US2365411A - Deseaming apparatus - Google Patents

Description

Dec. 19, 1944. w. J. JACOBSSON ,7 2,365,411

' DESEAMING APPARATUS I Filed July 24, 1940 INVENTOR WI I G OT J. JACOBSSON ATTORNEY Pdttthtdd h1g9, Haiti 2,365,411 nasaarvmvo arrane'rvs Wiigot .r. .lacobsson, Plainfleld, n.

Unlonfiarhlde and C notation of New York 3., assignor to arbor: Corporation, a cor- Application July 24, 1940, @cflal No. 347,196

This invention relates to the art of thermochemically conditioning the surfaces of ferrous metal bodies, such as ingots, billets, blooms, slabs,

and the like, and more particularly to apparatus for deseaming, in which a stream of surface conditioning fluid, such as oxygen, is discharged from a nozzle against a surface undergoing thermo chemical treatment.

Surface seams and other defects frequently appear in steel billets, blooms, slabs, etc., in the early stages of production; These are sometimes caused by imperiectionsin the surface of a steel body or ingot, which imperfections are elongated in the first rolling and, as rolling is continued to produce a billet or bloom from the ingot, progress the length of the bloom or billet and form seams which also extend to an appreciable depth,

face deiectsfroin ferrous metal bodies, a surface area on the metal body to be conditioned is heated to the kindling temperature by an oxyacetylene preheating flame and then a stream of oxidizing gas, e. g. oxygen, is applied obliquely against the highly heated area. The greater part of the surface metal in the path. of the oxygen stre is oxidimd and the remainder melted and blown away. Thus, as the inclined oxygen stream is advanced with respect to the surface of the body, successive surface portions are removed. The surface portions therebyremoved include the defects or imperfections which would tend to cause seams during later'rolling operations, and the body is thus deseamed.

The efficiency of deseaming and surface conditionin operations is normally measured by the relation between the amount or oxygen used and the amount of metal removed. That is, approximately t? to 4.6 cubic feet of oxygen are theoretically required to oxidize one pound of steel, and when the amount of oxygen used is reduced, say to about 3 cubic feet of oxygen per pound of steel removed, the efllciency is in creased. However, when the efilciency of the Jperation is increased so that less oxygen is used;

ess metal lsoxidized and more metal is removed my melting. The reaction products which are ilown ahead of the advancing jet'of oxygen tend .o preheat subsequent surface portions to be re-.

s Claims. (or. lea-27.4)

blown'or flow to either side of the advancing jet solidify on the surface at either side of the deseamed area", and produce what may be termed .fins." Since solidified ferrous oxides are friable" and rather brittle, fins composed principally of such oxides are easily removed, but fins having a greater proportion of solidified steel or ferrous metal are more diflicult to remove. In some cases, such fins tenaciously adhere to the latvera] edges ofthe deseamed area, and may be bent back and forth several times before brealzing. In addition, it is also desirable to remove lateral slag accumulations and formations to v provide the best condition for-subsequent rolling.

Among the objects of this invention are: to

provide a blowpipe for thermo chemically con-.

ditioning a surface of a ferrous metal body, in which a novel stream of surface conditioning fluid. such as oxygen, is produced and utilized to inhibit slag and fin production; to provide a nozzle inlet construction for controlling the fin and slag inhibiting characteristics of a stream of surface conditioning fluid or oxygen discharged from such nozzle; to providean im proved deseaming nozzle thatiis simple and economical in its parts, and very efilcient and ofnoveol, but the reaction products which are 56 fective in operation; to provide novel means for improving the slag and fin inhibiting characteristics of an oxidizing gas stream discharged from a desearning nozzle; and to provide improvements'in the art of thermo-chemically conditioning the surfaces. of'ferrous metal bodies with a, single oxygen stream or a plurality of oxygen streams. I

Further objects and novel features of this invention will be apparent from the following description and accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view of the head and nozzle of an oxy-acetylene blowpipe adapted to operate in accordance with the principles of this invention; and

Fig. 2 is an enlarged and of the nozzle of Fig. 1.

'In accordance with this invention, a stream ,of oxidizing gas or oxygen, a portion of which plan view of the. inner oxygen stream need not be uniform. For example, in deseaming a steel body with a stream of substantially pure oxygen, excellent results are obtained with a stream in which the velocity of the central portion of the stream varies over a range from 600 to 1000 feet per second and the velocity of the most effective peripheral portion charge passage it of a nozzle N, removably se-.

cured to a head H of a conventional blowpipe. A stream of oxygen is discharged from orifice ii of passage it, at the lower or outer end of the nozzle. Spud S is provided with a central passage i2 and a plurality of outer passages i3, six in number as illustrated, although other numbers of passages, even down to two, may be used. The passages i2 and i3 collectively constitute the nozzle inlet means for admitting the oxygen to. the passage I0. Passages l2 and iii are relatively small in diameter, are much shorter than passage i0,'and outer passages 53 preferably symmetrically surround central passage l2. The passages .in spud S are each considerably longer than their respective diameters and distribute the flow of oxygen through the nozzle in such a manner that the central portion of the stream discharged from orifice ll has a higher velocity than the outer or peripheral portion of the stream; but, at the same time, the stream flows smoothly and without excessive turbulence, which is a highly desirable characteristic, because the metal removal emciency of a non-turbulent stream is considerably greater than that of a turbulent stream.

