The Iron Age 1943-01-21: Vol 151 Iss 3

ANUARY 21, 1943 STEEL 4 SHEARED TEEL ATES A FLANGED AND SHE Critical days for war production are just ahead. Workers must released the armed today’s huge output must maintained. Whiting Victory Cranes are helping sustain the production tempo many plants. These cranes are specially engi- tant out holding neered units designed make use immediately available materials and parts. They are guaranteed job with all the efficiency, ease ation, quietness, and durability that characterized Whiting Cranes for sixty years. Whiting Corporation, Lathrop Ave., Harvey, FOR SAFETY’S send for copy the new Crane Op- Handbook just published Whiting, containing rules for the safe op- eration Overhead Traveling Cranes. OVERHEAD TRAVELING Offices Chicago, Cincinnati, Detroit, Los Angeles, New York, Philadelphia, Pittsburgh, St- Agents other principal cities. ) JANUARY 21, 1943 This Week President and Editor BAUR Vice-President and General Manager ° Technical Editor, OLIVER Associate News Editor JAMES Associate Editors Art Editor, WINTERS Editorial Assistents Washington West Coast Dear Editor Advertising Robert Blair, Union Cleveland Herman, Chilton Philadelphia Raymond Kay, 2420 Cheremoya Los Angeles, Cal. Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Detroit Ober, East 42nd St., New York obinson Fitzgerald 428 Park Pittsburgh Johnson, Market Research Hayes, Production Manager. Baur, Typography and Layout. Technical Articles Resident District Editors Washington Pittsburgh Carburization and Decarburization Steel LLOY Cleveland Detroit Silica and Semi-Silica OSGOOD MURDOCK San Francisco Cutting Stainless with Reverse Angle Chip Boston Angeles Working Out Techniques for Welding Armor Plate HUGH SHARP JOHN Milwaukee Birmingham Steep Rock Iron Ore SANDERSON ROY EDMONDS Toronto, Ontario St. Louis BACON Seattle DIX, Manager, Reader Service Features ° ° ° News and Markets This Industrial Week ° ° Member, Audit Bureau Circulations Member, Associated Business Papers use Indexed the Industrial Arts Index. Pub- if Si | 35 t * Cable Y." Machine Tool Activity Iron and Steel Scrap Executive Editorial Comparison Prices Sts. East 42nd St. Finished Steel Prices thia, Pa. New York, U.S.A. AND DIRECTORS RULES MUSSELMAN, President DRETH, Vice-President GRIFFITHS, Vice-President Index Advertisers ERHUNE, Vice-President DEVENTER, Vice-President Vice-President BARBER, Treasurer BLAIR MOFFETT, Secretary CHASE, THOMAS KANE, UZBY, FAHRENDORF, UFFY CHARLES HEALE Copyright, 1943, by Chilton Company (Ine.) ‘ at 7 | | | | ‘ } | | 108 > St. | pro holding Critical days for war production units designed make use just ahead. Workers must released available materials imp releasi the armed today’s huge parts. They are guaranteed output must maintained. job with all the efficiency, ease Whiting Victory Cranes are helping durability that sustain the production tempo characterized Whiting Cranes for plants. These cranes are specially engi- sixty years. Whiting Corporation, send for copy the new Crane Op- Lathrop Ave., Harvey, Illinois. erator’s Handbook just published Whiting, containing rules for the safe op- eration Overhead Traveling Cranes. ; Offices Chicago, Cincinnati, Detroit, Los Angeles, New York, Philadelphia, Pittsburgh, St- Agents other principal cities. ICTORY ly JANUARY 21, 1943 VOL. NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager ° Managing Editor, LIPPERT News Markets Editor, ROWAN Technical Editor, OLIVER Associate News Editor, JAMES Associate Editors Art Editor, WINTERS Editorial Assistents BUTTERS Resident District Editors Washington Pittsburgh Washington Chicago Cleveland Detroit OSGOOD MURDOCK San Francisco Editorial Correspondents uffa FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. BACON Seattle ° DIX, Manager, Reader Service ° ° ° Advertising Staff Robert Blair, Union Cleveland Herman, Chilton Philadelphia Hottenstein, Otis Bidg., Chicago Raymond Kay, 2420 Cheremoya Los Angeles, Cal. Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York Johnson, Market Research Mar. Hayes, Production Manager. Baur, Typography and Layout. use ° ° ° Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub- lished every Thursday. Subscription Price North America, South America and Possessions, $8; Foreign, $15 year. hat Owned and Published 1560! Executive Editorial and Offices Advertising Offices Chestnut and Sts. East 42nd St. Philadelphia, Pa. New York, OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President Vice-President Vice-President GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALE This Week THE IRON AGE Editorial Technical Articles Carburization and Decarburization Hardness Tin Base Silica and Semi-Silica Cutting Stainless with Reverse Angle Chip Cleaning and 155 Mm. Shells. Wheel Forging Replaced Brazed Steel Disks Working Out Techniques for Welding Armor Plate Steep Rock Iron Ore Features Assembly Line Washington West Coast Dear Editor News and Markets This Industrial Week News Industry Personals and Obituaries Machine Tool Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Comparison Prices Finished Steel Prices Index Advertisers Steel Copyright, 1943, by Chilton Company (Inec.) a | | | | | . ° ° ° | | | ° ° | | 4 | 108 112 114 ues | RUL CRANE St. EXTRAVAGANT! Solid, alloy tool below ties from one one and one-half pounds scarce alloys. PINK the above tool shows alloy diffusion through cubic inches. needless waste! ECONOMICAL! Firthite-tipped tool below con- tains only grams—not pounds —of scarce and essential alloys. This Firthite sintered-carbide tip, RED the above tool plain carbon-steel shank, shows alloy concentra- only 34" tion, 3/16 cubic will remove metal faster than high- inch, placed effectively steel, give better finish and the cutting edge! more accurate work. POINTS THE WAY SAVE ALLOYS speed steel tool, only that part the alloy the cutting edge immediate usefulness—the balance lost for present requirements. Offices: McKEESPORT, PA. YORK STEEL COMPANY PHILADELPHIA CLEVELAND DAYTON DETROIT CHICAGO LOS ANGELES 4 Ai \ THE the Ratio Rations JANUARY 21, 1943 ° ° ESTABLISHED 1855 ONFRONTED with critical shortage manpower, the men indus- try and government