The Iron Age 1943-06-03: Vol 151 Iss 22

roo JUN 9 1943 ‘rub your desk . . ia ane H Se | ! | | ji f \ NEW DEPARTURE BALL BEARINGS | Pit Covers Bea ae yi ~ < ( . Stripper | Soaking Pit Cranes Cranes ... on Modern Soaking Pits and Blooming Mills With your urgent need to make every production minute count, you appreciate more than ever the quiet, dependable performance of the sturdy Cleveland Units that are driving your present Soaking Pit and Blooming Mill equip- ment. Doubtless you are specifying Clevelands for new machines as well. For 25 years you have been installing Cleveland Worm Gear Speed Reducers successfully on your toughest jobs, knowing they will take punishment in their stride and come up smiling. Clevelands stand the gaff—require but nominal maintenance—with no parts replacements for years on end. The Cleveland Worm & Gear Company «+ 3252 East 80th Street, Cleveland, Ohio Affiliate: The Farval Corporation, Centralized Systems of Lubrication In Canada: PEACOCK BROTHERS LIMITED afb _ ed ne THE IRON AGE, published every Thursday by the CHILTON CO. (INC.). Entered as second class matter November 8, 1932, at the Post Office # Philadelphia under act of March 3, 1879. $8 yearly in North America and South America, Foreign $15. Vol. 151, No. 22 —_—" Office a J. H. VAN DEVENTER President and Editor Cc. S. BAUR Vice-President & General Manager ° ° ° - Editorial and Advertising Offices 1 fast 42nd St., New York 17, N. Y., "6. 1. Johnson, Market Research Mg B. H. Hoyes, Production Manag R. —. Baur, Typography and Layo ° ° ° Regional Business Managers “©. H. OBER H. E. LEONA ‘New York |7 New York 17 — East 42nd St. 100 East 42nd St, B T F. BLAIR W. S. FITZGER sleveland 1/4 Pittsburgh 22 Guardian Bldg. 428 Park Bidg. -L. HERMAN H. K. 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This Week in The IRON AGE Vol. 151, No. 22 Editorial Nameless Children Technical Articles June 3, 1943 43 Magnesite Refractories, Manufacturing and Applications(1) 46 Plant Layout for Aircraft Mass Production Use of Rolled Zinc and Zinc Alloys World’s Most Modern Brass Plant Bridgeport Ordnance Plant Description Phosphate and Oxide Treatments for Steel Standard Carbide Tips for Special Tools Super-Hard Rivets for Aircraft New Equipment — Plant Service Apparatus Features News Front Assembly Line Washington West Coast Fatigue Cracks Dear Editor News and Markets This Industrial Week Ingot and Pig Iron Weekly Production Data Steel Trends Appraised at Institute Meeting Small Firms Get 45 Per Cent of Contracts Drastic Changes at War’s End Unlikely Powder Metallurgy Center Has No Fears Time Cycle for Aircraft Steel Charted The CMP Fact Finder Warehouse Price Zones Are Set Personals and Obituaries Machine Tool News Non-Ferrous Metals News and Developments Non-Ferrous Metals Prices; Scrap Prices Iron and Steel Scrap News and Prices Comparison of Prices, by Year Finished Iron and Steel Prices NE Steel and Warehouse Prices Stainless Steel, Tool Steel Prices Semi-Finished Iron and Steel Prices Pig Iron Prices Ore and Coke Prices Ferroalloy Prices Index to Advertisers 52 55 58 61 63 65 70 74 78 82 $4 145 146 148 150 151 152 154 155 156 156 157 160 161 162 e Many skills and complete modern equipment for testing, cutting, forming, handling, shipping — all combine in Ryerson Steelmanship. All are devoted to the single purpose of this vast highly specialized steel warehouse system. All contribute to the job of getting the steel you want — in the quality, form, size and place exactly when you want it. « True, there 42—THE IRON AGE, June 3, 1943 ed Many Skills Combine in Ryerson Steelmanship are our war problems of shortage here and there, but most generally Ryerson Steel- Servicemen can take care of you. ¢ Whether it is a question of selection, fabrication or just quick delivery—call Ryerson first. Joseph T. Ryerson & Son, Inc. Plants at: Chicago, Milwaukee, St. Louis, Cincinnati, Detroit, Cleveland, Buffalo, Philadelphia, Boston, Jersey City. 20M Fle g ESTABLISHED 1855 J. H VAN DEVENTER President and Editor Cc. S$. BAUR nt and General Mana A. H. DIX pMonoger, Reader Service ° ° ° ging Editor.......T. W. LIPPEREE arkets Editor...D. R. JAME P iiditer..3...... F. J. OLIV OF... J. WINTERS ° ° ° Associate Editors D. C. MacDONALD S. H. BARMASEL Be J. lt. BUTZNER a R. E. BENEDETTO > 2 X e: Editorial Assistants “si : M. M. SCHIEN ; G. B. WILLIAMS = G. P. BUTTERS® “s anal News and Technical Ed ors T. C. CAMPBELL Pittsburgh 22 428 Park Bldg. W. A. PHAIR Chicago 3 1012 Otis Bldg. L. W. MOFFETT Washington 4 National Press Bidg. J. D. BROWNE Washington 4 National Press Bldg. T. E. LLOYD Cleveland 14 1016 Guardian Bldg. S. H. BRAMS Detroit 2 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 3 1355 Market St. Editorial Correspondents ROBERT McINTOSH Cincinnati C. M. PENLEY Buffalo G. FRAZAR Boston HUGH SHARP Milwaukee F. SANDERSON Toronto, Ont. R. RAYMOND KAY oo Los Angeles “JOHN C. McCUNE Birmingham ‘ i. “ROY M. EDMONDS : ~ Ste Louis Nameless Children fa NDING cattle so as to indicate ownership is a well recognized and appreved method of protecting property rights. The owner of a herd selects his brand which becomes, so to speak, his trade mark. Out in the big open spaces where men are men and cattle the principal product, any one who obliterates'a brand is considered a criminal and treated accordingly. In the past, when crime was not as highly regarded or as softly treated as it is today, shooting or hanging were considered suitable punishments. One can well understand that attitude on the part of the cattlemen. They risked their lives, not to speak of their money, faced the hazards and hardships incident to exposure to extremes of heat and cold and gave all that they had to building up their business of beef on the hoof. And all that they had to protect what they had so painfully built were their brands. I presume that cattle rustlers may have had an organization or trade association and perhaps a lobbyist or two to protect their interests. If so, they may well have considered how beneficial it would be to them if a law could be passed making it illegal to brand cattle. They