APPARATUS FOR VERIFYING THE TREATMENT OF DUCTILE CAST IRON AND METHOD THEREOF
Disclosed is an apparatus and method for verifying the treatment of molten metal wherein a sensing device detects an in situ response resulting from the treatment of the molten metal. The in situ response is compared to a pre-set limit or condition in order to determine whether or not proper treatment of the molten metal has occurred. In particular, the sensing device detects an in situ response resulting from the mixture of a molten metal addition to a molten metal. An electronic transformation device can be used to transform the in situ response into a response data set. The response data set can be transmitted to and received by a microprocessor. The microprocessor can manipulate the response data set. The in situ response to the treatment of the molten metal can be in the form of heat, light intensity, light wavelength, density of smoke particles, composition of smoke particles, mechanical vibration and combinations thereof.
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This application claims priority of U.S. Provisional Patent Application Ser. No. 60/793,207, filed Apr. 19, 2006, and U.S. Provisional Patent Application Ser. No. 60/802,934, filed May 24, 2006, both of which are incorporated herein by reference.
FIELD OF THE INVENTIONThis invention relates generally to an apparatus and method for verifying the treatment of a molten metal. More specifically, the invention relates to the verification of the treatment of ductile cast iron.
BACKGROUND OF THE INVENTIONCast metals are used to produce a vast number of useful products and have significant industrial importance throughout the world. One of the most used and developed cast metals is cast iron. Cast irons are a family of ferrous metals with a wide range of properties. Objects, components and articles are made from cast iron by being cast into shape as opposed to being formed. Cast irons typically contain 2 to 4 weight percent (wt %) carbon and 1 to 3 wt % silicon, with other elements used to control specific properties for particular applications. Cast irons have a wide range of mechanical properties which make them suitable for use in a multitude of engineering components.
Cast iron production is typically initiated with the remelting of charges which consist of pig iron, steel scrap, foundry scrap and other ferro-alloys in order to give a desired composition. A small blast furnace, also known as a cupola, is a typical melting unit wherein cold pig iron and scrap are charged from the top of said furnace onto a bed of hot coke through which air is blown. In the alternative, a metallic charge is melted in a coreless induction furnace or in a small electric-arc furnace.
Various types of cast iron can be produced depending on alloying additions and/or the thermal processing of the material. For example, gray cast iron is comprised of ferrite and graphite or pearlite and graphite structures resulting from iron with 2.5 to 4 wt % carbon and greater than 2 wt % silicon. White cast iron has a structure of pearlite in a cementite matrix and is hard, brittle and very difficult to machine. Malleable cast iron is typically a heat treated form of white cast iron which improves the ductility while maintaining the high tensile strength of white cast iron. Ductile cast iron is obtained by adding magnesium to the molten iron just before casting. The magnesium results in the graphite within a melt forming spheres or nodules. The spheres or nodules of the graphite afford for much of the improved mechanical properties of the cast iron when compared to graphite in the form of flakes in gray cast iron. As such, ductile cast iron competes favorably with steels since it possesses improved strength, ductility, toughness and hot workability.
Although the melting and casting of molten metals can be relatively unsophisticated, determining whether or not a particular batch or heat of a molten metal has been sufficiently treated prior to pouring can be a time-consuming process. For example, the correct composition of the molten metal just prior to pouring is critical to obtaining the desired properties of a subsequently cast component. Typically, the composition of the molten metal just prior to pouring is obtained by taking a sample of the molten metal and performing a chemical analysis thereon. The chemical analysis of the sample can be obtained using wet chemistry or methods such as optical emission spectrometry (OES) using arc and spark excitation of a solidified metal sample.
