US 3805621 A
A sampler for obtaining a sample of metal from a molten metal bath such as steel includes a soluble deoxidant such as zirconium or titanium located in the inlet passage or sample cavity for killing the molten metal. The deoxidant has a melting point higher than the melting point of the steel melt and dissolves in the melt at a rate which provides uniform deoxidation of the sample. The sampler also includes a smooth fused quartz inlet tube which is connected to a sample mold in the sample cavity and projects from the sampler body to prevent the formation of a skull around the inlet passage to facilitate removal of the sample. The projecting inlet tube also prevents carbon pickup resulting from combustion of the cardboard sleeve typically employed to carry the sample cartridge.
Description (OCR text may contain errors)
United States Patent [191 Falk IMMERSION SAMPLER WITH A SOLUBLE DEOXIDANT  Inventor: Richard A. Falk, 519 Westminster Dr., Waukesha, Wis. 53186  Filed: May 1, 1972  Appl. No.: 249,296
[ Apr. 23, 1974 Primary Examiner-Richard C. Queisser Assistant Examiner-Daniel M. Yasich Attorney, Agent, or Firm-Henry C. Fuller, Jr.
[ 5 7 ABSTRACT v A sampler for obtaining a sample of metal from a mo]- ten metal bath such as steel includes a soluble deoxidant such as zirconium or titanium located in the inlet passage or sample cavity for killing the molten metal. The deoxidant has a melting point higher than the melting point of the steel melt and dissolves in the melt at a rate which provides uniform deoxidation of the sample. The sampler also includes a smooth fused quartz inlet tube which is connected to a sample mold in the sample cavity and projects from the sampler body to prevent the formation of a skull around the inlet passage to facilitate removal of the sample. The projecting inlet tube also prevents carbon pickup resultingfrom combustion of the cardboard sleeve typically employed to carry the sample cartridge.
6 Claims, 6 Drawing Figures BACKGROUND OF INVENTION Molten metal samplers of the type disclosed in my US. Pat. No. 3,481,201 are typically provided with a coil or strip of aluminum to kill or deoxidize the molten steel as it enters the sample cavity of the sampler. The aluminum readilycombines with the oxygen in the steel and thus minimizes the free oxygen in the sample which can result in a non-homogeneous or pitted sample which interferes with spectographic analysis of the sample. The aluminum has a melting point less than that of molten steel and thus the aluminum quickly melts upon contact with the molten metal and is washed from the inlet passage by the initial flow of melt. The aluminum does not remain in the desired location to deoxidize additional metal as the sample cavity is filled. This results in non-uniform deoxidation of the sample. Difficulty is also encountered in removing the sample from some sample lances because the metal skull formation which forms around the exterior of the sampler is connected to the metal in the inlet passage and thus the sample when the lance is cooled.
SUMMARY OF INVENTION The present invention provides an immersion sampler with a soluble deoxidant for killing the sample which has a higher melting point than the molten metal bath and which dissolves in the molten metal at a rate which insures presence of the deoxidant in the inlet passage during filling of the sample cavity to afford more uniform killing or deoxidation of the sample and thus improved spectographic test results. Zirconium and titanium have been successfully used as soluble deoxidants.
The invention also provides a sampler which has a smooth fused quartz inlet tube connected to a sample mold for conveying molten metal from the bath to the mold and in which the inlet tube projects beyond the bottom wall of the sampler. The molten metal does not adhere to the tube because the tube surface is smooth and the portion of the tube exposed to the bath quickly reaches bath temperature. The skull which forms around the sample does not enclose the end of the tube and thus is not connected to the sample. The projecting tube also prevents carbon pickup from the bath resulting from combustion of the cardboard sleeve carrying the sample cartridge.
Further objects, advantages and features of the invention will become apparent from the following disclosure.
DRAWINGS the sampling FIG. 6 is a view on reduced scale of a sample obtained with the sampler shown in FIG. 5.
BRIEF DESCRIPTION OF DRAWINGS 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. The scope of the invention is defined in the claims appended hereto.
