US3481201A

US3481201A - Device for taking a molten sample

Info

Publication number: US3481201A
Application number: US676005A
Authority: US
Inventors: Richard A Falk
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-10-02
Filing date: 1967-10-02
Publication date: 1969-12-02
Anticipated expiration: 1986-12-02

Description

R. A. FALK DEVICE FOR TAKING A MOLTEN SAMPLE Dec. 2, 1969 3 Sheets-Sheet 1 Filed Oct. 2. 1967 Dec. 2, 1969 A R. A. FALK I DEVICE FOR TAKING A MOLTEN SAMPLE 3 Sheets-Sheet f;

Filed 001;. 2, 1967 Dec. 2, 1969 R. A. FALK DEVICE FOR TAKING A MOLTEN SAMPLE 3 Sheets-Sheet 3 Filed Oct. 2, 1967 United States Patent O 3,481,201 DEVICE FOR TAKING A MOLTEN SAMPLE Richard A. Falk, 519 Westminster Drive, Waukesha, Wis. 53186 Continuation-impart of application Ser. No. 589,296,

Oct. 25, 1966. This application Oct. 2, 1967, Ser.

Int. Cl. G01n 1/10 US. Cl. 73425.4 13 Claims ABSTRACT OF THE DISCLOSURE A sampling lance for molten metal comprising a refractory cartridge with side, top and bottom walls and with a side entry port is mounted in an insulating cardboard sleeve and is utilized for obtaining a sample directly from any source of molten metal such as a bath, ladle or ingot. The various embodiments of the cartridge provide pin samples, disk samples, smooth pin samples and samples with a fiat side. Further embodiments include thermo-couples for measuring bath temperatures and cooling curves of the samples simultaneously with taking the sample.

The present application is a continuation-in-part of my copending application Ser. No. 589,296 filed Oct. 25, 1966 now abandoned.

BACKGROUND OF THE INVENTION The invention relates generally to the sampling of molten metal and in particular to a sampling lance therefor. Prior art sampling devices have failed to provide apparatus which furnishes samples initially of appropriate sizes for the various analysis techniques used in the industry. Furthermore, prior art apparatus has failed to provide homogeneous samples with a uniform kill and a high degree of chill. Prior art devices are also extremely expensive to produce and do not provide a sample that is easily and quickly removed from the sampling lance.

In practice, continual testing of a heat of metal is necessary to obtain a steel of the desired composition and with the desired properties. In a 24 hour period in a typical oxygen furnace operation the number of samples taken can be several hundred. Accordingly, it is desirable that the sampling apparatus be inexpensive.

The cost of operating an oxygen furnace per minute is very substantial and the time required to take samples, to recover the samples from the sampling device and make chemical analysis of the sample is extremely important.

Heretofore apparatus for obtaining a sample useful for immediate analysis, and simultaneously obtaining bath temperature and recording cooling curve of the sample has not been available in the art.

SUMMARY OF INVENTION My invention provides a sampling lance which is inexpensive to manufacture and which furnishes samples initially of appropriate sizes for gas or spectrographic analysis or other conventional analysis techniques. The sample is easily removed from the sampling lance by shattering the refractory cartridge. With my sampling lance a sample can be directly obtained from any source of molten metal, such as a bath, ladle or ingot. Some embodiments of the invention are adapted to provide an extremely high homogeneity of the crystalline structure which is necessary for accurate analysis of all elements in the sample, some of which may be in very large or minute quantities.

The use of a refractory cartridge with a closed chamber except for a side entry port prevents slag forming on the 3,481,201 Patented Dec. 2, 1969 ice sample which can be caused by oxygen combining with the sample within the cartridge. The uniformity of the samples obtained with my sampling lance minimizes the need for repeated testing of a melt, thus resulting in a substantial cost savings in the testing program.

In one embodiment of the lance both a disk and pin sample can be simultaneously obtained. The disk sample is suitable for slicing for spectrographic analysis or can be drilled for wet analysis if desired. The pin sample is suitable for use in a gas analyzer.

Further embodiments of the sampling lance include thermocouples which permit recordation of the bath temperature and the cooling temperature curve to facilitate location of the inflection point caused by precipitation or crystallization of austenite from the melt. An important feature is that the sample and the temperature determination'are obtained simultaneously, giving improved correlation of results with less expenditure of time. Moreover,'the sample and temperature can be obtained without turning down the vessel, thus saving valuable time.

