The Iron Age 1929-04-25: Vol 123 Iss 17

THE IRON ACE New York, April 25, 1929 ESTABLISHED 1855 VOL. 123, No. Heat and Corrosion-Resistant Alloys Stainless Steel, What and How Was Discovered Analyses and Properties Three Chief Types —Chrome Irons for Structures HOLLAND NELSON TTACK due corrosive conditions liquids at- normal temperatures, the one hand, and destruction material due loss (scal- ing) high temperatures various gases, the other, are subjects that may not seem closely enough associated for treatment one series articles. Yet the author hopes deal some extent with both subjects and show how series steels and alloys de- signed combat corrosion become equally interesting the field heat resistance. This not really strange, for the very necessity that led the discovery “stain- Re-Aerated Water Dif fusing Downward forms Rust Band Here Water With Iron Solution Rising Fig. (Above)—A Simple Explana- tion the Formation Rust. Fig. and (Upper Right)—Photomicro- graphs Pure Iron (Left) Showing Grains Same Type and Mild Steel Showing Dissimilar Grains (by Brearley). Fig. Rust- ing Iron (Center Piece) and Steel (Cushman) & less steel” Brearley was problem involving both con- ditions. How Stainless Steel Was Discovered The story well known today that details are un- necessary. Brearley’s problem was produce gun lining that offered increased service. The destruction gun lining due two causes—erosion and corrosion. Suffi- cient heat generated the firing gun large cali- ber actually fuse thin film metal the lining. This was apparent the early stages the investigation and .* - > ~ 4 4 A. G 1139 ORN Shefheld, England, 1890, Mr. Nelson was educated the metal- lurgical department Shefheld University. His early experience was gained with Thomas Firth Sons, that city. finally became assistant Harry Brearley, inventor stainless steel, when the latter was head the Brown-Firth Research Laboratory, also Shefheld. Later joined Messrs. Darwin assistant works manager charge five plants. Coming the United States 1913 metallurgist the Simonds Mfg. Co., the Lockport, Y., plant, later became superintendent the steel works Henry Disston Sons, Philadelphia. returned England, joined the army and later was associated with Peter Stubs, Ltd., works manager, finally becoming managing director that com- pany’s Rotherham Works. keturning America 1920, rejoined Henry Disston Sons production manager, being finally placed control all heat treatment and metallurgical research. Within the last three four years Mr. Nelson has been associated with prac- tically all the large chromium-iron installations built for the American chemical in- j the Widener Building, Philadelphia immediately brought the need material with high melting point and considerable heat resistance. accomplish this Brearley commenced study chrome-iron combinations varying percentages: Low- carbon chrome alloys were chosen because low carbon was essential maintain high melting point and chrome was expected aid obtaining the physical properties neces- sary the absence carbon. happened the author’s privilege and pleasure associated with Harry Brearley this time. Those steadily engaged research fully appreciate that often “real discoveries” are the outcome careful observation “along the road” rather than the actual re- sult previously laid-down formula. research mind must ever open grasp possible lead, for often the solution lies far from the beaten track. Non-Etching Property Real Factor Brearley’s case was gun lining which prompted the investigation, but was the observed fact that some the alloys produced this research did not “etch” ordi- narily that ultimately led the discovery stainless steel. The lay mind delights weave romance around such discoveries and will call them “accidents.” Such term grossly unfair the research chemist. “Careful observation” more often the true reason. How did this observed fact that certain acids did not etch some the alloys under investigation lead the discovery stainless steel? The art etching immerse material suitable solution which will attack its various component parts different rates, leaving condition light and shade which gives micrographi- cally opportunity observing the various component parts. This result due the different rates solu- bility the various elements compounds contained the metal. What then, was the chief discovery this research? certain alloys chrome iron were insoluble certain liquids.” There seems little romance these words, and yet that sentence represents definite accom- plishment and should sufficient inspiration every re- search mind that there may other alloys iron insol- uble other corrosive liquids. have yet find entirely satisfactory metal deal with such acids sul- and hydrochloric commercial scale. Various Theories Corrosion the present time there much technical research into, and considerable discussion of, the phenomena corrosion. There are claims that passivity produced oxide film coating the material; others contend that gaseous film oxygen renders certain materials 1140—April 25, 1929, The Iron Age dustry. member the American Iron and Steel Institute, American Society for Testing Materials, American Society for Steel Treating, (British) Iron and Steel Institute, Society Engineers and Metallurgists, and the American Insti- tute Mining and Metallurgical Engineers. now consulting metallurgist, with passive; then, course, have the acid and electrolytic theories. Whatever may the phenomena that render certain materials active passive under certain corrosive condi- tions may still debatable, but know that certain materials will withstand attack where others fail, and, while thoroughly appreciating the work these various investigators, the actual user often more directly inter- ested whether material will withstand his condition than with the explanation the phenomena that govern the result. Corrosion Simply Explained The explanation offered Brearley the author the early days stainless production readily understood and does not clash with any reliable work date, that for the purpose this series articles, corrosion can made appear very simple subject without con- flicting with any these theories. Corrosion generally expressed terms such “loss weight” and “pitting,” These two expressions are sufficient for purpose. Few people realize that iron soluble water just the same sugar salt, but lesser degree. sim- ple experiment carried out your office desk will illus- trate this. Take ordinary “bright” carpenter’s nail and place (after weighing) previously boiled water test tube. Pour enough the boiled water cover the nail, and then ram pad cotton wool filter paper pulp, illustrated, and continue the addition water. (Fig. 1.) the course time band rust will form the cot- ton wool, whereas the nail will remain bright. The experiment may continued until flocculent rust begins form the water beneath the cotton wool. What established that rust will form with the nail remaining bright, and careful weighing the nail will show distinct loss weight, confirming the fact that iron soluble water, and that “rusting” secondary condition. Therefore, possible add iron some alloy that will render insoluble any particular solution, also rendered rustless and resistant corrosion under those same conditions. Chromium Makes Iron Insoluble Water Brearley, therefore, discovered that chromium cer- tain proportions iron rendered iron insoluble water and many acid and alkaline solutions. But the field corrosion-resistant metals has been barely touched, and venture say ere long other alloys will available deal with such acids sulphuric, hydrochloric, ete. Alloys are already known, but most = cases either price the unworkability the materials retards their development. What Stainless Steel? the first place would perhaps well ask ourselves what stainless steel is. The term “stainless,” “rustless,” has led great deal misunderstanding. considering the name should borne mind that the iron-carbon-chromium stainless steel first made its commercial appearance through the cutlery industry, and its success was due the fact that, under such conditions those under which ordinary cutlery used, the mate- rial was both rustless and stainless. should, however, remembered that cutlery articles are invariably hard- ened, tempered, ground and polished. These materials are not stainless, nor are they rustless, under all con- ditions, and the author feels that the term “rust and corrosion resistant” much less misleading. Why Are Certain Types Resistant Corrosion, Stain Rust? obtain understanding the prin- ciples governing corrosion-resisting steels, should first thoroughly understood that iron soluble water and, secondly, that iron combined with carbon not only soluble water and, therefore, rusts like iron, but that the corrosion much more rapid, due the galvanic action between the iron itself and the carbides iron. This cre- ates selective corrosion and pitting. For this reason iron the purest varieties, under corrosive conditions, has al- ways withstood such corrosive action better than steel. obtain corrosive-resistant iron, therefore, necessary introduce some alloy, alloys, iron which will first render insoluble, and then, there carbides present, prevent, possible, galvanic action from setting selective corrosion pitting. Brearley apparently covered his patent the range chromium between and per cent, knowing that heat treatment was essential produce homogeneity, and real- izing that over per cent chromium additions rendered the material immune heat treatment the sense hardening. Since that time, however, the higher chro- mium alloys have been further developed and, even where free carbides exist, the material found extremely resistant corrosive attack. With the knowledge, therefore, that certain percent- ages chromium combination with iron render the resultant iron-chromium insoluble water and many other solutions, and that the carbides present such alloys, with less than per cent chromium, can dif- fused throughout the mass (i.e., dissolved into the iron- chromium matrix) heat treatment, seen that material can produced which insoluble water, and which possesses that homogeneity which removes the pos- sibility galvanic action. Such material, therefore, could termed corrosion-resistant alloy. Stainless steel, the last years, has found many and varied uses, particularly the cutlery industry, the manufacture turbine blades, various hydraulic and automobile parts such pump shafts, and the engi- neering trades general, where material with high physical properties and substantial corrosion resistance required. Output Stainless Steel The increased production stainless steel can best gaged from the fact that the year 1913, when first became commercial article, was the product the clay pot crucibles Sheffield, England, and the entire tonnage for that year was probably under tons. Dur- ing the war its development was delayed, due the fact that chromium was substantially controlled for the manu- facture munitions. The manufacture this material passed from the crucible the electric furnace, with the increasing demand for tonnage, and the year 1926 sales the United States reached 4000 6000 tons. The pro- duction lower carbon ferrochrome made possible the Fig. 5—One Towers the First Chrome-Iron Nitric Acid Installation the United States The Iron Age, April 25, introduction the chrome-iron series, and the tonnage the combined stainless steels, chrome irons and nickel- chrome alloys related types ever increasing one. Chief Types Stainless Steels The physical properties stainless steel vary substan- tially with the carbon and chromium contents. This illustrated the tables: Analysis and Properties of Stainless Steel Per Cent Manganese . 0.15 Silicon . 0.19 Chromium 12.00 Treatment: Air-hardened from 1700 deg. Fahr. and reheated is shown: Re- ! iting I is Ultimate Red. ot Limit Strength, Elong., Area Deg Lb. per Lb. Per Per Impact, Brinell Fahr. Sq. Sq. Cent Lb. No. 925 ; 232,900 9 24 S 444 1100 126,300 141,100 285 1300 104,800 120,900 241 This material air-hardens from hot working temperatures and should annealed, tempered, any machining and iny degree toughness are necessary Analysis aud Properties of Mild Stainless Steel Per Cent Analysis: Carbon 0.15 0.16 Silicon 0.09 Chromium 11.8 Nickel 0.77 Treatment: Oil-hardened 1700 deg. Fahr., and reheated shown : Re- heating Elas. Ultimate Red. of Temp., Limit, Strength, Elong., Area Izod Deg. Lb. per Lb. Per Per Impact, Brinell Sq. Sq. Cent Cent Ft. 925 : 199,600 10 36 16 402 13200 85.100 104,800 26 5S 60 223 1400 69,900 98.300 28 61 68 207 Analysis and Properties Stainless Per Cent Carbon 0.07 Manganese 0.12 Silicon nie 0.08 Chromium 11.7 Nickel .... 