US3765248A

US3765248A - Molten metal sampler and method of use

Info

Publication number: US3765248A
Application number: US00175990A
Authority: US
Inventors: S Ramachandran; G Scoff
Original assignee: Allegheny Ludlum Industries Inc
Current assignee: Allegheny Ludlum Corp; Pittsburgh National Bank
Priority date: 1971-08-30
Filing date: 1971-08-30
Publication date: 1973-10-16
Anticipated expiration: 1990-10-16

Abstract

A method and means for obtaining a sample, such as a thin cross section sample, from a molten bath of metal, particularly a molten bath subjected to a pressure other than atmospheric pressure. The invention involves a sample mold comprising a tubular generally U-shaped or J-shaped member having generally unequal length legs characterized by a substantially unobstructed internal bore.

Description

United States Patent [191 Ramachandran et al.

[ MOLTEN METAL SAMPLER AND METHOD OF USE Oct. 16, 1973 FOREIGN PATENTS OR APPLICATIONS 1,038,278 8/1966 Great Britain 73/425.6 [75] Inventors: Sundaresan Ramachandran; George 1,526,144 4/1968 France 73/DIG. 9

J. Scuff, both of Natrona Heights, Primary Examiner-S. Clement Swisher [73] Assignee: Allegheny Ludlam Industries, Inc., Attorney-Vincent G. Gioia et al.

Pittsburgh, Pa.

[21] 175399 A method and means for obtaining a sample, such as a thin cross section sample, from a molten bath of [52] US. Cl. 73/425.4 R, 73/DIG. 9 metal, particularly a molten bath subjected to a pres- [51] Int. Cl. G01n 1/12 sure other than atmospheric pressure. The invention [58] Field of Search 73/4254, 425.6, involves a sample mold comprising a tubular generally 3/ G- 9 U-shaped or J-shaped member having generally un- I equal length legs characterized by a substantially un- [56] References Cited obstructed internal borev UNITED STATES PATENTS 7 I 5 D 2,485,492 10/1949 Hubbard 73/4254 C guns MOL TEN 20 ME TA L r PMENTEDBBI 18 I975 FIG. 5.

GAS

MOLTE/V METAL 1 20 MOLTEN METAL SAMPLER AND METHOD OF USE BACKGROUND OF THE INVENTION The field of art to which the invention pertains comprises sampler implements having a receptacle for a liquid, specifically a molten metal, to obtain a substantially gas free sample of a small cross section to facilitate chemical and physical testing thereof. This invention is of particular utility when extracting samples from a metallurgical furnace, which is enclosed and under pressure or vacuum. A sound pin sample, i.e., gas free sample, greatly simplifies and speeds analysis of the sample, especially for C, S, 0, H and N.

One prior art method and means for obtaining a thin cross section sample, usually called a pin sample, generally involves extracting the sample by inserting a straight tube, for example formed of glass and supported in a carrier, into the molten metal and drawing the sample into, or allowing the sample, to flow into the tube. Sometimes an evacuated glass tube is used. In such a case, the tube has a thinned end which is inserted into the molten metal by being supported in a spoon. The molten metal melts the thinned end of the tube and the metal is forced into the evacuated tube by the pressure differential. In addition, a number of prior art sampling devices that yield both a pin and a disc, or quantometer sample, are available. These devices generally are made of metal and ceramic material which is enclosed in a cardboard tube and the sample receiving chamber fills from the bottom. When devices such as these are put into a vacuum furnace system, they out gas and therefore cannot be used to extract a satisfactory sample.

Further, in another prior art attempt to obtain a satisfactory sample, a refractory tube, within a shielding sleeve, has been mounted in one end of a tubular or hollow handle, and the upper end of the refractory tube provided with a closure adapted to be burned out on contact with molten metal. Such a device includes an air vent at the bottom of the refractory tube, but the vent, generally an orifice in a disc, causes prompt solidification of the metal at the bottom of the tube, thus greatly increasing the likelihood of trapping gas in the sample. In all of the above described prior art devices, as in the present device, the sample is recovered from the mold by destroying the sample mold tube as by shattering, or otherwise cutting the mold away from the pin sample subsequent to the solidification of the sample.

