US3236103A

US3236103A - Method for sampling molten metal

Info

Publication number: US3236103A
Application number: US308501A
Authority: US
Inventors: Fred F Kooken
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1963-09-12
Filing date: 1963-09-12
Publication date: 1966-02-22
Anticipated expiration: 1983-02-22

Description

Feb. 22, 1966 KOOKEN 3,236,103

METHOD FOR SAMPLING MOLTEN METAL Filed Sept. 12, 1963 IIVI/EIVTO/P FRED KOO/(EN A f/arney United States Patent 3,236,103 METHOD FOR SAMPLING MOLTEN METAL Fred F. Kooken, Hammond, Ind., assignor to United States Steel Corporation, a corporation of Delaware Filed Sept. 12, 1963, Ser. No. 308,501 2 Claims. (Cl. 73425.2)

This invention relates to the taking of a sample from a pool of molten metal and, in particular, to a method therefor.

The sampling of molten metal, e.g., steel, as teemed from a ladle into the conventional ingot mold, has heretofore been effected by throttling the stream from the ladle as the level of molten metal in the mold rises to the maximum desired height, and holding a dip spoon in the stream. The sample thus collected is poured into a cast iron mold to provide a specimen for analysis. This procedure is open to serious objections but has continued in use, nevertheless, for lack of anything better.

In the first place, the diminished stream from the ladle, the handling of the sample in the spoon and the pouring therefrom all increase the possibility of atmospheric oxidation. As a result, the specimen analyzes lower in certain contents such as manganese, than the ingot itself. This has led to the discard of many ingots for failure to meet specification when they were actually within the ranges required in respect to certain elements, as shown by subsequent check analyses of the ingots. A further objection is that the samples form heavy skulls in the spoon necessitating violent abuse thereof attempting to clear them for another sample. Thus spoon life is short and the cost of spoons is substantial. In addition, there is a distinct safety hazard in collecting samples from a teeming stream.

I have invented a novel method of sampling ingots as cast. My method involves dipping a sample holder into the top of a mold or other vessel containing molten metal. The problem of obtaining a representative sample by dipping is complicated by the fact that slag and other impurities normally float on the surface of the liquid metal making difficult the lifting of a clean sample therefrom. In fact, it has been generally agreed that a sample dipped from the surface could not be truly representative. My investigation and further analysis, however, have proved that this view was erroneous. On the contrary, samples taken in accordance with my invention have proved highly representative of ingot chemistry on comparison with check analyses of specimens taken from the ingot after freezing and stripping of the mold therefrom.

In a preferred practice of my method, I insert bottom first a tubular sample holder, closed at the bottom, open at the top and having a filling port intermediate the top and bottom, downwardly through the slag floating on the liquid metal and into the latter until the port is below the surface thereof. I hold it therein three or four seconds with the top of the holder projecting above the slag layer. The holder is quickly filled with clean molten metal and any slag or floating impurities drawn in with it rise to the surface. The upper end of the holder projecting above the floating slag and impurities prevents their entry. The holder is then lifted out of the molten metal and the slag floating thereon, with the result that excess metal in the holder and any entrapped slag flows out through the port. The thickness of the holder wall is such that the clean metal left in the holder is not immediately chilled but is solidified in a minute or so after Withdrawal by air cooling. Thereafter the holder and metal therein are cut through transversely, affording one or more specimens as desired.

"ice

The holder is preferably formed from a length of steel pipe and should have a substantial wall thickness to withstand immersion in molten metal for a few seconds without loss of integrity, but should not be so heavy as to act as a chill mold.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment of the sample holder. In the drawings, the single figure is an elevation of my sample holder with parts broken away and in section, to reveal the interior.