0.57 Oil-hardened from 1700 deg. and reheated how heating Ela Ultimate Red. of Temp Limit Strength, Elong., Area Izod Deg Lb. per Lb. per Per Per Impact, Fahr Sq. Sq. Cent Lb. 400 163,500 12 3S 34 340 750 162,200 332 925 131,700 162,200 340 1100 85,100 109,700 241 1300 68,500 90.500 26 66 79 196 This material termed stainless iron Europe, and the American manufacturet operating under Euro- pean patents. is, however, apparent from the above figures that this material, exhibiting, does, distinct hardening properties, would more correctly designated very mild stainless steel, and, while it does not possess the maximum resistance corrosion, has physical properties distinct value certain fields, and view the low-carbon content and the consequent small amount free carbide that exists, it does possess in all conditions a substantial resistance to corrosive attack. These Alloys Structural Work OLLOWING the development the material covered the Brearley patents, various modifications the per cent chromium alloy were advocated and dem- onstrated both Europe and the United States. Dr. 25, 1929, The Iron Beckett has done much this line, had also Armstrong, the development extremely low- carbon, higher chromium with silicon alloys, but generally speaking, these high-priced alloys had become the product the tool steel manufacturer, and while some them were available sheet form, practically nothing had been done the field general structural work, was gen- erally considered that the price the material itself ren- dered impractical for general structural fabrication. was this stage the industry that one the largest chemical and explosive manufacturing concerns the world discovered that some these chromium alloys offered sufficient resistance nitric acids varying strengths warrant building manufacturing installations covering tanks, towers, connections, pipe lines, etc., using high-chromium material the form plates, angles, channels, I-beams, tubes, rivets, etc. and assembling the whole along the lines ordinary mild tank steel. this time the author was called pass opinion the possibilities building such equipment. The materials available were substantially the stain- less steel hardening types, except some few instances where the materials referred under the Beckett and Armstrong patents had made steady progress develop- ment bar form and the sheet industry. With this somewhat limited range materials draw from, some the difficulties confronting the production fabricated installations the type illustrated Fig. can imagined. The building such installations re- quired material malleable the cold, obtainable all the variety shapes and sections called for the de- signing engineers, and capable being assembled substantially standard boiler shop practice which, course, included riveting welding the shell together. With the materials available, perhaps not surpris- ing that the early attempts either rivet weld plate material were far from satisfactory. little was known general regarding the chemical analysis, and its effect upon the physical properties and hardening tendencies the material, that many troubles were first encountered those who made some early attempts with the limited knowledge available. should clear those interested that use air-hardening material for rivet would lead disaster, because driving the hot rivet into cold shell would harden the rivet effectively plunging water. This produced brittle rivets. fact, the author, the early stages, saw material put together with such rivets, the heads which would fly off they became cold. The same difficulty was encountered with welded areas, which were hard and brittle after cooling, except that the welding problem was aggravated other difficulties also. This phase was rather discouraging. the one hand, had the chemist stating that needed material con- taining over per cent chromium; the other hand, the fabricator was trying buy material this de- sired chemical composition, not realizing that one crit- ical point (i. e., per cent chromium) the physical prop- erties and general behavior the material underwent substantial change. Therefore, obtaining material per cent chromium content one instance, and per cent another instance, some the early fabri- cating experiences were not only expensive experiments, but also led disappointing results. build installations such the tower shown the illustration was speedily determined that material show- ing either hardening tendency all, least slight almost negligible, was essential, and this leads into the subject the type chromium iron that has been extensively used over the past four years the United States manufacturing the various large in- stallations for the production nitric acid. This will the subject the next article. | | Sponge Iron the Smith Process Vertical Ovens Like Coke Ovens Used —100 Per Cent Reduction Claimed —Will Directly Assist Blast Furnace DR. GEORGE WATERHOUSE* process the General Reduction Corporation, Detroit, for the production fine sponge iron, the invention William Smith, president the company. For many years Mr. Smith was connected with the Ford Motor Co., and had important part every step the building that company’s many great plants. recent years had charge the examination and acquisition extensive coal, ore, mineral lands carrying out the Ford policy making his indus- tries independent regard raw materials. also was head the research division and active many and varied metallurgical developments. Creation the Smith process and the low-temperature reduction ovens was meet the demand for better iron and steel and make available the abundant iron ore reserves not being worked the present methods iron smelting because their low iron content unsuitable gangue. However, has proved economical with high-grade ores and magnetic concentrates the reduced material requires further work concentration. Ovens Similar Coke Ovens Used The process consists the reduction iron ores iron oxide materials such roll