US1056627A - Method of oxidizing steel or iron sheets. - Google Patents

Description

Patented M APPLICATION FILED NOV. 8, 1912.

i all when@ it may concern:

l Application led.Novemlier 8, 1912. .Serial No. 130,126.

UNiTED 'STATES PATENT 'onirica i, JOHN E. 'cAnNAHAN A Np-AR'ri-ivnc. MASKREY, orf-carmen, omo.

vini'rlon or QXIDI'ZIG STEEL on IRON Simms.

- sneotcation of Letters Patent. Patented Mar. 18,1913.

-Be'it known that 'Wa-JOHN E.A CARN'AHAN' and ARTHUR J. MAs'KREY, both citizensof the United States, aritlboth residing at'Canton, lin the county of Stark `and State of Ohio, `have invented a newv and useful Methodof ,.Oxidizing Steeler .Iron Sheets, of which the followingis a specification.

`. (The-.invention relates -to 'the oxidation-'of the surfaces of steel or iron sheets,- for the purposel of givin them a uniform bluish color, and especia ly to'that method of bluing -whereby vthe sheets are. heated 1n^an annealing box and .wherein steam is'- em.

ploy'ed as lin-'oxidizing agent.

. 'A well known method of oxidizing very. chea .grade of steel',` sheets, Vas for use 1nmaking ordinary stove.' ipes, is to heat them in `an annealing box an blue them vby a bath of steam immediately fafter the sheets come "from thereducing rolls, 'and before the 4`sheets have been ,",Ipickled yor otherwise Aff'zleansed, and then tosubsequently anneal I Jthesheets and finish them `between cold rolls;

fbut it is obvious that theunclean condition j ofthe sheets beforel theyr are pickled andthe anneal and cold roll the sheets, and t en to heat them-in anannealing boxjand blue' them with' a bath' of steam;'but it' is obvious that the smcothing'and' polishing of, the surface bythe pressure of the cold rolls',

and the close contact 'of the surfaces of the A finished sheets .when `packed for annealing, prevents thefdevelopment of a.v deep and uniformoxidation on the surfaces, and does' 'not give therich color` which. is muchdepresent inventi'omin the practice. of which. ythe black sheets are first pickled and .then

sired. .These diiiculties are overcome by the i packed in apile and annealedI in theilsual manner; and then cooledand separated and repacked fand reheated inan annealing box,-

`and-then oxidized by steam' When? partially cooled, after lwhich they arec'oldrolledv for finishing, Vandvagain heated yfor softening and` steamed for .preserving .the uniform color, after] which theym'ay be again cold rolled for certain special uses.

`.., T1he i1vention. thus set .forthf "general 'terms-1s preferably practised by the'us'e of an ordinary annealingpan and boa, as illus- 'trated in the accompanyingdrawingform.-

ing part hereof, in Which- Figure 1, is aside elevation of an annealing'pan and box, with part. of the box broken away to show a pile of sheets packed therein; Fig. 2, a cross 'section of the annealingpan and box', on a track androller truck,

showing a pile of annealed sheets packed therein; Fig.. 3, a similar section showing .a pile o'f sheets loosely repacked therein, foi' j the improved bluing process.. Fi .4, af'rag- .mentary View of the surface o a pickled unfinished sheet showing the comparativel f rough and convoluted condition thereo and Fig. 5, a fragmentary exaggerated section of a pile of repacked uninished annealed sheets, showing the slight interval .between the rough and convoluted surfaces thereof. A l

Similar numerals refer. to similar parts throughout'the drawings. f

For the purposes fof the present process, when ythe black'sheets'have been reduced by rolling, they are first'pickled Vin sulfuric ormuriatic acid and'then'washed. in clear Water in the usual manner, for completely cleaning the surfaces thereof, which then presents a rou-ghened and 'somewhat porous condition', as illustrated in Fig. 4. f The sheets' .are then packed'in'a' pile 1, on an annealing pan 2 and thencoveredwith an annealing' box 3, the rim of which lated with sand 4.- in .the lusual manner, to seal the box. The sheets arejthen annealed by dieating them in. 'a furnace to some 15000 F., fora substantial period, andare then cooled by With-1 drawing' them .from the furnace, while covered by the box, in the usual manner.

The' high heat( ofthe annealing process andthe softening iniuence thereof, causes the sheetsof the pile to subside and to packand stick so closely together. as to substantially ,exclude the entrance of air or steam.

between them.,' v'1 `hi s.adhesion ofthe sheets together 1s 'so tenacious, that it requires eon-V siderable .forceto separate one sheet from another, and no doubtthe principal reason Why sheets have not vheretofore been oxidize'd immediately after being pickled and annealed.

i When: the "shee`ts are` cooled after being'v annealed, the box is-removed and the sheets..