would hardly have the effrontery to ask that cattle stealing be eliminated from the criminal codes, but the elimination of brands would do just as well because it would completely abolish the identity of the product. Under such circumstances it would be a simple matter for a strong arm man with political protection to take over in a matter of hours or days what had cost another man years or even a lifetime of honest work to build. Silly even to think of such an absurd proposal, isn’t it? Free men in a free country would not stand for anything like that. But that is exactly what an important and powerful group of economic recon- structors are proposing to do in connection with brands applied to products — net to cattle on the hoof, but to beef and other foods in the can, to stockings, to shoes and a multitude of other products. The effect on property rights and the destruction of lifetimes of work of both men and money would be exactly the same as it would be in the case of the elimination of cattle brands. But beyond this, the effect on quality of product would be deplorable. No manufacturer can afford to put a brand or a trade name on an inferior product. Anonymity is the only cloak under which the “just as good” product can be handled and sold. A brand name on a product is the best possible protection for the consumer because it automatically forces the maker of that product to maintain quality. We have a word in this language, and it is not a pretty one, that we apply to nameless children. Do we want this same term applied to the products of America’s farms and factories? Ae | 1 1 i i 1] it re How to Cut Replacement Costs and Send More Steel to War Regular inspections, adequate painting, and fre- quent lubrication, will cut replacement costs and save steel that is vitally needed in every quarter of the globe by America and her Allies. Initiate, today, a special wartime inspection service. Examine roofs, siding, and structural members of buildings—especially where atmos- pheric conditions, or process fumes, result in destructive corrosion. Clean and paint steel that shows signs of deterioration. Consult a reliable paint manufacturer if standard paints do not prove satisfactory. Many types of manufacturing equipment—trucks, cranes, and the like—operate in and out of doors. \ 38 S. Dearborn Street, Chicago Sales Offices: Milwaukee, Detroit, St. Paul Such equipment should not only be painted, but moving parts should be adequately lubricated to save the steel that otherwise would be needed for replacement of parts. The moving parts of all types of machinery should be regularly inspected to make certain that operators are applying lubricating oils and greases of the correct qualities, and in the right quantities. If undue wear of moving parts continues, ask a lubricant manufacturer for advice. Take better care of the steel now serving you. Less steel used for replacement means more steel for the fighting fronts. 4 _ St. Louis, Kansas Cit) _—o News Front Despite current surplus of both pig iron and scrap on the Pacific Coast, Pacific Northwest again is putting on the heat for a blast furnace. proposed location is Everett, Wash. plans are to ship the pig iron east. terrific political pressure the The latest Brassert has submitted a furnace design and WPB again may be unable to withstand the , just as in the case of the: Texas facilities. Captured German armor—-piercing shot recently showed an alloy steel nose flash welded to a tough carbon steel body. American Ordnance officials have taken note. shifting their small Jelenco (dental inlay) centrifugal casting machines over to war production. Many brass, copper, bombsight parts, New York gold jewelry uanafeoturees in the throes of severe curtailment are aluminum, and even steel instrument and and numerous other intricate small shapes are now being turned out. Far heavier orders are in prospect. A promising tin mining scheme for South Dakota has been unable to secure Government money. So, two months. with private backing, production will be initiated within Magnesium supply is a little easier, and the Signal Corps will soon advise considerable replacement of aluminum by magnesium in much aircraft and portable radio equipment. Biggest problem for Ford Motor Co. posed by Edsel Ford's death is to find an equally sales and style conscious administrator. Ford top management, comprising candidates for the succession, is heavy on the manufacturing end; Edsel is credited with having kept a finger on the public pulse. a poor solution may mean twilight of the company. The problem is so serious Current alloy steel consumption exceeds production by over 10 per cent in the Chicago and Detroit districts, and production exceeds consumption by about 15 per cent in the Pittsburgh district and 10 per cent in the Canton district. mately half of WPB's alloy expansion program has been in two plants, Chicago and one in Warren, Ohio. Approxi- one in Retribution: Only a year and a half ago the most populaf marching song in Germany was, "Bomben uber London". British estimate that post-war exports will have to exceed pre-war totals by 40 to 50 per cent, if pre-war standards of living are to be maintained and if the various plans for social security are to be more than idle dreams. Reports on export of scrap are exaggerated. Mexico is getting a small amount (shredded tin cans that used to go to Japan) for copper precipitation plants along the border, Canada a little for steel making. Vermiculite, used in a new process of porcelain enameling developed by a South African firm, gives a variety of pastel shades with a metallic finish. Switchgear & Cowans, Ltd. , England, recently offered to pay a workman $2500 a year to keep away from the vine because he was a troublemaker. So far the courts haven't decided whether the offer can be accepted. THE IRON AGE, June 3, 1943—45 fs | a ar] coe |i * “a |i ea a aA ¥ te i s p 2m 1 4 3 “a 4 a f 1 5 = |i ic: Sk i ie aa a Ss Sa eos ra eee See ¥ 2 ee Bh ot + Bi inh aati os? i he ee Magnesite Refractories ot sin peculiar distribution of magnesium minerals throughout the earth’s crust and