Wet chemistry analysis can take hours and sometimes days to perform. Optical emission analysis can be performed in minutes once the sample has been taken, solidified and properly prepared for the OES analysis equipment. However, while a metal sample is being evaluated with respect to its chemical composition using OES, the molten metal from which it was obtained must be held at elevated temperatures until confirmation of an appropriate composition is determined and pouring can ensue. In the event that the chemical composition of the molten metal is determined to be outside an acceptable range, additional alloying conditions must be input into the charge, the molten bath allowed to equilibrate, and samples taken again for chemical composition analysis. During this time, molds waiting to be poured remain idle and productivity of the given casting process is reduced. Therefore, a method and apparatus to verify the sufficient treatment of a molten metal which provides feedback in a more timely fashion is desired.
SUMMARY OF THE INVENTIONDisclosed is a method and an apparatus for verifying the treatment of molten iron wherein a sensing device detects and monitors an in situ response resulting from the treatment of the molten iron. The in situ response is compared to a pre-set limit or condition in order to determine whether or not proper treatment of the molten iron has occurred. In particular, the sensing device detects and monitors an in situ response resulting from the mixture of a molten iron with magnesium. An electronic transformation device transforms the in situ response into a response data set. The response data set is then transmitted to and received by a microprocessor, said microprocessor comparing the response data set to a pre-set limit and/or condition.
The in situ response to the treatment of the molten iron can be in the form of heat, light intensity, light wavelength, density of smoke particles, composition of smoke particles, mechanical vibration and combinations thereof. In one embodiment of the present invention, the sensing device is a photodetector that detects and monitors the light intensity resulting from the mixture of a molten iron with magnesium. In a second embodiment, the sensing device is a hydraulic pressure sensor within a hydraulic line that is attached to a ladle. The hydraulic pressure sensor detects and monitors the change in hydraulic pressure in the hydraulic line caused by ladle mechanical vibrations resulting from the mixture of the molten iron with the magnesium.
The electronic transformation device can be an analog-to-digital converter that converts an analog in situ response signal to a response data set in digital form. The response data set is transmitted to and received by the microprocessor. The microprocessor can manipulate the received response data set by storing the data set, graphically displaying the data set, mathematically transforming the data set, comparing the response data set to a pre-set limit and/or condition and combinations thereof. The microprocessor can also determine whether or not the response data set has met a pre-set limit and/or condition that may or may not be a function of a threshold data set stored within the microprocessor.
The present invention comprises an apparatus and method for the automated and quantitative verification of molten metal treatment. As such, the present invention has utility for increasing the efficiency and productivity of casting operations such as the casting of metal parts, components, articles and the like. The apparatus of the present invention is comprised of a sensing device that detects and monitors an in situ response resulting from the treatment of a molten metal. In addition, an electronic transformation device receives the captured in situ response from the sensing device and transforms said response into a response data set. The response data set is transmitted to and received by a microprocessor for the purpose of automatically and quantitatively verifying the treatment of the molten metal.
In some instances, the in situ response resulting from the treatment of the molten metal is in the form of heat, light intensity, light wavelength, density of smoke particles, composition of smoke particles, mechanical vibration and combinations thereof. The sensing device can include a photodetector and/or a hydraulic pressure sensor within a hydraulic line attached to a ladle wherein molten metal is treated.
Referring now to
The in situ response resulting from the mixture of the magnesium with the molten iron is detected and monitored by a response sensing device 100. The response sensing device 100 can be any sensing device that detects and monitors an in situ response by a molten metal undergoing a treatment, illustratively including a photodetector, a photoconductor, a photoresistor, a light meter, a camera, a hydraulic pressure sensor, a thermocouple, a smoke detector, a smoke particle density detector and combinations thereof. The response sensing device 100 typically captures the in situ response in the form of an analog signal. In the alternative, the response sensing device 100 captures the in situ response in the form of a digital signal.
