US1714040A - Continuous annealing process - Google Patents

Description

y 1 H. M. NAUGLE ET AL CONTINUOUS ANNEALING PROCESS Original Filed April 4, 1924 4 Sheets-Sheet 1,

v u 1 Q Q gwventoq gnoentou 4 Sheets-Sheet H. M. NAUGLE ET AL CONTINUOUS ANNEALING PROCESS Original Filed April 4, 1924 May 21,1929.

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9' lmm a May 21", 1929.

H. M. NAUGLE El AL 'C ON'I'INUOUS ANNEALING PROCESS Original Filed April 4, 1924 4 Sheets-Sheet I L IIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIL IIIIIIIIIIII/ A r final 16 and m 75017256110. v

I 6mm;

Patented May 21, 1929.

I pUNlTED-f STATES m 1:. xauem m xa'rnua J. 'rowxsann, or omen, omo, microns. BY

PATENT ol-" lca;

' m ASSIGNMENTS, TO THE COLUHBIA- STEEL COMPANY, OF PITTSBURGH, PENNSYLVANIA, A. CORPORATION OF PENSYLVANIA.

con'rnwous examine raocnss.

Application filed April 4, 1924, Serial No. 704,157. Renewed October 13, 1928.

The invention relates to a continuous method of annealing highly finished strips of steel and like ferrous metal; and the obj ectof the improvement is to properly and uniformly anneal such a stripthroughout its length and breadth, by passing it through a tubular annealing chamber sealed at both ends against 1 the admission of air, and at the same time to clean the surface of the metal from scale and oxidation and reserve it from discoloration and abrasion uring the annealing process.

The use of sand and similar materials for sealing the ends of an annealing chamber, abr'ades and otherwise defaces the surface of highly finished metal; the use of oil and like liquids for sealing purposes, coats the strip with an adhering film which is objectionable in the annealin chamber; the use of molten metal for sealing purposes plates the surface of the metal; and an important feature of the present invention is the use of a water seal at each end of the annealing chamber. 4 The use of Water and like liquid, however, for sealing the ends of an annealing chamber, impairs the surface as 'well as the structure of a highly finished steel strip, unless the same is reduced to a low temperature before passin through the outlet sealing medium; and

a urther feature of the present invention is v to cool the strip in the rear end of the annealing chamber to a temperature of less than 100 C. before passing it through the outletwater seal, so as to prevent a discoloration of the surface or an impairment of the structure of the metal.

The improved process may be carried out bythe apparatus illustrated in the accompanying drawings, forming part hereof, in

which- Figure 1 is amdiag'rammatic side elevation of the apparatus, in three sections, show in the line of travel of a-metal strip by a so 'd line;

Fig. 2, a lo 'tudinal elevation sectionof the water seale box at the forward end of the annealing chamber; I

- Fi 3, a similar section of the annealing '60 cham r'in front of the annealing furnace; Fig. 4, a similar view of the annealing furnace, showin the heating pm'tion of the annealing tube erein;

Fig. 5, a plan section of the annealing fur-.

nace on line 5-5, Fig. 4;

Fig. 6, a longitudinal elevation section of the cooling end of the annealing chamber, omitting the conveyer rolls therein;

Fig. 7, a similar view showing the .conveyer rolls therein, as on line 7 7 Fig. 8; and

Fig. 8, a cross section of the coolin end of the annealing chamber on line 88, ig. 7.

Similar numerals refer to similar parts throughout the drawin The annealing cham t er for carr ing out the improved process may be in the orm of a cast or wrought iron tube 9, extending continuously from the water seal box 10 at the front or inlet end of the tube to the water seal box 10 at the rear or exit end thereof, and within the chamber maybe provided a series of rollers 11 mounted on standards 12 upon which a steel strip 13 may travel through the chamber.

The steel strip 13 to be annealed may be taken from a coil 13' mounted for unwinding in front of the apparatus, and may be delivered to acoil 13" mounted for winding at the rear end of the apparatus. In front of the inlet water seal box the strip may pass between electrodes 14 of a spot welding machine. for connecting the ends of successive strips together, whence the strip may pass over a roller'15 to properly'guideit into the inlet water seal box, all as shown diagrammatically in Fig. 1.

