US3369406A

US3369406A - Molten material sampling apparatus and method

Info

Publication number: US3369406A
Application number: US421792A
Authority: US
Inventors: Marvin J Lowdermilk; Frank A Herbsleb; Frank C Arrison
Original assignee: Electro Nite
Current assignee: Grimes Aerospace Co
Priority date: 1964-12-29
Filing date: 1964-12-29
Publication date: 1968-02-20
Anticipated expiration: 1985-02-20

Description

Feb. 20, 1968 M, J. LOWDERMILK ET AL 3,369,406

MQLTBN MATERIAL SAMPLING APPARATUS AND METHOD I Filled Dec. 29, 1964 INVENTORS. MA/PV/IV J. LOWDERM/LK FRANK A. Hf/PBSLEB FRANK C. ARR/SON 8V an-A.

ATTORNEYS.

United States Patent 3,369,496 MOLTEN MATERIAL SAMPLING APPARATUS AND METHOD Marvin J. Lowdermilk, Haddonfield, N..I., and Frank A. Herbsleb, Langhorne, and Frank C. Arrison, Huntingdon Valley, Pa, assignors to Electro-Nite Co., a corporation of Pennsylvania Filed Dec. 29, 1964, Ser. No. 421,792 12 Claims. (Cl. 73-4256) ABSTRACT OF THE DISCLOSURE An expendable evacuated vitreous vessel closed at both ends and partially surrounded by insulating refractory is provided for sampling molten metal. One end of the vessel projects beyond the refractory by a distance of 3 to 5 times its inner diameter and is closed by a vitreous button having a lower melting point.

This invention relates to a material sampling apparatus and method. More particularly, this invention relates to apparatus and method for sampling molten metal.

Heretofore, a large variety of devices have been pro posed for sampling molten material such as molten metal. For example, see Patents 2,143,982; 1,442,444; and 2,485,492. Other methods included a small ladle or spoon which is dipped into the molten metal and a sample of the molten metal retrieved. For one or more reasons, none of the devices proposed heretofore have been universally accepted. Some of the devices proposed heretofore are not foolproof, others are too complicated and time consuming, others require the dexterity of an operator, etc.

With the advent of high quality steel manufacture for various aircraft component parts and other high-priced steels which are increasing in demand, the steelmaker has added vacuum degassing equipment to his normal processing line to insure high quality steel. It is essential that an easy and reliable method of taking liquid metal samples be provided. The samples obtained are used to ascertain one or more of the constituents of the metal, such as the gas content (oxygen, nitrogen, hydrogen, etc.) as well as the percentages of the various constituents of the steel.

The need for an easy, rapid and reliable means for sampling molten metal has also been more desirable with the advent of the large number of steel makers employing the oxygen process having a very short cycle.

In this process, initial carbons ranging to 250* points are reduced to finishing levels in twenty to thirty minutes. It is then necessary to withdraw the oxygen lance and tilt the vessel 90 so that an operator may take the metal temperature as well as the sample by a spoon test. Since the production rate varies by the size of the vessel and the practice employed produces from four to seven tons per minute, it can be readily seen that twenty to thirty tons per hour are lost in production when samples are taken by the spoon test.

The molten material sampler of the present invention is expendable in nature. That is, the sampler is utilized only once and then discarded in its entirety. In this manner, maintenance on steel samplers may be completely eliminated. At the same time, the sampler of the present invention is structurally inter-related in a manner whereby it is reliable and can be manufactured inexpensively.

The molten metal sampler of the present invention is adapted to be inserted into ladles, melting pots, furnaces and the like which may be evacuated. The sampler includes a hollow tube of heat resistant material such 3,369,4d6 Patented Feb. 20, 1968 as cardboard having one end adapted to be coupled to a supporting structure. The other end of the cardboard tube supports an evacuated vessel. One end of the evacuated vessel extends beyond the end of the tube and has a button adapted to melt at a temperature lower than the melting temperature of the remainder of the sampler thereby permitting molten metal to enter the evacuated vessel. The evacuated vessel is surrounded by a refractory material to insulate the same from the heat of the bath and facilitate solidification of the molten metal sample Within the vessel. A more complete description of the sampler is set forth hereinafter.

It is an object of the present invention to provide a novel molten metal sampling apparatus and method of making the same.

It is another object of the present invention to provide an expendable molten metal sampler and method of making the same.

It is another object of the present invention to provide a molten metal sampler which is light in weight, inexpensive to manufacture, expendable in nature, and reliable.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIGURE lis a side elevation view of the apparatus of the present invention, with a portion thereof shown in section.