Calibration of the instruments used in this method by more conventional analysis methods provides a rapid technique for determination of carbon content.

The sampling lance of the present invention consists of a tube, desirably of paper board, which has a refractory cartridge inserted in the lower end. The tube has an opening in the side wall which communicates with an opening in the side of the cartridge providing an entry port for the molten metal sample. The paper board tube lasts from 10 to 15 seconds when immersed in most baths providing adequate time for filling the cartridge. Upon removal of the lance from the bath the paper board tube may be allowed to burn away allowing access to the cartridge for removal of the sample. In the alternative the sample can be removed by striking the end of the lance containing the sample cartridge thereby shattering the refractory and releasing the sample. Both the tube and cartridge are relatively inexpensive and expendable which is desirable in the steel industry which requires continual testing of the steel melts.

The side entry port in the tube and cartridge can be closed by a fusible cap such as aluminum or steel so that the lance can be immersed beneath the slag interface for obtaining a representative slag free sample. An aluminum cap melts very quickly, while a steel cap will melt after a few seconds delaying entry of the molten sample until the cartridge is pre-heated. The cartridge can also be provided with a coil of aluminum wire or the like to kill the sample.

Further objects and advantages of the present invention will become apparent from the following disclosure in which:

FIGURE 1 is a fragmentary sectional view of a sampling lance embodying various features of the invention with the cartridge partially immersed in molten metal.

FIGURE 1A is an enlarged view of a portion of FIG- URE 1.

FIGURE 2 is a view of the sampling lance shown in FIGURE 1 with the cartridge completely immersed in molten metal.

FIGURE 3 is a steel sample obtained with the sampling lance illustrated in FIGURE 1.

FIGURE 4 is a full perspective of the sampling lance shown in FIGURE 1.

FIGURE 5 is a modified embodiment of the present invention for obtaining a disk sample only.

FIGURE 6 is a modified embodiment for obtaining an extremely rapid chill.

FIGURE 7 is a further embodiment which provides a pin sample with a smooth surface.

FIGURE 8 is a modified embodiment provided with a thermocouple.

FIGURE 9 discloses an end view in section of the cartridge illustrated in FIGURE 5 modified to provide a sample with a flat surface.

FIGURE is an embodiment of the lance as shown in FIGURE 1 provided with a thermo-couple.

FIGURE 11 is an embodiment of the lance as shown in FIGURE 6 provided with a thermo-couple.

FIGURE 12 is an embodiment as shown in FIGURE 7 provided with a thermo-couple.

FIGURE 13 is a fragmentary sectional view of the embodiment shown in FIGURE 9 provided with a thermocouple.

FIGURE 14 is a further embodiment of the lance for obtaining multiple samples with different quantities of kill and a thermo-couple.

Referring now to the drawings, FIGURE 1 shows a sampling lance generally designated 10 which includes a refractory cartridge 11 inserted within lance tube 12, which contains and molds the metal sample. The lance 10 is partially immersed in a melt 13 which has a slag layer 14. The tube 12 can be paper board or any other insulating material which will protect the cartridge and facilitate immersion of the cartridge in a bath of metal.

Cartridge 11 is constructed of any suitable refractory and has a cylindrical side wall 15. The side wall 15 has a radial aperture 16 which provides an entry port into the cartridge cavity 17. The cartridge 11 is sealed at the bottom by a refractory plug or bottom 18 sealed in the cartridge by a refractory cement. The top of cartridge 11 may be sealed by an integral top wall or separate plug 19. The entry port 16 is desirably near the top wall 19 to prevent undue escape of the sample as it is removed from the melt. In the embodiment shown in FIGURE 1 plug 18 is provided with an axial passage 190, to form a pin sam le 20. In withdrawing the lance 10 from the bath, killed metal runs from chamber 17 through passage 190, expelling unkilled metal and giving a uniform sample. When the lance leaves the bath the metal cools in passage 190 and ceases to escape.

Port 16 is initially closed by an aluminum or steel cap 22 cemented over port 16 with refractory cement 2 4 to seal the cartridge 11 as it is lowered into the steel melt and prevent entry of slag 14. Tube 12 has an aperture 23 larger in diameter than the entry port 16 which facilitates flow of metal into the cartridge and tends to keep contaminants from the tube out. In use an aluminum cap will melt substantially instantaneously. A steel cap will take up to three seconds to melt before permitting entry of the sample. This allows preheating of the cartridge and pre- 'vents chilling of the outer edges of the sample when contacting the cartridge walls, resulting in more uniform cooling and accordingly, a more homogeneous sample.

