The Iron Age 1935-07-18: Vol 136 Iss 3

emp- otel- ngly the oked Co., out hotel thing the perb, wy er, New rticle ficial your CHESTNUT AND 56TH STREETS, PHILADELPHIA, PA. Sales Offices 239 WEST 39TH STREET NEW YORK, Owned, Published and Copyrighted CHILTON COMPANY Executive and Publication Chestnut and 56th Sts., Philadelphia, Pa. Cc. A. MUSSELMAN, President FRITZ FRANK, Executive Vice-President FREDERIC C. STEVENS, Vice-President JOSEPH HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, ERNEST HASTINGS, WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary FRITZ FRANK, President VAN DEVENTER Editor LACHER Managing WINTERS FINDLEY Editor Emeritus Washington News Editor MILLER Machinery Chicago Cleveland Pittsburgh Detroit Contents Boston Cincinnati July 18, 1935 Zinc Ammonium Place Galvanizing .... A.S.T.M. Committee Reports Corrosion Data ..... How Secure Are Your Constitutional Rights? ......... Increased Light Values with White Personals and Obituaries Rate Activity Capital Goods............... Construction and Equipment BAUR, General Advertising Manager DIX, Manager, Reader Service Member, Audit Bureau of Circulations Member, Associated Business Papers Published every Thursday. tion Price: United States and Pos- sessions, Mexico, Cuba, $6.00; Can- ada, $8.50, including duty; Foreign $12.00 year. Single copy, cents. Cable Address, “‘Ironage, N. Y."’ Emerson 311 Union Cleveland Hottenstein, Otis Bidg.. Chicago Peirce Lewis, 7310 Woodward Ave.. Detroit Charles Lundberg. Chilton Bidg.. Chestaut & 56th Sts.. Philadeiphis. Pa. C. H. Ober. 239 W. 39th St.. New York W. B. Robinson, 42% Park Bidg.. Pittsburch W. C. Sweeteser, 239 West 39th St... New York D. C. Warren, P. 0. Box 81, Hartford, Conn. end this were calls dio’s em- nant, fer a than divi- BETHANIZED Alexander Calder, made Bethanized Wire combat salt air ENCES, strand and other zinc-coated prod- ucts made Bethanized Wire are better able withstand the corrosive attacks salt air. fact, wherever corrosion in- volved, Bethanized Wire will give far longer service than the conventional hot-galvanized product. The longer life Bethanized Wire under corrosive conditions due principally the heavier zinc coatings which Bethanizing makes possible. When desired, the Bethanized coating can made two, three more times the weight hot-dip galvanizing. The zinc applied electrolytic process, and differs both physically and chemically from ordinary galvanized coatings. not only heavier but the purest zinc ever produced and has bright, silvery lustre. tougher, more uniform, IRON AGE, July 18, 1935 more ductile, and more adherent the steel base. Even with the heavier coatings, Bethanized Wire can spiral-twisted, wrapped around its own diameter, even bent back flat itself, without injury the zinc coating. easily withstands weaving into chain-link fence, thus making possible fence with heavier and more uniform coating than could ever produced the galvanized-after-weaving process. The unusual qualities the Bethanized coating open the way tothe application zinc-coated wire new uses. Bethanized Wire being used for twisted wire brushes, for springs, for bicycle and baby-carriage spokes—and for host other uses which the heavier coatings, improved appearance, higher ductility, and other advan- tages contribute better, longer-lasting product. 4 | | THE IRON AGE JULY 18, 1935 ESTABLISHED Vol. 136, “Time for Complacency extract from address Charles Brinley, president, Amer- ican Pulley Co., before the Annual Meeting Machinery and Allied Products Institute. not time strip off the mask and cease prating reform and those good inten- tions with which hell paved? Let ac- cept the truth, face the music and realize where are going and what have fight. The time for complacency over. Men have been comfortable and rich and secure this country for many years that even now seems impossible make them understand and appreciate what going before their very eyes. this Ad- ministration has its way, shall better than puppets dancing upon strings. The program plain enough see for anyone who will take the trouble read it. involves complete revolution our social and economic structure; gradual destruc- tion capital and opportunities which capital provides, forced disintegration large units into small ones, less able pro- tect themselves and therefore more easily controlled, and so-called distribution wealth which actually and fact distri- bution poverty. powerful centralized Government with great bureaucratic follow- ing which will carry out the orders the sovereign and man the political machine, and finally, heavy curtailment those privileges personal liberty which for 150 years have been the attribute American citizenship. Every sign points down this road, which you will travel unless you realize the danger and dig your toes, for great forces have been unloosed. The propaganda chine which the Government controls, paid for your money and mine, unlimited extent and vast the power its persua- sion. Class hatred has been deliberately cul- tivated this country which before now knew class distinction and the the Congress has shamefully surrendered the will the President, the members voting often contrary their own convic- tions because fear for their political lives because otherwise their constituents may Gentlemen, this sorry situation find once proud, prosperous and self-reliant nation. The pity that has all been utterly unnecessary, wasteful the products human endeavor, and destruc- tive national morale. may judge the experience other countries and the history our own former depressions, should have, this time, been far the road prosperity, had only been allowed employ our wits and resources the old familiar ways. Civilizations are product evolution and the man who attempts change them over night suit his whim playing with the lightning. The bill, when the accounting made, predict will heavy one. | | ase. can ter, zinc link and pen hes, ngs, uct. wile ie Methods for Checking RINCIPAL requirements production accurate gears are outlined, and few de- vices for checking individual gear tooth elements are il- lustrated and described this abstract the first part the paper, pre- sented the recent annual meeting the American Gear