scale, mill scale and magnetic concentrates vertical ovens retorts, com- paratively low temperatures and without fusion, usually contact with materials. The ore should crushed size depending its character, usually not over in. mixed with carbonaceous material and charged into the ovens shown diagrammatically. Here may seen battery reduction ovens, partly section. The charge heated and cooled means horizontal flues, the general construction being similar battery by- *Professor metallurgy, Institute Technology, Cambridge, and consulting engineer and metallurgist. _ Briquettes Reduced and Magnetically Concentrated Sponge Iron product coke ovens. preheated the upper part the oven the waste gases, which leave the stack about 400 deg. Fahr. Then enters the reduction zone where temperatures range from about 1600 2000 deg. Fahr., and after reduction the charge cooled the incoming air for combustion the heating flues, being discharged less than 250 deg. Fahr., usually cool enough Unlimited Amount Heat 1500 2000 Deg. Arrangement the flues may clearly seen from the sectional part the diagram. After reduction, the mate- rial further crushed necessary, magnetically concen- trated and usually briquetted. Two views battery five ovens with daily capacity tons reduced mate- rial are shown illustrations, also some briquettes. One factor leading the success the process the ability apply unlimited amounts heat 1500 2000 deg. Fahr., just where needed for the reduction reaction without affecting the rest the apparatus. Also precise and automatic regulation can employed quantity and duration heat the various zones, more particu- larly the reduction zone. The ovens shown are in. wide, ft. in. high, and ft. long. Standard steel sections and fire brick shapes have been used construc- tion and special materials for good heat interchange be- tween the cooling and heating flues and the charge. For instance, carborundum being used the reduction zone. The special type design leads minimum loss heat radiation. With the 5-oven plant, this esti- mated per cent with temperature 1600 deg. Fahr. the reduction zone. more ovens are added the battery, this loss decreases until, with ovens, would Battery Smith Reduction Ovens, Partly Diagrammatic The Iron Age, April 25, Battery Five Smith Reduction Ovens for Sponge Iron about per cent, after which there would very little further decrease. The cost these ovens, based results with the 5-oven plant, about $3,000 per ton iron produced. Many Kinds Ore Have Been Worked Ores from all the principal ore producing countries have been received, worked and studied this method, but most work has naturally been carried out with Lake Superior ores readily obtainable Detroit. Very good results have been obtained with pyrites residues. Also many kinds carbonaceous materials have been used reducing agents, such charcoal, hardwood waste, coke, coke breeze, anthracite, peat, brown coal, oil shale, tar, and gilsonite which natural pitch. Special materials have been tried, such pressed sugar cane, coffee bean husks, Babassu nuts from Brazil, These nuts were important source supply for charcoal for gas masks during the war. Some Interesting Results Obtained Many interesting results have been obtained. The ovens act gas producers well reducing ovens and one more could used produce gas needed. The gas tank, shown the left one illustration, for the storage the excess gases burned the heating flues. produced before they are The table gives analyses and heating value per cubic foot some the gases. Non-coking and brown coals are very suitable for the process. may necessary prepare coking coals 25, 1929, The Age one more ovens, saving the gases given off and using the coke. Much work has been done with hardwood waste, which sent com- pressed air through pipe from neighboring automobile body plant. This being used soon received, not stored any way, the ligneous gases produced being directly con- sumed. However, sufficient work been done show that the by-products recoverable from such wood waste would great value, including acetic acid for making lacquers, and present 1470 lb. such wood waste are being used for each ton per cent iron ore; charcoal used, 460 lb. are employed. Reduction 100 Per Cent iron oxides metal 100 per cent. interesting feature that, time given, the reduced iron will absorb carbon. The amount carbon taken can controlled about 1.8 per cent. This will importance the reduced material subsequently remelted into steel pig iron. few operating results may given. per cent magnetite, the reduced material showed tion the iron with per cent total iron After separation and preparation showed “%S per cent iron. Mahoning hematite ore with per cent iron showed per cent after reduction and final result per cent. Imperial, Lake Superior hematite with per cent iron, showed per cent after reduction and final result per cent. Roasted pyrites “blue with per cent iron showed per cent after re- duction and after concentration per cent. Also this last material showed final sul- phur of only 0.08 per cent. Many Uses for Sponge Iron the field application the process, sponge iron has found use pre- cipitating agent the metallurgy copper, lead and sil- ver. Such applications and others are covered Bul- letin No. 270 the Bureau Mines, 1927, “Sponge Iron.” The Smith process provides commercial practical method for the making sponge iron either large small scale from many raw materials and with the use different heating agents. The gas produced the process can burned the heating Fuel oil being used with great success. Producer gas, coke-oven gas, other available gaseous fuels can employed. Electric heating coils have been successfully used and, electricity available, installation would excellent for balancing the power load. The radiation loss being low, the furnaces could maintained little cost below working temperature until off-peak power was available. Better Iron and Steel Claimed Possible mentioned earlier, one incentive for the develop- ment the Smith process was the need for better iron Reduction Materials and Percentage Gases Obtained Material Wood waste.... 40.0 14.0 41.6 2.8 0.6 277 58.4 5.2 19.9 1.1 0.2 12.0 3.2 280 Brown coal.... .. 