in particu- lar the fact that two of the main sources, Austria and Manchuria, are under Axis control, make magnesia the most “political” of all refracto- ries. The problem thus presented to the United Nations has been answered in a way that until recently would have seemed quite fantastic. The magnesia has been extracted from sea water. Its presence as magnesium chloride and sulphate in concentration, second only to that of salt, had long been known, but it was only comparatively recently that it was shown, for exam- ple, by Marine Chemical Co. of Cali- fornia, that use could be made of the extremely low solubility of magnesium hydroxide to extract magnesia from sea water by a chemical precipitation process. The obvious method, concen- tration by evaporation and subsequent separation of magnesium salts, would normally be quite uneconomic due to the enormous amounts of fuel re- quired. Where the salts occur natu- rally in greater concentration, as in magnesium-rich brines, or where solar evaporation is feasible, such methods might be economic, but in Great Brit- ain the cost would be prohibitive. The other factor that has made the extrac- tion of magnesia from sea water a practical proposition, is the discovery by Chesny that slaked dolomite could be used as the precipitating agent in- stead of slaked lime. As the simple formula for this re- action shows: Cota.) MgCl, + + ( Mgs0O,) Ca(OH), slaked ex dolomite sea-water the process performs the double feat of obtaining the magnesia simultane- ously from the sea water and the dol- 46—THE IRON AGE, June 3, 1943 = 2 Mg(OH). + By J. H. CHESTERS Central Research Department, United Steel Companies, Ltd., Stocksbridge, England Previous articles by J. H. Chesters, on steel plant re- fractories, that have ap- peared in The Iron Age are: “All-Basic Open Hearth Fur- naces,” Aug. 15 and 22, 1940. “Steel Plant Refractories,” Feb. 6 and 13, 1941. “Basic Open Hearth Above Sill Plate Level,’ May 22 and 29, 1941. “Basic Openhearth,”’ Aug. 7, 14 and 21, 1941. “Casting Pit Refractories,” Nov. 20 and 27, 1941. “Electric Steel Plant Refrac- tories,” March 5 and 12, 1942. “Acid Open-Hearth Refrac- tories,” May 28 and June 4, 1942. “Soaking Pit and Reheating Furnace Refractories,” July 16 and 23, 1942. “Acid and Basic Bessemer Refractories,” Nov. 5 and 12, 1942. “Silica and Semi-Silica Re- fractories,” Jan. 21 and 28, 1943. and time have been spent in trying to extract mag- nesia from dolomite and it is indeed strange that the answer to the prob- lem should come with the use of so cheap a raw material as sea-water. It was thought at first that even if magnesia were obtainable in this way, it might lack the qualities necessary Much money omite. CaCl, (CaSO,) soluble in this dilution insoluble for the manufacture of a good mag- nesite brick. Thus pure sand, though higher in refractoriness than the aver- age silica brick, is a poor material from which to manufacture this re- fractory. Three days’ work sufficed to show not only that the material could be readily dead-burned but that brick made from it were similar in properties to Austrian magnesite brick, and possessed in addition one remarkable advantage, namely a high thermal shock resistance. Magnesium hydroxide, known min- eralogically as brucite, is also obtain- ed in considerable quantities from the earth. Thus in Canada (Ontario and Quebec) useful deposits have been found which on concentration provide an economic source of magnesia, while considerable supplies are also being obtained from Nevada. These sources together with the available carbonate rocks of India, and of the State of Washington, provide Great Britain and America with the magnesite re- quired for magnesium metal produc- tion, for the manufacture of mag- nesite and chrome magnesite brick. Magnesia Although quite complex in its be- havior as a refractory, magnesia is fundamentally the simplest of all the materials used in furnace construce- tion. Fig. 1 shows a large crystal of magnesia over one inch in length and perfectly transparent, which was ac- cidentally produced by the Norton Co. as a result of prolonged heating in an electric furnace. Its perfection is such that it might be taken for a glass model, were it not for the obvious cubic cleavage on some of the faces. Apart from slight flaws it can be con- sidered as a single crystal and indeed as a multiplication of the simple lat- tice structure shown in Fig. 2. This structure is similar to that of common salt (NaCl) except that the “black” atoms, instead of being sodium, are magnesium, while the “white” atoms, instead of being chlorine, are oxygen. The charge on these atoms (or 10ns) is double that of the ions in sodium chloride and the electrical forces holding the structure together are therefore much greater. This shows gai pre Bin bel itse ing vib ato for cub onl anc in nes bet ifie. ing the oce Del for tio! anc Th me ene spe ma ma for wh lar gar cal Th usu by the ple rie mil ma dis jee wh ex} ma on ga’ Continuing his series on steel plant refractories the author investi- gates, in the first of two articles, sources of refractory magnesite, . properties and the influence on these properties of firing treatment. Binary and ternary magnesia systems are also discussed and their behavior considered. AAA 1 itself in the high refractoriness, melt- trian magnesite containing some 8 CaO-Mg0O-Al,0, and no silica, are rare- id ing only occurring when the thermal _ per cent of iron gives a value of about ly found, but the system is of interest j vibrations are sufficient to carry the 3.65, and since an addition of iron i” that it has been found possible to i] atoms beyond the control of these oxide is found to raise the specific employ the eutectic, which een t forces. The actual length of the unit gravity by about 0.01 for each 1 per approximately equal amounts of time n cubic edge is 4.20 A units. This is the ¢ent addition, it is probable that the and alumina and only about per cent e only form of magnesia, though it can value of 3.58 is close to the true value of magnesia, as a low melting point fe and does, of course, vary considerably