Manufacturers Asso- ciation. The second part, de- voted automatic inspec- tion all errors combina- tion, means record- ing machine, will included forthcoming issue. Presentation the paper GEARS are employed principally for trans- mitting motion from and successfully fulfill this func- 2—Close-up involute tester. Two cylinders the same diameter the base cylinder from which the involute gen- erated roll two straight edges attached the pedestal. They are held arbor and head provided facilitate rolling the manner shown. RAF SHAPER included Jones Lamson comparator projection actual gears having definite- known inaccuracies. Red, liner inspection the same gears were shown slides illustrating the inspection all errors combination. The desirability smooth finish the working surface the teeth and few the methods lapping after heat treatment were also discussed briefly. Mr. Hamil- ton associated with the Fellows Gear Shaper Co. and Mr. Beardsley with the Jones Lamson Machine Co., both Vt. tion, the tooth action must smooth and continuous, requiring: that the line action longer than the base pitch; that the teeth evenly spaced; that the mating tooth shapes provide conjugate ac- tion; that there interference; and that the contacting tooth sur- faces have smooth finish. These are the principal requirements that must considered the produc- tion accurate gears. Elaborating these require- ments: the teeth should suf- ficient length assure line action which equal greater length than times the base pitch. The proportions this tooth element are matter de- sign, although certain manufactur- ing errors, such as: too much tip relief, irregular tooth spacing, er- rors gear mounting, etc., can de- feat its successful attainment. Uneven tooth spacing causes the driven gear alternately acceler- ate and decelerate the mating teeth come into and out mesh. other words, the motion not smooth and continuous. Tooth shapes which not pro- vide conjugate action have simi- testing machine. * H : t a t | | | | | t | | ‘ | ya DOUGLAS HAMILTON and ROBERT BEARDSLEY lar effect, and this especially the active profile not suf- ficient length obtain line action that greater than the base pitch. Interference contact the teeth other point than along the line action and can result from improper tooth design, inaccurate cutting, and the mount- ing gears shorter center dis- tance than that intended. serious source vibration and hence contributes noisy opera- tion. Methods for Checking Gears The method best suited check- ing gears governed large ex- tent requirements. These can two distinct classi- fications: Checking original design determine specifications have been adhered to, which would com- prise principally check the in- dividual tooth elements. Checking gears when duced quantities, where manu- facturing tolerances must ad- hered and errors are considered combination rather than sepa- rately. Obviously, only one gear treated the same manner original design and separate checks would made the various ele- ments. If, however, the gear was produced quantities, then devices capable determining ac- cumulative errors would em- ployed. Devices which fulfill requirements met under the first classifica- tion gear tooth calipers, templets, pin gages, etc. the classification would be: testing fixtures employing needle dial gages, master gears combination with record- ing devices, etc. From the standpoint inspec- tion, the four most important ele- 1G. checking machine employing master involute cam than base cylinders. The testing fixture controlled the master cam and quide bars. ments are: tooth shape; tooth spac- ing; tooth thickness; and concen- tricity. Helical gears introduce fifth element: helix angle. Checking Tooth Shape Most gears use are involute tooth shape and checking the in- volute comparatively simple operation. The involute that curve traced point string known the base circle. device employing this fundamental prin- ciple shown Fig. This known involute testing ma- chine. operates follows: two straight edges are attached pedestal and are located the same plane. Two cylinders, the same diameter the base cylinder from which the involute gen- erated, roll these straight edges. These cylinders are held ar- bor and head provided facili- tate rolling the manner shown Fig. the central plane, and the point origin the involute located contact pointer trace the curve the gear tooth. This pointer through suitable arrange- ments operates dial indicator without multiplication, the multipli- cation being the indicator itself. obvious that the base inders roll along the straight edges without slippage, any movement the indicator needle indicates deviation from the true involute. employed where extreme accuracy desired the checking tooth shapes. Another method shown Fig. While the principle used here slightly different manner. master involute cam, rather than base inders, employed and the test- ing fixture controlled the mas- ter involute cam and guide bars. the testing fixture moved about the table with the involute mas- ter intimate contact with the guide bars, any variation the in- volute being checked from that the master reflected move- ment the indicator needle. This THE IRON AGE, July | 4 ni- } gear measuring machine particu- larly adaptable checking gears and easy operate. Checking Circular Pitch Tooth spacing circular pitch can checked very readily fixture generally termed circu- lar pitch testing fixture, Fig. This device has fixed stop against which the gear tooth brought bear, and movable pointer con- nected with dial indicator which the adjacent side the following tooth. The principle illustrated diagrammatically Fig. The gear held stud car- ried arm. One side the tooth brought contact with fixed stop being held against this stop spring block The contact pointer carried with the adjacent side the fol- lowing tooth. Any errors tooth spacing are registered the dial indicator. All the teeth the gear are checked withdrawing the arm and indexing the gear the stud. This same principle applied gear measuring machine, Fig. The fixture the table which stop also clamped. The fixture carries contact pointer, stop and spring IRON AGE, July 18, 1935 finger that fulfill the same func- tion similar members