have introduced broad, sweeping changes employment and training policies. Presidential decree 8802 set the policy for the United States war the hiring Negroes. The War Man Power Commission prophesies that the end 1943 six million women will employed war industries. While every effort being made increase the number war workers, the nation’s production effort may few months slowly sapped its vitality. The quart milk day promised every member the genus homo when victory ours not sufficient stimulus for our labor force break production records. Tantalizing visions not sup- ply driving energy. stay alive the average adult requires 2400 calories day. But steel worker, for example, must have 300 extra calories hour for each hour that works. Assuming works eight-hour day, must con- sume total 4800 calories daily expected work every work- ing day. Light work requires calories hour above the base 2400 for each hour worked and moderate work 150. The problem nutrition not simple just calorie Not only energy must supplied the living organism, but building mate- rials well. Just open hearth could produce steel only coke were supplied, the human body cannot sustain itself without the proper proportions iron, calcium, proteins, carbohydrates, fats and vitamins. The problem achieving higher and higher production rates vital that cannot afford overlook even one facet its complexity. The human factor always with us. foolish assume that controlled materials and manpower regulations alone can solve production prob- lems. whispered rumor that faulty materials are being supplied the armed forces enough start Congressional investigation. But should management sit quietly while their workers become less and less efficient because recognition had been made the greater food re- quirements laborers compared with sedentary workers! England has met and solved this problem differential rationing. There, shop canteens and cafeterias serving persons doing heavy work are allotted some cases much per cent more food per person under the point rationing system. The OPA loath start such realistic rationing for fear political and economic repercussions. Admittedly this simple problem, but winning war cannot reduced simple formulas. Ignoring prob- lem does not solve it. The food rationing division has said that present vitamin content satisfactory but what may develop the way shortages causes them some concern. Without doubt the OPA sincere its attitude, but rationing should used shortage preventive, not crutch after the damage done. And for preferential rationing, this practice followed, and is, for the men the armed forces, can certainly applied for the men doing the next most strenuous work, the work producing for war. 4 | j | q | | } q 7 | | SELES CONSERVE STEEL For Our Fighting Forces sible conserve the steel already service, making last that all new steel can into America’s war effort. Preventing corrosive destruction one effective way conserve steel and help fight the war the home front. The initial step critically examine all buildings and equipment—bridges, columns, trusses, floors, stairs, roofing, siding, ventilators, ducts, piping, tanks, fences, cranes, machinery, etc.—everything made steel that subject corrosion from dampness, the weather process fumes. Foresighted management now doing everything pos- SHEETS STRIP TIN PLATE RAILS BARS PLATES TRACK ACCESSORIES Paint manufacturers can offer good advice effective methods cleaning, and primer and finish coats that will protect and conserve steel and about your plant. program preserve steel has valuable secondary advantage, too. Many shades paint reflect light, and better lighting cuts spoilage, speeds production and re- duces the hazards accidents America’s war workers. conservation program more than pays for itself lower maintenance and replacement costs, but more important now, every pound steel that saved boost the war effort. FLOOR PLATE REINFORCING BARS STRUCTURALS PILING Sales Offices: Milwaukee, Detroit, St. Paul, St. Louis, that lant. dary and dre- kers. more lisa ° ° ° JAMES STANLEY Westinghouse Electric Co., East the literature car- burizing and decarburizing metaliuryist’s viewpoint voluminous, little basic chemistry and physics applied the processes make their treatment rational tematic. great deal empiri- cism still surrounds the practice commercial carburizing—case hard- ening—as well recarburization— formation soft spots skins. The physical chemistry car- burization and decarburization can considered comprising two parts. The thermodynamics the reactions involved, and the diffusion migration car- bon. Another factor, the reaction the gas-metal interface, might added but since the importance this has not been demonstrated these two processes, will not considered here. The simplified treatment volves the study the gas-metal reactions governed the vari- ables, temperature, pressure and concentration. The discussion kinetics deals with the formation the case, i.e. the rate diffusion carbon into the metal; and de- carburization, deals with the rate formation the decarburized layer, the migration the car- bon from the metal. Carburizing, related the ried out commercially (1) Solid pack car- burizing; (2) gas carburizing. and / Steel Decarburization Theoretical Analysis the industrial heat treater, understanding the physical chemical principles such gas equilibria and the diffusion carbon underlying commercial car- burization, well the nemesis decarburization, should immense practical value. this, the first three- part article, the author discusses types carburizers and the carbon monoxide-iron system from the stand- point simplified thermodynamics. (3) liquid fused salt carburiz- ing. Pack and gas carburizing may classed together, for has been shown that solid carburizers func- tion only when there gas phase the carburizing. liquid carburizers, the carburization also thought accomplished carbon monoxide except that the reaction occurs liquid, rather than gaseous phase. SOLID CARBURIZERS: discusses the action solid car- burizers which probably fol- lows: elevated temperatures, oxygen the limited air supply reacts with charcoal form CO, and CO. The CO, then further re- acts with the charcoal produce according the equation (1) The decomposition the CO, oc- curring the surface the steel, does the carburizing: argued often, particularly the older literature’, that car- phase, i.e. the charcoal reacts the solid state with the iron. however, states that intimate con- tact carbon with steel even under pressure results only very slight carburization, and finds ‘arburization soot even 2300 deg. (1260 deg. C). “ward iron not simple, but the answer may explained partly the adsorptive powers charcoal (since charcoal with adsorptive power has little value carburiz- ing compound) and the ash content charcoal (soft wood charcoal can made effective hardwood *Rodman discussing paper’. Energizers are almost always used for improving the carburizing quality the solid carburizer. These substances are the barium, and sodium oxides and car- THE IRON AGE, January 2 od ? 