835 67.2 25.2 7.0 0.4 0.2 253 21.6 14.6 31.8 7.8 0.2 21.0 1.8 263 1.0 22.6 40.0 18.0 10.0 758 Sugar cane.... 19.2 19.0 28.2 11.4 ced 1.4 18.8 2.0 280 Babassu nuts... 22.4 7.6 16.8 2.4 481 and steel. High-grade magnetite concentrates and other ores can reduced this proc- ess and the product used full part raw material for making high-grade steels and iron. Such practice being followed increasing extent the use imported Swe- dish sponge iron with claims made re- sultant improved final steel. Makers tool steels and high-grade alloy steels could install this relatively low cost equipment, using pure magnetite concentrates other good ores and supply part all their raw material. There would seem particular virtue Swe- dish ores compared with similar ores here other parts the world. Direct Assistance the Blast Furnace the large tonnage iron and steel indus- try, this process may looked upon direct assistance the blast furnace. pro- vides desired high-grade product sup- plement the present pig iron with less ini- tial plant cost and much less heat consump- tion and loss than the modern blast furnace. One striking fact that economical small units and may very properly in- stalled plants, countries and locations where blast furnace plant could not con- sidered. also seen great assistance the present steel industry immediate method producing good and high-grade raw material. would remove the necessity smelting fine ores the blast furnace where notably better operating results are obtained using coarse materials. The process has been protected patents over countries, two the United States patents being Nos. 1,692,587 and 1,692,588, Nov. 20, 1928. While publicity has been given, has been freely shown technical men and engineers this country, many coun- tries Europe, South America and Japan. backed very large financial resources and full engineering, technical and consulting staff the University Detroit and 1601 Frederick Street, Detroit. Finally, the intention Mr. Smith and the General Reduction Corporation exercise every effort the application these ovens and processes that will bring about economical production and improved quality reduced iron, cast iron and steel. Zinc Dust Cyanidation Zinc dust now generally used precipitate precious metals from the mill solution. well known that zinc enters the cyanide solution direct proportion the metals precipitated. Experiments conducted the Rare and Precious Metals Experiment Station the United States Bureau Mines, cooperation with the Univer- sity Nevada, Reno, Nev., indicate the importance avoiding the use any considerable excess zinc over that needed precipitate the metals from the cyanide solution, because the dust quite readily soluble the usual mill cyanide solution. large excess 2.9 lb. clean cynadide solution room temperature, approx- imately per cent dissolved hr., per cent hr., per cent hr., and per cent hr. Presence lime retards the action, but complete dissolution the zinc effected hr. the presence lb. lime per ton. Increased strength cyanide solution increased temperature solution hastens the dissolution zinc dust. The accumulation mill General View Battery Five Smith Reduction Ovens solutions adversely affects the extraction the precious metals, particularly silver. This quite noticeable when the content 0.1 per cent, and shows serious loss before the content equals 0.5 per cent. New Lining for Electric Furnace Hewitt, chief metallurgist Edgar Allen Co., Ltd., says that most important development high- frequency furnace work (as applied steel melting) new lining replace the plumbago crucible. “The bottom the furnace body packed usual with insulating material. Inside the inductor coil placed insulating sleeve. Now mild steel former made mild steel sheet, the shape the crucible that required, placed the center the coil that an- nular ring about in. left between the former and the insulating sleeve. This filled with silica grains, which least per cent the quartz has been inverted tridymite prolonged burning, and per cent boric acid. “This mixture tightly packed round the steel former and then small current put through the coil. the former becomes heated the current increased gradually until the melting point the steel reached. then runs down into the bottom and leaves fritted lining. “In this type container average heats can melted. Its initial cost not more than that plumbago crucible and the weight steel that can melted considerably more.” The Iron Age, April 25, 1929—1145 | 4 andling Materials the Foundry Best Way Transport Molds—Continuous Systems Reduce Amount New Sand—Anti-Friction Conveyors Discussed Foundrymen’s Convention AYS and means transporting materials foundry were described and their benefits analyzed the materials handling session the thirty-third annual convention the American Foundrymen’s Association, April 11, Chicago. “Mold Handling” was the theme paper prepared Heisserman, Link-Belt Co., Philadelphia, and read the author’s absence Hartley, Chicago. The presentation and discussion this paper formed the first half the program, the second half consisting exhaustive treatise “Materials Handling Gray Iron Albert Walton, consulting engineer, Philadelphia. The good attendance the meeting attested the interest that foundrymen are taking such prob- lems. How Molds Should Handled working conjunction with mold conveyors get the full benefits the latter, almost impossible determine the exact savings attributable mold con- veyors, declared Mr. Heisserman. However, there are number factors resulting from combination sand and mold-handling equipment continuous pour- ing gray and malleable iron foundry which contribute production economies. Continuous operation means steady flow materials and products and better service on rush orders. Castings can inspected min. after molds are made, stated the author, whereas under the old system imperfect castings, due poor sand, patterns, metal, are not discovered until day’s production poured. also possible standardize more flask equipment, larger volume sand some flasks will not affect molding costs. Moreover, reduction per cent the number flasks obtained, the volume production molds the same time being increased. The molders’ efficiency improved from per cent materials