Entry port 16 is desirably of a size suflicient to permit rapid entry of melt but prevent the sample from running out upon removal of the lance 10 from the steel melt. It has been empirically determined that an entry port of inch in diameter is sufliciently large to prevent rapid entry of material but small enough to prevent undue spill upon removal. With an aperture of less than one-half inch entry is too slow and the sample does not fill and cool simultaneously so the sample is not as homogeneous as desired.

The lower practical limit for the diameter of the entry port 16 is inch. With an entry port 16 less than inch the sample is stratified and has a poor kill distribution. The upper practical limit of the side entry port 16 is one inch in diameter with a larger port resulting in interchange of kill with the bath resulting in a non-uniform kill throughout the sample. The use of the thermo-couple as shown in FIGURES 10 through 14 may modify these sizes to a minor degree.

As illustrated in FIGURE 2, the cartridge 11 has been extended beneath the slag 14 in steel melt 13 and the cap 22 has melted and the cartridge has been filled with molten metal.

FIGURE 3 shows the general appearance of the sample after the refractory material has been cracked away. The pin 20 may be cut from the cylinder and analyzed by any conventional gas analysis technique and the cylinder sliced into disks for spectrographic analysis.

The embodiment illustrated in FIGURE 5 provides a disk sample only. It is otherwise similar to the above embodiment.

In the embodiment shown in FIGURE 6 the cartridge 11 is provided with a steel disk 26 which serves as a chill for quickly cooling the melt. The chill is sealed in the cartridge by plug 18 and thus insulated from the bath to afford an extremely high degree of chill. Spaced above the chill within the cartridge is an obstruction which in the disclosed construction is a refractory annulus 28 extending across the interior of the cartridge 11 and which has an axial aperture 30. Aperture 30 is desirably about inch in diameter. A smaller hole results in non-uniform killing and cooling, which causes lapped layers in the sample. The disk 28 serves as an insulator and prevents the sample from being remelted as additional iron flows into the chamber 17 through side entry port 16. This embodiment is particularly desirable for use in hot metal baths with a temperature range of 2100 to 2500 degrees F. Use of the chill 26 and the annulus 28 results in a disk sample with extremely high homogeneity which is desirable when attempting to analyze an iron melt containing a number of different elements, and spectrographic analysis of the sample is intended.

In the embodiment disclosed in FIGURE 7, the cartridge is adapted to provide a pin sample with a very smooth surface. In this embodiment the sample is primarily formed in a fused quartz tube 34 mounted be tween two refractory or ceramic

annular members

36 and 38, which have respective axial apertures 40 and 42.

Ferrostatic pressure causes some fill directly into the tube 34 from the melt 13 upon immersion of the lance 10. I have found that a sample with a smoother outer surface is obtained if a kill is placed in the end of tube 34 adjacent annular member 36. The kill 43 may be a piece of aluminum wire cemented in tube 34. When this device is removed from the melt 13 there is some run-out from tube 34. This permits the melt contained in the cartridge above member 38 to fill tube 34 providing a sample with a uniform distribution of kill.

In the embodiment disclosed in FIGURE 8, the cartridge is provided with a heat sensing device such as a thermo-couple which includes a pair of wires 44 which run through a ceramic sleeve 46. Although in the disclosed construction the sleeve 46 is shown located against the side wall 15 the sleeve can occupy a variety of positions in the cartridge 11. At least the exposed portion of the thermo-couple wire extends through a U-shaped fused quartz tube 48 for protection. The wires are adapted to be connected to registering means such a a meter or a known temperature recording apparatus to provide a time-temperature curve when the cartridge is withdrawn from the steel melt and the sample contained therein is cooling. It is known that as the melt cools, the temperature curve levels off briefly as the carbon in the sample crystalizes. The apparatus can be calibrated by comparison of samples from the same melt analyzed using conventional chemical analysis techniques such as gaschromatographic analysis or spectrographic analysis.

