearly 50,000 tons annually. large quantity No. secondary ingots (92 per cent alumi- num and about per cent copper) made smelters from old defective castings, borings and scrap, but the number alloys containing aluminum has greatly in- creased recent years, and the use No. alloy pro- portionately less than was. Secondary nickel recovered metal non-ferrous alloys and salts amounts annually over 3000 tons. Nitralloy Under the Microsope— How Such Hardened Steel Wears Corrosion Resistance Property— Remove Decarburized Areas necessity complete removal strains set forging, machining and hardening order prevent warping distortion during nitriding has been emphasized. Straightening parts after nitriding may required this precaution not observed. This especially likely occur thin flat sections parts having large diameter one end and long section with smaller diameter the other end, such cer- tain types spindles, fine pump plungers, etc. has been found quite possible straighten such parts even when done cold. Since the hardness the case not affected 1000 deg. Fahr., obvious that the straight- ening operation can well applied the hot material. Decarburized Layers Must Removed Great emphasis should given the necessity for the complete removal the decarburized layer before nitriding. this precaution not observed, the nitrided case will lend itself chipping and flaking. Photomi- crograph Fig. shows the appearance the case resulting from the nitriding decarburized specimen. The black areas the decarburized zone represent cient material must left for final machining grinding before nitriding insure the complete removal traces decarburization resulting from the forging and the heat-treating operations. typical procedure follow the case article machined from annealed bar rough machine, heat treat, finish machine and then nitride. The rough machin- ing should done with proper observance the precau- tion mentioned above. The heat treatment involves quenching oil from the proper hardening temperature, followed draw least high the nitriding tem- perature obtain proper physical properties for the core and relieve machining and hardening strains. Suf- ficient time should allowed for this operation order prevent warping distortion nitriding. The final machining grinding must remove all traces decar- burization. Nitriding for the proper time meet the *Assistant professor physical metallurgy, Massachusetts Institute Technology, Cambridge, Mass., and consulting met- tallurgist the Ludlum Steel Co. This the concluding sec- conditions completes the operation except for possible finishing operation, such lapping, the nitrided article. The treatment forgings should considered with due precaution eliminate decarburization before case hard- ening with ammonia. Structure Nitrided Specimens The photomicrographs, Figs. and 11, show the depth and character the case obtained nitriding heat-treated specimens Nitralloy “H.” The specimens were oil-quenched from 1750 deg. Fahr. and tempered 1000 deg. Fahr. before nitriding 950 deg. Fahr., for 24, 48, and hr. the nitriding heat-treated specimens, the line demarcation between the case and the core frequently impossible determine microscopic examination. dark band, representing the structure which etches most rapidly with alcoholic nitric acid, generally present indicated the photomicrographs. Fig. the case occupies the greater part all the micrograph. The fineness the structure the nitrided zone each in- stance quite evident. Fig. shows the case produced nitriding nitralloy previously oil-quenched from 1650 deg. Fahr. and tempered 1000 deg. Fahr., followed nitriding for hr. 950 deg. Fahr. The excellent structure the case clearly indicated. Growth Due Nitriding slight growth takes place during nitriding. Table III shows the increase length and diameter cylinders Nitralloy “G,” previously oil-quenched from 1650 deg. Fahr. and tempered 1000 deg. Fahr. for hr., followed nitriding the indicated temperature for hr. Prior nitriding, these cylinders were accurately ground, after which they measured 5.8160 in. length and 0.7100 in. diameter. This growth can allowed for the final machining grinding before nitriding, can removed after- ward lapping other suitable means. greater surface hardness can obtained this method case hardening than any other means. surface hardness equivalent 1000 Brinell common. The Iron Age, June 27, Hardening Steel with Ammonia Fig. Photomicro- graph the Appear- ance the Case Resulting the Nitriding Decar- burized Specimen. 100 Since the case gradually merges with the core there tendency for the two separate. Another valuable property which accompanies the ex- treme surface hardness nitrided Nitralloy the re- sistance atmospheric, water and salt water corrosion. The maximum resistance corrosion exhibited the SF, PSO Fig. 9 hardened. Nickel plating depth least 0.0005 in. has proved satisfactory. coating tin solder also good protective agent. Tin melts temperature great deal lower than the nitriding tem- perature. The cleaned article dipped into the molten tin and held for short time become heated somewhat order that the tin will not freeze immediately the part when removed from the bath. The ex- cess tin can shaken off removed with wire brush. sufficient coating will adhere the articles surface tension, insure ample protection. Before the article dipped into the molten tin solder, should cleaned and flux applied. The flux used has the following com- position: Hydrochloric acid......... 500 Ammonium chloride.......... grams Add scrap zinc until further action takes place. The articles tinned must free from rust scale. obvious that protective agent, which might applied paint, highly desirable. This problem has received great deal attention the author’s labora- tory, with positive results. The composition this mate- rial will divulged soon all details have been thor- POLE Fig. Fig. Fig. 8—Structure Nitralloy Oil Quenched from 1750 Deg. Fahr., Tempered 1000 Deg. Fahr., Nitrided 950 Deg. Fahr. for Hrs. 100. Fig. 9—Same