the fix- ture previously shown. The circular pitch checking de- vices previously shown are appli- cable external gears only. fix- ture for checking circular pitch internal gears also available. Fic. 4—Fixture checking tooth spacing, circular pitch. IG. 5—Diagram illustrating the principle the circular pitch testing fixture. The same principle for mounting the contact pointer employed, and the entire apparatus attached swinging arm, which can ele- vated remove and replace the work. The position this arm can definitely set check gears various diameters, within cer- measuring machine employing same principle the fixtures } | | | | | t | | | ture. le- er- tain range, means adjust- able stop located the rear the bracket. Tooth Thickness, Backlash and Center Distance Tooth thickness, backlash, and center distance bear direct re- lation each other. Where two gears having the same number teeth are operate together, back- lash generally provided for thinning the teeth both gears equal amount. Where one gear much smaller than the other, the practice leave the teeth the pinion standard thickness and provide for backlash thinning the teeth the gear. This would the recommended practice where both were made from the same material, would tend more nearly balance the strength the teeth gear and pinion. There are two methods mea- suring backlash: one the use feeler gage placed between the teeth when they are located the required center distance; and the other bringing the teeth into intimate contact and then determin- ing the difference between the standard and measured center dis- tance. This last check does not in- dicate backlash directly, but can determined the following formula: Tan. Pressure angle Difference between standard and measured center distance. Checking Eccentricity Eccentricity the pitch circle chine for checking the lead right) one fixture for check- pitch circle. Errors concen- tricity are shown directly the indicator. cone point testing fixture, Fig. The gear checked held fixed stud and free ro- tate the latter. The stud re- tained arm. The cone pointer held spring ac- tuated plunger, this plunger con- tacting the plunger the dial indicator. The cone pointer lo- cated the tooth spaces and any errors concentricity are reflected directly the indicator. checking helical gears, element not present spur gears introduced. The teeth are not parallel with the axis, but are lo- cated angular relation it. obtain the best results from helical gears, that operate paral- lel axes, imperative that tooth contact between mating gears ex- tend across the face width the gears, necessitating that the helix angle mating gears held within close limits. checking this element heli- cal gear teeth, the sine bar method generally employed, Fig. Two settings are required: one with the pointer the fixture located about 1/10 in. from the upper end the tooth; and the second similar distance from the lower end. The fixture fulerumed the table, the pointer holder adjusted bring the pointer the correct relation near the top the tooth, and the stop the table set bring the pointer the vicinity the pitch line. gage block 0.100- in. thick placed under the in- dicator plunger and the needle set zero. The next step set the ma- chine for the second setting, but determine the arc through which the table should rotated and the height the work with relation the pointer. The angu- (CONTINUED PAGE 92) THE IRON AGE, July 18, tongs the moving chain are drawing this pipe from the galvanizing bath, and air jet blows out the interior the pipe. This view courtesy the Byers Pittsburgh. THERE considerable merit the use zinc ammonium the galvanizing pipe. First, tangible reduction dross obtained the elimina- tion hydrochloric acid the “bosh” tank. Second, there with its use solution thorough fluxing material, whereas impossible conceive several more pieces pipe, in. O.D. even larger, ft. long, re- ceiving thorough fluxing the inside while being forced bloc through deep and viscous vola- tilizing flux. For operation this nature cold solution the only prac- tical one, due the compactness large and heavy lift pipe with the consequent impossibility for each piece pipe become thoroughly dried inside and out- side the heat absorbed from any hot rinsing and solution into which the lift might im- mersed. Likewise immense “hot plate” surface area would necessary one could used assist this drying and pre- heating. The use cold solu- tion requires that each lift pipe drained thoroughly when re- moved from the pickling tank and again when taken from the rinse tank, minimize the acid “carry-over” and dilution the fluxing solution. the same time speed essential during these two periods draining order get the lift into the solution before oxidation sets in. The solution should carry deg. Bé. and will serviceable IRON AGE, July 1935 until outside dirt and contamina- tion necessitate its dumping. oughly rinse and drain heavy lifts pipe, several slabs zinc should kept the solution consume any acid “carry-over” and keep substantially neutral. Merely dipping the lift pipe into the solution three four times will not thoroughly and com- pletely coat each piece pipe in- side and out with flux, especially the lift large and the pipe diameter. Because this, measures should taken roll the lift while the solution, and the lift removed should drained thoroughly minimize solution waste. The volatilizing flux zinc ammonium chloride carried the surface the molten zinc can mostly foaming agent, inasmuch the actual flux content would used more body for the foaming agent than active flux for additional fluxing the pipe. The normal strength and depth this flux, sufficient mini- mize the splattering zinc, are maintained the wet flux adher- ing the pipe and the additions solid flux and foaming agent. Note: The seeming “bugaboo” liquid flux, i.e., the combina- tion the expensive dilution the fluxing solution wet ma- terial, and its inability remove the oxide which will form should the draining the rinsed material slow and immersion into the solution delayed, not great would indicated the re- peated references made the various chapters this ar- HOBBS Steel Service Engineer, Cleveland ° ticle. Both are problems which must