In the device shown in FIGURE 10 the quartz tube 48 containing the thermo-couple wire projects through the side entry port 16. This orientation is preferable over the construction illustrated in FIGURE 8 for measurement of bath temperature. In FIGURE 11 the tip 51 of the tube 48 extends slightly below the lower lip 53 of the side entry port 16. This orientation is preferable for measuring the cooling curve to locate the carbon precipitation point. In this construction the tip 51 of the thermocouple must be below the lip so that it will not be in the shrinkage cavity formed around the entry port as the sample cools. This orientation of the thermo-couple also insures immersion of the thermocouple in the sample. It also is preferable to have the tip 51 located adjacent to the interior wall of the cartridge near the entry port 16 wherein the metal flow into the entry port will raise the temperature of the refractory wall around the entry port to the bath temperature giving a more accurate reading of the bath temperature than if the thermo-couple were concentric to the interior of the cartridge. It has been empirically determined that satisfactory results are obtained if the tip 51 of the thermo-couple is located at approximately one-half the radial distance from the cartridge center to the side wall having the side entry port.

In the constructions illustrated in FIGURES and 11 the upper end 54 of the quartz tube 48 is surrounded with refractory cement 55. The upper wall 19 of the cartridge is spaced from the side entry port 16 and is provided with an aperture 56 which receives a plug 57. The refractory cement and the top wall 16 form a cold junction which insulates the wires 44 from the bath. The upper ends of the wires 44 are formed around the upper lip of the plug 57 and are exposed to make contact with a connector59 containing wires for connection to instruments.

In FIGURE 10 a thermo-couple is shown incorporated in the cartridge illustrated in FIGURE 1 to obtain a pin sample for gas analysis. In FIGURE 11 a thermo-couple is shown incorporated in the embodiment illustrated in FIGURE 6 with a steel chill 26. In FIGURE 12 the thermocouple is shown in the cartridge illustrated in FIGURE 7 with a fused quartz tube 34 to obtain a pin sample with a smooth surface. The thermo-couple arrangements shown in FIGURES 6, 10 and 11 can be used with any of the embodiments of the sampling lance.

Because my apparatus may be dipped directly into the bath without destruction, and because the sample is in an insulated chamber and need not be poured into other apparatus so that the cooling curve is less distorted than in previous apparatus, and because my device is disposable, it is far more accurate and convenient than prior art apparatus used in cooling curve analysis.

My apparatus permits the taking of bath temperature, determination of carbon inflection point of the cooling sample, and obtaining a sample in one rapid operation rather than a series of individual steps as is presently done in the art to accompilsh the same objective. Heretofore, the vessel had to be turned down or tipped to permit taking of a sample and temperature which might take four to six minutes.

In FIGURE 9 a cartridge is shown with a member 49 comprising a segment of a cylinder which has a cross-section defining a segment of a circle inserted within the cartridge cavity 17, Member 49 has an arcuate face 50 and a flat face 52 and is generally semi-circular or less in crosssection. Insert member 49 provides a sample with a relatively fiat surface which is useful for certain types of analysis apparatus. In the past it has been necessary to cut or grind a flat, which takes critical time. Also shown in FIGURE 9 is a coil of aluminum wire 54 which serves as a kill.

In the embodiment illustrated in FIGURE 13 the thermocouple is shown in a lance containing a refractory flat 49 as shown in FIGURE 9.

Referring to FIGURE 14, there is shown a cartridge 60 having

multiple chambers

62, 64, 66 and 68 with each chamber having a side entry port 70. The lance also includes a thermocouple 48 extending through the side entry port 70 of chamber 68.

Chambers

62, 64 and 66 contain varying quantities of kill which, as shown in FIG- URE 14, are coils of aluminum wire. This cartridge is useful in determining the amount of kill that must be added to a ladle to obtain the optimum kill to deoxidize the steel. Upon removal of the lance shown in FIGURE 14 from the bath upon cooling, the refractory can be 6 shattered and the samples in the various chambers examined to determine the required quantity of kill for the particular bath.

In use, the sampling lance 10 may be immersed at an angle in the molten metal 13 beneath the slag layer 14 with the entry port 1 6 of the cartridge 11 positioned upward as shown in FIGURES 1 and 2 to prevent spill of the sample as the lance is removed. The immersion time varies with the temperature of the melt 13 and will typically be between two and seven seconds. Gas bubbles or cavities in the sample grnay indicate improper killing or insufficient imersion time.

The sample can be removed from the lance by striking the cartn'dge and shattering the refractory.

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure.