4 Si waar. bonates, and their role appeais that catalysts rather than reactants. GAS natural gases are good carburizers. Natural gas approximately per cent and such very easy handle. city gas (coal gas), the methane ranges from per cent, and the carbon monoxide about per cent City gas, with its relatively high carbon dioxide, water and hydrogen content, has low carburizing power; these con- stituents must removed their concentrations reduced. some cases the city gas enriched passing the gas through liquid hy- drocarbons such turpentine, di- pentine, aniline, gasoline zine; sometimes such gases tane and propane are bled into the system, and still other instances the gas passed through hot car- bonaceous material. Other carburizing atmospheres have been prepared and have been Atmospheres have been prepared volatilization such substances turpentine, gasoline, aniline and benzine. How- ever, the gases are conspicuous soot-formers because the amount carbon per unit volume such vapor, and provision made usu- ally for control soot. Desirable mixtures have been made bling hydrogen nitrogen through the various liquids certain tem- perature that their vapor pres- sure increased decreased. Bu- tane has been diluted with dissoci- ated ammonia and good results have been obtained. Rich gases such those mentioned can mixed with air and used for carburization. Partially completely burned heating gas another source carburizing gas. Depending the combustion ratio gas and air, the products combustion will mixture water, carbon dioxide carbon monoxide and hydrogen. moisture and carbon dioxide are re- moved controlled, carburizing gas results. Flue gas has been suc- cessfully mixed with gas and used carburizing agent. Flue gas often has been passed over heated charcoal and the resulting gas has excellent carburizing qual- ity. LIQUID CARBURIZERS: Liquid carbu- rization quite different from pack gas carburization. this case the carburization carried out fused salt bath sodium cyanide with various additions. The trans- fer the carburizing material through the liquid and not the gas phase. The principle liquid carburiz- ers that the breakdown sodium potassium cyanide oxidation produces carbon monoxide which goes into solution, the form which available for carburiza- tion. Further, the decomposition the cyanide also introduces nitro- gen. Since the solid solubility car- bon austenite large and oc- curs more favorable tempera- tures for diffusion, most commercial carburization conducted the austenite range, i.e., above the line. should mentioned that carburization and decarburization are possible both the alpha and gamma states iron. TABLE Equilibrium Constant Equation Fe) + CO, Temperature Best* Exp. from Equation 1380 750 —1.99 —2.02 10.2 1470 800 —2.33 —2.38 4.7 1560 850 —2.59 —2.55 2.6 1650 900 —2.86 —2.82 1.4 1740 950 —3.06 —3.02 1830 1000 —3.25 —3.27 2010 1100 —3.64 —3.66 from equation 32—THE IRON AGE, January 21, 1943 should recognized that the solid solubility carbon the iron cannot exceeded any particu- lar temperature. not possible keep adding carbon the iron matter fact, this method can used determine limits solubil- and certainly more reliable than microscopic examination, concentrations can more easily determined, and less time. insisted that formation Fe.C due temperature fluctuation. This assumption has been proved erron- eous. the austenite saturated one temperature and cooled, separates; the same austen- ite heated the same tempera- ture, the precipitated redis- solved. Atomic vs. Solution The nature the solid solution carbon gamma iron has often been the subject considerable dis- pute. The been whether not the carbon dis- atomically carbon. The atomic theory offers little encouragement for the supposition that solid solutions are molecular. volume considerations bear out the contentions that carbon exists atom- solid solutions have been proposed often, but there evidence for solutions. Arguments based anomalies considerable question; density mea- have been deceptive; evidence molecular aggregation has been found solid solution suggestions molecu- lar solid solutions liquids have been made for certain systems with- out complex intermetallic phases, such Fe,W.C, appear dissociate into atoms the iron base The state aggregation solu- tion best determined the kin- etic behavior the components the system. For instance, could shown that two solutes quasi- binary system (that is, Cu-Ni.Si, with considerable variation their rates diffusion diffuse molecular ratios, then some basis for the molecular solid solution might exist. found that the quasibinary system, that Mg.Si tended dif- fuse molecular proportions when the alloy core contained magnesium - - | | | Temperature per cent AND AUSTENITE 0.60 0.30 25 0.08} ‘= | | = ATA 13 a ° | _(Ne)(Peo2) carburization and decarburization can expressed tle equilibrium with the iron. The data equilibrium con- stants the CO-Fe reaction given Table are plotted above, the straight line representing the equation T (CO)? N.. graph paper take the form rectangular hyperbolas. ave more practical way picture these relationships plot them scales where the resulting curve straight line. Since difficult interpret equilibrium for these ratios observation, the percentages and are plotted the top and the right ordi- nate, respectively. The left ordinate the ratio and silicon this ratio, but the while the bottom abscissa the ratio allic hand, Mehl and found definite evidence for molecular dif- the reaction; thermodynamics and one the equation iron fusion the quasibinary system, concerned only with reversible A+2B2C+D (3) equilibria and not with kinetics. then, the law mass action kin- The main justification for the (C) (D) diffusion process. For the sake where has definite numerical simplicity, however, will as- value for any given temperature, Solid solution, i.e., that solute atoms sumed that equilibrium between the and the quantities (A), (B), (C), the solvent iron stantaneously, such might result (effective concentrations) the solid carburization an_ infinitely four substances.