considered when using zinc ammonium chloride liquid flux; but the fact that they can and are handled successfully the average plant proved the wide and extensive use this flux- ing medium and practice pres- ent-day galvanizing. While zinc ammonium chloride its solid form used very often flux the gavanizing nails, does not offer any advantage over sal ammoniac. However, made into hot (180 deg. 190 deg. F.) deg. solution and used liquid flux into which the nails are immersed just prior galvan- izing, becomes the better and more economical fluxing agent the two, for solution form offers several fundamental vantages which cannot obtained from solid flux. Briefly, these advantages are follows: liquid flux, regardless strength, coats each nail thorough- ly; thus economy effected that the strength the fluxing solution can experimented with until the strength found which will coat the nails with the mini- mum amount flux necessary for good galvanizing. each nail thoroughly coat- with more less even coating flux, the galvanizer obtains satisfactory galvanizing operation, smoother and brighter finish and from spots and poor coating. When using the liquid “sal fumes” are reduced materially with consequent improvement the working conditions the de- partment and reduction the | } | q | q | | > ie Chloride: Its Place Modern Galvanizing amount finished product dis- colored excessive and heavy fuming the flux. The overall period time re- quired for galvanizing less with liquid flux than with solid flux inasmuch time required for the breaking down and volatil- izing the latter and for fluxing the nails, whereas with liquid solution the nails are already coat- with flux which completely volatilizes the first few moments the operation. While strength deg. Bé. given the proper strength for fluxing nails, local plant conditions and the type nails galvanized will affect this figure certain extent; hence each plant should conduct experiments ascertain the strength solution most suit- able and economical for its require- ments, Except few isolated cases have brought about measure suc- cess, ammonium chloride used liquid flux the preparation wire for galvanizing has failed show sufficient economy op- eration and sufficient improvement the finished product warrant its adoption place “killed zinc” dissolved hydro- acid) plain hydrochloric acid. This failure attributable several factors. For instance, the pickling and fluxing operations employed most wire galvanizing plants consist pickle hydro- tailed view the tion, showing the attached the pipe arid the air jet re- zinc the pipe emerges from the bath. this article, the conclud- ing installment three- article series, the author pre- sents review the cation zinc ammonium vanizing pipe, nails, wire, buckets, boilers, drums and line hardware. THE IRON AGE May 23, the history galvanizing fluxes was re- viewed, and June the advantages disadvan- tages using zinc ammoni- ing castings and sheets were discussed. chloric acid with rinse. The wire goes directly from the pick- ling solution into cleaner and weaker solution the same acid, this being the flux “bosh” tank solution, and from there into the molten Both solutions are kept hot, usually open-end steam line. few cases, mostly where zinc chloride made “killed the place acid, rinse tank used between the pickling tank and the flux “bosh” tank, but such installations are the minority. However, with the use liquid ammonium chloride solution the rinse tank absolutely es- sential. Properly equipped, such tank should have the entrance end strong spray for the purpose eliminating acid “carry-over” into the fluxing solution. The temperature the water, regardless this spray, should sufficiently high induce self- drying. The fluxing solution should hot (180 deg. 190 deg. F.) and should average deg. deg. Bé. strength. the solution should done with steam coil inasmuch open-end steam line would rapidly dilute the solution the point where its strength would insufficient properly flux the wire. stronger solution than deg. deg. Bé. not necessary, and increase this strength would merely add the objectionable tendency the flux accumulate and volatil- ize the back-end the pan, which has been carried the fluxed wire such quantities that time dragged down through the pan the steady pull the wire being galvanized. cold fluxing solution requires the same strength and method operation does hot solution, but, inas- much the constant “dragout” the cold solution expensive, this practice not recommended. Wire galvanizers, except when “double-dip” galvanizing, seldom ever use sal ammoniac the back- end pan, their one objection — = y — - t } d e e ' | this volatilizing flux being its “dragging through” into the pan, where rises and “messes up” the surface the molten zinc. Therefore, their extension this objection include the steady accumulation and “dragging through” the volatilizing zinc ammonium chloride flux can readily understood. that the proper use am- monium chloride liquid flux place hydrochloric acid will show tangible reduction the. amount dross produced (this reduction ranging from per cent per cent the average plant) the galvanizing wire. How- ever, the difference the initial cost and the daily consumption the two fluxing agents, the cost the additional equipment re- quired most cases, the closer supervision necessary with the zinc ammonium chloride solution, and the fact that little noticeable improvement evident the finished product, minimize the economic advantage this dross reduction the point where offset nearly all cases. Furthermore, some cases the dross reduction advantage more than offset the increase the overall cost fluxing. For the sake brevity the term “buckets” will used chapter designate all galvanized fabricated articles, such wash- tubs, buckets, ash cans, pails, gar- bage cans, etc., which are usually made plants manufacturing and galvanizing buckets. These buckets are fabricated IRON AGE, July 18, 1935 NSPECTING galvanized pipe the Byers Co. plant. After leaving the galvanizing pot, the pipes are cooled the water sprays shown the background. the foreground, inspectors are examining the pipes for defects coatings. and sheets, and usually undergo cer- tain amount