Fig. but Nitrided for Hrs. Fig. —Same Fig. but Nitrided for Hrs. Fig. Fig. but Nitrided for Hrs., All 950 Deg. Fahr. unpolished surface. view this fact, preferable place nitrided articles directly into service without ad- ditional polishing whenever the question corrosion involved. obvious that this property rustlessness with extreme surface hardness renders nitrided articles highly desirable for great many purposes. Nitrided Nitralloy retains great hardness elevated temperatures. shows practically the same degree h when tested deg. Fahr. room tem =}, re 7 } perature and shows excellent degree hardness when tested 1400 deg. Fahr. Protecting Sections from Hardening frequently happens that threaded portions other areas must protected order not become i N f Nit nt a ] i Ss Ly 4 ada 1929, The Iron Age oughly studied. number experiments have been per- formed demonstrate its adequacy protective agent. Service Tests Wearing Properties The use nitrided Nitralloy various commercial op- erations has fully demonstrated its great wearing prop- Fig. Nitralloy Oil Quenched from i650 Deg. Fahr., Tempered 1000 Deg. Fahr., Nitrided 950 Deg. Fahr., for Hr. 100 & 7 a a < Fig. erties. Many instances actual service tests might mentioned. instance such test which the ni- trided article showed great superiority over the material previously used involves application the shoe indus- try, where small anvil receives the impact two wires the rate 150 times minute. Besides receiving this impact, the required loop the wires. The life this part has been increased many times the use nitrided Nitralloy. Guillet* has studied the wearing properties nitrided steel, especially with respect the automotive industry. Some the data presented him are included the following table: Table Wear Cylinders car with cast iron cylinders after 30,000 car with nitrided cylinders............. 0.0008 in. Aviation motor after 100 hr. running: Wear cylinders heat-treated steel *Lecture Academy Sciences Paris, France. . 0.0032 to 0.004 in Qualities Molding Sands ECHNICAL requirements for molding sands are: (1) permeability gases; (2) refractoriness; (3) free- dom from generation gas; (4) non-adherence the metal, which must give good surface, and (5) must not temper nor harden the surface the metal, says Marcel Guedras Revue Fonderie Moderne. These qualities depend upon the characteristics the sand, the agglomerant, the preparation the mixture and the dry- ing. ideal sand comes from Fontainebleau, Nemours and and also from Belgium. The sand from Fontaine- bleau consists silica, 98.90 per cent; alumina, 0.20 per cent; lime, 0.12 per cent; magnesia, 0.10 per cent; com- bined moisture, 0.28 per cent, and oxide iron, traces. Grains sand must uniform size, held together with agglomerant which must uniform quality. Although these two requirements are vital importance, many foundrymen not appreciate them their true Steel Foundry Adds Electric Department order diversify more thoroughly its products steel castings, the Union Steel Casting Co., Sixty-sec- ond and Butler Streets, Pittsburgh, has recently placed operation electric furnace which will supplement the several 25-ton open-hearth furnaces operated the company. The installation will enable the company furnish steel castings from 70,000 in- cluding all types light section work and meet the demand for alloy castings. The new furnace, shown the accompanying illus- tration, has capacity 4000 every hr., and operated from 750-kva. transformers, stepping down three-phase 60-cycle, current 205 The molding machines are the Herman pneumatic type, both straight jar and roll over, worked out the unit system. One section the molding floor de- voted small work squeezers and another section devoted bench work. large proportion the castings are made green sand molds. The finishing shop laid out for straight line production and castings have continuous flow from each successive operation until ready for shipment. The finishing shop equipped with sandblast shop and full equipment for annealing and grinding. Oil consumption (same conditions) per hphr.: New motor After 100 hr. treated steel 75 grains) (180-225 grains) Cylinder of nitrided 4 to 5 grams (60- 4 to 5 grams (60- steel 75 grains) 75 grains) Some the uses nitrided Nitralloy are follows: Crankshafts Cams Ring Gears Wrist Pins Bushings Celluloid Molds Spinning Rings Valves Worms Spindles Timing Gears Chucks Pinions Small Gears Master Gears Steam Nozzles Clutches Tappets Camshafts Gages Steering Mechanisms Piston Pins Pump Shafts Sectors Relay Shafts Rollers Master Cams view the properties nitrided Nitralloy, the statement made the beginning this paper, that its development represents one the most important metal- lurgical accomplishments recent years, well justified. the French See Them value, says the author. Crushing sand frequently stroys its value. Mixing should dealt with spe- cialists should also the construction mechanical mixers, Each grain sand leaving the mixer should inclosed skin agglomerant and this impossible with crusher. The classic agglomerant, linseed oil, not sufficient and various preparations molasses, rosin, are added, each foundry usually having its own formula. This problem alone often requires many years patient re- search the laboratory. Germany agglomerants are prepared specialized chemists means methodical tests which are able guarantee the uniformity their product. Foundrymen are thus relieved fruifful cause anxiety, and are assured freedom from blisters and cracks complicated castings which, the absence satisfactory molding sand, would have been impossible for them undertake make. = » The Age, June 27, 7 4 Building Erected Gas Welding Use Oxy-Acetylene Method Factory Structure— Valuable Data Secured for Future Work Along Same Line XY-ACETYLENE welding has been used fabri- cation and erection large factory building used for research department the Niagara Falls, Y., plant the Union Carbide Co. This be- lieved the largest structural building that has been gas welded and the first its type fabricated and erected under usual procedure construction. mill-type, single-aisle building ft. wide be- tween column centers and 260 ft. long, with thirteen 20- ft. bays. The building took 298 tons steel, which 203 tons was shop welded and the remainder either field welded bolted. the total amount welded about per cent was done the shop and per cent the field. 