* ‘ound Equilibrium Reactions thin sheet foil. For discussion the law equi- considering any chemical reaction where librium from the viewpoint the law when tween the gas and solid phases, one molecule reacts with two mass action and activities, see any text assumed that time has effect molecules form one molecule physical THE IRON AGE, January 1943—33 ~ per cent +——+ +4 + Equilibrium 950°C 05060708 1012 1517 7 Oo 0.8 0.7 w 0.002 } | > 5 S > ¢ Sao aos FF ss LEFT G.4—Significance equilibrium constant carburization. RIGHT assumed here that the activities the solids are proportional the mol fraction. Mol fraction, binary solid solution, defined where the number mols each component. also follows that For gases assumed that the activities are proportional the partial pressures. where mol fracion the gas and the total pressure: See Dunwald and The concentrations the gaseous and solid phases carburizing re- actions can written follows: The empirical equation CO, (g), (2) but the thermodynamic one, terms activities, Acre) A co)? — A + Aco,). (5) Or, writing activities** mol frac- tions for the solids and partial 34—THE IRON AGE, January 1943 Variation the equilibrium constant various pressures. pressures for the gases, the equa- tion becomes: Nre (Peo)? — Fundamentally, there are two re- versible reactions for carburization- decarburization. Equation (2) the first one and the methane re- action the second: (g) (7) Another theoretical possibility the simultaneous carburizing and nitriding with the cyanogen com- pounds. Carbon Monoxide-lron System Equation (2) becomes: 0.6 1.0 1.2 where and are the mol trac- tions carbon and iron, and and are the partial pressures the gases equilibrium with the iron. The data numerous investiga- have been recalculated that the above equilibrium could ascertained. These are given Table and plotted Fig. The equation the line and the best values calculated from the above equation and the experi- mental values are given Table II. These best values are the ones which were used calculate data for subsequent curves for the mon- oxide reaction. The plotting ratios rectangular hyperbolas ordinary graph paper difficult, for the curves are hard draw and the in- terpolation can very inaccurate. more practical way plot the log-log scales where the result- ing curve straight line. This shown Fig. Obviously such curves are easy draw and inter- polation simplified. The ordinate the left the ratio while the abscissa the bottom the ratio difficult interpret equilibri- 030 | 4 9 | | > SO | T 0.0 5) at 950 | | | 16 | | n | rom eri- data non- nary the in- rate. the Nee) nis such nter- the the percentages carbon and car- bon dioxide are plotted the top abscissa and right ordinate, respec- tively. From Fig. the equilibrium be- tween steel and the gas phase can found. For instance, prevent decarburization per cent tool steel 1740 deg. (950 deg. C.) atmosphere about 98.3 per cent and 1.7 CO, must main- tained. another example, the ef- fect temperature the equilib- rium between per cent carbon steel and the atmosphere, can demonstrated from the figure which shows that more carbon monoxide necessary for the equilibrium with the increasing temperature. far the discussion carburiz- ing has been restricted gases total pressure one atmosphere. That say that commercial practice, the car- burizing gases are actually lower pressure—the sum the partial pressures less than at- mospheric—being diluted with N.. Pco Peco, + Py, Pa atmosphere) (12) This type carburizing atmos- phere produced when natural gas burned air. the equilibrium constant known for one atmosphere, the amount carbon equilibrium with the gas any pressure can calculated. known from equation (9) that algebraic processes can es- tablished that (Ne) (Pco) TABLE Equilibrium Constant Equation where Temperature 1650 900 8.5 2.6 1830 1000 7.8 1920 1050 7.6 Equilibrium Constant 10° 0.7 9.6 —2.018 3.9 4.2 —2.377 1.02 .93 1.5 1.5 —2.824 —3.658 Takahashi (II) Bramley and Lord Johansson and von Seth Becker (V) Average can expressed the straight line relation logiok = — 8.43 ao 6560 (=) where T = °K known, however, that Nye that the carbon content can found. Per cent Pressure Effect Equilibrium From the above equation can seen that (18) The variation the equilibrium constant various pressures given Fig. The effect this variation the equilibrium con- stant and its significance carbu- rization seen Fig. Numerous observations are pos- sible from the log-log plot Fig. For instance, with constant ratio (CO,)/(CO)* (constant CO, con- tent) the carbon equilibrium with the steel increases with in- creasing pressure. Also lower pressures carburizing gas, the higher must the content preserve the original carbon con- tent the steel. Ed. week, the author con- tinues with discussion the methane- hydrogen mixture and its effect car- burization steel. The thermodynamics decarburization will also explained. Hardness Tin-Base Alloys effect hardness, pro- duced quenching from the highest practicable temperature followed prolonged tempering 212 deg. and 284 deg. has been examined the Tin Re- Search Institute, London, for tin-base alloys containing cent antimony and per cent cadmium. This research Part program conducted the institute determine methods obtaining new stronger tin-base alloys suitable for use bearing metals. The results the hardness tests Pell-Walpole, Ph.D., the Journal the Institute