punching, forming, seaming, riveting and welding. Also, for the most part they ac- quire one more bands heavier metal and bail handle, and nearly always become more less smeared with grease and oil. Therefore, stack nest buckets does not present much one cleaning for the removal this grease. Many plants have the necessary equipment de-grease and rinse the buckets before pickling, but there are sufficient number with- out this equipment warrant elaborating what the lack can mean. Lacking de-greasing solution, the removal grease from the buckets must done the pickling solution which, .be- cause this grease, has car- ried much higher strength and temperature than otherwise would Intensive pickling with this strong solution often leads overpickling and sel- dom removes all the grease from the buckets. The grease re- maining carried through the through the flux “bosh” tank containing hydrochloric acid so- lution, and into the volatilizing flux the galvanizing kettle, there carbonize and materially assist “killing” the flux. rather difficult conceive economical and successful galvanizing operation plant where the total equipment for the complete operation (de-greasing, rinsing, pickling, rinsing, liquid fluxing and galvanizing buckets spotted with grease and oil) con- sists pickling tank, rinse tank which acid has been added that will flux well rinse, and galvanizing kettle. However, this the equip- ment set-up which will found today more than one plant fab- ricating and galvanizing buckets. The practice removing nest several more buckets from the pickling solution, rinsing and fluxing this nest unit, and still unit setting them within reach the pot man who breaks immersing the buckets, one time, into the galvanizing kettle, presents difficulties the proper rinsing, liquid fluxing and draining the buckets. Allowing for the fact that the nest loos- ened each time immersed into the rinse water fluxing solu- tion, the speed operation most plants such that between the time the nest removed from the pickling solution and the time reaches the pot man, there can little time allowed for proper rinsing the pickling so- lution and thorough draining the rinse water and the hydro- acid “bosh” tank solution. The result that the latter solu- 7 | | | t | | . = tion steedily diluted with rinse water, and most the buckets enter the volatilizing flux coated with heavy film acid. increased cost pickling due premature dumping greasy solutions, increased cost maintaining volatilizing flux be- cause premature decomposition from fluxing greasy buckets, and greater economic incurred through the increase dross pro- duced heavy and constant addi- tions acid the volatilizing flux, can all attributed grease, and poor rinsing and drain- ing. addition, when considera- tion given the seams, ridges, indentations, the overlapping metal bucket, all which pre- sent pockets traps for acid film, and particularly for dead flux, there every reason believe that the complaint heard many plants the excessively high percentage flux spots the galvanized bucket, necessitating regalvanizing, and the highly corrosive attack these flux spots overlooked the final inspection, also can justly attributed consistently dirty and highly acid volatilizing flux which has been made and kept that way the steady fluxing grease-spotted product carrying excessive film acid. While zinc ammonium chloride used plants where the equip- ment and practice necessitate the galvanizing operation containing some all those factors which have been described and which ma- terially and detrimentally affect the flux and the whole operation, sufficient has been written already plant hand dips the pails flux, after which they are ized. Zinc ammonium chloride can used quite advantageously the galvanizing pails and containers. regarding the importance and ne- cessity proper de-greasing be- fore pickling, and thorough rinsing and draining all solutions em- ployed before galvanizing; there- fore, describing the proper use zinc ammonium chloride flux this operation, will with the assumption that the buck- ets reach the fluxing solution free grease, properly pickled, and thoroughly rinsed and drained. must not taken for granted that complete and thorough rinsing and draining the solutions into which the buckets are immersed during the course the entire operation will mean the elimination nest- ing and the handling several more buckets unit. Some plants have tried and adopted practice pickling, rinsing and fluxing the buckets loosely nested together, and removing them from the various solutions unit, but upon removal temporarily breaking this unit removing and draining each bucket separate- ly, then renesting for passing the next operation. This method materially reduces the objection- able “carry over” the various solutions, and does not increase the time the operation the point where retards production. The fluxing solution used this operation should average deg. Bé. strength and should used cold conjunction with volatiliz- ing flux the surface the molten depth minimize the splattering zinc, which the primary pur- pose for its use. The usual pre- cautions should taken prevent acid “carry over” into the fluxing solution; and consume any which might carried over the rinsed material, one more slabs zine should kept the solu- tion. Due the amount solu- tion which can entrapped the average bucket similar product, far more economical drain the fluxed buckets over the fluxing solution than stack them the feeding table, where they drain un- til dry the pot man disposes them. While possible this opera- tion use hot fluxing solution conjunction with “hot plate” and volatilizing flux the surface the molten zinc, scarcely feasible. The size some the products galvanized requires pre- heating oven rather than “hot plate,” and the smaller products, unnested before placing the oven, would almost always out the reach the pot man. Note: zinc ammonium chloride volatilizing flux made the same manner one made from sal ammoniac, and the foaming agents which have been successfully used with the latter flux will react equally well with zinc ammonium chloride. With the exception that por- tion the chapter devoted the handling small articles and (CONTINUED PAGE 