FIGURE 2 is a sectional view taken along the line 2-2 in FIGURE 1.

FIGURE 3 is a sectional view taken along the line 33 in FIGURE 2.

FIGURE 4 is a partial elevation view of the righthand end of another embodiment of the present invention.

FIGURE 5 is a sectional view taken along the line 5-5 in FIGURE 4.

Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIG- URE 1 an elevation view of a molten metal sampling apparatus of the present invention designated generally as 10.

The apparatus It] includes a support structure 12 having a handle portion at one end and an expendable sampler 14 removably secured at its other end. The support structure 12 facilitates the immersion of a portion of the sampler 14 ino a molten bath as will be made clear hereinafter.

The support structure 12 may be a hollow pipe made of any convenient material such as steel. Any suitable handle or gripping means may be provided on the portion 16. The end of support structure 12 remote from portion 16 includes a reduced diameter receiver 18 extending in an axial direction from a tapered shoulder 20 to a tip 19. Receiver 18 has a length which is more than about one-half the length of sampler 14 and extends thereinto to provide internal support against buckling. Receiver is preferably a hollow steel pipe. Shoulder Zll may be integral with or threadedly connected to the remainder of structure 12.

The expendable sampler 14 includes an elongated cardboard tube 24 which may have a length of about 7 to 60 inches. The cardboard tube 24 is hollow and may have a wall thickness of one-eighth of an inch when the outside diameter of the tube 24 is seven-eighths of an inch. The tube 24 has one end telescoped over the receiver 18 and in force-fitted contact with the shoulder 20. The diameter of receiver 18 is slightly smaller than the inner diameter of the tube 24 by a distance of about one-sixteenth to one-eighth of an inch. The tapered shoulder facilitates mounting the tube 24 on the support structure 12. If desired, means may be provided for positively retaining the tube 24 on the structure 12 such as a bayonet connection, a latching device, etc. However, satisfactory results have been obtained by merely providing a force-fit between the shoulder 20 and the tube 24.

The other end of the tube 24 designated as 26 is adapted to be immersed in the molten material of which a sample is desired.

An evacuated vessel 30 is disposed in the end 26 of the tube 24. The vessel 30 is closed at one end 32 in any conventional manner such as by heating and crimping. The vessel 30 may be made from any high temperature vacuum-tight vitreous or ceramic material such as quartz, Vycor, etc. The other end of vessel 30 is closed by a button or window 34. Button 34 is preferably a vitreous material having a much lower temperature melting point than the vessel 30. With a quartz vessel, a suitable material for button 34 may be GSC No. 1 sealing glass. Button 34 should preferably have a coefiicient of expansion compatible with vessel 30 to prevent cracking when subjected to heat shock.

Within the evacuated vessel 30, there is provided means for killing the steel. As illustrated, the means for killing the steel is a sheet of aluminum foil 36. The aluminum foil 36 is rolled in the form of a hollow tube so as to provide maximum surface area for contact with the molten steel sample. The use of aluminum foil which will contact the entire periphery of the molten metal within the vessel 30 is preferred. However, the material within the vessel 30 for killing the steel may be other materials or aluminum in other form, such as aluminum powder, an aluminum coating on the inner surface of the vessel 30, etc.

The vessel 30 is constructed as follows:

A tube made from quartz and open at both ends is provided. The button 34 is fused to one end of the quartz tube. Thereafter, aluminum foil in the form of a hollow tube or in some other form is inserted into the quartz tube. The aluminum foil is preferably provided in an amount so that the aluminum foil constitutes approxi mately 1 percent of the volume of the steel which can be received within the vessel 30. Thereafter, the vessel 30 is evacuated and closed at end 32 by heating and crimping the same.

The thusly-formed vessel 30 is then inserted into a tapered ceramic housing mold not shown. Thereafter, a heat insulating refractory such as Sauerisen cement No. 1, 7 or 8 is then introduced in liquid form into the mold. The refractory is designated as 38 in the drawing. The refractory 38 is then permitted to harden. Thereafter, the refractory protected vessel 30 is force-fitted into end 26 of tube 24. The slight taper of .0001 to .001 inch over the refractory length of 3 inches facilitates ease of pressing the refractory into the tube 24. The exposed end of refractory 38 projects beyond end 26 by a distance of about one-sixteenth of an inch as will be explained hereinafter.

