US3295171A

US3295171A - Frangible ceramic test mold

Info

Publication number: US3295171A
Application number: US375450A
Authority: US
Inventors: Robert R Strange; Sherwood G Haw
Original assignee: Jones and Laughlin Steel Corp
Current assignee: Jones and Laughlin Steel Corp
Priority date: 1964-06-16
Filing date: 1964-06-16
Publication date: 1967-01-03
Anticipated expiration: 1984-01-03

Description

1967 R. R. STRANGE ETAL 3,295,171

FRANGIBLE CERAMIC TEST MOLD Filed June 16, 1964 Fig.2.

/'-' 26 INVENTORS.

ROBERT R. STRANGE SHERWOOD G. HAW

ATTORNEY United States Patent M 3,295,171 FRANGIBLE CERAMHC TEST MGLD Robert R. Strange, Nor-thtieid, and Sherwood G. Haw,

North Canton, Ohio, assignors to Jones & Laughlin Steel Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Filed June 16, 1964, Ser. No. 375,450 1 Claim. (Cl. 22-1) This invention relates to test molds of the type used in obtaining samples of metallurgical beats for purposes of analysis. More particularly, the invention relates to a method and apparatus for obtaining a sample of molten metal directly from a stream of such metal.

As is known, it is customary in the refining of steel and other metal products to obtain samples of the melt during various stages of the refining process in order that tests may be performed on the samples to determine the composition or other properties of the material. For example, when steel is poured from a ladle into ingot molds, a sample is obtained to determine the aluminum content or other chemical properties of the cast ingot, these properties determining the use to which the steel may be put.

Any process for obtaining samples of steel to be tested on a production basis must be simple and fast, while at the same time having a relatively high degree of accuracy. In the past, samples of steel poured into ingot molds have been derived by means of a long-handled metal spoon which is thrust into the stream of molten steel being teemed from the ladle into the mold. The sample thus obtained is then poured into a cast iron mold where it solidifies.

The foregoing procedure, although used for many years in the steel industry, has certain inherent disadvantages. If the steel being cast contains uncombined oxygen, it must be killed as it is poured into the cast iron mold. This method of removing oxygen, however, is not altogether satisfactory since, in transferring from the spoon to the mold, the molten metal is exposed to the air where oxygen pick-up can occur. Furthermore, the sample cools quite rapidly in the cast iron mold, and the resulting grain structure of the sample cannot be readily controlled.

As an overall object, the present invention provide a method and apparatus for obtaining samples of metallurgical heats which overcomes the foregoing and other disadvantages of prior art methods.

Another object of the invention is to provide a method and apparatus for obtaining a sample of a metallurgical heat directly from a stream of molten metal being teemed from a ladle into a mold without the necessity for transferring the molten metal into the mold by means of a long-handled spoon as in the prior art.

A further object of the invention is to provide a method and apparatus for obtaining samples of metallurgical heats, particularly steel heats, which minimizes the possibility of oxygen pick-up and consequent altering of the analysis of the heat.

A still further object of the invention is to provide a frangible ceramic test mold which permits solidification control and subsequent quenching of the sample to enable determination of the grain structure and cleanliness of the steel at different solidification rates if desired.

In accordance with the invention, a ceramic frangible mold is provided comprising a refractory body having an open-ended, funnel-shaped cavity formed in its upper end and a mold cavity formed at its lower end and adapted to receive molten metal to be solidified from the funnelshaped cavity. Preferably, the mold cavity is separated from the funnel-shaped cavity by means of a relatively small diameter opening, of smaller cross-sectional area than that of the mold cavity. In this manner, the refractory body may be inserted into a stream of molten metal Fatented Jan. 3, 1967 to fill the funnel-shaped cavity, whereupon the metal will flow through the reduced diameter opening at a substantially even and controlled rate to form a test sample of good quality. Thus, the necessity for employing a longhandled spoon for the purpose of transferring the molten metal from the stream to the mold is eliminated along with the consequent possibility of oxidation. At the same time, the frangible ceramic mold may be fractured and the sample quenched after it has solidified to obtain grain structures not possible with conventional practices.

The above and other objects and features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form a part of this specification, and in which:

FIGURE 1 is an elevational plan view of the frangible ceramic test mold of the invention;

FIG. 2 is a cross-sectional view taken substantially along line IIII of FIG. 1; and

FIG. 3 is an illustration of the use of the frangible mold shown in FIGS. 1 and 2.