Cita watch exited slag. In contact with the magnesite h in erystal size. The idea that mag- ; lining of an induction furnace this hesia exists in two forms, alpha and MgO-SiO.. slag does comparatively little damage re beta ( comparable with the silica mod- Of the Weare codes wi tar Wal a only small amounts of magnesia | ifications) is no longer held, it hav- ” M 0-Si0, is ees es saat pick-up cause it to freeze. Thus with " ing been proved beyond doubt that ‘“ i ate ee - (eves about 15 per cent MgO the melting ™ the only fundamental change which ee in connection with oa point is already over 2912 deg. F. d occurs during the firing of magnesia a a . — aanereneenss ee: n ¥ eis a eutectic (Fig. 3) at approximately MgO-FeO-Fe.O,. le is the growth of the crystals; the 65 per cent silica, 35 per cent mag- The additi fi eg ‘ le Debye Scherrer patterns are identical neain. whic mélte at aly 2000°der. 7 e oe lon 0 7 oxide to mag- for the material produced by calcina- ee ; 2 . nesia has long been used as a method 3 tion of magnesite at say 1830 deg. F., The most porns! compound ae of promoting sintering and recrystal- _ and the electrically ‘fused product. series is forsterite (2Mg0.Si0.) whic — ae _ —— ee . lhe fundamental structure is of im- has a melting point of 3470 deg. F. naturally whenever the Breunnerite . mediate practical interest because it This is not only used as & refractory type of magnesite is fired. The main - enables an estimate to be made of the but also —s mixed with ae points of interest are that considera- specifie gravity of pure crystalline "®S!® ™ high silica magnesite rie ble amounts of iron oxide can be add- “3 magnesia. ; such as are made from the Norwegian ed to magnesia without any serious B- The density a $ _ raw material. drop in refractoriness, the nature of 1 density of a perfect crystal of the reaction product depending on the magnesia can be calculated from the CaO-MgO-AI.Os. atmosphere of the furnace. Thus, if formula : Refractories containing the oxides the atmosphere is strongly reducing, tM the iron remains in solid solution as e~ = FeO, whereas if it is oxidizing, mag- is e er eee nesio-ferrite (MgO.Fe,0,) tends to a Where p is the density, M the molecu- od nee ~ noe the Bae, c- ler wold of cunmiaind aad 36 dec. cluding these reactions has been very of be a S sho ue IG. | — Magnesia crystal formed by ably studied by Fisk and McCaughey nd gadro’s number. If the value 4.20 is prolonged heating at high tempero- = in their Ohio State University publi- ois assumed for the lattice edge then the tures. dubia a ‘o. calculated density is found to be 3.59. ; an This is considerably lower than the MgO-Ca0-SiO:. 3 usually quoted value of 3.65 first given This system is the basis of com- iSS by Moissan, which is doubtless due to mercial dolomite brick production and us the effect of impurities in their sam- as such will be discussed in a later es. ples together with the difficulty expe- section. In relation to magnesite it n- rienced in making an accurate deter- shows that such minerals _ dicalcium ed mination of the specific gravity of silicate (2Ca0.Si0,) and Wollastonite at- magnesia. The use of water as the (Ca0.Si0.) may be expected _ —_—s" his displacement liquid is open to the ob- nesite brick or clinker containing lime on ae : and silica. With certain magnesites, E jection that hydration may occur . : 1 . : * while if organic liquids are used their ee pe: expansion with temperature increase ae i Aer ae — ms, ts wo gece’ that veel Shane: Sues cium ailiente tends to invert on cooling en. ; below 1247 deg. F. to a dicalcium sili- 1s) may result. cate with a 10 per cent volume ex- um A determination made by the author pansion. The dusting which is associ- ces on the single crystal shown in Fig. 1 ated with this change can be overcome are gave the value of 3.583. Since Aus- by the use of stabilizers such as ws THE IRON AGE, June 3, 1943—47 1G. 2—Atomic structure of magnesia, showing simple cubic arrangement of the magnesium (black) and oxygen (white) atoms. borates or phosphates and must al- ways be guarded against where such compositions are involved. MgO-A { 2O3;-SiO>. Alumina and silica frequently oc- cur in appreciable amounts in mag- nesite and in at least one refractory brick the alumina or clay addition is made intentionally with a view to de- veloping spalling resistance. The point to be noted is that the eutectic in this system has a very low melting point, namely 2453 deg. F. Its com- position, however, is MgO 20.3 per cent, Al.O; 18.3 per cent, Mg, 61.4 per cent and hence it would not be ex- pected as a dominant phase in a mag- nesite-rich material that had attained equilibrium. MgO-FeO-SiO.. All the above mentioned systems may be conveniently referred to in the October, 1933, issue of the Journal of the American Ceramic Society. The ,630 Periclase + liquid 3400 °F 5470°F ° ° ° lu RIGHT _— IS. 3—Behavior 5 under heat of the —_— a ; - i 1 Feric/ase MgO-SiO, system. § + a (Shown in deg. F.) forsterite 7 Cristobalite Niquid : 0 © © 2910 — 2845°F be forsterite| N 2815 - Soe Clinoenstatife 7 | Se ~ 0 20 40 80 100 MgO Per cent Sid, present system is dealt with in the April, 1938, issue. It can be seen from this diagram that whereas FeO and SiO, form very low melting point mixtures (2151 deg. F.) the addition of only about 20 per cent magnesia brings the melting point above 2912 deg. F. The real need is for the working out of the system MgO-CaQ-Al,0,- Fe,0.,-SiO,. Those who have attempted even a preliminary evaluation of a ternary system know how much more difficult this is than a binary system due to the large number of mixtures that must be studied and the complex- ity of the relationships. With a qua- ternary system the additional difficul- ty of representing the data arises since solid models must be used. This being so, nothing short of a refracto- ry Einstein would be required to pic- ture the reactions involved in a quin- ternary system such as that mentioned above. Nevertheless, even cone melt- ing points on this system, and some TABLE | Influence of Firing Treatment on the Specific Gravity, Crystal Size and Hydration Tendency of Indian Magnesite | Hydration Tendency—5 Hr. | Specific Crystal Size, in Steam—Loss on Ignition, Treatment, Deg. F.