handling equipment. Night Shifts Can Done Away With Elimination night shifts saves from $100 $150 per night, asserted Mr. Heisserman, who said that complete continuous unit requires less than per cent the floor space floor type foundry and has double the capacity. Continually performing one operation, the workmen become specialists and large part the work, formerly done them, can done common laborers. Furthermore, there less tendency break mold placing mold conveyor than when the molder out and sets the floor. The author pointed out that continuous pouring re- quires minimum number men working the entire day the pouring gang, does away with the extra labor required when large volume metal poured comparatively short time. Another factor contributing economy the delivery castings one point the conveying unit. The continuous system reduces substantially the amount new sand which 1146—April 25, 1929, The Iron Age must purchased. addition, continuous operation tends speed production. Conveying Systems Mean Savings Any type foundry that has increased its volume business warrant new buildings can make three-fold saving the introduction conveying system its old buildings, said Mr. Heisserman. The first saving comes from the advantages continuous semi-continuous production. The second accrues from the fact that sand and mold handling equipment costs less than half the amount required for erection new buildings. The third saving results from curtailment floor space which makes possible sufficient room accom- modate the extra core and cleaning room requirements. Mr. Heisserman outlined the history and development power mold conveyors. Among recent installations cited conveyor for handling molds 500 600 lb. over great distance with low power consumption. This conveyor known the “anti-friction” type, because the liberal use high-grade tapered roller bearings. The tracks the conveyor are attached the under side the trays, making impossible for metal sand fall them for, besides being inverted, they are always under the tray. The chain likewise protected its position under the inside edge the tray. The inverted tracks ride large-diameter rollers, having pressure lubricating attachments for the roller bearings which they revolve. The trays completely cover the rollers, they are overlapping, making con- tinuous moving platform, and the rollers are thus pro- tected from sand and iron. Production Increased 400 Per Cent Discussing the points brought out Mr. Heisserman’s paper, Linabury, Oakland Motor Car Co., Pontiac, Mich., stated that one the General Motors foundries production has been increased 400 per cent and floor space reduced per cent the adoption new methods, including installation materials handling equipment. emphasized that full advantages mechanical trans- portation are not gained unless the entire problem instead only that conveying molds considered. Care must exercised picking out the right conveyor for the right job. Ohio Foundries, Inc., Cleveland, remarked that the main development materials handling the foundry must small foundries. added that in- stallation new equipment old buildings not always possible, even though might desirable. Referring Mr. Heisserman’s description conveyor capable handling molds weighing 300 Russell Scott, Packard Motor Car Co., Detroit, said that his company’s gray iron foundry handling molds 3600 lb. similar conveyor. The day the sliding conveyor passing, according who stated that the tendency toward reduction power and wear. Protection equipment and the materials | ‘ beneath the equipment, safety the workmen and the reduction wear are primary considerations design- ing materials handling devices. Present-day production methods are forcing the smaller operators, especially the non-ferrous field, into adopting these comparatively new practices. Mr. McKinnon declared that the current tendency toward making the entire manufacturing system, from the pattern the finished casting, con- tinuous process. discussing the question determining responsibility for defective castings, Russell Scott said that, the Packard foundry, the entire group workmen penalized, even though the fault traced one man. advan- tage the continuous conveyor for carrying molds, stated Mr. Hartley, lies the fact that designed have from per cent excess capacity and have variation speed, these two factors giving the conveyor flexibility which prevents tieups case interruption regular schedules. Hill, Jr., Palmer-Bee Co., Detroit, written comment, described pendulum trolley type mold conveyor which comparatively inexpensive. also referred improved design the tray type conveyor. How Handle Materials for Gray his paper “Materials Handling Gray Iron Foundries,” Mr. Walton said that the modern foundry should have handling facilities for the following opera- tions: Unloading raw materials. Stocking them yards and bins. Rehandling from yards and bins cupola charging floor and cupola. Rehandling from yards and bins molding and core rooms, Receiving and storing, suitable stock rooms, necessary materials and supplies, repair parts, re- quired conducting operations, and not stored bulk yards and bins. Necessary facilities for withdrawing such store rooms, and delivering the place which needed, the various commodities kept therein. Handling molds from molder pouring floor suitable conveying tables, etc. Handling molten metal molding and pouring floors. Handling molding and core sand their respec- tive floors. 10. Shakeout flasks and removal castings, scrap and sand, 11. Delivery castings cleaning room and tum- bling barrels and sand blast machinery, etc. 12. Removal castings from cleaning room in- spection and manufacturing and shipping departments. 13. Removal dust from cleaning rooms and from tumbling barrels and sand blast equipment. 14. Conveying foundry sand sand removing and bonding equipment, and subsequent delivery foundry molding sand hoppers and bins. 15. Handling flasks from storage foundry and return. 16. Handling patterns from storage foundry and return. 