In the drawings, FIG. 1 shows a sampling lance 10 having a tubular wall 12 which can be steel. The lance 10 has a hollow interior 14 which contains a pair of allochiral sample mold sections 16 and 18. The sample mold sections 16, 18 are clamped around a fused quartz inlet tube 20 by a paper tube or sleeve 21. The tube 20 provides an inlet passage to the internal sample cavity 22 defined by the mold sections 16 and 18. The sample thus formed provides a pin portion 19 (FIG. 4) suitable for carbon, sulphur, or wet analysis in an induction combustion analyzer as shown in my US. Pat. No. 3,392,970 and a disc portion 25 of an appropriate size for spectographic analysis.
The inlet tube 20 extends through and is supported by a refractory disc 23 which is cemented in the tubular wall by refractory cement. The disc 23 is recessed inwardly from the end of the tube so that a bead or ring 24 of refractory cement can be placed between the end of the tube and the disc 23 to retain the disc 23 in position. A fusible cap 30 can also be provided for enclosing the open end of the sample passage to prevent slag from entering the inlet passage as the lance 10 is lowered into the melt.
Sampling lances having a steel casing such as those shown in FIGS. 1, 3, 4 receive a skull formation 42 (FIGS. 3, 4) upon immersion and withdrawal from the bath.
FIG. 3 shows a prior art sampler in which the end 34 of the tube providing the inlet passage is coterminous with the surface 36 of the sampler. The skull 38 that is formed around the end of the sampler upon withdrawal of theilance from the molten metal bath-is connected to the pin portion of the sample 40 and, interferes'with quick release'of the sample from the sampling lance when the sample has cooled.
FIG. 4 shows the skull formation 42 with a sampling lance in accordance with the invention in which the tube 20 projects A inch or more from the refractory disc 23. The exposed end 43 of the tube quickly reaches bath temperature when the sampler is immersed and the skull formation 42 does not adhere to the smooth exposed outer end 43 of the tube and is not connected to the pin portion of sample 44 in the inlet tube enabling quick release of the sample from the lance. A skull formation does not occur around the entrance port of the sampling lance shown in FIG. 5 because of the combustible paper board tube which is partially consumed during use. However with the inlet tube 78 projecting a distance of :4 inch or more from the adjacent end 71 of the tube 70 carbon pickup in the sample cavity and inlet tube 78 caused by combustion of the cardboard tube 70 is minimized.
The sampling lance of the invention further includes a soluble deoxidant with a melting point higher than the bath temperature to deoxidize or kill the molten steel as it enters the sample passage or the sample cavity.
3 The killing or deoxidation-of samples is typically done with immersion sampling'lances to provide a sample with a smooth non-pitted surface suitable for spectographic analysis. In FIG. 1 the soluble deoxidant 50 is in the form of a strip of metal which spans the sample mold sections 16 and 18 and is located between adjacent edges of the sample molds to space the mold sec- .tions 16 and 18 to provide for escape of air and to vent the sample cavity as the molten steel rushes in the inlet tube 20 upon immersion in a bath. The deoxidant 50 can be from the group of zirconium and titanium, both of which have a melting point higher than a temperature of a typical molten steel bath of about 2800F. and are soluble in a molten steel bath. The melting point of zirconium is about 3 lF. and the melting point of titanium is about 3250F. Other soluble deoxidants having a melting point highenthan bath temperatures can be employed. A strip or coil of soluble deoxidant 52 can also be located in the inlet tube. The strip. 52 can also be aluminum- FIG. shows a modified embodiment of the invention. Two individual sample molds 72 and 74 are located in the interior 76 of the lance 71. The sample molds 72 and 74 are also provided with inlet tubes 78 which are anchored in the lance 70 by a refractory disc 80. The inlet tubes 78 have fused quartz segments 82 and 84 which are interconnected to provide a. continuous flow passage by a tubular segment 86 formed from zirconium or titanium. The tube segment 86 can also bev aluminum. The tube segments 82 desirablyhavean inside diameter less than the inside diameter oftube segment 84 to prevent loss of the sample when the lance is withdrawn from the molten metal bath and to prevent rapid filling of the sample cavities which can cause incomplete deo'xidation. An inside diameter of tube section of 7mm and an inside diameter of tube section 82 ofmmican be employed. The inside diarneter of the deoit'idant tube section 86 can be larger than the inside diameter of the tube segment .82 and the same diameter as the tube section 84.