As shown in FIGURE 2, the refractory 38 envelops the outer periphery of the major portion of the vessel 30 including end 32. The remainder of the vessel 30 projects beyond the end 26 and the adjacent end of the refractory 38 by a distance corresponding to the dimension X. The dimension X is between three and five times the inner diameter of the vessel 30. It has been found that more uniform results have been obtained with this structural inter-relationship. The refractory 38 acts as an insulator for the molten metal which enters the vessel 30. When the dimension X is substantially less than the abovementioned range, there is a tendency for the molten metal entering the vessel 30 to solidify before the entire vessel 30 is filled. When the dimension X is greater than the above range, there is a tendency of the sample to run out through the open end of the vessel 30 when the sam- 4- pler 12 is being removed from the bath thereby resulting in a vessel 30 which is not completely filled with metal.

A retaining ring 41 is applied around end 26 of tube 24. Ring 41 may be a plastic bushing made from a polymeric material such as nylon or may be plastic coated tape. As shown, ring 41 projects beyond end 26 by a distance which may be approximately three-sixteenths of an inch. This projection of ring 41 forms a moat for refractory 43 which may be Sauerisen cement No. 31.

A cup-shaped cap 40 is provided. The open end of the cap 40 is juxtaposed to the end 26 on tube 24 and centered around the projected exposed end of refractory 38. The cap 40 provides protection for the vessel 30 and button 34 during passage through any slag on the upper surface of the bath. During or soon after passage of the sampler 10 through the slag, the cap 40 will melt. Cap 40 may be made from any one of a wide variety of materials such as copper, sheet steel, brass, aluminum, etc. Cap 40 is provided with a hole 39 to permit escape of gases during fusion thereof.

The molten material sampling apparatus 10 is utilized as follows:

The sampler 14 is preassembled, positioned in line with the support structure 12, telescoped over receiver 18, and force-fitted on the shoulder 22 as illustrated in FIGURE 1. Thereafter, the apparatus 10 is held by an operator at the handle portion 16. The righthand end of the sampler 14 is immersed in a molten bath. Due to the structural interrelationship of the components of sampler 14, the depth of immersion is not critical. When the cardboard tube 24 has a length of approximately 24-48 inches, it may be immersed for a distance of approximately 12 to 15 inches on the end 26. Generally, the depth of immersion is determined by the slag layer. Since the object is to get a representative slag-free sample, the depth of immersion may be 3 inches in a slag-free bath and 12-15 inches in a bath having a substantial slag. During passage through the slag or immediately soon thereafter, the cap 40 melts away. The melting of cap 40 exposes the button 34 to the bath and it likewise melts away. Thereafter, a sample of the molten metal enters the evacuated vessel 30 and solidifies therein due to the insulation of the refractory 38 and tube 24.

The sampler 14 will have its righthand end portion normally immersed in the bath for a period of approximately three to five seconds. For some baths, notably those having a substantial amount of manganese, an additional three to five seconds may be necessary. Thereafter, the sampler 14 is withdrawn and separated from the support structure 12. The cardboard tube 24 cooperates with the refractory 38 to insulate the sample and thereby facilitate the rapid solidification of the sample within vessel 30. When the sampler 14 is removed from the bath, the tube 24 will be charred but generally is not consumed completely by the bath due to the lack of sufiicient oxygen. Thereafter, the righthand end of the sampler 14 may be smashed or crushed in any convenient manner such as by hitting with a hammer to retrieve the solidified metal slug from within the vessel 30. After retrieval of the sample slug, the components of sampler 14 are discarded.

The support structure 12 is a permanent portion of the apparatus 10 and is used over and over again. When it is desired to take another sample of the molten material, a new sampler 14 is telescoped over receiver 18 and secured to the shoulder 20 and the above process repeated.

In FIGURES 4 and 5, there is illustrated a portion of another embodiment of the sampler 14 which is designated generally at 14'. The sampler 14' is identical with the sampler 14 except as will be made clear hereinafter. Accordingly, corresponding elements are provided with corresponding primed numerals.

In certain molten metal baths, there is a reaction between the bath and the cardboard tube 24. This is exhibited by violent bubbling of the bath and splashing of the bath. To alleviate the reaction between the tube 24' and the bath, a refractory sleeve 44 is provided in sufficient length so as to envelop the tube 24 for a length greater than the depth of immersion of the tube 24. In addition to avoiding splashing of the bath, the refractory sleeve 44 provides additional insulation for the vessel 34 The sleeve 44 may be made from a refractory material such as referred to above. Sleeve 44 may be retained on the tube 24 in any convenient manner. For example, the sleeve 44 may be retained on the tube 24' by applying re fractory cement 46 to the end 26 and the adjacent end of the sleeve 44 and similar cement .17 to the other end of sleeve 44-. It will be noted that the moat for cement 46 is obtained by extending sleeve 44 beyond end 26' by a distance of one-eighth to three-sixteenths inches.