17. Handling cores from core room foundry. Cost Factors Considered the installation labor-saving equipment for handling purposes, Mr. Walton said that the following factors relating costs must considered: Present labor cost doing work over reasonable period time. One month would fair average when foundry running output. Maintenance, repair and other overhead expenses for present equipment. Cost present method handling materials which will affected improved mechanical devices. Estimated cost new equipment, Maintenance and repair new equipment, includ- ing fair charge for depreciation and for other general expenses. Labor cost operating new equipment for same time and under same conditions old equipment. Total cost proposed method handling. Salvage value, any, equipment discarded Saving effected adoption new plan. The author described various foundry uses for lifting magnets, the prime advantage inside the foundry being the elimination the labor necessary place sling chains around loads and the time necessary this, especially heavy work. Magnets can with weight lifting capacities from few hundred high 65,000 Such installation will replace men. The saving one man foundry opera- tion can set approximately $1,300 $2,600 year. This based average wage rate 40c. for laborer and 75c. for skilled man. Savings Due Tractor Trucks The value using portable cranes with single-line grab bucket was emphasized Mr. Walton. With well laid concrete floors around yards and the foundry, large amount work can done with tractor crane that for some classes jobs preferable the use overhead traveling crane. old-style foundries, the tractor crane invaluable. cited savings detail from using tractor trucks. For foundries having low head room and for others where molders’ floors are located irregular areas instead straight-away runs, and also where the work light weight, often preferable use monorails tramrails for handling materials, stated Mr. Walton. Such equipment, when properly placed, will reduce labor costs least per cent. Charging Cupolas Mechanically Means Savings Mechanical means charging cupolas and un- loading raw materials were described Mr. Walton, who cited the following examples economies realized certain foundries: Charging 84-in. cupola with 147 gross tons metal per day and with coke and limestone total cost $17.86 per day, 121/7c. per ton charged. 9 Making and charging 175 tons per day, one man charging floor, one elevator, one transfer car and four yard making charges, total for labor seven per day per ton handled. conveyor table mechanism desirable see that slides and other wearing surfaces are made high- test iron, with the most efficient wearing factors. case space limitations, often problem locate the cleaning room properly. one foundry, described Mr. Walton, cleaning room was dug beneath the foundry floor and sand reclaiming equipment also was placed the basement. Equipment Should Standardized Mr. Walton recommended that foundrymen stand- ardize their materials handling equipment much possible. The benefits derived from standardization often are worth far excess the few dollars saved buying little cheaper. urged daily inspection equip- ment. Natural Molding Sand Soon Obsolete Economies derived from the mechanical handling sand were described Mr. Walton. Sand costs can reduced from per cent properly designed and installed sand-preparing and bonding units. “Much has been written this sand renewing proposition, but The Iron Age, April 25, longer experiment. Its adoption any fair- sized foundry decided economy and within the next few years this method will standardized, both for grain size and percentage bonding material and other factors, that natural molding sands will tend become obsolete and too costly find market. One the largest molding sand producers the eastern States possessing this vision well the way developing method bonding silica sand for molding purposes and manner that will meet specifications consistently all shipments from his shipping point.” means the least important foundry handling problems the elimination dust from tumbling barrels, grinders, sand blast apparatus and the atmos- phere the foundry general, said the author. Benefits Mechanical Handling discussing the benefits handling materials mechanically, Mr. Walton said: you can reduce your payroll for handling men, you cut your payroll approximately $12,000 per year, that per cent investment $200,000, and such reduction gives you ample opportunity modern equipment reasonable cost. Also remember, that doing you are going improve conditions throughout your entire plant. Simplicity and ease handling heavy flasks, pouring metal and subsequently cleaning the foundry floors, will re- entrée the American field electrical equipment manufacture few years ago the formation the American Brown- Boveri Electrical Corporation lends interest the accompanying views the parent plant Baden, and Boveri, young engineers who had the im- agination see that the electrical industry offered great opportunities, the Brown-Boveri works Baden has grown one the largest mechanical plants Branch plants have been established Miichenstein Switzerland (formerly the Alioth Electrical Works); Mannheim, Germany; Bourget, Havre and Lyons, France; Milan, Italy; Oslo, Norway; Vienna, Austria; Budapest, Hungary; Zychlin, Poland; Drasow, Czechslovakia, addi- tion the American works which the Brown- Boveri Co. Switzerland has large interest. The combined European plants employ 40,000 men. All The illustration the Europe. plants use identical designs. right the Baden works. 