I claim:

1. A cartridge for sampling molten metal comprising refractory side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, insulating means for protecting said cartridge and for extending said cartridge into a bath of molten metal, said insulating means having an aperture communicating with said entry port in said cartridge, the margins of said aperture being spaced radially outwardly from the margins of said cartridge.

2. A cartridge for sampling molten metal comprising refractory side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, consumable insulating means surrounding said cartridge, said insulating means having an aperture communicating with said entry port in said cartridge, the margins of said aperture of said insulating means being radially outwardly spaced from the margins of said entry port of said cartridge.

3. A cartridge in accordance with claim 2 further comprising a fusible cap located over said aperture of said entry port, and refractory cement securing said cap to said refractory cartridge and said insulating means,

4. A refractory cartridge for sampling molten metal, said cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and wherein said bottom wall of said cartridge has a cylindrical passage extending therethrough.

5. A refractory cartridge for sampling molten metal, said cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and wherein said cartridge contains a steel chill at the lower end thereof, said cartridge being further provided with an insulating refractory member within said cartridge and extending across said cartridge and spaced between said chill and said entry port, and passage means extending from the portion of said cartridge containing said port to the portion of said cartridge containing said chill, said passage means being sized for free passage of molten metal at bath temperature. I

6. A refractory cartridge for sampling molten metal, said cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and wherein said bottom wall of said cartridge comprises a first annulus, a second annulus spaced from said first annulus, and an elongated sgmooth-walled refractory tube extending through and supported by said annuli.

7. A refractory cartridge for sampling molten metal, said cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and wherein said cartridge is provided with a sample shaping member having a generally semi-circular crosssection.

8. A refractory cartridge for sampling molten metal, said cartridge having side walls and a bottom wall, a plurality of partitions extending across the interior of said cartridge to form chambers in said cartridge, and a sample entry port in each of said chambers.

9. A device in accordance with claim 8 with each of said chambers provided with different quantities of kill.

10. A sampling lance for sampling molten metal comprising a refractory cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and an elongated thick paper board tube telescoped over said cartridge and having an aperture communicating with said entry port in said cartridge, the margins of said aperture being spaced from said port, and wherein said bottom wall of said cartridge has a cylindrical passage extending therethrough.

11. A sampling lance for sampling molten metal comprising a refractory cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and an elongated thick paper board tube telescoped over said cartridge and having an aperture communicating with said entry port in said cartridge, and wherein said cartridge contains a steel chill at the lower end thereof, said cartridge being further provided with an insulating refractory member within said cartridge and extending across said cartridge and spaced between said chill and said entry port, and passage means extending from the portion of said cartridge containing said port to the portion of said cartridge containing said chill, said passage means being sized for free passage of molten metal at bath temperature.

12. A sampling lance for sampling molten metal comprising a refractory cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and an elongated thick paper board tube telescoped over said cartridge and having an aperture communicating with said entry port in said cartridge, the margins of said aperture being spaced from said port, and wherein said bottom wall of said cartridge comprises a first annulus, a second annulus spaced from said first annulus, and an elongated smooth-walled refractory tube extending through and supported by said annuli.

13. A sampling lance for sampling molten metal comprising a refractory cartridge having side, top and bottom walls, a sample entry port in said side wall sized to freely admit molten metal at bath temperature and to retain a substantial quantity of said metal upon withdrawal from said bath, and an elongated thick paper board tube telescoped over said cartridge and having an aperture communicating with said entry port in said cartridge, the margins of said aperture being spaced from said port, and wherein said cartridge is provided with a sample shaping member having a generally semicircular cross-section.

References Cited UNITED STATES PATENTS 3,236,103 2/1966 Kooken. 3,298,069 1/1967 Acre.

3,313,159 4/1967 Vanderbeck. 3,367,189 2/1968 Curry.

3,369,406 2/ 1968 Lowdermilk et a1.

LOUIS R. PRINCE, Primary Examiner D. E. CORR, Assistant Examiner US. Cl. X.R. 73354, 359

" UNITED STATES PATENT OFFICE 5 69 CERTIFICATE OF CORRECTION Patent No. 5,48l,2[ )l ted December 1969 Inventor) Richard A. Falk It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, Line jf), After "cartridge, INSERT -the margin:

CLAIM ll, of said aperture being; spaced from said port,-

SIGNED MID SEALED IN 121% (SEAL) Attest:

. WRLIAM E. 'SOHUYLER, JR- Edward M. Flewlldkrfi Gomissioner of Patents Attesting Offieer