US3457790A

US3457790A - Metal sampling device

Info

Publication number: US3457790A
Application number: US560723A
Authority: US
Inventors: Robert J Hackett
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-06-27
Filing date: 1966-06-27
Publication date: 1969-07-29
Anticipated expiration: 1986-07-29

Description

y 1969 R. J. HACKETT I 3,457,790

METAL SAMPLING DEVICE Filed June 27, 1966 2 Sheets-Sheet 1 INVENTOR ROBERT J. HACKETT ROBERT H. ARE

ATTORNEY July 29, 1969 R. J. HACKETT METAL SAMPLING DEVICE Filed June 2'7. 1966' 2 Sheets-Sheet 2 INVENTOR ROBERT J. HACKETT ROBERT H. WARE ATTORNEY United States Patent 3,457,790 METAL SAMPLING DEVICE Robert J. Hackett, Cross Road, Brookfield, Conn.

Filed June 27, 1966, Ser. No. 560,723 Int. Cl. Gllln Z/12; B28b 7/28; B22d 41/12 US. Cl. 73--425.4 13 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a metal sampling device and, more particularly, to such a device for sampling metal while it is in the molten state.

It is often desired in the metal industry to obtain samples of a metal at various stages during its production in order to closely control the quality of the finished product. For example, the analysis of molten metal samples removed from an operating furnace may be employed to determine the necessary additions to the mix which are required to produce a metal of the desired quality and composition. Furthermore, sampling during various stages of degasiiication would permit the determination of the effectiveness of the procedure. However, the accurate sampling of molten metal is exteremly difiicult and has been relatively unsuccessful. This is particularly true in the case of the basic oxygen furnace, now Widely used in the steel industry. It is not possible to insert a ladle directly into the metal in such a furnace because it has a single top opening. Accordingly, in the past it has been necessary to tilt a furnace weighing several tons in order to remove a small sample for analysis. In other types of furnaces even this has been impossible and no sampling was possible until an ingot had been poured. After cooling, a section of the ingot was removed and machined for further analysis. Furthermore, the floating slag layer often prevents the obtaining of a true sample of the underlying metal.

In addition to such mechanical difficulties, it has heretofore been virtually impossible to obtain molten samples for analysis of oxygen and other gases. This requires determination of 16-35 parts per million and previous sampling techniques often introduced gases, ruining the sample.

Accordingly, it is a primary object of the present invention to provide an improved molten metal sampling device. Other objects are to provide such a device which may be readily and easily handled by a single workman; which takes a sample of molten metal from below the overlying slag; which permits the taking of a sampl from directly overhead through the top surface of the melt; and which produces accurate and uniform samples of desired configuration for analysis.

In accordance with the present invention, there is provided a molten metal sampling device comprising a chill block which has a cavity therein. The cavity communicates with the outer surface of the chill block. The chill block is releasably secured to one end of an elongated lance and a protective tube encloses the chill block to protect it during immersion in the molten metal.

A specific embodiment of this invention which achieves the objectives hereinbefore set forth will now be de- 3,457,790 Patented July 29., 1969 scribed, particular reference being bad to the drawings, wherein:

FIG. 1 is a perspective view of a single chill block member and the metal sample formed therein;

FIG. 2. is a longitudinal cross section of an assembled sampling device in accordance with the invention;

FIG. 3 is a cross section taken substantially along the line 33 of FIG. 2;

FIG. 4 is a perspective view of an end cap for use with this invention;

FIG. 5 is a perspective view of a protective plug for use with this invention;

FIG. 6 is a partially diagrammatic, partially pictorial illustration of the manner in which a metal sample may be taken with the device of this invention; and

FIG. 7 is a longitudinal cross section of the end of a modified sampling device of the invention.

In FIG. 1 there is illustrated one of the two chill block members which mate to form the chill block portion of the sampling device. The member M comprises a semicylindrical body 10 of copper or other suitable heat conducting material. The flat upper surface 12 of body 10 is machined to provide a semicylindrical cavity 14 which extends from one end of the body 10 inwardly to a transverse passage 16. The passage 16, in turn, communicates with a pair of vents 18a, 18b which extend to the opposite end of the body 10. At this opposite end and intermediate the vents 18a, 18b, there is a semicylindrical axially positioned recess 20 and a hole 22 which extends radially downward from the recess 20 and through the body 10.

The sampling device of the invention utilizes two of the chill block members M having their surfaces 12 abutting as shown in FIGS. 2 and 3. In these illustrations, the lower member is given the designation M and the upper member is given the designation M. Similar reference numerals are used for similar parts but with a prime attached in the case of member M. The chill block is formed by the chill block members M, M being placed with the upper surface 12 of member M positioned against the corresponding surface 12' of member M. In this manner the various recessed portions are aligned to form enclosed cavity 14, passage 16, vents 18a, 18b, and recess 20. The chill block is secured to the end of a lance 24. The lance is formed from a length of standard pipe having a T connector welded or otherwise secured to one end. The T connector comprises a cylindrical stem 26 which fits within the recess 20 and a transverse pin 28 which extends into the

holes

22, 22. A protective tube T comprising an inner metal tube 30 having an outer coating 32 of a heat resistant ceramic, encloses the chill block and extends along the end of lance 24 a distance suflicient to protect that portion to be inserted into the molten metal. Tube T may be of the type disclosed in the copending patent application of Oscar W. Ehrhorn and Robert J. Hackett, Ser. No. 236,754, filed Oct. 15, 1962, now abandoned, for Heat Resistant Objects, to which reference may be had for a more detailed description of its construction.