4 » One-Ha/? \ x KAA O38 % ~ ) fA 4 «8s — 0; C//p Details Truss Heel Joint and Column Con- nection, with Welding Contacts Shown Black Following usual practice, bolts were used joining such members erection would have been bolted had the building been riveted. The building ft. in. high lower chord trusses. Mezzanine floors ft. wide extend along one side, single-stage bays and three-stage two bays. The main and first mezzanine floors will served full-span 10-ton traveling crane. This the first series welded structures contempiation for construction under the development sec- tion the Linde Air Products Co. This type building was selected for the initial product primarily because contained miscellany structural joints and offered opportunity for more general application structural welding than would have been given multi-story structure. addition, its erection would provide struc- tural welding data for number types industrial buildings. was decided for reasons handle the welded steel manner similar that which would have been followed the building had been riveted. First was the fact existing construction facilities and consequent max- imum speed production. Secondly, was desired obtain practical experience with gas welding when applied this class structure under conditions similar rou- tine production and construction. Designs for welding general followed the lap method 1762—June 27, 1929, The Iron Age assembly parts, utilizing fillet weld. This was par- ticularly true for truss web members and for beam-and- girder connection details. Exceptions were made the heel and ridge joints the trusses, where combination fillet and butt welding was utilized, and anchorage details for principal columns. Liberal use was made Carnegie beam and column sections. Through elimination built-up columns and girts, using their place rolled single sections, and placing assembly bolt holes details wherever possible, the major tonnage had only gas cut milled prior transfer the welding skids for jigging and attach- ment details. roof purlins and chord bracing would ordinarily not riveted place, these sections were not welded. Each main building column consists two milled beam sections, one in. and one 14% in., offset the elevation the crane beam. These sections were shop spliced fillet welding plates the face the column flanges, the inner plate being cut straddle the web the 24-in. column below the web joint. Base plates for columns were provided with anchor bolt holes before framing, that they could set and grouted before the columns arrived. Anchorage for the columns provided double extra heavy pipe lugs, double-fillet welded the edges umn flanges. Through these pipe members the anchor bolts are passed and secured nuts. The columns are capped bearing plates fillet welded thereto along the outer face flanges. Bolt holes these plates provided for field assembly, with corresponding holes bearing plates welded the under section the bottom chord the truss. Bracketed plates are used for the crane beam seats, these beams, offsetting the 24-in. columns, preventing direct bearing. The connecting details the column for girts, lintels and beams were made angles, providing landing seats and side connections where necessary. These details, provided with assembly bolt holes, were welded How the Welded Heel Joint Appears After Comple- tion, with Purlin Attached Lower Right 7 7 q 7 7 7 or. /4 Pla te /4 x /64 7 § 4 : Pay the columns, thus avoiding shop work other than milling and welding the column sections. Trusses are ft., designed permit their weld- ing half-sections the shop, thus keeping dimensions within shipping limits. Upper and lower chords were made from 16-in. and 14-in. beam sections, split longitudinally. This produced T-sections with sufficient leg length re- ceive the web members without using gusset plates. Where these T-sections meet the heel the truss the webs were butt welded the shop, and the ridge the flanges were butt welded the field. the heel the upper chord flange was extended engage the flange the lower chord. Web and knee brace members are angles secured %-in. fillet welds. For floor beams flat flanges beam sections were used wherever possible for landings, welded connection details being provided for beam ends only. designing connec- tions for beams and girders, per cent was added pres- ent floor loads provide for possible increase; addition, increase 100 per cent the crane load will permit later installation 20-ton crane the present runway. Unit stress 16,000 lb. per sq. in. was provided for the base metal design and for the weld metal design, 11,300 lb. for shear and 15,000 lb. for compression. Welding shop the outset was somewhat slow, from unfamiliarity the welders with this class work, Steel Plate Anchorage Design for Side Columns, Which Utilize Pipe Welded the Column Means Holding Place but later the rate increased steadily. Each welder was required pass qualifying tests the American Welding Society code. Smooth looking welds were not obtained all cases, but the job progressed this detail was im- proved. The trusses were assembled jigs secured the welding skids, which the truss members were clamped for welding. Simple clamps were developed for shop as- sembly details. Field welding began joining the half-truss sections the ground. Bolts the splice and ridge joints per- mitted bolt assembly these sections. The assembled trusses were laid flat blocks along one side the aisle, each truss lapping the other, that the welders could get the joints. This procedure required one-half the weld- ing the trusses done overhead and said have demonstrated the feasibility joining welded trusses the fie