SUMMARY OF THE INVENTION A sampling method and device is provided for obtaining a generally gas free sample, such as, although not restricted to, a pin sample, from a molten metal bath, particularly a molten metal bath enclosed under pressure or vacuum.

It is thus a primary object of this invention to provide a method and means for extracting generally gas free samples from molten metal baths by the provision of a sampler which simply and economically effects the collection of such a sample.

In accordance with the aforestated object, it has been found that the provision of a sampling tube having a generally unrestricted bore, and formed in a generally U-shaped or J-shaped configuration, i.e., two upwardly opening upstanding legs in communication at their lower ends, when submerged into molten metal results in the molten metal entering the shorter tubular leg and pushing the gas out of the longer tubular leg. Thus, a generally gas free sample can be obtained. This method and means for obtaining a sample has been found to be particularly advantageous with regard to extracting samples from a molten metal in furnaces under pressure or vacuum.

It will be understood that a sample tube holder means is generally provided for supporting the sample tube during its brief submergence in the molten metal, and that in the event the molten metal is in a furnace under pressure or vacuum, a conventional pressure lock means is provided for introducing and removing the holder supported sampling tube from the furnace.

Other objects and advantages will become apparent after the description hereinafter set forth is considered in conjunction with the drawings wherein:

FIG. 1 is a schematic representation of the method of the present invention wherein a generally U-shaped sampler tube, having an exemplary configuration, is at least partially submerged in molten metal;

FIG. 2 is a perspective view of an exemplary embodiment of a holder suitable for supporting a generally U- shaped sampler, in carrying out the method shown in FIG. 1;

FIG. 3 is a vertical section taken through the sample tube supporting portion of the device of FIG. 2;

FIG. 4 is a schematic representation of another embodiment of a sampler tube constructed in accordance with the invention; and

FIG. 5 is a schematic representation of another embodiment of a sampler tube constructed in accordance with the present invention.

Referring particularly to FIG. 1, the method of the present invention of extracting a generally gas free sample from a bath of molten metal is carried out by at least partially submerging a generally U-shaped sampler tube 10 within the molten metal 12. In referring to a generally U-shaped tube, it will be understood that a sampler tube, such as the exemplary sampler tube 10, comprises a tube having a continuous bore, which tube is bent back upon itself, thus providing a relatively short leg 14 terminating in an open end 18, and a relatively long leg 16 terminating in an open end 20. In this regard, it has been found that the utilization of a truly U-shaped sampler tube, i.e., wherein the legs of the tube are of equal length, does not fill in a manner which results in obtaining a gas free sample. As a matter of fact, such a tube will sometimes not fill at all. It should be noted that the sampler tube is at least partially submerged inasmuch as the tube 10, to function as required to obtain a satisfactory sample, need only be immersed to an extent sufficient to submerge the opening end 18 of the relatively short leg 14 of the tube 10. The tube is composed of heat-resisting glass, cast iron, steel, copper, or any other suitable material capable of withstanding the temperature of the bath of molten metal for a short period of time sufficient to enable extraction of a sample. However, the use of glass to form the sampler tube is preferred as it produces better results and upon the easiest and least expensive to use. In addition, pon removal of the sampler tube 10 from the molten metal, the glass sampler tube is merely shattered to recover the solidified sample. Although not specifically shown in FIG. 1, the method of the present invention can be carried out by completely submerging the tube in the molten metal, in which case the molten metal will fill both of the legs 14 and 16 of the sample tube 10 to the level of the end 18 of the relatively short leg 14.

Turning now to FIGS. 2 and 3 illustrating an exemplary means for obtaining a sample from a bath of molten metal, particularly a pin sample, i.e., a sample of relatively small cross sectional dimension relative to the length of the sample, it will be seen that a holder designated generally at 30 includes relatively long handle members 32, 32'. Rigidly affixed to a plate member 34 which in turn forms a connecting bight between After members 32 is a sampler tube holder member 36. In the exemplary embodiment shown in FIG. 2, the holder member is a metallic tube, and as best seen from a consideration of FIG. 3, the sampler tube 10 is received within the holder 36. The sampler tube 10, such as when formed of glass, for example, can be inserted in the holder 36 by heat softening the tube 10 to permit its being inserted into the holder. After the tube 10 has cooled sufficiently, it can be scored at the

upper ends

37 and 39 of the holder 36 and the projecting portions of the tube 10, not shown, snapped off.

