US2828956A

US2828956A - Top blowing oxygen nozzle in molten metal

Info

Publication number: US2828956A
Application number: US459582A
Authority: US
Inventors: Chester E Bieniosek; Edward F Kurzinski; Jr David H Fleming
Original assignee: Union Carbide Corp
Current assignee: Union Carbide Corp
Priority date: 1954-10-01
Filing date: 1954-10-01
Publication date: 1958-04-01
Anticipated expiration: 1975-04-01

Description

April 1, 1958 'c. E. BIENIOSEK ET L 2,828,956

TOP BLowiNc OXYGEN NOZZLE m MOLTEN METAL F'ild 0ct. 1, 1954 I INVENTORS CHESTER E. 'BIENIOSEK DAVID ,H. F MING,JR.

' RNEY EDWARD. E KURZINSKI l United States; flt

Tor BLOWING OXYGEN NOZZLE 1N MOLTEN METAL a 5 Chester E. Bieniosek, Jersey City, Edward F. Kurzinski,

, Cranford, and David H. Fleming, Jr.', Chatham, N. 1., assignors to Union Carbide Corporation, a corporation of New York Application October 1, 1954, Serial No. 459,582 sciaims. Cl. 266-41) In a process for removal of impurities from molten steel 7 by blowing oxygenunder pressure into the hot metal from p a nozzle spaced about 4 to 12 inches above the surface of the metal, the temperature at the center of the reaction zone or impingement point in such a process has been estimated to be about 4200 P. which is far above the melting temperature of around 198051. for copper, the material which has heretofore been used in such nozzles. Operation of a nozzle'in conditions involving such great temperature difference is possible only by rapidly circulating water through the thermally conductive copper nozzle. Yet with rapid circulation of water the nozzle life has been short.

One cause has been found to be the abrasion and wear from hot particles of slag and molten metal striking the nozzleand wearing the peripheral edge. The trouble from this cause has been alleviated by rounding of the nozzle periphery. .If the radius of curvature for such rounding is too large not enough room will be left for the necessary coolingwater passageways. On the other hand if too small a radius of curvature is used the wear and the abrasion is present. We have found what is believed to be thebest compromise for such radius of curvature to be about .25 to .30 of the maximum diameter of the nozzle.

Another cause of short life in these nozzles has been found to be the melting of the copper starting at locations where it has been welded or brazed. The thermal conductivity of the metal in a welded or brazed portion has been found to be not as good as it is elsewhere, due perhaps to such welded or brazed portion being more porous. Cast copper nozzles possess an objectionably short life and we believe such to be due to its being too poor a thermal conductor. One feature of this invention resides in our providing a type of copper that is a better thermal conductor, namely a more dense copper which has been both deoxidized andforged.

The life of such'a nozzle has been prolonged as much as a thousand percent by a number of factors contributing to this new result. One factor is the use of deoxidized and forged copper possessing the best available thermal conductivity because less porous and freer from impurities. Another feature is the construction of the nozzle to avoid the presence of any welded or brazed portions 2 I nozzle without any portion of them having to be trans versely drilled, plugged and welded, we have formed such passageways by longitudinally drilling in the nozzle body pairs of passagewaysat an angle from about 10 to 45 to one another and arranged in pairs close together to take full advantage of turbulence in the coolant at the vertex 'of these passageways. A change in direction of the coolant'at the end-of the nozzle has been found to be eflficient in heat transfer from the nozzle to the water. We have also discovered that the lower limit for the velocity of the coolant should be at least 10 ft. per second. There is no upper limit for this velocity except the questionable practicability of operating at an'unnecessarily high pressure. We have also found the desirable closeness in circumferential spacing between adjacent edges of these passageways should be not less than A and not more than /s". With closer spacing more water is needed and with more spacing between these passageways there is greater danger of the nozzle melting. Approximately 3000to 5000 gallons of water per hour are consumed in the illustrated nozzle of 6 /2- inches outside diameter.

previously used in the formation of water cooling passage- Referring to the drawing Fig. 1 is a longitudinal section through a preferred embodiment of this invention. Fig. 2 is a section on the line 2--2 of Fig. 1. a

A central oxygenpassageway 10 leads the gas under pressure to a nozzle 11 of forged and deoxidized copper. A water inlet 12 leads to the water passageway 13 around and contiguous to the oxygen passageway 10 for supplying'coolant to the passageways 14 in the nozzle 11. The water coming through passageways 14 impinges upon the end wall 15 absorbing heat from the nozzle 11 and passing out passageways 16 as shown in Fig. 1. The cooling water then moves through the passageway 17 around the outside of passageway 13 and out through the outlet connection 18. 7 Any convenient type spacing members 19 are welded to the innermost pipe which they separate and may be angularly spaced as much as about when three of them are used connected to any one pipe or passageway. O ring 20 or other convenient type packing is provided around the wall of passageway .10 between it and the nozzle 11. A pressure drop in the coolant is inversely proportional .to the 5th power of the passage diameter and it has been found a desirable size for the

passageways

14 and 16 should be from inch to A inch in diameter although from inch to inch may be useful as the diameter. of these passageways; A thickness of the copper outside the coolant passageways should be preferably between inch and inch. The ratio of the total cross sectional area of the

coolant passageways

14 and 16 to the total cross sectional area of copper in the nozzle in the same transverse plane should be from about 1:25 to about 1:5.