In further accordance with this invention, as has been found by experiment, the character istics of the stream may be altered by changing the length or longitudinal position of the spud within the nozzle N. As an example of the latter, a spud ainch long used in connection with the nozzle shown in the drawing, which is about five inches in length, the passage I being about 0.281 inch in diameter, produced the most satisfactory all-around results when the upstream end of the spud was flush with the inner end of the nozzle, in the position shown in Fig. 1. When the spud per second and up to about 600 feet per second. That any portion of the oxygen stream having a velocity above 600 feet per second apparently tends to remove metal, whereas any portion of the stream having a velocity somewhat below 600 feet per second, and located at or near .the edge of the stream, apparently tends merely to remove slag and oxidme metal previously removed in molten form. The most effective range for the latter, which apparently supplies the fin inhibiting and slag removal characteristics, was found to be about 200 to soii'feet per second.

The nozzle N is a conventional. type, consisting of a generally tubular body member of metal, such as swaged copper, which may be chromium plated, but provided with a shoulder it on which spud S is seated. In addition to central oxygen passage it, which is rectilinear or straight and is substantially uniform in cross-section from endto-end, nozzle N is provided with a plurality of equally spaced heating gas passages it surrounding the central passage. Head H is also a part of a conventional type of blowpipe, and is provided with an oxygen passage i! and a heating gas passage it, to which tubes is and 20, respectively, conduct oxygen and a combustible mixture of heating gases, such as a mixture of oxygen and acetylene. Heating gas passage it connects with an annular space 2i formed between head H and nozzle N, the annular space 2i distributing the heating gas to passages it in nozzle N. To provide gas-tight seals between head H and nozzle N, and to prevent leakage of oxygen or heating gas, the head and nozzle are provided with cooperating conical seating surfaces 22 and 2t.

Nozzle N is secured to head H, and the conical seating surfaces 22 and 223 are held in gas-tight engagement, bya nut 25 which engages threads 26 in head H and which bears against an annular flange 21 formed on nozzle N. The inner or upper end of nozzle N extends into an annular space 28, formed as a slight enlargement of oxygen passage ii, while the outer or lower end of the nozzie'is provided with a protective ring 28 of relatively hard metal. Ring is may be formed of a cobaltchromium-tungsten alloy of the type known as Stellite," and is preferably cast separately, then secured to the nozzle in any suitable manner, such as by welding, as shown. Head His also provided with a, protective shield 30, formed of the same or'similar metal as ring 29. Shield so may be cast onto head H, being locked securely thereto by a key 38 which is formed by metal flowing into was moved 3% inch, or a distance of its own length, into head H so that the opposite or downstream end of the spud was flush with the inner end of the nozzle, the efiiciency of metal removal was increased, i. e. slightly less oxygen was used to remove the same amount of steel, but the slag removal and fin inhibiting qualities were slightly decreased. Again, when the spud was moved toward the outer end of the nozzle so that the inner or upstream end of the spud was spaced inch, or its own length, from the inner end of the nozzle, the metal removal efficiency was slightly decreased, but the slag removal and fin inhibiting qualities were slightly improved. In

each of the above instances, the slag removal and fin inhibiting qualities were. of course, a considerable improvement over those qualities in instances when the spud was not used.

In addition, it was also found by velocity measurements of the streams discharged from the nozzle during the above experiments, that a critical range apparently exists above 400 feet and solidifying in a suitable hole in head H, provided for the purpose. Ring Nanci shield 30 protect nozzle N and head H from excessive wear.

To thermo-chemically condition the surface of a ferrous metal body, the combustible gas mixture supplied by tube 20 is turned on, and the heating flames ignited in the usual manner es they issue from passages HS of-nozzle N. The

heating flames are applied to a relatively small erosion the surface of the body, and as soon as this area is heated to the ignition temperature, oxygen supplied through tube i9 is turned on. The stream discharged through orifice ii of passage i0 is then applied to the heated area, thereby'removing a surface layer and forming a depression. The blowpipe is held with the nozzle at .a constant angle of about 30 with respect to the surface and advanced relatively thereto substantially in the direction of discharge of the oxygen stream, to cut a smooth groove having sloping sides in the surface of the metal body.

