Method of adding high vapor pressure magnesium to steel liquid and apparatus for performing the method

Abstract

An apparatus of adding high vapor pressure magnesium to a steel liquid, includes a magnesium additive device and a tube furnace. The magnesium additive device includes a storage barrel, a conveying pipe, a control valve, and an insertion tube. A method of adding high vapor pressure magnesium to a steel liquid, includes placing the magnesium additive device in the tube furnace, and delivering pure magnesium particles into the storage barrel. When the temperature at the mediate lower position of the conveying pipe is increased to reach a preset value, the control valve is opened to pour the pure magnesium particles into the conveying pipe to form a magnesium vapor, and an argon regulating valve is opened to introduce the argon into the conveying pipe so as to add the magnesium vapor to a steel liquid by carrying of the argon.

Claims

1. A method of adding high vapor pressure magnesium to a steel liquid, comprising: placing a magnesium additive device in a tube furnace; and adding pure magnesium particles when a temperature at a mediate lower position of the magnesium additive device is increased to reach a preset value, so that the pure magnesium particles form a magnesium vapor which is carried into a steel liquid by argon.

2. The method of claim 1, further comprising providing an argon regulating valve to introduce the argon whose flow rate is at the range of 0.5-1.5 L/min.

3. The method of claim 1, wherein the magnesium vapor is carried into the steel liquid by the argon whose flow rate is at the range of 0.2-0.5 L/min.

4. The method of claim 1, wherein each of the pure magnesium particles has a diameter of 0.5-2 mm.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

(1) FIG. 1 is a table showing an oxygen content demand of a conventional steel product in accordance with the prior art.

(2) FIG. 2 is a graph showing the relationship of the vapor pressure and the temperature of Mg and Al in accordance with the prior art.

(3) FIG. 3 is a cross-sectional view of a magnesium additive device in accordance with the preferred embodiment of the present invention

(4) FIG. 4 is a cross-sectional assembly view of the magnesium additive device and a tube furnace in accordance with the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) Referring to FIGS. 3 and 4, a magnesium additive device 1 in accordance with the preferred embodiment of the present invention comprises a storage barrel 11, a control valve 12 and a main body 13. The main body 13 has a conveying pipe 131. An insertion tube 132 is mounted in a hollow interior of the conveying pipe 131. The insertion tube 132 has a sealed bottom provided with a plurality of air holes 1321. A three-way pipe 133 is mounted on a side wall of the conveying pipe 131 to allow entrance of argon. A temperature sensor 14 is mounted on the bottom of the insertion tube 132. A corrosion resistant coating 15 is formed on an inner all of the main body 13. The above-mentioned elements are connected tightly and closely to prevent entrance of air.

(6) The magnesium additive device 1 is mounted in a tube furnace 2 which has a hollow interior 20. The upper and lower ends of the magnesium additive device 1 are respectively connected by a line 21 which is provided with valves 211, 212 and 213 which are located at different positions. A gas purifier 22 is mounted on the line 21 and located between the valves 211 and 213. The line 21 is also provided with flow meters 23 and 230. The line 21 has an upper end provided with a gas conveying pipe 24 connected to the valve 213. The tube furnace 2 includes a crucible 16 mounted in an inner wall of the magnesium additive device 1 for receiving a steel liquid 3. A temperature detector 4 is mounted on an outer wall of the tube furnace 2.

(7) The important core of the present invention is how to add magnesium into the steel liquid 3 safely with a high gain under the steelmaking temperature of 1600 C.

(8) When in use, the valves 211, 212 and 213 are opened. Then, the valve 212 is regulated so that the flow rate of the flow meter 230 is at the range of 1-2 L/min. At the same time, argon is introduced through the valve 211 into the line 21 during a time interval of ten minutes so that the oxygen pressure in the tube furnace 2 is reduced to the minimum. Then, magnesium with a diameter of 0.5-2 mm is poured into the storage barrel 11, and the valve 213 is regulated so that the flow rate of the flow meter 23 is at the range of 0.5-1 L/min to pass the argon during a time interval of five minutes. Then, the valve 213 is closed. Then, the tube furnace 2 is energized to increase the temperature in the crucible 16 of the tube furnace 2 to 1600 C. so that the steel in the crucible 16 is melted completely to form the steel liquid 3 whose temperature is distributed evenly.

(9) At this time, the magnesium additive device 1 is located above the crucible 16 of the tube furnace 2. When the temperature sensor 14 detects that the temperature of the magnesium is kept constantly at the range of 1120 C. to 1200 C., the control valve 12 is opened to introduce the magnesium from the storage barrel 11 into the insertion tube 132 at a determined speed, so that the magnesium is vaporized under the high temperature to form a magnesium vapor. At this time, the valve 213 is opened to introduce the argon at the flow rate of 0.2-0.5 L/min to accomplish the process of adding the magnesium to the steel liquid 3.

(10) Accordingly, in accordance with the present invention, the technology of adding the high vapor pressure magnesium to the steel liquid 3 has the following advantages. The present invention adds the pure magnesium to the steel liquid 3 without introducing other element, thereby preventing the component of the steel liquid 3 from being complicated. In addition, the characteristic of the present invention is in that, after the magnesium is vaporized, the argon functions as a carrier to add the magnesium vapor to the steel liquid 3 so as to prevent the solid magnesium particles from directly contacting the steel liquid 3 and to prevent from incurring the danger of explosion. Further, the argon functions as a protective gas during the process to prevent the magnesium from directly contacting the air. Further, the temperature of the hollow interior 20 of the tube furnace 2 is kept at the range of 1120 C. to 1200 C. to vaporize the solid magnesium, without having to additionally provide a heating device. Further, the solid magnesium is vaporized at the temperature range of 1120 C. to 1200 C., and the vapor pressure of the magnesium is only 4 atm under such a temperature range. Further, the insertion tube 132 is made of a stainless steel that can tolerate a high temperature so that the conveying pipe 131 will not be broken during the magnesium vaporizing process. Further, the argon functions as a carrier when the magnesium vapor is added to the steel liquid 3 so that the magnesium is distributed evenly in the steel liquid 3. Further, when the magnesium is added to the steel liquid 3, the magnesium has a better recovery ratio. Further, the quantity of the magnesium added into the insertion tube 132 is controlled by the storage barrel 11, and the time interval of adding the magnesium is controlled so as to exactly control the magnesium content in the steel liquid 3.

(11) In conclusion, the magnesium is added to the steel liquid 3 safely and stably, without having to introduce other alloy element, so that the cost of production is low, the magnesium recovery ratio is high, and the magnesium is distributed evenly in the steel liquid 3.

(12) Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.