If an analog signal 110 is captured by the response sensing device 100, the analog signal 110 is transmitted to and received by an electronic transforming device 200. The electronic transforming device 200 preferably transforms the analog signal 110 into a response data set 210 in digital form. For the purposes of the present invention, the term response data set is synonymous with the term response data and is defined as at least one piece of datum that is related to the in situ response described above and is transmitted, received and/or stored by an electronic device. Any electronic transforming device 200 known to those skilled in the art can be used to transform the analog signal 110 into data acceptable by a microprocessor 300, illustratively including an analog-to-digital converter. In one embodiment of the present invention, the electronic transforming device 200 transmits the response data set to the microprocessor 300, as shown in
Turning to
After comparing the digital response data 210 with the threshold hold data 310 and/or threshold criterion 320, the microprocessor determines whether said data 210 meets a pre-set limit or condition 340. In the alternative, the present invention affords for the determination of whether or not the response data 210 meets the pre-set limit 340 before comparing said data 210 with the threshold data 310 and/or threshold criterion 320. In fact, the comparison of the response data 210 with the threshold data 210 and/or threshold criterion 320 is not required. Furthermore, the pre-set limit or condition 340 may or may not be based or derived from the threshold data 310 or threshold criterion 320. For example, and in no way limiting the scope of the present invention, the operator may dictate that the digital response data 210 must exceed or be less than the threshold data 310 by a specified amount. Exceeding or being less than the threshold data 310 by the specific amount could be the threshold criterion 320. In the alternative, a criterion at step 340 can be established which is not dictated or based upon the threshold data 310 or threshold criterion 320.
If comparison of the response data 210 does meet the pre-set limit 340, the microprocessor 300 can afford for an alert communication 350 to an operator that the molten metal treatment was sufficient. In the alternative, if the comparison of response data 210 does not meet the pre-set limit 340, the microprocessor 300 can afford an alert communication 360 to the operator that the molten metal treatment was not sufficient. In this manner, an apparatus and method automatically and quantitatively verifies a molten metal treatment is provided.
In order to aid in the understanding of the present invention and yet not limit the invention in any way, two examples are described and provided below.
EXAMPLE 1Turning to
After the pouring iron 15 into the treatment ladle 20 has been completed, the magnesium addition 30 is placed within the ladle 20 as shown in
When magnesium is the addition to molten iron, the reaction of magnesium with oxygen and molten iron results in an exothermic combustion reaction that produces light. The magnesium reacts with oxygen to form magnesium oxide that exits the treatment ladle 20 in the form of smoke particles 50. Some of the magnesium alloys with the molten iron and affords for the casting of ductile cast iron. The heat of formation for the manganese oxide is approximately −600 kilojoules per mole which produces heat. In addition, approximately 10% of the energy of combustion when manganese reacts with oxygen occurs as light 60. The response sensing device 102 detects and monitors the intensity of light 60 escaping from the treatment ladle 20 as illustrated in
Turning to
As shown in
Turning to
As illustrated in
Turning to
In contrast,
Referring back to
Comparison of
It is understood that a sensing device 100 can be in the form of any sensing device that will detect an in situ response resulting from a molten metal treatment. In addition, if the sensing device is capable of providing data to the microprocessor 300 in a form usable by said microprocessor 300, the electronic transformation device 200 is not required. The microprocessor can be in the form of, or within, a computer, electronic meter, sensing device, and the like. It is also within the scope of the present invention for the apparatus to include not only a sensing device, an electronic transforming device, and a microprocessor, but also a communication system wherein the results of a comparison of the response data set to a threshold data set or a threshold criterion are communicated to additional electronic equipment and/or personnel.
The foregoing drawings, discussion and description are illustrative of specific embodiments and examples of the present invention, but they are not meant to be limitations upon the practice thereof. Numerous modifications and variations of the invention will be readily apparent to those of skill in the art in view of the teaching presented herein. It is the following claims, including all equivalents, which define the scope of the invention.