| Gravity Diameter, mms. Per Cent ee Se is = - - —- - | Fired to 2370... 3.494 0.01—0.03 8.91 Fired to 2540... 3.496 0.01—0.02 7.36 Fired to 2730... 3.539 0.02—0.03 1.92 Fired to 2910. . 3.544 0.03—0.04 1.13 Fired to 3000.... . 3.551 0.04—0.05 1.06 Held 14 hr. at 3000 3.565 0.04—0.05 1.04 48—THE IRON AGE, June 3, 1943 Forsterite Serpentine Tale data regarding the phases which ap- pear, would be of help to the mag- nesite worker, as has become most evident in connection with the work on sea water magnesia. The recent pa- per by Birch on equilibrium diagrams as applied to refractory materials will be of interest to the reader who wishes to pursue further this aspect of the problem. Raw Materials The main sources of raw material have already been mentioned. It is perhaps useful to divide them more clearly. They fall roughly into five main groups: Spathic, that is, coarse- ly erystalline magnesite (MgCO,); crypto - crystalline (sub-microscopic) or “compact” magnesite (MgCO,); breunnerite, which is a solid solution of magnesium and ferrous carbonates (MgCO;-FeCO;); brucite (Mg- (OH):); sea water magnesia. The original developments were mainly in the Veitsch district of Sty- ria (Austria) where in 1880 dead- burned magnesia was produced from the breunnerite type of rock. When the first World War started this was the only magnesite used in consider- able quantities for the production of brick. During that war the compact Greek material and the high lime Canadian magnesite were developed on a commercial scale and more re- cently large quantities of magnesite have been mined in Russia and Man- churia. Considerable developments also occurred during the last war in the production of dead-burned mag- nesite from the Washington material. These various sources, together with brucite and sea water magnesia, form with mate ing put, is fc nesit a ter used servi to hy the 1 bonat eral preci ent. carbe work last ¢ quite with stone has s| rapid This the break bonat that | carbo inter main plant cinati prese and t The ¢ Fig. result made India: ing ai SiO Fe, Al.( Cat Mg The 12 me fred Above was k UD to 5 ic) ds) 5 pion ates Mg- vere Sty- ead- rom ‘hen was der- n of pact lime oped 2 re- esite M an- nents ay in mag- erial. with form with Indian magnesite the principal materials in use today. The follow- ing table gives a picture of the out- put, in tons, in 1936 (Canadian figure is for 1935, Russian for 1934): PGRN hoon nk oen eee 17,888 RUMI, 6-62.06 cea oda bok CORN wk 553 doa dai 27,129 MGRCHMTIA oi 568s 68 0088 206,000 Czechoslovakia .......... 83,270 PUUES Se Sasaee nc cheeks 116,106 POD 6 2 tie wscinesdsaue 15,716 MRO sic a Nin train eon 482,000 RI IUOUE FHEBEEB i we os 187,894 WGrOVIe ca dee 39,008 Dead-Burned Magnesite By “dead-burned” is meant a mag- nesite that has been calcined at such a temperature as to enable it to be used in subsequent brick-making and service without undue difficulty due to hydration or shrinkage. Whether the material is made from the ecar- bonate or the hydroxide the same gen- eral considerations apply, though the precise reactions are of course differ- ent. The dissociation of magnesium carbonate has been studied by many workers, even before the close of the last century. It has been studied again quite recently by Conley in connection with calcination conditions for lime- stone, dolomite and magnesite. Conley has shown that the dissociation is very rapid at about 1110 deg. F. (Fig. 4). This conclusion was also reached by the author, who showed that the breakdown temperature of the car- bonate is considerably higher than that of the hydroxide, while the basic carbonates dissociate over a long and intermediate temperature range. The main point of interest to the steel plant operator is the effect of the cal- cination temperature and the fluxes present on the rate of crystal growth and the stability of the final product. The data summarized in Table I and Fig. 5 give an example of the kind of result obtained. These tests were made on a sample of lightly calcined Indian magnesite having the follow- ing analysis: BR, ta wiea ae. wanes 5.36 per cent et i 0.68 per cent | Pe ere ne 0.40 per cent RR 6 iets ill a a a 2.58 per cent PO -isccied. asain ct 90.82 per cent The material was ground to pass a i2 mesh sieve, moulded into pills and fred in a laboratory gas fired kiln. Above 1830 deg. F. the heating rate was kept steady at 390 deg. per hour up to 3000 deg., this being the order 1830 ° ° ° 1470+ “ IG. 4 — Dissocia- 3 ; “ ~1110 tion of magnesium g carbonate (after 5 Conley). & 750 5 ° ° ° w oO Oo 0 nities 40 80 120 of heat treatment received in a ro- tary kiln. Samples were withdrawn every half hour and specific gravity tests made. It will be seen from the figure that above 2540 deg. F. the spe- cifie gravity began to rise quite rap- idly, reaching a maximum value of 3.56 at 3000 deg. The crystal size, as determined by the X-ray monochrom- atic pinhole method, rose from 0.01 mm. to 0.05 mm. The change in crys- tal size is clearly shown by the X-ray photographs (Figs. 6a, 6b and 6c). The hydration tendency, which was 3.60 Ww uo uo Specific gravity ° ° ° o & IG. 5 — Effect of a firing treatment = on the specific grav- Ss ity, crystal size and hydration tendency of Indian magnesite. = 8 ° ° ° > eR @ - Cc 2.5 S+ . Cc , = =: & So SY > IS € 8 © a Ss a a o > WwW S oO 160 200 240 280 320 =. 