It will be understood that the holder 36 need not necessarily completely encompass the sampler tube 10 as long as the holder means supports the sample tube 10 in the generally U-shaped configuration for a sufficient length of time to permit submergence of at least the short let of the sample tube 10 and extraction of a sample therewith. As seen in FIG. 3, the exemplary holder 36 has been severed along a plane passing through its axis to remove the glass tube encased sample 50 which is then retrieved by shattering the tube 10, if the tube has not in fact already been shattered during severing of the holder 36.

Finally, turning to the alternative, but not preferred embodiments illustrated in FIGS. 4 and 5, it will be seen that sampler tubes 1 10 and 210, respectively, having the cross sectional configurations shown are consistent with the teaching of the present invention wherein molten metal entering at the

open ends

118 and 218, respectively, of the relatively

shorter legs

114 and 214 displaces gas through the vent provided by the

longer legs

116 and 216. In this regard, it will be understood that the communicating passages or ports 111 and 211 between the relatively shorter and longer legs is sized so as to preclude solidification of molten metal entering through the shorter leg for a length of time sufficient to obtain a gas free sample. Although not previously discussed, it will be understood that the method and means comprising the present invention can be utilized in situations wherein a molten bath contains both slag and metal layers. In such a situation, as schematically shown in FIG. 5, samplers constructed in accordance with the invention can be provided with destructible closure members, such as the

closure members

220 and 222, on the sample inlet and gas outlet ports of of the

sampler legs

214 and 216. A suitable destructible closure may comprise a cardboard closure, although it will be appreciated that any material will be suitable if it will maintain its integrity for a period of time to allow the sampler to be inserted through the slag layer. Once through the slag layer the

closures

220 and 222 disintegrate and the sampler functions as previously described with the additional advantage that slag is not allowed to penetrate into the sampler.

From the foregoing, it will be appreciated that both the vent, i.e., relatively longer leg of the sampler, and the sample inlet side, i.e., relatively shorter leg of the sampler, can be filled up with the melt to be sampled. Accordingly, the provision of a plug with a chill is not necessary to prevent filling. Thus, the present invention provides a method and means for effecting the unidirectional smooth exit of sample contaminant gases, namely, exit of the gases out through the relatively longer venting leg of the sampler tube.

Having thus described the invention, it is obvious that various modifications may be made in the same without departing from the spirit of the invention.

We claim:

1. A device for sampling molten metal from a bath comprising an open-ended sampler tube having a continuous, unobstructed bore, said sampler tube being generally bent back upon itself to form conjugated leg portions and a intermediated bight portion, said conjugated leg portions including a relatively short length leg and a relatively long length leg, and means for supporting said sampler tube for at least complete immersion of said relatively short length leg in the molten metal bath.

2. The device of claim 1 wherein said sampler tube comprises a generally U-shaped tube.

3. The device of claim 1 wherein one of said leg portions has a continuous bore greater than the bore of the other of said leg portions.

4. The device of claim 1 wherein heat destructible closure means is provided on the end of said relatively short leg portion of said sampler tube.

5. A device for sampling molten metal fromv a bath comprising an open-ended sampler tube having a continuous, unobstructed bore, said sampler tube being generally bent back upon itself to form conjugated leg portions and a connecting bight portion, said leg portions including a relatively short length leg and a relatively long length leg, and means for supporting said sampler tube for at least complete immersion of said relatively short length leg in the molten metal bath and heat distructable closure means provided for the ends of both said conjugate leg portions.

6. The device of claim 2 wherein said bore of said sampler tube is of generally constant diameter throughout.

7. The device of claim 6 wherein said sampler tube is formed of a heat resistant glass.

Claims

5. A device for sampling molten metal from a bath comprising an open-ended sampler tube having a continuous, unobstructed bore, said sampler tube being generally bent back upon itself to form conjugated leg portions and a connecting bight portion, said leg portions including a relatively short length leg and a relatively long length leg, and means for supporting said sampler tube for at least complete immersion of said relatively short length leg in the molten metal bath and heat distructable closure means provided for the ends of both said conjugate leg portions.