Metals, Vol. 68, October, 1942. shown that these alloys can hardened heat treatment and maintain useful degree improvement for least 1000 hr. 212 284 deg. The best al- loys this respect are those the range: Antimony per cent; cadmium per cent, balance tin. The degree im- diamond pyramid hardness tests. the normal non-heat-treated condition. THE IRON AGE, January 1943—35 | res sO > (9) (Nre) L’ Silica and LTHOUGH silica, even when chemically pure, melts temperature little above that employed make good steel, its other properties, particular its ability carry load within few degrees its melting point and its tolerance for comparatively high concentrations iron oxide and lime, have enabled maintain its position the No. steel-works re- fractory. Thus recent study costs one steel plant, was found that even all the casting pit re- fractories and the dolomite used for fettling were included, the cost silica brick represented over one third the total expenditure re- fractories. Since silica brick cheap compared with basic brick, with the special shapes used the casting pit, will seen that weight percentage the proportion silica used about one half the total, even account taken the sand used for molding and for fettling open hearth furnaces. The numerous modifications silica have long been the subject lectures and articles. involved have some these discussions be- come that the mere mention cris- tobalite and tridymite enough arouse annoyance and confusion many steel plant operators. Noth- ing can done reduce the num- ber modifications, though the sil- ica brick manufacturer can, con- trolled firing, insure that the steel plant man relieved least worries due free quartz. actu- fact, the relations between those steel plant refractories, that have ap- peared THE IRON are: “All-Basic Open Furnaces,” Aug. and 22, “Steel Plant Refractories,” Feb. and 13, 1941. “Basic Open Hearth Above Sill Plate Level,” May and 29, 1941. “Electric Steel Plant Refractories,” March and 12, 1942. “Acid Open-Hearth May and June 1942. “Soaking Pit and Reheating Furnace Refractories,” July and 23, 1942. “Acid and Basic Bessemer Refrac- Nov. and 12, 1942. 36—THE IRON AGE, January 1943 silica modifications which affect the steel plant are not particularly com- plicated, hoped the following description wil demonstrate. Quartz, being one the most common minerals the earth’s crust, known everyone, only sand sandstone. The quartz crystals the rocks from which silica brick are made are similar rock crystal but are much smaller and are cemented together, usually rapid increase rate this same temperature, while cooling curves show this change “inversion” reversible. Jay has shown calculation from Debye-Scherrer X-ray photo- graphs (Fig. that the expansion the lattice not the same each direction, say with mag- nesia. This offers explanation why the inversion since clear that relative dis- IG. silicon atoms (a) beta, high temperature quartz and alpha, low temperature quartz. finely divided silica, form ag- gregates known quartzites. The relation between the positions the silicon atoms the silicon-oxy- gen lattice quartz shown Fig. The oxygen atoms, which are considerably larger than the silicon atoms, are not shown, but are located the linkages between the silicon atoms. and X-ray photographs are taken intervals can shown that about 1065 deg. the structure un- dergoes small change, which ac- cording Gibbs due altera- tion the lattice type like that shown Fig. la. will seen that there has not been any disrup- tion the lattice, but merely straightening out the linkages give truly hexagonal structure. Thermal expansion curves made any material high quartz show placement the atoms might !ead state which the forces acting these atoms would longer maintain equilibrium. Fig. also shows the rapidity the deg. change and the slight contraction which occurs with quartz (though not with fired silica brick) above this temperature. Working Face Structure the heating continued above 2000 deg. found that the quartz pattern begins disappear giving place the pattern an- other silica, known cris- tobalite, which can shown pycnometer determinations have lower specific gravity. X-ray amination shows that this modi- fication the silicon and oxygen atoms are distributed the man- ner illustrated Fig. 34. This solu- tion the structure so-called ves to ion ach ‘cur dis- (b) lead onger also deg. action hough above above the an- cris- have ay ex- man- solu- Refractories beta cristobalite was worked out Wyckoff from photograph taken 555 deg. may differ slight- from the absolute configuration but least serves show rather striking manner which has occurred the lattice. should emphasized that there has been loss either silicon oxygen this process, but merely re-orientation the atoms give cubic structure. this mineral which constitutes the working face open hearth furnace roof, already discussed previous section the basic open hearth (THE IRON AGE, May and 29, 1941). Like quartz, undergoes inversion cooling from the beta the alpha form. This latter different from the high temperature variety; being tetragonal though with axial ratio only slightly greater than one. The temperature which the in- version takes place varies over considerable range according the calcination temperature the quartzite from which the cristo- With unused balite was formed. CHESTERS Central Research Department, United Steel Companies, Ltd., Stocksbridge, England ° ° ° ... This the first two articles continuing the author's series steel plant refractories. Here describes the behavior silica brick under varying temperatures and its reactions with oxides, and compares customarily used raw materials. silica brick the range can conven- iently limited the temperature interval 390 570 deg. but with used bricks from open hearth furnace roofs, the inversion tem- perature much more closely de- fined. One further mains: Beta cristobalite, held for appreciable time between 1600 and 2680 deg. F., tends form tri- dymite, the mineral with the arrow head twin crystals, illustrated the section testing (THE IRON AGE, Feb. and 13, 1941). The for- mation this mineral greatly accelerated the presence cer- tain