A series of closely spaced parallel grooves may be produced by two or more deseaming nozzles operated side by side, and a layer from an entire surface of a metal body may be removed by a sumcient number of nozzles. When two or more deseaming nozzles are thus used side by side, there is a tendency for a fin to form between each set of adjoining parallel grooves, but with nozzles constructed in accordance with this invention, such fins are eliminated -or easily removed.

From the foregoing it will be apparent that this invention provides a blowpipe for thermochemically conditioning surfaces of ferrous metal bodies which is effective and can be constructed to produce a desired relation between the fin inhibiting qualities and the metal removing efficiency of a stream of deseaming Ox gen. It will also be apparent that the apparatus necessary, over and above conventional parts, is simply and easily constructed, and very little change in a conventional deseaming nozzle is required to produce .a considerable improvement in the fin inhibiting qualities of the oxygen stream discharged therefrom.

Although several changes have been described,

such as variations in the length and longitudinal position of spud S, and also variations in the number and/or size of the passages in spud S, it will be apparent to those skilled in the art that other changes and modifications may be made without departing from this invention. It is therefore intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of this invention. a

What is claimed is:

1. A deseaming nozzle comprising, in combination, a generally tubularbody member having a central oxygen passage with a delivery portion of substantially uniform cross-section from endto-end, and a plurality of heating gas passages surrounding said oxygen passage in spaced relation thereto; and'a spud disposed within said oxygen passage adjacent the inlet end of said delivery portion and having a plurality of spaced symmetrically arranged passages each of considerably greater length than diameter, parallel to said oxygen passage and extending through saidspud, for increasing the slag removal efllciency of the oxygen stream discharged by said oxygen passage. v

2. A deseaming nozzle having a centrally disposed longitudinal passage of cylindrical shape for discharging a stream of deseaming oxygen; and means associated passage for controlling the stream of deseaming oxygen discharged from the outlet end, of said passage and comprising an insert having a central passage concentric with the longitudinal axis ofsaid nozzle passage and a plurality of unirormly spaced passages surrounding said central passage.

3. A deseaming blowpipe nozzle for thermochemically removing metal from the surface of a ferrous metal body, said nozzle having a central longitudinal passage of cylindrical shape for discharging a stream of oxidizing gas against the surface of said body; and means associated with the inlet portion of said passage for causing said stream of oxidizing gas to have a central portion with the inlet end of said of relatively high velocity and an outer portion of relatively low velocity, said means comprising an insert having a central passage concentric with the longitudinal axis of said nozzle passage and a plurality of uniformly spaced passages surrounding said central passage.

4. A blowpipe nozzle having preheating gas passages and an oxygen passage extending longitudinally thereof, and also having a plurality of inlet passages each considerably longer than its diameter but much shorter and of smaller diameter than said oxygen passage, said inlet passages collectively constituting the nozzle inlet means for admitting oxygen to said oxygen passage.

5. A blowpipe for thermochemically removing metal from a metal body comprising nozzle means having preheating gas outlet passages and a main cylindrical passage for discharging a stream of oxidizing gas against a surface of said body; and a plurality of inlet passages collectively constiuting the inlet means for supplying oxidizing gas to said main passage, said inlet 1 passages being each much shorter and of smaller cross-sectional area than said main passage, and one of said inlet passages being coaxial with said main cylindrical passage.

6. A blowpipe for thermochemically removing metal from a metal body comprising nozzle means having preheating gas outlet passages and a main cylindrical passage for discharging a stream of oxidizing gas against a surface of said body;

body; and at least three inlet passages collectively constituting the inlet means for supplying oxidizing gas to said main passage, said inlet passages being each much shorter and of smaller cross-sectional area than said main passage, and one of said inlet passages being coaxial with said main cylindrical passage.

'7. A blowpipe for thermochemically removing metal from a metal body comprising nozzle means having preheating gas outlet passages and a main cylindrical passage for discharging a stream of oxidizing and-seven cylindrical inlet passages collectively constituting the inlet means for supplying oxidizing gas to said main passage, said inlet passages being each much shorter and of smaller cross-sectional area than said main passage, and one of said inlet passages being coaxial with said main cylindrical passage.

8. A blowpipe for thermochemically removing ,tively smaller diameter than said inlet portion in axial alignment with said inlet portionfor discharging a stream of oxidizing gas against a surface of said body; and a spud device fitted into said inlet portion and provided with a plurality of open-ended passages extending length- Wise thereof said plurality of open-ended passages each having a substantially greater length than its greatest transverse dimension and collectively constituting the inlet means for supplying oxidizing gas to said delivery portion.

WILGOT J. JAcoBssoN.

gas against a surface of said

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