' are first separated and then re acked one by one, the order of the sheets veing preferably reversed to avoid a'contacting of .the

same sides in the repacked pile; and itis evident that the rough and porous condition of the unfinished surfaces of the sheets, together with the slight distortion in lshape caused by their separation, prevents them from being repacked so closely together as to exclude air or steam from between them. i' I=`1ct, it ha.-y been found that the separating and repacking ot the sheets as described, will leave such a substantial interval between them as to permit a free entrance of steam between them and cause a. complete and uniform oxidation of the adjacent snrfaees. The. sheets are again covered by an annealing box, the rim of which luted by .sand as before` and the repacked sheets are then heated in a furnace to a dull red heat or about 1000@` l".` after which they are withdrawn from the furnace and cooled while yet covered by the box, to a dark red heat: whereupon dry live steamris. introduced into the box, which in practice is done by slightly elevating one end ofthe box and inserting thcrennde a nozzle through which steam is discharged into the box, the luting sand being packed around the nozzle. The bath of steam is preferably maintained until the sheets are so cooled that the. steam will not be further decomposed, after which the box is removed and the sheets are smoothed or polished by passing them a sufficient. number of times between the cold rolls to produce the finish desired.

lt has been found that by separating and repacking thc previously pickled annealed sheets, and blning them by a bath of steam before they have been smoothed or polished by cold rolling, a very. deep, and substantially `complete and uniform oxidation of the surface is attained: which is no ldoubt caused by the factY thatthe separation and repacking of the sheets. permits the steam to enter freely between them, and the roughness of the unfinished surfaces, permits the steam to pentrate more deeply into the body iof the sheet than would be possible if the same had been previously smoothed. Furthermore the lower degree of heat required for the bluing, does not cause the sheets to pack so closely together as in the annealing process. The subsequent cold Vrolling of the sheets for finishing the surfaces. serves to impress the deep oxidation thus formed into` the surface of the sheet, so that the oxida#` tion is not'. merely a superficial film, but has a deep'interengagementwith the body of the sheet. Tty is preferred to give the sheets an odd number of passes between the cold rolls, thereby again reversing' the order of the sheets in the pack for the subsequent step in the process.

Thqamount of cold rolling necessary for finishing the more highly polished sheets and impressing the oxidation therein, usually makes thc sheets too hard forgencomparatively soft condition of the sheets after the rcheating permits a finer `gloss to be obtained b v the final cold rolling. Furthermore, the rcarrangement of the pack to bring the sheets which were at the bottom of? the pack for the first steaming n'ocess, to the top of the pack for the seeonil steaming process. relieves these sheets from the superimpesed weight of the pack, and permits` the steam to fl'ow more freely between them: and it is evident that if these sheetsare not uniformly and deeplyoxidized by the first steaming, they vwill be so oxidized by the second steaming. By these means, a deeper and more tenacious oxidation is produced on the surfaces of the sheets, and while `it may not be possible to produce an absolutely uniform color from the middle portions to the edges of the sheets by any method of oxidizing them'while cooling in packs, it is believed that a greater uniformity of color is attaiired by the method herein set forth, than by any other process of the same character. Thatevcr variation in color which may result from this method, is a gradual, uniform and undefined change from the middle portion to the edge portion, Without showing any well defined or distinct-ive zeges or bands of color on the surfaces of t-lie\sheets.

Te claim 1. The method of oxidizing steel or iron sheets whichconsists in pickling and annealing them. then .separating and repacking them in reverse order, then oxidizing them by heating and steaming them in an annealing box, then cold rolling them, then repacking them in reverse order and repeatin; r the oxidizing process, and finally cold rolling the sheets.

2. 'lhe method of oxidizing steel or iron sheets which consists in pickling and anneal- \in-g them, then separating and repacking :them in reverse order, then oxidizing them by heating and steaming them in an annealing box, then cold rolling them, and then repacking them in reverse order and repeat-ing the oxidizing process.

The method of oxidizing steel or iron sheets which consists in pickling and annealing them, then cooling, separating and repacking them one hy one, :hen oxidizing them bv heating and steaminer in an annealprocess.

'- e`ss, and finally cold rolling the sheets.

el. The method of oxidizing steel or iron sheets Which consists in pickling'and annealing them, then cooling, sept ating and repacking them one byone, then oxidizing them. by heating and steaming .in `ein annealing box, then cold rolling them and then repacking them and repeating the oxidizing 5. The method of'oxidizing steel or iron sheets which consists in pickling and anneah.

ingth'em, then separating andV repaeking them in reverse order, then oxidizing them in :inA annealing box, then cold rolling them, then repaoking them in reverse order and repeating the oxidizing process, and finally` cold rolling vthe sheets.

(l.v The method of oxidizing steel or ir'on sheets which consists in piekling and annealing them, then separating land repacking them in reverse order, then oxidizing them in an annealing box, then cold rolling them, and then repacking them in reverse order and repeating the oxidizing process.'

. 7. The method of oxidizing steel lor iron sheets which consists in pickling and annealing them, then cooling, separating and repaeking them one by one, then oxidizing them in an annezilingbox, then cold rolling them, then repaeking them andrepeating the oxidizing process and finally cold rolling the sheets.

8.l The method of oxidizing iron orsteel sheets which consists in pieklingandanneal-A ing them, then cooling, separating and repacking them one by one, 'then oxidizing` them in an annealing' box, then cold rolling them, and then repacking them and'repeat# ing the oxidizing process.

9. The method of oxidizing steel or iron sheets which consists in piekling and annealing them, then' cooling. and separating the sheets one troni another and oxidizing;l them in nn annealing box, then cold rollingtheim' then repeating the' oxidizing process, and finali)v cold rolling the sheets.

10. The method ot' oxidizing steel or iron sheets `which consists in pickling and annealingthem, then cooling! und separating the sheets one from another and oxidizing them in an annealing box, and thencohl rolling` them, then repeating the oxidizing process.

JOHN E. CARNAHAN.

ARTHUR J. MASKREY,

"'itnesses z Flinn J. Zn'r'rnnn, llLrnncDi SCHMIDT.

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