Due to the fact that the metal chill block will expand upon heating and might not be readily removable from the tube, and further due to the fact that molten metal must be prevented from entering the space between the tube and the chill block, there is provided a thin cardboard liner 34 on the block receiving end of the metal tube 30. In practice, a cardboard thickness of .025 inch has been found satisfactory for this purpose. The tube T and the cardboard liner 34 extend beyond the end of the chill block, as illustrated in FIG. 2. A ceramic plug 36, also shown in FIG. 5, is inserted in the end of Tube T and abuts against the end of the chill block. Plug 36 defines an axial opening 38, aligned with the cavity 14, and also includes an outwardly extending annular lip 40 which prevents molten metal from entering the space between the metal tube 30 and the chill block when the cardboard 34 is destroyed, as will be later explained. A thin metal cap 42, also shown in FIG. 4, is fitted over the end of the assembled device to prevent molten material from entering the opening 38 until after the overlying slag layer has been pierced. A small hole is provided in the end of cap 42 and is sufficiently small to prevent the entrance of molten slag but expedites the melting of the cap after immersion in the molten metal.

ASSEMBLY AND OPERATION In assembling the sampling device of the invention, a tube T of appropriate length is slid over the end of the lance 24. The chill block members M, M are then assembled, the pin 28 being positioned in the

holes

22, 22. The tube T is then slid back over the assembled chill block and slightly beyond its end. A snug fit within the cardboard liner 34 may be guaranteed by providing the chill block members with a taper which is too slight for convenient illustration. The ceramic plug 36 is then inserted in the end of tube T, abutting against the end of the chill block, the lip 40 simultaneously contacting the end of tube T. The cap 42 is then positioned over the end of the ceramic plug.

In FIG. 7, there is illustrated a modification wherein a ceramic plug of simpler construction may be employed. In this modification, the cardboard liner 34 does not extend to the end of tube T but, rather, terminates at the end of the chill block. This permits the use of a ceramic plug 54 in the form of a simple cylinder which abuts against the ends of both the chill block and liner.

FIG. 6 illustrates schematically a furnace 46, containing a charge of molten metal 48, topped by a slag layer 50. The end of the sampling device is inserted through the slag layer and into the molten metal. The cap 42 immediately begins to melt and molten metal flows upwardly into the cavity 14. Air and gases are simultaneously vented through the vents 18a, 18b. Heat flow into the chill block members M, M causes the molten metal to solidify within the cavity 14, forming a pin 52 as shown in FIG. 1. Simultaneously, the cardboard liner 34 chars and burns away. In sampling molten steel, it has been found that an immersion period of eight to ten seconds is sufficient to secure a suitable sample. The lance is then withdrawn and the tube T is slid backward along its length. The tube slides readily, in spite of the expansion of members M, M, due to the destruction of the cardboard liner 34, and the ceramic plug 36 falls away from the end. After the end of the tube has been slid beyond the T connector, it is then merely necessary to shake the lance 24 and the chill block members M, \M readily separate, freeing the solidified sample pin 52.

It will be readily appreicated that the size and materials of the various components may be altered to fit the circumstances. However, in one embodiment for sampling molten steel, the lance 24 was a three quarter inch pipe approximately ten feet in length. The tube T was approximately three feet in length and its cardboard liner was approximately .025 inch in thickness. The chill block members M, M' were of copper, approximately seven inches in length and one inch in diameter. The cavity 14 was inch in diameter and each of the vents 18a, 18b was @1 inch in diameter. Two vents were employed because it was deemed desirable to keep the chill block as small as possible. Furthermore, two vents offer more surface area for rapidly chilling metal which may extend into them. The two inch vents have approximately the same cross sectional area as the inch cavity, but approximately double the surface area. In the disclosed embodiment, the vents are approximately twenty-five percent longer than the cavity 14.

Use of the sampling device of this invention in actual steel making operations, has been found to be highly successful. For example, as disclosed above, it has been virtually impossible, heretofore, to obtain accurate samples for oxygen analysis. Such analysis requires a sample which is accurate enough to determine gases in amounts of 16 to 35 parts per million. Such samples have been readily obtained by the device of this invention. It is believed that the existence of the vents contribute substantially to this success as it allows entrapped air and gas to escape without contaminating the metal sample. However, it will be understood that for obtaining samples of metal for other analyses, it may be possible to eliminate the vents entirely.