Welded to the outer surface of the passageway 10 is a flange 21 of the general type shown in Fig. 1 to which is bolted a flange 22 welded to the outside of the pipe 23 constituting the outer wall of the coolant inlet passageway 13. This pipe 23 also constitutes the inner wall of the water outlet passageway 17. Spaced from

flanges

21 and 22 by an amount approximately the same as the spacing of the axes of the inlet and

outlet connections

12 and 18 respectively, is flange 24 welded to the outer surface of the pipe 23. A flange 25 is bolted to flange 24 and welded to the outer surface of the pipe 27. O ring 26 or other type packing is placed between the outer surface of pipe 23 and the rear end of the nozzle 11 into which the pipe 23 extends. As shown in the drawing the pipe 27 constituting the outer wall of the water outlet passageway is threaded to the nozzle 11 to permit ready removal of the nozzle when worn.

Pipes

10, 23, and 27 connected to the nozzle 11 are preferably of stainless steel and need not have the high thermal conductivity of the nozzle 11 because they are not subjected to the same intense heat TPatented A r. 1, 1958? and abrasion to which the nozzle 11 is subjected. To re move the nozzle llit is unscrewed from the threads on the lower innerend of the pipe 27 when the .0

ring'packings

20 and 26 permit the nozzle to be disconnected from the pipes and 23 as the nozzle is unscrewed from the pipe 27.

The central oxygen passageway tapered as shown in the drawing. The edge 28 of the nozzle is rounded ona radius of curvature stated above, namely-between about .15 to .40-of the' maximum diameter of the nozzle and preferably between .25 to .30 of that maximum diameter.

The water passageways l4 and 16 are arranged in pairs in the same radial plane as shown" in Figs. 1 and 2 or they may be connected in a plane angled to the radial plane. Before the nozzle 11 is connected to the gas and, water pipesthese passageways are drilled from the rear end of the nozzle and arranged to meet at a small acute-angle. Anadvantage'of this arrangement for these

coolant passageways

14 and 16 is that no lateral drilling of anytransverse connecting passageways is necessary and -no plug has to be brazed or otherwise secured in -place.- Ithas been found that such plugs cannot be molecularlysecured in place to possess as good conductivity as isdesired in the main body portion of the nozzle because under; the intense heat to which the nozzle is subjected any such plug tends to melt and threaten the life of the nozzle. The longitudinal and tapered outer surface of the nozzle is approximately parallel with the axes of the passageways 16.

Among the advantages of this invention may be mentioned the fact that the increase in life of the present nozzle has been as much as 2000% as compared with that of a copper nozzle which is not both forged anddeoxi dized and which may be possessed of a pluggedtransversely drilled hole. The spacing of these pairs of passageways has been mentioned above and is important to obtain satisfactory cooling.

We claim:

1. Apparatus for the top blowing of oxygen into molten metal having a nozzle portion for insertion into a furnace and a rear body portion communicating therewith and adapted for connection to an oxygen and coolant source, said nozzle portion having a unitary construction of high thermal conductivity metal, a central longitudinalpas sageway for the passage of oxygen therethrough, plurality of coolant borings radially arranged in pairs 'around said central passageway, each pair of borings lying inthe same radial planeincluding the nozzle axis and extending from the rear face of saicllnozzle portion and converging to a point of intersection short of the forward face of -saicl is constricted and I nozzle portion, said'pairs of borings being circumferentially spaced between about and thereby forming a plurality of radially-arranged series coolant paths through the nozzle.

2. A nozzle according to claim 1 in which the thickness of copper radially outside the radially outer coolant borings is between about 7 of an inch and of an inch and the ratio of the total cross sectional area of coolant borings to the total cross sectional area of copper is between about 1:25 and 1:5.

3. A nozzle according to claim 1 in which the radius of curvature at the forward face of the nozzle portion is between about .25 to .30 of the maximum nozzle diameter.

4. An apparatus for blowing of oxygen into molten metal and including a nozzle of deoxidized and .forged copper free of any weld or brazed portion, pairs of coolant passageways arranged in a generally radial plane with the passageways of each pair meeting adjacent the outer end portion of ,said nozzle, thepairs being arranged circumferentially an oxygen .supply pipe centrally of and attached to .said nozzle, a projection secured to said pipe at a rearportion thereof, asecond pipe forming an outer wall of a coolant passageway for .saidnozzle, the inner wall of saidpassagewaybeing constituted by an outer SUI.- face of said oxygen supply pipe, spaced flanges secured to said second. pipe,imeans. removably securing the rear one of said spaced flanges to .the.flange on said oxygen supply pipe; a: third pip'eisurrounding thesccond and forming a coolant; passageway between them, arear flange secured on said third pipe, means removably holdingthe last mentioned flangetto the forwardso'ne ,of said flanges on the second pipe, and. a removable connection between said nozzle .and .eachof the threeof said pipes.

5. ,.A nozzle according. to claim 1 in which said coolant borings meet adjacentthe forward .face .of the nozzle portion at anangle of between about '10 to References Cited in the file of this patent

Claims

1. APPARATUS FOT HE TOP BLOWING OF OXYGEN INTO MOLTEN METAL HAVING A NOZZLE PORTION FOR INSECTION INT A FURNACE AND A REAR BODY PORTION VOMMUNICATING THEREWITH AND ADAPTED FOR CONNECTION TO AN OXYGEN AND COOLANT SOURCE, SAID NOZZLE PORTION HAVING A UNITARY CONSTRUCTION OF HIGH THERMAL CONDUCTIVITY METAL, A CENTRAL LONGITUDINAL PASSAGEWAY FOR THE PASSAGE OF OXYGEN THERETHROUGH, A PLURALITY OF COOLANT BORING RADIALLY ARRANGED IN PAIRS AROUND SAID CENTRAL PASAGEWAY, EACH PAIR OF BRINGS LYING IN THE SAME RADIAL PLANE INCLUDING THE NOZZLE AXIS AND EXTENDING FROM THE REAR FACE OF SAID NOZLE PORTION AND CONVERTING