360 Time, minutes determined by maintaining a small sample in contact with steam for 5 hr. also fell off rapidly with increased firing temperature, being less than one quarter at 2730 deg. F. of the value obtained for the 2370 deg. sam- ple. These conclusions illustrate the general problem which is analogous for all the materials involved. On firing the magnesia crystals grow; the amount of surface exposed is re- duced, and there is a drop in the hy- dration tendency. The material shrinks as the minute pores ia the Li 2540 2730 2910 300 Temperorture,deg.F. ('4 hour) $000 THE IRON AGE, June 3, 1943—49 magnesia disappear and the specific gravity increases. A great deal of work has been done on the effect of various fluxes on the rate at which these changes occur and numerous patents have been taken out to cover the materials stated. Thus in the Alterra process calcium ferrites are added to pure magnesite of the compact type to increase the rate of dead-burning and thus reduce the risk ROOM yy, maa rae, tlt of after-contraction in the final prod- uct. Those who wish to study the types of periodic and rotary kiln employed in the dead-burning of magnesite, are referred to the excellent books by Comber and Banco referred to in the bibliography. A description of the Austrian plants has also been given in some detail by Endell. At the Radenthein works where a Breunner- ite of the 4 per cent iron type is dea”- burned, one of the rotary kilns is 228 ft. long and produces some 200 ton:, of magnesite a day. The diameter o* the kiln, which is fired with pulverized 50—THE IRON AGE, June 3, 1943 fuel, is 9 ft., the fuel consumptien be- ing approximately 895 lb. per ton of product. The material is fed in as lumps of about 1 in. size and is cal- cined at a temperature between. 3000 and 3180 deg. F. The advantage of the rotary kiln over the earlier peri- odie shaft kiln type is, of course, the uniformity of the firing treatment. Mention should also be made of electrically fused magnesia which al- IG. 6—X-ray back reflection photo- graphs of Indian magnesite after fir- ing to (top) 2370 deg. F., (middle) 2910 deg. F., and (bottom) 3000 deg. FP. though at present is only a small pro- portion of the total, will doubtless be used in increasing amounts as the de- mands on furnace structures increase. It has been found to give quite satis- factory results in ports and in other positions where the conditions are particularly severe and the extended use of this material is mainly a ques- tion of the cost of electrical power. Properties Typical chemical analyses of the principal brands of magnesite are given in Table II. In general the “Veitsch magnesite runs about 8 per cent iron oxide and the Radentheiy and Trieben about 4 per cent iroy oxide. The silica content varies from 2 to 4 per cent and the alumina is gen. erally about 1 to 2 per cent. The lime is usually less than 38 per cent. ‘This analysis is not obtained automatically, but results from careful sorting of the raw materials and even magnetic sep. aration of the fired product. The Greek magnesite is much purer, the magnesia usually exceeding 90 per cent. Most of it comes from deposits in the island of Eubobea, though con- siderable amounts also occur on the mainland and in the island of My. tileno. It is a difficult material to dead-burn though complete success has been achieved by the Anglo-Greek Magnesite Co. (Fig. 7). The difficulty lies in the fact that a high tempera- ture is required and that in the shaft kilns used it is possible for caustic material to exist side by side with well dead-burned magnesite. Attempts to add suitable mineralizers in shaft kilns have not been successful and consequently very careful supervision and sorting of the product is required to insure that it is up to standard. The Russian magnesite is fairly similar in composition to the Austri- an, but tends to be lower in iron oxide. The main difficulty with its use is the presence in the clinker of a consider- able amount of free lime. This may occur as discrete particles of appre- ciable size which hydrate during the drying of the brick and cause serious cracking. A great deal of work has been done in Russia on the pre-treat- ment of the clinker, to eliminate the more active lime and magnesia. One method that has been used is the auto- claving of the magnesite using a plant similar to that employed in the pro- duction of sand-lime brick. The ad- vantage of this method is its rapidity and the consequent large tonnages that can be handled by a comparative- ly small plant. Provided some such souring treatment is carried out, n0 serious difficulty need occur during brickmaking. Manchurian magnesite was extel- sively used both in Great Britain ané in America prior to the war and offers no particular problem as a brickmak ing material. The Canadian magnesite is generally high in lime, a figure of 18 to 20 per cent being typical. Sta bility is achieved by the addition d iron oxide in the rotary kiln, the amount of iron present generally be ing about 8 per cent. With all these fluxes present the material can scarce ly be considered as straight mag nesit man} brick mag! a va ceme Cane WwW pure in b nesit tent used brick hear mag’ is gi ably the } mace pure frac’ per | ca, 1 presi cent, from erall as | per utm«< and At past nesit perie year ous now shou alysi hydr age. inde: but relat Thus cont: eral] Silica Alum Ferri Lime Magi — *Anal and ion red rly tri- ide. the ler- nay pre- the ous has eat- the One uto- lant pro- ad- dity ages tive: such » no ring <ten- and ffers mak- esite re of Sta- m of _ the y be these arce- mag: nesite. Nevertheless, it has found many useful applications, both in brickmaking (magnesite and chrome magnesite) and in the production of a variety of stabilized clinkers and cements such as are manufactured by Canadian Refractories, Ltd. Washington magnesite is also quite pure, but behaves rather differently in brickmaking than Austrian mag- nesite, due to its relatively low con- tent of iron oxide. used in the United States, both in hick form and as a clinker for open hearth furnace bottoms. Sea water magnesia, a typical analysis of which is given in Table II, varies consider- ably in composition according to how the process is worked. Thus for phar- maceutical It is extensively purposes an extremely pure product is obtained, but for re- fractory work a content of about 88 per cent of magnesia is normal. Sili- ca, iron oxide and alumina, are all present to the extent of about 2 per cent, while the lime content varies from about 3 to 6 per cent. It is gen- erally considered that this should be as low as possible but a value of 3 per cent can be achieved only by the utmost control over the raw materials and