The water seal at the forward or inlet end of the tubular chamber may include a box 10 open at the to 34 of its lower forward end, with a covere top 35 at its higher rear end anda pendent cross partition 16 extending downward from the rear end of the cover 35 to a point near the bottom 17 of the box. The rear end 18 of the box is coupled to and communicates with the forward end of the chamber 9.

A pair of guide rolls 19 and 19' are mounted in the box, one in front and the other in rear of the pendent partition 16, for guiding the steel strip 13 downward and freely under. the lower end of the pendent partition 16; and a roll 20 is mounted in the rear end of the box for guiding the steel strip upward into the forward" end of the tubular chamber 9.

1quid, to a point I well above the lower edge of the pendent partition 16 so as to seal the end of the chamber from the admission of air, and the steel strip is entered into the forward end of the chamber by passing first down and thence upward through the water under the pendent partition 16, as shown in Fig. 2.

A similar water seal box 10, is coupled to and communicates with the rear or exit ends of the tubular chamber 9, with a reverse arrangement of its parts substantially as described for the front or inlet box 10, and the enclosed portions of the boxes as well as the charged from the sealing boxes entire length of the chamber are completely filled with either. a neutral or a reducing gas; that is to say, a non-oxidizing gas. This gas may be received into the front sealing box 10 through a gas inlet pipe 22, and may be disandthe chamber or its presence determined therein, by pilot valves 23 and 23. Y y

A heatingfurnace 24maybe built around the forward end portion of the tubular chamber v. 9 at an interval in rear of its forward end,

by means of which the annealing chamber may be heated by the combustion of gas entering through burners 25 at one end of the furnace and dischargin through a .chimney flue 26 at the other end thereof; and a tubular jacket in the form of a pipe 27 may be provided around the tubular chamber in rear of the heating furnace to form an annular chamber 28 around the tubular chamber, through which cooling water may be circulated through inlet and outlet pipes 29 and 29.

The length of the tubular chamber between the inlet sealing box and thefront end of the heating furnace is proportioned to prevent a heating of the forward inlet box to a temperature approaching the .boiling point of the sealing liquid, and also to permit a drying of the liquid from the surface of the steel strip before it enters the heating section of the chamber.

The length of the tubular chamber from the rearendof the heating furnace to the exit water sealing box is so roportioned that thesteel strips will be coo ed to a temperature well below the boilin point of the water or other sealin liquid, bore emerging from the rear end 0 the-apparatus.

An expansion couplin 30 ma be provided at the rear end of the tu ular c amber 9 and an expansion coupling 31 may be provided in the tubular jacket 27, as shown in Fig. 6, to b accommodate expansion and contraction calbisedby the varying temperature of these tu es. v

In the operation of the described apparatus for carrying out the improved process, 0

a steel strip is passed continuously through the annealln chamber as above described, and is heated by the furnace so asto bring the strips to an annealing temperature while passingthrough the portipn to the chamber.

this period of the operation,

After leaving the heated portion of-the tu- 7 bular chamber, the steel strip is gradually cooled as it passes through the rear end of the chamber until the tem erature thereof is reduced to below the boiling point of the sealing liquid, being 100. C. when water is used; 7

whence the stri emerges through the exit" water seal into t e atmosphere, in a cleaned,

bright, annealed condition, ready for any ordmary commercial use.

We claim:

I 8 1. The method of annealing the body and preserving thesurface of a strip of ferrous metalfwhich consists in heating the metal 1 in a non-oxidizing gas to an annealing temperatureand then cooling. the metal to a temperature less than 100 C. while'still in the non-oxidizing. gas, all during a continuous, endwise movement of the strip. 7

2. The methodof annealing the body and cleaning-the surface of a strip of ferrous" 7 metal, which consists in heating the metal in areducing gas to an annealing temperature and then coolin the metal to a temperature less than while still in the reducing gas, all during ment of the strip. 7

In testimony that we claim the above, we have hereunto subscribed our n'ames.-'

HARRY M. NAUGLE. ARTHUR J. TOWNSEND.

a continuous endwise move- 100

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