Claims
1. An apparatus for the automated and quantitative verification of a molten metal treatment comprising:
- a sensing device, said sensing device monitoring an in situ response resulting from the mixture of a molten metal addition with a molten metal;
- an electronic transformation device, said transformation device transforming said in situ response into a response data set; and
- a microprocessor, said microprocessor receiving said response data set, for the purpose of automatically and quantitatively verifying the treatment of molten metal.
2. The invention of claim 1, wherein said in situ response is selected from the group consisting of heat, light intensity, light wavelength, density of smoke particles, composition of smoke particles, mechanical vibration and combinations thereof resulting from the mixture of said addition with said molten metal.
3. The invention of claim 2, wherein said sensing device is a photodetector, said photodetector monitoring the light intensity resulting from the mixture of said addition with said molten metal.
4. The invention of claim 2, further comprising a ladle with a ladle hydraulic line, wherein said sensing device is a hydraulic pressure sensor, said hydraulic pressure sensor monitoring the change in hydraulic pressure in said ladle hydraulic line resulting from mechanical vibration caused by the mixture of said addition with said molten metal in said ladle.
5. The invention of claim 1, wherein said addition to said molten metal is an alloying addition.
6. The invention of claim 1, wherein said electronic transformation device is an analog-to-digital converter, said converter transforming an analog signal from said sensing device into said response data set in digital form.
7. The invention of claim 6, wherein said microprocessor compares said digital response data set to a threshold data set.
8. The invention of claim 7, wherein said threshold data set is light intensity data.
9. The invention of claim 7, wherein said threshold data set is hydraulic pressure data.
10. The invention of claim 1 wherein said molten metal is molten iron.
11. The invention of claim 10 wherein said addition to said molten metal is magnesium.
12. The invention of claim 7, wherein said microprocessor manipulates said digital response data set.
13. The invention of claim 12 wherein said manipulation is selected from the group consisting of storing, graphically displaying, mathematically transforming, comparing to said threshold data and combinations thereof, for the purpose of automatically and quantitatively verifying the treatment of molten metal.
14. An apparatus for the automated and quantitative verification of molten metal treatment comprising:
- a photodetector, said photodetector monitoring an in situ light intensity response resulting from the mixture of an addition to a molten metal with said molten metal;
- an analog-to-digital converter, said converter transforming said in situ light intensity response into a response data set in digital form; and
- a microprocessor, said microprocessor receiving said digital response data set and comparing said response data set to a threshold data set stored therein, for the purpose of automatically and quantitatively verifying the treatment of molten metal.
15. The invention of claim 14, wherein said photodetector is in the form of a light intensity meter.
16. The invention of claim 14, wherein said addition to said molten metal is an alloying addition.
17. The invention of claim 14, wherein said molten metal is molten iron.
18. The invention of claim 14, wherein said addition to said molten metal is magnesium.
19. An apparatus for the automated and quantitative verification of molten metal treatment comprising:
- a ladle, said ladle having a hydraulic line and containing a molten metal therein;
- a hydraulic pressure sensor, said hydraulic pressure sensor monitoring the hydraulic pressure response in said hydraulic line resulting from the mechanical vibration caused from the mixture of an addition with said molten metal;
- an analog-to-digital converter, said converter transforming said hydraulic pressure response into a response data set in digital form; and
- a microprocessor, said microprocessor receiving said digital response data set and comparing said response data set to a threshold data set stored therein, for the purpose of automatically and quantitatively verifying the treatment of molten metal.
20. The invention of claim 19, wherein said addition is a magnesium addition into molten iron.
Type: Application
Filed: Mar 20, 2007
Publication Date: Oct 25, 2007
Applicant: THYSSENKRUPP--WAUPACA DIVISION (Waupaca, WI)
Inventors: Ronald Thurston (Iola, WI), Robert Jezwinski (Waupaca, WI), Gene A. Johnson (Stephenson, MI), Timothy Owens (Wallace, MI)
Application Number: 11/688,611
International Classification: B22D 27/00 (20060101); B22D 46/00 (20060101);