mineralizers, notably alkalies Chart showing thermal expansion quartz parallel and perpen- dicular the axis. Note the effect the alpha-beta tran- sition 1065 deg. Expansion per unit 400°C 600°C 800°C 752°F 1472°F Temperature and iron oxide. cooling, tridy- mite also undergoes inversions low temperature stable forms. For those who prefer have their in- formation the form phase dia- The temperatures given this dia- gram are based the early work Fenner. The precise tem- peratures and the nomenclature used describing the different modifications vary considerably throughout the literature, but the data given Fig. are all that the steel plant man requires. The interest this plex problem the steel maker lies the fact that the expansion characteristics silica brick are function the nature and amount the silica modifications which contains. Furthermore, appreciable amounts raw quartz are still present when the brick put into service, considerable growth may expected soon the brick approaches temperature above that which was fired. Since the expansion which occurs when cristobalite passes through its inversion 390 570 deg. about 0.5 per cent, essential that furnaces built silica brick should heated slowly through this range, shattering the brickwork due differential ther- mal expansion the hot and cold face not occur. Two other properties pure sil- ica that may affect its durability use are its volatility and its ten- dency form silicon monoxide (SiO) reducing atmosphere. unlikely that its volatility THE IRON AGE, January 1943—37 ’ | ° ° ° f | | | | | | | = | | | | | | | F | Po | | y j P } | \ O O | 200°C 392°F 3—Arrangement silicon and oxygen atoms beta (high tem- perature) cristobalite. this min- eral which constitutes the working face open hearth furnace roof. sufficient steelmaking tempera- tures result much loss brickwork, but the formation SiO may well factor fur- nace roof life. description this little known and most unstable ma-* terial has recently been given THE IRON AGE (Jan. 22, 1942), Zappfe and Sims. The summary given above much compressed and those who wish study the subject more detail and gain knowledge the historical aspects the work are referred Sosman’s classical work, The Properties Silica. Reactions with Oxides The raw material for silica brick 4—Phase re- lationships the ° ° ° 573 4 tr, dymite cent silica. Lime normally added bond, the amount varying be- tween and 2.5 per cent. The ef- fect lime the melting point silica, which illustrated Fig. erable will seen from this diagram that the effect lime (and incidentally one two other oxides) peculiar that replacement almost per cent the silica results only small drop melting point. This unusual phenomenon attributed the fact that lime and silica not react heating form single liquid, but form two liquids that are immiscible much the same way water and kerosene. The addition even small quanti- diagram for the system SiO.-CaO, illustrating the effect lime the melting point silica. and Crystobalite and liquid Temperature, deg. Upper high -tridymite +1000 | > Q +2000 ties certain other oxides, such alumina, destroy this immisci- bility and lead steady drop refractoriness. Hence most important that lime used bond, the quartzite should not high alumina alkalies. The reactions between silica and iron oxide are set out the phase diagram given Fig. Here again there immiscibility and only small drop melting point even with per cent substitution FeO. This vital importance the steelmaker since otherwise silica refractories would idly slagged away the iron oxide the furnace atmosphere. actual practice, the iron contact with the silica means all the ferrous state but the same tendencies are present even the ternary Sosman suggests that oxide pick-up and its effect the melting point roof limits the safe operating temperature 3000 deg. Since pure iron melts about 2795 deg. will seen that the furnace must kept with- quite small temperature limits good steel made without excessive damage the silica re- fractories. many works, dead- line 3000 deg. considered rather low, operating tempera- ture 3055 deg. being considered quite reasonable. Much higher tem- peratures (well over 3090 deg.) are periodically recorded roof py- rometers but these are usually as- sociated with dripping the roof and consequent drop roof life. The reactions silica with alu- mina are also great importance (| 1400 38—THE IRON AGE, January 21, 1943 and oint tion wise rap- xide itact all the ‘e.03. iron the the 3000 seen with- imits thout dead- dered dered tem- are roof life. alu- rtance since alumina occurs the natural rock, while clay sometimes used bond for silica bricks and al- ways bond for the so-called “ganister,” used for patching laun- ders, and acid Most silica cements used for setting silica bricks contain clay addition and here most essential that the amount present should not be. sufficient result the joints run- ning out top temperature serious attack the cement the adjacent bricks. The equilibrium diagram will discuss- more detail the section dealing with fireclay. For the pres- ent suffices state that the low- est melting points occur with alumina content only about per cent. Raw Materials has been suggested Sosman that silica suitable for brick mak- ing could probably found any county the United States, even though the cost mining and the quality the product make silica brick manufacture uneconomic ex- cept certain regions. The main American deposits now use are the Tuscarora formation Penn- sylvania, the Baraboo formation the Devil’s Lake region Wiscon- sin, and the Weisner formation Alabama. The first two these are usually described the terms eastern and western quartzite, While the operation the Alabama deposits doubtless dependent Sale the local steel industry. Aus- tin, Pierce and Lundberg have dis- the effect varying raw the properties bricks from these different deposits and find higher thermal conduc- 1600 Cristobalite and liquid 1400 Tridymite and 1200 Weight (%) 6—Equilibrium diagram for the system SiO.