Referring now in detail to the drawing, the holder 10 is conveniently a length of steel pipe closed at the bottom by pinching, compression or flattening as indicated at 14. The upper end of the holder is open and fits snugly but removably in a carrier collar 12. The holder is secured in the collar by a set screw 17, in abutment against an internal seating shoulder or ring 16. A handle 13 has one end bent at an angle 18 and is attached to collar 12 as by welding. Filling ports 15 are formed by drilling transversely through the holder intermediate its ends. The depth of the holder below the ports should be sufficient to provide a sample of the desired size and the height above the ports should sutfice to extend from a level well below the surface of the molten metal to a level above the surface of the floating slag.

Upon use in the manner already explained, the holder and sample in the lower portion, after solidification of the latter and removing the holder from collar 10, are cut through transversely to provide metallurgical specimens. Although the holder is thus destroyed after a single use, it is expendable because it is so cheap that the cost thereof is not a substantial item.

In a typical example of the holder disclosed, it was formed from a 12" length of common steel pipe 1.25" in outside diameter having a Wall thickness of about .0 The ports 15 were about A" in diameter. The bottom was closed by pinching or flattening in a press for about /2" from one end.

The invention is useful in taking samples from a tapping ladle as well as from an ingot mold since conditions are quite similar in both cases, i.e., a pool of molten metal with slag or impurities floating on the surface.

My invention has other advantages in addition to affording a representative sample of clean metal and reducing the cost incident to the use of sampling spoons. The wall thickness of the holder is such that the sample cools relatively slowly on being removed from the molten metal yet avoids the segregation which occurred in the mold used with the stream-dipping practice by spoons. The invention also reduces the hazard to personnel collecting the samples as compared with stream dipping. It further makes possible a final correction of ingot composition by additions to the ingot mold while the contents are still molten, because the samples can be observed and tested at the pouring floor by known means and methods, within a few minutes after being taken.

Although I have disclosed herein the preferred practice of my invention, I intend to cover as well any change or modification therein which may be made without departing from the spirit and scope of the invention.

I claim: I

1. A method of securing a solidified sample of molten metal from a pool thereof having slag floating on its surface, comprising lowering bottom first into the pool a tubular holder having a closed bottom, an open top and a filling port intermediate the top and bottom, until said port is below the surface of the metal, while keeping the top of holder above the surface of the slag, whereby the portion of the holder above the port prevents the entry .top of the holder above the surfaceof the slag, whereby the tom and the -port, thereb'y affording a specimen for 10 metallurgical analysis and inspection.

References Cited by the Examiner UNITED STATES PATENTS Sargent 73-425.4 Splaine 141-110 Jones 2283 Reeve 22-209 Peine 73425.2

J. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, Examiner.

UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,236,103 February 22, 1966 Fred Fe Kooken It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 1, strike out "top of the holder above the surface of the slag, whereby the".

Signed and sealed this 31st day of January 1967.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer Commissioner of Patents EDWARD J. BRENNER

Claims

1. A METHOD OF SECURING A SOLIDIFIED SAMPLE OF MOLTEN METAL FROM A POOL THEREOF HAVING SLAG FLOATING ON ITS SURFACE, COMPRISING LOWERING BOTTOM FIRST INTO THE POOL A TUBULAR HOLDER HAVING A CLOSED BOTTOM, AN OPEN TOP AND A FILLING PORT INTERMEDIATE THE TOP AND BOTTOM, UNTIL SAID PORT IS BELOW THE SURFACE OF THE METAL, WHILE KEEPING THE TOP OF HOLDER ABOVE THE SURFACE OF THE SLAG, WHEREBY THE PORTION OF THE HOLDER ABOVE THE PORT PREVENTS THE ENTRY TOP OF THE HOLDER ABOVE THE SURFACE OF THE SLAG, WHEREBY THE OF SLAG, THEN, WHEN THE PORTION OF THE HOLDER BELOW THE PORT HAS BEEN FILLED WITH METAL, RAISING THE HOLDER ABOVE THE SURFACE OF THE POOL, PERMITTING ANY SLAG AND EXCESS METAL THEREIN TO ESCAPE THROUGH SAID PORT, AND THEN ALLOWING THE HOLDER AND THE METAL REMAINING THEREIN TO COOL UNTIL THE LATTER SOLIDIFIES.