1148—April 25, 1929, The Age NSTANCES arise where the American Brown-Boveri Elec- trical Corporation draws upon the Baden plant for equipment. Such was the case filling order for large electrical gen- erating unit for the Hell Gate station, New York. One 160,- 000-kw. units was built the Brown-Boveri works Baden and the other was furnished the Westinghouse Electric Mfg. Co. The view the left shows the erecting shop the Baden works, with the Hell Gate high-pressure turbine and turbo-generator for Edinburgh, ing anufacturing J | ay! flected in a better satisfied body of workmen, both skilled and unskilled, and this again reduced costs. fact, our visits scores foundries have often heard serious criticisms certain other foundries, be- cause they took business less than cost the other fel- low, and more than once have had opportunity later find that the low-priced foundryman was making monev because had saved his various handling operations. Views Various Foundrymen the discussion which followed, Hough, Mathews Conveyor Co., Ellwood City, Pa., stated that wooden bottom boards connection with gravity roller conveyors are preferable metallic handling molds 100 Another speaker declared that runouts are more damaging wooden bottom boards than metal, but the latter are heavier handle. Mr. Linabury stated that the disposal waste material often serious matter and cited the fact that one foundry refuse sand put concrete pit and mixed with water, sand sucker then being used carry the sand low land nearby, where deposited. Hill, Jr., suggested that several additions might well made Mr. Walton’s list operations handling materials the modern gray iron foundry. Operation No. 11, which included delivery castings cleaning room, tumbling barrels and sand blast Machinery Switzerland phase transformers coupled together had been used for this purpose. 3-phase transformers, each 65,000 kva., for plant Italy. Higher temperatures and pressure turbine work Practically all the materials used the Baden works are imported. Steel forgings, for example, come from Witkowitz, Moravia. its transformer department, shown the right, the Brown- Boveri Co. has undertaken the building three 36,000 kva. 3-phase units for 252,000 volts the high tension and 11,000 volts the low tension side. These are thought the transformers for 250 kva. short time ago three single- | inents the company’s engineers. boilers have been designed and built connection with the experiments that have been made. development combined heating and power produc- tion, the Brown-Boveri Co. states that the cost Work has also been begun two High-pressure the high-pressure steam plants very little more than that low-pressure plants. and the steam high pressure first expanded primary turbine before being used again for heat- ing the boiler feed water and, eventually, stand- ard low-pressure turbine. (about $7.70) per ton Switzerland one kilowatt- hour can produced, said, for fuel cost 0.6 centimes. There condenser With coal francs The Age, April 25, 1929—1149 | | = gte f j machinery, might broadened adding the cooling castings during the period travel from shakeout tumbling mills. the system applied several automobile foundries, the castings are picked the shakeout, either singly perforated buckets con- tainers, overhead trolley conveyor. The conveyor designed leave the foundry building proper, traveling underneath cooling shed which permits the castings exposed the air much possible. The course travel can long required cool the castings the desired temperature for handling. Castings with large quantity coarse sand are con- veyed the knockout building, where the coarse sand removed and recovered, together with wires, gaggers, ete. Castings then are sent the cleaning room, where they are unloaded section the gravity conveyor located front the tumbling mills. Operation No. 18, suggested Mr. Hill, consists handling cores through the core ovens. The use continuous core ovens recent years has cut core room costs considerably and has increased production the same floor space. These ovens also have eliminated ex- pensive lift trucks and core racks and have reduced breakage cores from rough handling. Cores are better baked because proper baking time and because continuous movement through the ovens. They are re- ceived the discharge end the oven temperature which permits their being handled. Conveyors covering this type work may extended past the confines the ovens, serving the core makers manner that cuts down unnecessary motions loading cores. feature the system the sloping the conveyors they pass along the line core makers, permitting top and bottom shelves loaded with equal ease. Pump Shaft Hardened With Nitrogen Detroit Automobile Manufacturer Finds New Case Hardening Process Can Replace Stainless Steel Part ITRIDING special alloy steel for automobile parts has been started production basis one the leading Detroit motor car manufacturers. Sev- eral other automobile makers Detroit and elsewhere are experimenting this direction, and Cleveland manu- facturer gas-engine valves for automobiles and air- planes has installed furnace preparatory getting production basis. The part nitrided quantities the Detroit automobile manufacturer first mentioned water pump shaft, used models brought out later the year. This shaft heretofore has been made stainless steel with per cent chromium. grade Nitralloy* now being used having the following chem- ical analysis: carbon 0.36 per cent, manganese 0.51 per cent, silicon 0.27 per cent, aluminum 1.23 per cent, chro- mium 1.49 per cent, sulphur 0.010 per cent, phosphorus 0.013 per cent, molybdenum 0.18 per cent. The shafts are made bar stock in. long and 41/64 in. diameter, and nitrided “Homo” electric furnace (Leeds Northrup Co.) remodeled for this work. regularly designed, hot air this furnace through the parts being heat treated fan the bottom. the new process liters ammonia taken per hour the top the furnace and forced through place the hot air, the heat being conveyed the gas. used for nitriding the furnace provided with air jacket around the outside through which compressed air forced cool the work nitriding. There also oil seal the top the furnace pre- vent the escape gas. operation, while important have the proper gas supply (and the ammonia introduced meas- ured rate), the gas pressure not important factor. certain amount the ammonia bleeds off and goes into exhaust. The chemical reactions the hot furnace are such that the gas breaks down into hydrogen and nitro- gen, the latter being absorbed the steel, and the hydro- gen continues circulation with surplus ammonia until exhausts through the vents. For checking the rate reaction, the escaping gas passed through pipette, where the ammonia absorbed water, leaving volume *Nitralloy is the trade name of steels of special analysis used for nitrogen hardening by methods patented by Krupp (German). 1150—April 25, 1929, The Iron Age hydrogen read directly the graduated pipette. the pipette shows excess amount hydrogen, the input fresh ammonia gas increased. The furnace fille