process employed. Attempts have been made in the past to assess the value of a mag- nesite clinker from a single test. Ex- perience gained during the last few years shows how exceedingly danger- ous such a procedure can be. It is now considered that at least five tests should be made, namely, chemical an- alysis, specific gravity, crystal size, hydration tendency and firing shrink- age. Specific gravity affords a rough index of the degree of dead-burning, but must always be considered in relation to the chemical analysis. Thus the Radenthein magnesite, which contains 4 per cent of iron oxide, gen- erally has a specific gravity of 3.56, 1G. 7 — Grecian dead-burned mag- nesite showing char- acteristic fibrous structure. while that of Veitsch which contains 8 per cent of inon oxide, may be as high as 3.65. For the very pure Greek material a value of 3.50 may be con- sidered quite good. Roughly the spe- cific gravity figures may be corrected to the extent of 0.01 for every 1 per cent of iron oxide, though this is only a very rough approximation as it takes no account of the other impuri- ties, for example, silica. The crystal size supplies confirmatory evidence of the degree to which the material is dead-burned—well burned material being 0.03 mm. or over—but from the brickmaking standpoint the two im- portant characteristics are the hydra- tion tendency and the firing shrink- age. If the hydration tendency ex- ceeds the safe value or if the material contains a small amount of highly reactive material, then trouble may be anticipated in drying the brick. In view of this latter qualification the hydration figure alone may be mis- leading, and it may be necessary to pick out discrete particles of material for separate test. Firing shrinkage tests are again only comparative but if the firing shrinkage of a new ma- terial is considerably greater than that of the normal, cracking is liable to occur in the kiln and the brick, if made in the standard molds, are likely to be undersize. The ease with which magnesite sint- ers is also a factor of some impor- tance, particularly in connection with monolithic hearths. Summing up, it may be stated that the finer the grind and the less pure the material, the more easily will sintering occur. Need- less to say, both increase in tempera- ture and time of soak also increase the amount of sintering which occurs. Editor’s Note: Next week the author concludes this study with a discussion of the manufacture, properties, specifications and applications of magnesite brick. TABLE Il Selected Analyses of Dead-Burned Magnesite, Per Cent Austria Greece United States Source ca a te a Sea Water Veitsch | Radenthein | Eubobea Russia Manchuria India Canada Washington Magnesia Silica 1.7 2.1 z¢ 4.7 2.8 5.4 7.9 3.2 2.5 Alumina. . 0.9 2.4 04 ; 1.1 2.3 0.4 0.2! 3.2 1.5 Ferric Oxide 8.2 3.9 0.5 | 2.7 1.9 0.7 7.8) , 2.4 Lime... .. 2.5 ne 2.0 5.7 1.8 2.6 19.5 2.0 5.0 Magnesia 86.9 89.0 95.3 85.2 90.8 90.8 64.5 91.6 87.6 = *Analysis by J. Lumsden (Imperial institute) SS I THE IRON AGE, June 3, 1943—5! IG. I1—Nelson Metcalf (left), head of Vultee's methods and con- trols department, and the author at chart followed in setting up new high speed production method for wing center section assembly. The chart is similar to the master process flow chart shown in Fig. 3. Layout board is at rear. Overhead conveyors are represented with worsted yarn strung between pins extending out of the board | in. e 2 oO solidated-Vultee Aircraft Corp., the world’s number one pro- ducer of basic training airplanes, has achieved many “firsts” in aircraft production. Awarded an army con- tract for trainers three years ago as a result of competitive design com- petition, Vultee production men began then to apply techniques entirely new to aircraft manufacture. The first pub- lished evidence of this transition in methods came in the spring of 1941, when the first powered aircraft as- sembly line went into operation at Vultee Field. That line has never stopped. As a result, today the “B. T.’s” from this assembly line are numbered in thousands rather than hundreds, and provide the basic training for virtually every new pilot in America’s Army Air Forces. The assembly line delivers the fin- ished product, and provides the dra- matic side of mass production that is appreciated by the outside world. But production men know that the real drama takes place behind the scenes. Feeding a moving line which con- sumes thousands of detail parts each hour, presents a tremendous produc- tion control problem. V ULTEE Field Division of Con- 52—THE’ IRON AGE, June 3, 1943 The smooth control of production here is accomplished not by compli- cated systems and paperwork, but by a preplanned and engineered scheme of manufacture. Into this scheme are integrated the essentials of mass pro- duction. Paramount among these es- sentials is the function of plant layout. .Plant layout at this plant is an in- dustrial engineering function, and for this reason exercises unusually broad jurisdiction. The plant layout engi- neer heads a section of methods and controls, the management department which centralizes all industrial engi- neering work at Vultee. As a part of this department, the layout engineer has available all time study and plan- ning data for every project, and em- ploys the services of methods of engi- neering personnel to whatever extent required. Every layout, whether it entails setting up a line for a new contract or rearranging a department to meet changing conditions, is han- dled as a project. There is no indis- criminate moving of equipment at the whim of interested individuals. Prac- tically all changes in existing layout are the result of cost reduction sur- veys made jointly by factory super- vision and methods engineering. lant Layout By C. HARPER BRUBAKER Methods & Controls Department, Vultee Aircraft Inc., Vultee Field Division The procedure followed in making such a move can be best illustrated by a specific example now in progress. This project is a complete revision of the wing center section department layout. The objectives in this case were fourfold: To