92) THE IRON AGE, July 18, le, ise ip- est hin aks ing the ing nto een ime can for dro- ‘ion. olu- Committees Report ASSEMBLED their annual meeting, about 1000 members the Amer- ican Society for Testing Materials were entertained varied and highly informative technical ses- sions during the week June Detroit. About technical pa- and reports from the vari- ous committees were presented during the meeting’s fifteen ses- sions. extensive exhibit testing apparatus equipment also was which afforded members unique opportunity examine many types standard equipment and also variety special instruments used the testing fraternity. The report committee E-4 metallography was particular interest laboratory workers in- asmuch included the recom- mendations subcommittee These recommendations included extensive revision the standard methods metallographic testing iron, steel and non-ferrous * 22—THE IRON AGE, July 18, 1935 metals and alloys. They are follows: Cleanliness during polishing and etching essential. All grease and oil must first removed. For galvanized material, the should removed dissolving cold, concentrated HNO; di- lute unless, course, the galvanized coating itself studied. The nitric acid method requires some care prevent over- heating large samples generate much heat. The container should immersed cooling medium during use. Rusted fractures may cleaned with dilute solution ammonium citrate phosphoric acid. Iron and steel specimens should prepared the following man- ner: (a) Rough grinding abra- sive wheel coarse emery paper usually sufficient, and even ma- chined surfaces may sometimes prove satisfactory for deep etching specimens for macroscopic exam- ination. somewhat smoother fin- ~ ish may desirable when less severe etching, such with am- monium persulfate, follow, sulfur printing. polishing for microscopic examination, the specimen should not too large, preferably not over in. square and about in. thickness. flat surface obtained either rubbing the grinding abrasive wheel. The specimen then ground emery paper, which may mounted disks revolving about 500 1200 r.p.m.; three suc- cessive grades paper, such Nos. 00, are sufficient. The grinding each paper should one direction, preferably deg. that the preceding stage. This followed the wet polish- ing stages cloth-covered wheels revolving about 400 r.p.m. these are applied water suspen- sions No. 320 alundum, No, 600 alundum, and levigated alumina, respectively. The cloth should not too thick and should have inner surface specimens after corrosion tests. Reading from left Material used successively five runs totaling weeks: material before run softened water: material after one run tap water; and material chined before softened water. 3 j | | ; | 4 : { | Corrosion and Metallographic Data cotton cloth resembling ordinary linen table cloth weave and weight works well. The final polishing remove all scratches velveteen cloth with Merck’s heavy magnesia; this should ap- plied dry rubbing into the mois- tened cloth; any rough particles can felt with the fingers and wiped off the edge the disk hand. During these polishing stages the specimen should in- termittently continuously turned about the vertical axis avoid pit- ting. The specimens should washed after each stage avoid carrying over any the abrasives the next stage and must not allowed stand without drying, deep pits, due rusting, may form very rapidly. After polishing, the specimen should washed warm water (21 deg. maximum) alcohol, swabbed with absorbent cotton moistened alcohol, and dried blast warmed air (21 deg. maximum). Special care should taken wash the magnesia wheel water contain- ing trace after using, the magnesia cakes and hardens taking CO, from the air. Other Polishing Methods can obtained with the procedure described paragraph (6), but many other satisfactory variations have been suggested. Vilella omits the intermediate wet polishing stages and goes directly from fine emery paper (No. 000), smoothed rubbing with graphite, the final polishing wheel. This reduces the chances dragging out non- metallic inclusions steels and graphite gray and malleable cast iron. good flat crepe with alumi- satisfactory substitute for velve- teen and magnesia for studying in- clusions. essential that pit- ting and dragging out inclusions and graphite avoided; this can accomplished the general method outlined paragraph (b), care used. Other investiga- tors also recommend final dry polishing for material containing graphite. Wheels covered with paraffin are used number laboratories, generally with the abrasives suspended solution per cent liquid soap and per cent water. Impregnating the abrasives the paraffin wheel has been tried. Pulsifer omits the final polishing stages and etches after wet polishing emery flour; alter- nately etching and polishing. recommended method for polishing cast iron consists run- ning through the four grades abrasive papers (from Nos. 180 400) vertically mounted wheels rotating about 500 600 The center portion the No. 400 disk, where the paper has been glazed with graphite, used for the fifth polishing step. The final polish made moistened flat silk crepe which mounted horizontal-type disk rotating 750 alumina (which settles the rate in. per hr.) used the abrasive. Table Data Non-Ferrous Alloys Sulfuric Acid (Pickling Solutions) Material A—Commercial C—Cu-Si-Mn Alloy (96 Cu, Si, Mn).. D—Tin Bronze (92 Cu, Sn)...... J—Low-Carbon Ni-Cr-Fe-Alloy (22 Ni, Cr, bal. K—Manganese L—Brass (85 Cu, Zn).. M—Brass (70 Ou, Zn)... N—Admiralty Metal (70 Cu, Zn, Sn). P—Cu-Ni-Zn Alloy (75 Cu, Ni, Zn)... Q—Cu-Ni-Sn Alloy (70 Cu, Ni, R—Cupro-Nickel (83 Cu, (99 per cent).... X—Silicon Cast Iron. Bronze (75 Cu, Sn, Pb).... Two specimens lost due brittleness. All specimens lost due brittleness. All specimens lost. Series Test No. 31, days exposure Test Location No. 32, days exposure Series C Series C Test Location No. 33, days exposure Corrosion Corrosion Corrosion Change in | late, Change in | Rate, Change in Rate, Weight, gm. mg. per sq. mg. per Weight, mg. per dm. per day dm. per day dm. per day 19.9 451 17.8 286 320 18.0 408 15.6 251 26.3 272 23.0 521 17.6 32.0 330 15.6 354 248 238 19.2 435 18.5 298 292 18.2 413 28.5 204 18.8 427 18.6 299 