The refractory 38 can be provided by pouring it in liquid form into end 26 of tube 24. In this case, a stopper of cotton or some other material will be provided in tube 24 about three inches from end 26 and during said pouring, the vessel 30 will be supported upright within tube 24 and spaced from the wall of tube 24.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

It is claimed:

1. An expendable sampler comprising an evacuated vessel closed at both ends, said vessel having one end constructed and arranged to enable molten material to enter the vessel when said one end is at a temperature below the melting temperature of the vessel, said vessel being made from a vitreous material, said one end of said vessel being closed with a vitreous button whose melting temperature is below the melting temperature of said vitreous material, an expendable tubular member, said vessel being substantially shorter than said tubular member, said vessel being supported adjacent one end of said tubular member by a heat insulating refractory, said refractory being disposed within said tubular member and around a substantial length of said vessel, said one end of said vessel projecting beyond the adjacent end of said tubular member and refractory material, and the other end of said tubular member being adapted to be connected to supporting structures to facilitate immersing said one end of said vessel into a molten material of which a sample is desired.

2. A sampler in accordance with claim 1 including a cup-shaped cap, the open end of said cap being fixedly coupled to said tubular member in a manner so that said one end of said vessel is disposed within said cap and protected thereby.

3. A sampler in accordance with claim 1 including a refractory sleeve surrounding the end portion of said one end of said tubular member.

4. A sampler in accordance with claim 1 including a thin layer of aluminum within said vessel, said layer of aluminum being a hollow sleeve of aluminum foil constructed and arranged so as to contact substantially the entire outer peripheral surface of a sample of the molten materal which enters the vessel.

5. A sampler in accordance with claim 1 wherein said vessel projects beyond the adjacent end of the refractory by a distance corresponding to about three to five times the inner diameter of the vessel, and said vessel being a vitreous tube of uniform cross section through substantially its entire length.

6. A sampler in accordance with claim it including an elongated supporting structure, one end of said supporting structure being constructed and arranged to telescopically receive said other end of said tubular member whereby said tubular member may be supported on said one end of said supporting structure and to form a continuation of said supporting structure in an axial direction thereof.

7. A sampler in accordance with claim it wherein said tubular member is a cardboard tube, said vessel being made from a vitreous tube, and said refractory constituting the sole means for mounting said vessel within said cardboard tube.

3. A method of making a molten metal sampler comprising the steps of providing a hollow cardboard tube, providing a tubular vessel of generally uniform cross section, closing one end of the vessel with a material which will permit the ingress of molten material within the vessel at a desired temperature, providing a steel-killing material within the vessel, evacuating the vessel, then permanently sealing the other end of the evacuated vessel, positioning the thusly formed vessel within said one end of said cardboard tube so that said one end of said vessel projects therebeyond, spacing the vessel from the wall defined by the inner surface of said tube, and fixedly supporting the thusly positioned vessel within said one end of said tube by a refractory which circumscribes a part of said vessel within said tube and envelops said other end of the vessel.

9. A method in accordance with claim 8 wherein said closing step for said one end of the vessel includes providing a vitreous button which melts at a temperature lower than the melting point of said tubular vessel, and fusing said button to said one end of said vessel.

it A method in accordance with claim 8 wherein said positioning step is accomplished so that said one end of said vessel projects beyond said one end of said tube by a distance of about three to five times the inner diameter of the vessel.

Ill. A method in accordance with claim 8 wherein said step of providing a steel-killing material within the vessel includes introducing a layer of aluminum into said vessel so that at least a portion of the layer of aluminum contacts the inner Wall surface of the vessel.

12. A method in accordance with claim 8 wherein said spacing step includes molding the refractory around said vessel and enveloping the other end of said vessel, permitting the refractory to harden, and said step of fixedly supporting the vessel including the step of coupling said refractory to said tube.

References Cited UNITED STATES PATENTS 1,979,737 11/1934 Francis 73-4252 2,485,492 10/1949 Hubbard et al. 73425.2 2,970,350 2/1961 Feichinger 22-73 3,038,951 6/1962 Mead 136-234 LOUIS R. PRINCE, Primary Examiner. S. SWISHER, Assistant Examiner.