-FeO, illustrating the reactions between silica and iron oxide. tivity for the western brick which they attribute its lower porosity. This difference porosity raises IGS. 7a, and Note the large and irregular crystal size the Welsh quartzite (a), the small form grain size the Sheffield ganister (b), and the small but varying grain size the German Findlings quartize (c). interesting point which clear- brought out the raw materials employed Germany. Until re- 1800 Fayalite and Tridymite and fayalite Fayalite 100 ich . in ost THE IRON AGE, January 1943—39 > aa cently most the German brick were made from the so-called Find- lings quartzites which have unique structure and are eminently suitable for the manufacture sil- ica brick. Whereas the American and British quartzites are medi- & a — 4 * > s coarse crystal size, the Find- lings shows wide range, including some very fine material. This illustrated Figs. 7c, which show photo-micrographs Welsh quartzite, Sheffield ganister and Findlings quartzite. One result this difference crystal size that the Findlings quartzite shows much more rapid rate conver- sion cristobalite and tridymite. X-ray photographs taken simi- lar samples, those shown Figs. 8c, revealed even more inter- esting contrasts. will seen that the pattern given Sheffield ganister consists rings fairly uniform dots, while with the Find- lings quartzite the pattern consists smooth rings, due reflections from extremely fine crystals with occasional larger dots superim- posed. With the Welsh quartzite the spots are larger and more ir- regular. Back graphs published recent Iron and Steel Institute paper operative Investigation the Fac- tors Influencing the Durability the Roofs Basic Open Hearth Furnaces” show that this quartzite strained condition and that, although from microscopic point view the rock coarsely crystal- line, can also considered 40—THE IRON AGE, January 1943 made large number sub- microscopic crystals arranged very slight inclinations one an- other. well known that quartz converts more rapidly heating the crystal size small, and that conversion can therefore speed- the three quartzes which were shown section Fig. The Welsh quartize shown (a), the Sheffield ganister (b) and the Ger- man Findlings quart- zite fine grinding. With this Welsh material the sub-mi- croscopic crystals which determine the rate conversion and hence found that firing, the conver- sion far more rapid than would have been expected from the chemi- cal analysis and the petrological examination. The ease with which brick may made from Findlings quartzite and the resul- tant quality the brick which tend have not only low porosity but higher thermal shock resistance, has led world wide search for similar material. far, however, commercial Findlings type ma- terial appears used, other than Germany, with the excep- tion comparatively recent em- > a * ployment the South African crypto-crystalline quartzite de- scribed Bosazza. Quite important the crystal size the quartzite its porosity before and after firing. The results obtained number rocks are set out Table and may con- sidered typical the problem whole. will seen that the Findlings material had only 0.3 per cent before firing, compared with 1.0 per cent for 4 | ° ° ° = de- ystal osity sults are con- the rosity for Welsh quartzite, 4.6 per cent for Sheffield ganister and 13.9 per cent for bastard ganister (used for launder material but not considered suitable for silica brick manufac- ture). firing, the advantage the Findlings material becomes still more obvious. Its porosity has risen only per cent, compared with 12.2 per cent for the Welsh quartzite, and 11.6 per cent for the Sheffield ganister. obvious that the individual grains which brick made are them- selves highly porous after firing, then the problem making low porosity silica brick from this ma- terial greatly increased. Further- more, the fired brick like the cined rock likely weak. The difference conversion rate judged from the drop specific gravity not striking, though here again the Findlings material the best, showing drop 2.41 after hr. 2640 deg. com- pared with 2.46 for the Welsh quartzite and the Sheffield ganister. The extent the conversion can judged from the fact that cris- tobalite has gravity 2.32 and tridymite 2.26 com- pared with 2.65 for raw quartz. An- other characteristic the Find- lings quartzite its high titania Cutting Stainless unusual solution the prob- lem machining stainless steel has been discovered the Firth-Sterling Steel Co., McKees- port, Pa. Stainless steel soft but extremely tough and nec- essary cut through scale rough turning operation. Although many types carbide tool angles were tried, including negative top and side rakes, posi- tive rakes with negative lands, parallel and angular type chip breakers and dulling the cutting edge the scale line, the tools in- variably chipped the scale line were worn away that point after only about min. run. The solution was found re- the angle the chip breaker groove. The usual prac- tice the grinding carbide tools for cutting steel grind the chip breaker wide the nose the tool and taper the groove TABLE Properties Quartzites Before and After Firing For Hr. 2640 Deg. Sheffield Bastard Welsh Findlings Ganister Quartzite Quartzite Chemical Analysis Percent Percent 96.8 97.8 97. 0.9 3.2 0.6 0.4 0.7 0.5 0.4 0.3 0.1 0.1 0.1 0.1 2.66 2.64 2.66 2.64 2.46 2.42 2.46 2.41 Apparent Porosity 11.6 22.8 12.2 3.0 content which usually about per cent, compared with about 0.2 per cent for most quartzites. made suggest that this titania, which evenly distributed throughout the quartzite, may well that has high thermal shock re- sistance and which matures readily use. Other materials used sil- ica brick making are high grade silica sand and prefired brick. ‘The former added unground small amount ball milled fines. The latter provides use for shapes cracked the kiln and con- siderable help making large blocks since reduces the firing ex- pansion. Editor’s Note: Next week the author concludes this study with discussion the manufacture and properties silica brick and brief comments semi-silica and silicosis. with Reverse Angle Chip Breaker off the direction the shank. This procedure was reversed. indicated the drawing, the chip breaker was ground angle deg., with the narrow end the groove starting the nose radius. This