28.0 289 19.3 437 | 19.2 | 308 20.4 | 303 14.5 329 20.3 326 25.2 260 14.4 327 441 | 25.6 337 33.9 i 320 43.6 263 THE IRON AGE, July 18, | ess m- pic | ns | ts. ve H er ir; | This method permits the retention graphite with good, scratch- free surface. general, very soft specimens are more difficult pol- ish than hard ones. Specimens about in. square are pre- ferred larger sizes, due the shorter time required for any given step the polishing procedure, particularly the silk crepe wheel. The less time spent the last stages polishing, the better are the chances for complete reten- tion graphite. Sulfur has been found satisfactory mount- ing material, (e) Polishing machines which the specimen held and rotated automatically have been employed and are being more and more ex- tensively used. Various abrasives have been used. Rodda has described meth- for preparing graded abrasives for metallographic polishing but for most work, however, the com- mercially obtainable abrasives and polishing powders are satisfactory. Ordinary levigated alumina pur- chased bulk may re-levigated just before using suspending water for about minute longer and siphoning. Silicon carbide and boron carbide powders and dia- mond dust have been recommended Hoyt for polishing tungsten car- bide. general, polished metal shows trace crystalline structure; etching used clearly delineate the structure and produce opti- cal contrast between the various constituents. great number etching reagents and methods for iron and steel have been pro- posed, but the majority work can done with relatively few reagents. deep etching, hot solutions acids, are generally used; deep etching reveals physical and chemi- cal non-homogeneity such poros- ity, cracks, seams and segregation; aqueous solution ammonium persulfate brings out the grain structure; Stead’s reagent brings out phosphorous banding; Fry’s re- agent brings out Cooling low-carbon steel specimens either ordinary “dry” ice pri- grain boundary contrast. For photographing, increased contrast obtairfed washing after etch- ing and applying glycerin the etched surface. Table are given the etching 24—THE IRON AGE, July 1935 Etching Reagent No. Nitrie acid per cent No. 1A. Nitrie acid per cent Nital). per cent No. Ferricyanide peroxide and so- dium hydroxide.. No. Mixed acids No. Chrome-regia{ No. 10. Ferrie No. 12. Copper sul- fate and No. 13. Ferricyanide No. 14. Neutral sodium No. 15. Chromic acid per cent chromic acid, and Steel (For Microscopic Examination) Composition HNOs cone.)............ HNOs Ethyl 100 cent NaOH, aqueous Ethyl 100 Ethyl (cone.)........... part Acetic acid (28 per part parts parts Ferric Dilute 1000 ml. with per cent ethyl al- cohol. per cent neutral sodium picrate solution. heat tinting. Remarks Only clear white HNOs (sp. gr. 1.42) should used; time, few seconds about minute. See reagent No. Clean, dry, acid tals should used; time, few seconds about minute more. Use boiling, min. May used cold, but pref- hot; should freshly made; time, min. min. Dissolve the salts the least possible quantity hot water; etch for about minute; should used with discrimination. Time, about Time, about sec. longer; method alter- nate polishing and etch- img should used. The activity this solution the amount acid. Time, about minute. May also used hot; time about minute. Chemicals should ac- curately weighed. Time, minute. Use freshly made boiling solution for min. Wash salt well with alcohol remove excess picric acid alkali, immerse boiling solution for min. Etch first acid, then for min. chromic acid; heat tint placing specimen face hot ate heated about 250 (500 F.) for about minute. Table A.S.T.M. Etching Reagents for and and Its Uses For carbon steel, iron, and out grain boundaries ly, earbides are unetched for the structures trided steels. For tempered samples. Same reagent 1A; the grain size quenched steels brought out after prolonged etching; picra shows detail more cately than nital. Colors cementite, but not carbides high tungsten steels, iron- tungstide and iron-tungsten-carbide (Fe:W:C) are colored, but tungsten carbide affected; attacks Darkens carbide containing chromium; carbides and tungstides and high-speed steels. room temperature colors ternary carbides onds, several minutes, and barely mentite. Darkens iron tungstide alloys. When present this solution dark- ens the compound amount carbon present tungsten carbide dark- ened. For showing segregation phosphorus; copper tends deposit first areas poorer phosphorus. reveal strain lines and precipitation effects “aged” steel. careful examination. For per cent chromium, per cent nickel steel; also for structure iron-chromium base containing aluminum, tungsten, vanadium, man- ganese, niekel and denum. For per cent chromium, per cent nickel steel. For austenitic For structure steel, particularly revea! tion per cent chro- mium, per cent steel; total depth ni- trided case. For showing total depth, structure, and zones nitrided steels. Shows difference carbides and nitrides; mentite pearlite turned and massive nitrides Darkens iron tungstide high speed steel but not the complex carbide; dark- ens iron-phosphide iron but not cementite. Distinguishes phosphide and the phosphide cast iron; phide colored — f . picrate.......... solution......... No. micro reagent......... reagent.......... solution......... and and el, iron, Nital brings ndaries clear. unetched tures mples. nt 1A; the quenched tht out after hing; more but not steels, iron. colored, but cks sulfides. containing and tungsten steels. es (Fe;W;C few see- tungstide ral minutes, on-tungsten dark- ind (FeW rtion the present dark- regation tends f on areas horus. lines and Requires tion. stainless ructure of yase alloys uminum, jum, man- molyb- to reveal ent chro- nt nickel of ni- depth, various steels. between des; ce- ackened, brown, ides re- stide Aluminum and Its Alloys, Copper and Its Alloys, and Nickel Alloys Reagent Composition Remarks Uses parts silicon areas more lightly etched. 