Referring now to the drawings, and particularly to FIGS. 1 and 2, the frangible mold of the invention comprises a refractory body 10 having formed in its upper portion a generally funnel-shaped cavity 12. As will hereinafter be seen, the cavity 12 is adapted to receive a stream of molten metal being poured from a ladle into an ingot or the like. Due to the Weight of the metal, a relatively severe turbulent condition with attendant splashing will be produced in the funnel-shaped cavity 12 at this time.

Formed in the refractory body 10 beneath the funnelshaped cavity 12 is a mold cavity 14 which, in the present embodiment of the invention, is cylindrical in shape. Separating the

cavities

12 and 14 is a Wall 16 having a centrally-disposed opening 18 therein which interconnects the

cavities

12 and 14. At the top of the cavity 14, and extending through the wall of the refractory body 10, is an air vent 20 which permits the escape of air as the mold cavity 14 is filled. Unless a sample of steel is being obtained which is already killed, an aluminum wire, schematically illustrated at 22, is inserted into the funnelshaped cavity 12. In accordance with well known pracflee, the wire 22 acts to kill the steel poured into the cavity 12,

With reference now to FIG. 3, the method of the invention is shown for obtaining a sample of molten steel being teemed from a ladle 24 into an ingot mold 26. In accordance with usual practice, the steel flows in a stream 28 from a pouring nozzle 30 in the bottom of the ladle 24. In order to obtain a sample in accordance with the present invention, the flow of stream 28 is reduced as much as possible; and the test mold 32, carried in a ring 34 on one end of a long handle 36, is thrust beneath the pouring spout 3% so as to be in the path of the stream 28. In this respect, it will be appreciated that the outwardly-flared outer surface 29 (FIG. 2) of the upper cavity 12 forms a supporting surface which rests against the ring 34.

As the molten metal flows down into the funnel-shaped cavity 12, a turbulent condition will result with attend-ant splashing. The metal captured within the funnel-shaped cavity 12, however, will flow in a more or less even and controlled stream through the opening 18 and into the lower mold cavity 14 where it solidifies.

The sample cools quite slowly in the mold cavity 14, so that it may be allowed to cool completely, or the mold may be broken and the sample quenched after it has cooled to a temperature below solidification. It is, therefore, possible to determine the grain structure of the steel at different temperatures below the solidification temperature if so desired. In the usual case, the mold will be broken and the sample transferred to an analytical laboratory where its composition is determined by means of a spectrometer or the like.

Although the invention has been shown in connection With a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention as defined in the claim,

We claim as our invention:

A ceramic frangible mold for use in obtaining a sample of molten metal, comprising a refractory body having an integral funnel-shaped cavity in its upper end, the largest diameter end of the funnel-shaped cavity being open to receive a stream of molten metal, a single mold cavity in the lower portion of said refractory body adapted to receive molten metal to be solidified, a wall separating the lower smallest diameter end of the funnel-shaped cavity from the mold cavity, an opening in said wall, said opening being of cross-sectional area less than the crosssectional area of said mold cavity to provide an orifice through which a substantially even and controlled stream of molten metal may flow from the funnel-shaped cavity into the mold cavity, the outer surface of said lower mold cavity being generally cylindrical and of constant diameter throughout its length, the outer surface of said funnel-shaped cavity being flared outwardly from the outer surface of said lower mold cavity whereby the generally cylindrical lower mold cavity may be slipped into a ring at the end of an elongated handle and supported by contact of said ring with the outwardly flared surface of the funnel-shaped cavity to permit the mold to be held in said ring at the end of said handle while the mold is positioned in a stream of molten metal being teemed from a ladle, and an opening in the upper end of the side wall of said lower mold cavity immediately beneath said separating wall for permitting air to escape from the mold cavity while turbulent and splashing molten metal in the funnel-shaped cavity flows through said opening in an even and controlled stream.

References Cited by the Examiner UNITED STATES PATENTS 1,500,741 8/1924 Howard et a1.

1,914,037 6/1933 Norton et al 22l29 2,288,661 7/1942 Wadman 25129 2,736,077 2/1956 Bartlett 22-196 3,041,688 7/1962 Wilder 22134 3,132,388 5/1964 Grant 22-496 J. SPENCER OVERHOLSER, Primary Examiner,

MARCUS U. LYONS, Examiner.

E. MAR, Assistant Examiner.