provide more me- chanical handling and permit women to replace men, to shorten the sub- assembly work cycle to cope with material scarcity problems, to accom- modate a new engineering design, and to incorporate substantial methods improvements for saving manpower. Let us follow this project: The first step was to send methods and time study engineers into the department for several weeks in order to analyze and time study the assem- bly of the center section in its en- tirety. Not only did the study cover the assembly of the center section, but each of the many subassemblies involved. During the time that the time study men were doing their job, material handling engineers studying every part of the unit determining the best method of transporting the various subassemblies, major assem- blies, and the complete center section through their various stages of as- sembly. Conveyor lines of types were finally agreed upon as applicable to most of the handling. were several Process Charts Prepared Following the complete time study analysis, process charts of various types were prepared. Among these chart showing the process time of the present method of as- sembly, and another chart showing the process time of the proposed was a method to note new lay the pre: The ever for mind, a complet major 1 well as valuable and ass tion are operatic To a layout to mak develop each of schedule the pict detail assembl of time what hi IG. 2- ter sec conveyor actual la section « was done ventional with sex cutouts. | For Aircraft Mass Production method of assembly. It is interesting to note that the process time of the new layout is to be only one-third of the present method. The reduction of process time is ever foremost in the layout engineer’s mind, and is the basic reason why a complete schedule is set up for each major unit of the center section as well as every subassembly, so that valuable time is not lost in material and assemblies sitting in accumula- tion areas waiting for an unscheduled operation. To accomplish this objective, the layout engineers, before attempting to make a scale model layout, first developed a complete schedule for each of the many assemblies. This schedule, part of which is shown in the picture, shows the time when each detail part, subassembly and major assembly must be started, the length of time allowed for process, and at what hour it must be ready to meet IG. 2—Wing cen- ter sections on the line. The actual layout for this section of the plant conveyor was done in the con- ventional manner with scaled paper cutouts. (See Fig. 1}. . . . At Vultee, complete process flow charts are worked out in detail to assure the right amount of time and space for manufac- turing parts and for subassembly banks to feed overhead conveyor lines. An example is worked out on a new line for wing center sections. another unit at a given point for further operation. The time studies taken are used to balance completely every operation and station. Therefore, when com- pleted, this master chart represents length of process time, sequence of operations, number of stations re- quired, and the number of men re- quired for each operation and station. It also is the basis for the schedule from which each subassembly and de- tailed part is manufactured. With this information worked out for the peak schedule expected the plant layout engineer has little to take for granted, but rather has com- plete factual data from which to start the actual layout. The making of the layout itself fol- lows the conventional method. Tem- plates of all equipment are placed on the layout board and moved into various arrangements in accordance with the master process chart. With the making of this scale model of the complete department, the material handling methods which have been determined by thorough study, are worked out with the arrangement of each piece of equipment. A great deal of consideration is given to the hand- Bor] BANK 26 SHIPS LH NOSE SUBASSEMBLIES PROCESS TIME "TT WING CENTER SECTION ASSEMBLY PROPOSED METHOD RHNOSEASSY] BANK 26 SHIPS RH NOSE SUBASSEMBLIES [BANK BANK] | BANK 26 SHIPS MAIN BEAM SUBASSEMBLIES Pg TINAL ASSEMBLY CONVEYOR +] MASTER JiG | BANK { | 2 SHIPS | | BANK! TANK ASSEMBLY BANK _26 SHIPS BANK LH SPLICE ASSEMBLY L.H.TANK SUBASSEMBLIES L.H_ NOSE _SUBASSEMBLY {3SOSHIPS DETAILS) R H.NOSE _SUBASSEMBLY BANK 350 SHIPS DETAI! {350 SHIPS DETAILS =. & @ 6¢ 2B MB MB MR § pb $ Hours 48852 «#456 060) (648 nr 6 8 8 8 2 % 4100 om 1G. 3—Master process flow chart for wing center section subassembly. This is purely diagrammatic and represents the time interval for subassembly as related to final assembly and indicates banks of parts or subassemblies in terms of hours required to fabricate them. ° ° ° ee 4—Breakdown of specific operations at three work stations for making nose panel parts for the subassembly of the wing center section. A graphical analysis of this kind is made for every unit shown on the master process flow chart, Fig. 3. In this way. z v= © 8.2 2.4 . te voc [2235 wo St Sn oO 22S a $38 Sea “fo mo @M ces o > ec YZES zac SF 30H - sc ZaS WING CENTER SECTION SUBASSEMBLY, NOSE PANEL PARTS @ wa om] SN SQ Ht Detail parts dispatched to begin assembly operations. LEGEND wD “Part No > Operation time — From previous ote tO next operation operation 2 up time ~@ —>@Part complete Rise Total available hours per day (6x8) 48.0 —+ (2) Idle time per day 48 Utilized hours per day 43.2 Operating efficiency 90% S4—THE IRON AGE, June 3, 1943 . ling since it is felt a layout is right only when material handling is at an absolute minimum. The working out of the entire proj- ect is done carefully and in coopera- tion with the foreman whose depart- ment is involved. This is done so that when completed the layout will have complete support of the man who has to live with it and make it work. When completed, the layout is pre- sented to management with complete costs, cost reductions, and other items of expected accomplishment. A layout such as this, built from factual data, and accompanied by charts and figures showing the re- sultant cost reductions, needs little