0.5 etching ishing. iron. Current density 0.5 amp. per sq. dm. No. 19. Mixed part ride and let stand others high nickel min. before use. Swab. cobalt. No. 20. Nitrie parts Swab. Same for reagent No. 19. HNOs mi. Immerse specimen about For detecting te, solution ml. nitro- NaOH remove film,| reagent No. benzol. rinse aleohol. Use only Nickel and Alloys No. Flat ml. Make fresh ‘daily; use Nickel, Monel metal and Glacial acetic clear white avoid other nickel-copper alloys, staining; etch immer- Dilute with per sion room temperature cent acetone for alloys for less than per cent nickel. and platinum wires. than flat No.3. Nitrie HNOs Etch immersion. Macroetch for silver. No. Ammonium NH,OH............ ml. Eteh immersion. For high-zine nickel silver. Compositio Steel (For Macroscopic Examination) Etching Reagent 75 mil. ml. aleohol the steel. Recommended viteh, used above for from min. cracks, depth hard- ened sone tool steel soft spots, etc. Same for reagent No. works well for stainless Used cold for large surfaces Same for reagents Nos. such split ingots which conveniently heated Surface should rubbed with absorbent cotton during etching. The salts are dissolved the HC! with the addition the least possible quantity hot water. Most useful for mild steel, particularly bessemer steel; before etching, sam- ple should heated 200 250 (302 482 F.) for min., de- pending the condition the steel; during etch- ing the surface should rubbed with cloth soaked the solution; wash rinse (1:1) after prevent de- position copper. Same for reagent No. but modified may give more contrast; specimen can washed water deposit- ing and bring out grain structure cases excessive grain growth, welds, etc. bring out phosphorus- areas and phosphorus banding. show strain lines due cold work. Same for reagent No. sec. (10 per cent). to increase contrast. reagents commonly recommended for macroscopic examination iron and steel. Application Sulfur Printing Sulfur printing macroscopic method for revealing sulfur segre- gation and the size and distribu- tion the The surface the specimen pressed against sheet photo- graphic paper which has been mois- tened with dilute aqueous solu- cent). Matte-finish photographic paper preferable prevent slip- ping. few seconds about minute contact may necessary depending the sulfur content. Yellow brown specks the pa- per indicate the presence sul- fides the specimen. The prints are fixed sodium thiosulfate (“hypo”), washed, and dried. Transparent silver bromide paper can also used give sulfur print transparency from which con- tact prints any number can made ordinary photographic paper. There some question whether the presence phosphorus will also give yellow color. Royen and Ammermann state that prints made gelatin paper with use the following solutions reveal only sulfur; phosphorus having ef- fect: Solution cadmium acetate plus 200 acetic acid (80 per cent) which 950 H,O. No. 120 gm. plus 880 plus 120 ml. The specimen tested pressed for min. upon gelatin paper which has been treated with solution No. and yellow cad- mium acetate precipitated. immersion for min. solu- tion No. this transformed H,O the dark brown black Etching for Microscopic Examinations Mild etching solutions are gener- ally used for microscopic examina- tion. For carbon steels, solutions nitric acid ethyl al- cohol are most commonly em- ployed; alkaline solutions like sodi- picrate potassium ferricy- anide are used for darkening the carbides; for stainless steel aqua regia diluted glycerin gives good results while electrolytic etching frequently employed. THE IRON AGE, July 18, se but not dark- cast mentite | eutectic rker. The polished thoroughly cleaned sample immersed the solution face means nickel other corrosion-resisting etching tongs. During etching often desirable stir the solution gently swab the surface with absorb- ent cotton avoid deposition smudge; for stainless steel this necessary also prevent gas bub- bles from clinging the surface. The progress etching can gener- ally observed visually, but should also carefully timed. the sample not etched sufficient- ly, the process may repeated, but overetched the sample may have repolished even reground; too deep etching, there- fore, should avoided. may frequently necessary, especially with stainless steel, etch, repol- ish, and reetch, order remove the surface layer deformed metal produced during grinding and polishing. Table are given the etching reagents commonly recommended for microscopic examination iron and steel. Cracks are readily revealed deep etching per cent solu- tion sulfuric acid water works well for grinding cracks), but this method may too destructive for some purposes and may actually cracks. For fine cracks such may produced quenching, fatigue, grinding hardened steel, the magnetic method useful. Another method place the part tested warm oil, clean thoroughly, and paint with lime; the presence cracks revealed oil spots the lime. still another method the sample immersed sulfide solution; due the capillary effect some the solution sucked into any crevices present. The sample then cleaned and pressed against photographic paper mois- tened dilute sulfuric acid; black. silver sulfide formed the cracks. Preparation Aluminum and Its Alloys For preparing aluminum and its alloys for microscopic examination, the following procedures are rec- plane surface obtained and saw-marks removed rubbing medium mill file. After the file cut, the specimen rubbed succes- sively Nos. 00, and 000 metal- lographic emery papers coated with 26—THE IRON AGE, July 18, 1935 Copper and Its Alloys Etching Reagent No. Ammonium droxide-hydrogen No. Ammonium droxide-ammonium No. Ammonium hy- No. Ammonium per- No. acid-hy- No. Chromic No. Copper chloride-ammoni- hydroxide........ Composition rts parts Dilute solutions. part Saturated aqueous solution HCl Remarks Peroxide content varies di- rectly with copper content alloy etched. Im- mersion swabbing for about min. Fresh desirable for good re- sults. Immersion. Immersion. Use either cold boiling. Immersion. Immersion swabbing. Add time use. drops. per cent aqueous Immersion. solution copper ammonium chloride plus neu- tral alkalinity. Parts FeCl; HCl men thoroughly. Immersion swabbing. Etch lightly successive light etches required Use Generally used for coppe and many its alloy, Film etched bronze removed Grard’s solution. Polish-attack etching brass and bronze. Polish-attack copper some alloys. Copper, brass, bronze, si