was done with the thought that the chip cleavage would oc- cur further ahead the cutting CONVENTIONAL DESIGN CHIP BREAKER edge the scale line than the nose radius. This grind the tool prevented edge failure even double the feed and speed formerly used. tool life hr. was secured cut- ting dry speed 200 ft. per min. and feed 0.012 in. per rev., using grade Firthite. S* NEGATIVE LAND 0.02 WIDE CHIP CRATERS ALONG THIS LINE SCALE LINE ~ NOTE CHIP AT SCALE LINE BREAKS AWAY FROM CUTTING EDGE - ELIMINATING CHIPPING AT THIS POINT CHIP BREAKER PREVENT WEAR SCALE LINE THE IRON AGE, January | | | RAKE RADIUS DEPTH OF CUT 7 ee FF Cleaning and 155 HEN contracts were award- Willys-Overland Motors, Inc., the armed services for the manufacture and 155 mm. shells, mentation was necessary their cleaning and conditioning prior painting, since there were proved methods available along these lines. The types cleaners, washing machines, degreasers, etc., were all comparatively new, and there were many problems involv- ing rust contamination cleaning solutions iron oxide and scale from heat-treated forgings, con- tamination coolants cleaning compounds, and contamination coolants salts from liquid salt baths. First, was discovered that the solution the liquid bath that used heat shells for nosing oper- ations had changed. Various types acid cleaners were tried, but, while was found that the acid cleaners did very good job cleaning, they were impractical be- cause their corrosive effect the metal the washing equip- ment. Following these trials, various alkali cleaners were experimented with, and was found that alkali cleaners did only fair job inso- far metal cleaning was con- cerned. Partially because the washing equipment, alkali cleaners left thin film alkali the fin- ished shell, and this prevented per- fect adherence the lacquer the surface the shells. Another cleaner, Solventol, was tried and found successful all phases the process. Cleaning properties the cleaner were ex- cellent, rust preventive, and, after cleaning with Solventol, the base for the lacquer coating good. This cleaner used directly after the shot blast operation safeguard the inside surface the shell against rust. This cleaning operation performed special conveyor type dip tank built the Solventol Co., Detroit, and the cleaning after shot blasting takes place before the shells are heat treated. After heat treating 155 mm. shells, was found that iron oxide scale mixed with the Solventol cleaning material and would not settle the bottom the cleaning tank. With this mixture iron oxide the solution, caused oxi- dation the surfaces the shells. For the dip tank operation, conse- quently, Quasol No. 936 was tried, and was found that the oxide would settle the bottom the tank this solution Quasol prevented rust. Thus, was found most advantageous use Solventol for cleaning and for rust prevention. Close control over coolants after the salt bath heating operation for nosing the shells was found overcome most rust problems. close watching, the coolants-change all the machine operations, be- fore the separation the soluble oil and water has started, could controlled. separation soluble oil permitted, rust will appear very quickly. While present there not 100 per cent efficiency far rust elimination con- cerned, felt that the company has made big strides that direc- tion through experiments well aid from the suppliers salt, cleaning compounds and oil. Another difficulty that arose was that the rubber gravity conveyor rolls that carried the shell from the final washing operation had tendency deteriorate and pick dust, dirt, greases, oil, etc., and the clean surfaces the shells were being contaminated again interfering with the painting. wiping each shell with cloth sat- urated with lacquer thinner this Fifty-seventh Series Articles the Technical and Economic Aspects Metal Cleaning and Finishing 42—THE IRON AGE, January 1943 difficulty was overcome. This prac- tice use the present time and will likely remain use. mm. Shell Cleaning The mm. shell washer the spray type with capacity 240 gal. Solution level main- tained float valve and overflow device. The cleaning solution heated two gas-fired heat ex- changer tubes, the fuel gas flow being controlled thermostatically. The entire washer covered forced draft hood and the steam and vapors are exhausted through 10-in. pipe. Running through the washer hood roller type conveyor. Spray nozzles cated under the conveyor, along its sides and top. from four directions any work the washer. Cleaning solution supplied the spray nozzles single stage centrifugal pump the rate 150 gal. per min., ft. head 3450 r.p.m. the operating temperature, 180 deg. F., forceful jets are produced. Solventol No. 27, solvent type cleaning material, used wash concentration; gal. Solven- tol No. gal. water. Sol- ventol No. liquid concen- trate synthetic-organic solvents which neutral and partially mis- cible with water. partially miscible meant that about per cent the solvent mixes and creates solution with water. The remaining per cent exists insoluble which floats the water-cleaner solution phase blanket. This insoluble phase place, thus maintaining and stabi- lizing the cleaning solution. Cleaning with Solventol No. based upon dispersive effect rather than any chemical reac- tion. Its ability clean dis- persion makes possible the removal all types soil, grease, dirt and chips from all types cavities and grooves the metal part. Follow- ing the cleaning, all that quired air blow off, and the shells come out clean, bright and conditioned against rust and cor- | q q | , = type vash Sol- vents mis- tially and with floats phase phase the takes stabi- effect reac- dis- and and ‘ollow- the and rosion. addition the cleaning effects the shell itself, the dis- persion action tends keep the washing equipment, sprays and nozzles free from grease and dirt. The washing racks for holding the shells are two types, each holding 132 shells. They are welded construction and are either galvanized wire perfo- rated galvanized sheet, designed that each shell separated from other shells the rack parti- tion, thereby exposing its entire surface the sprays. The cavity t