It will be readily apparent to those skilled in the art that this invention achieves all the objectives hereinbefore set forth and is a significant advance in molten metal sampling. It will also be apparent that a number of variations and modifications may be made in this invention. Accordingly, the foregoing description is intended to be illustrative only rather than limiting. The following claims are to be construed as covering all variations and modifications which fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A molten metal sampling device which comprises: a chill block defining a cavity therein, said Cavity communicating with the outer surface of said chill block; elongated lance means having one end releasably secured to said chill block; protective tube means enclosing said chill block to protect it during immersion in molten metal, and vent means formed in said chill block connecting said cavity to the interior of said protective tube means.

2. The device of claim 1 wherein said chill block comprises matching half members defining said cavity therebetween.

3. The device of claim 1 wherein said tube means includes an expendable liner surrounding at least a portion of said chill block and destructible at molten metal temperatures.

4. The sampling device of claim 1 including first and second mating chill block members releasably engaging to form a chill block, said members defining a cavity therebetween communicating with the outer surface of said chill block; an elongated lance having one end releasably secured to said chill block; a protective tube enclosing said chill block and at least a portion of said lance; and an expendable liner within said tube and surrounding at least a portion of said chill block, said liner being destructible at molten metal temperatures.

5. The sampling device of claim 1 including first and second semicyclindrical chill block members releasably engaging to form a cyclindrical chill block having a first and a second end, said members defining a cavity therebetween communicating with said first end; an elongated lance having one end releasably secured to said chill block; a protective cyclindrical tube enclosing said chill block and the end of said lance, a first end of said tube extending beyond the first end of said chill block; an expendable liner within said tube and surrounding at least a portion of said chill block, said liner being destructible at molten metal temperatures; and a heat resistant plug substantially closing the first end of said tube and contacting said chill block, said plug defining a passageway communicating with said cavity.

6. The device of claim 5 wherein said cavity extends between both the first and second ends of said block.

7. The device of claim 6 wherein said cavity includes a mold portion communicating with said first end, first and second spaced vent portions communicating with said second end, and a passage within said chill block interconnecting all of said mold and vent portions.

8. The device of claim 5 wherein said one end of the lance includes a transverse pin extending radially outward from opposite sides thereof and wherein each of said chill block members defines an axial recess at the second end of said block, receiving the one end of said lance, and a hole-extending radially from said axial recess and receiving one end of said transverse pin.

9. The device of claim 5 wherein said plug includes a circumferential outwardly extending lip contacting the first end of said tube.

10. The device of claim 5 wherein an expendable cap encloses the exposed end of said plug.

11. The sampling device of claim 1 including first and second semicylindrical chill block members releasably engaging to form a cylindrical chill block having a first and a second end, said members defining a cavity therebetween communicating with said first end; an elongated lance having one end releasably secured to said chill block; a protective cyclindrical tube enclosing said chill block and the end of said lance, a first end of said tube extending beyond the first end of said chill block; an expendable liner within said tube and surrounding at least a portion of said chill block but not extending beyond the first end of said chill block, said liner being destructible at molten metal temperatures; and a substantially cylindrical heat resistant plug closing the first end of said tube and contacting said chill block, said plug defining a passageway communicating with said cavity.

12. The sampling device of claim 1 including first and second semicyclindrical chill block members releasably enaging to form a cyclindrical chill block having a first and a second end, said members defining a mold cavity communicating with said first end and a vent communicating with said second end, said cavity and vent being interconnected in fluid flow relationship; an elongated lance member; means releasably securing one end of said lance member to the second end of said chill block; a heat resistant protective tube enclosing said chill block, said securing means, and said one end of said lance member; a first end of said tube extending beyond the first end of said chill block; an expendable liner within said tube extending from the first end of said tube over at least a portion of said chill block, said liner being destructible at molten metal temperature; a heat resistant plug having a substantially cyclindrical portion inserted Within the first end of said tube and contacting the first end of said chill block and a radially outwardly extending annular lip contacting the first end of said tube, said plug defining an opening therethrough communicating with said mold cavity; and an expendable metal cap enclosing the exposed portions of said plug.

13. The molten metal sampling device defined in claim 1 including (A) means forming a hollow mold chamber (1) having an entrance end and an exit end and (2) having an effective cross-sectional area A, (B) means forming at least one vent chamber (1) having an effective cross-sectional area substantially greater than A (2) connecting the mold chambers exit end to a nearby atmospheric region above the surface of the molten metal, and (C) movable support means (1) for immersing the entrance end of the mold chamber means below the molten metal surface (2) including removable retarding cap means blocking the mold chambers entrance end during its immersion.

References Cited UNITED STATES PATENTS 1,837,452 12/1931 Le May 249-464 X 3,367,189 2/1968 Curry 164--4 X 3,369,406 2/1968 Lowdermilk et a1. 73-421 J. SPENCER OVERHOLSER, Primary Examiner EUGENE MAR, Assistant Examiner US. Cl. X.R. 164-4; 249-184-