. The sample cavities as of the molds-72, 74 can also be provided with a deoxidant 90 which can be a soluble deoxidant with a melting point higher-than bath temperature or analuminum coil.
- The use of a soluble deoxidant inthe inlet tube or .sample cavity insures the presence of deoxidant during filling of the sample cavity. This deoxidant dissolves in the melt as the. melt enters the sample mold at a rate suchthat the deoxidant remains present in the inlet tube until the molds 72 and 74 and inlet tubes 78 are filled thus providing uniform deoxidation of the sample. Aluminum in the inlet tube quickly melts upon contact with the molten metal and is washed away from its position in the tube and thus may not provide complete deoxidation of the sample.
Various combinations of aluminum and soluble deoxidants can be employed in different locations in the sample cavity and inlet tube for optimum results under differing conditions.
FIG. 5 also shows a modified arrangement for securing the sample mold sections 102,104 in spaced assem bly. A strip or spacer of metal 105 is located between the adjacent edges of the mold sections 102, 104 and welded at 101 to both mold sections. The strip 105 can be provided with a projecting tab 108 useable to affix data or information to subsequently identify the sample when taken from the mold. The information can be stamped on the tab 108 prior to use of the sampler. A tab portion 110 extends into the mold cavity and thusthe tab portion 108 is molded into and anchored in the sample 1 12 as shown in FIG. 6. Thus the samples can subsequently be identified.
What is claimed is:
l. A sampler for obtaining a sample of molten metal comprising wall means defining an interior sample cavity, walls defining a sample entry passage communicating with said cavityfor receiving a sample of molten metal, and wherein said wall means defining said sample cavity comprises an entrance passage and two opposed mold parts and including a soluble. deoxidant havinga melting point higher than the melting point of the molten metal in the form of a strip of metal located between adjacent edges of said two opposed mold parts of the wall means defining said sample cavity remote from said entrance passage and spanning said sample cavity and separating said mold parts to provide a gap between said adjacent edges for venting air from said mold as the sample enters and fills said mold and said sample cavity serving as a mixing chamber for mixing said deoxidant with said sample. I
2. A sampler in accordance with claim 1 wherein'said deoxidant is from the group of zirconium, titanium.
-3. A sampler for obtaining at least one sample of molten metal comprising walls defining an interior sample cavity, walls defining a sample inlet passage communicating with said cavity and for receiving a sample of molten metal, and wherein said walls defining said inlet passage comprise two tubular fused quartz segments and a soluble deoxidant in the form of a tubular segment located intermediate of and integrally connecting said quartz segments and arefractory disc having an aperture located in the end of the sampler for supporting said walls defining said sample inlet passage with said tubular deoxidant segment located wholly within said aperture and said quartz segments having portions located within said aperture and portions projecting outwardly therefrom with one of said quartz segments having a free end to provide'a nonskull adhering surface, said deoxidant tubular segment having an inner diameter greater than the inner diameter of the quartz segments to prevent loss of the sample as it is withdrawn from the molten metal. 7
4. A sampler in accordance with claim 3 in which said sampler has an end wall and wherein one of said quartz segments projects outwardly from said end wall at least l4 of an inch.
5. A sampler in accordance with claim 3 wherein said quartz segment projecting outwardly of said end wall has an inside diameter less than the other of said quartz segments to minimize outflow of said sample.
6. A sampler for obtaining a sample of molten metal comprising a sample cartridge having an internal sample cavity and an end wall, an inlet passage extending through said end wall and communicating with said sample cavity, said inlet passage comprising integrally connected segments formed of at least one fused quartz tubular segment and a tubular segment of a metallic deoxidant having a melting point higher than the temperature of the molten metal, said metallic deoxidant tubular segment being soluble in said molten metal and combinable with oxygen in said molten metal when dissolved in said molten metal, said deoxidant segment providing a portion of the flow path of said molten metal from the molten metal source through said inlet 6 less than the inside diameter of said metallic deoxidant segment to retard outflow of metal from said passage upon removal of said sampler from a bath of molten metal.