Alloy smelting method and device and application

Abstract

The invention relates to the technical field of non-ferrous metal smelting, in particular to an alloy smelting method and device and application. The alloy smelting method provided by the invention comprises the following steps: S1, conveying mixed gas into an alloy raw material melt, and stirring and reacting; s2, after the reaction, continuously conveying the mixed gas into the alloy raw material melt, stirring, adding other alloy raw materials into the alloy raw material melt according to alloy element composition, and tempering and smelting to obtain an alloy melt; s3, the alloy melt is subjected to continuous casting, and an alloy cast rod is obtained; wherein the mixed gas comprises reducing gas and inert gas. According to the alloy smelting method, the problem that non-metallic inclusions such as oxygen and sulfur are difficult to remove during alloy smelting is solved, and a high-cleanliness and high-performance alloy product can be obtained; and particularly, the oxygen and sulfur contents in the silver alloy can be reduced, so that the quality of the silver alloy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal smelting, and in particular to an alloy smelting method, device and application. Background Art

[0002] Silver has good electrical and thermal conductivity as well as good chemical stability and ductility. Therefore, silver and its alloys are widely used in the fields of electronics and electrical, pharmaceuticals and chemicals, disinfection and antibacterial, photosensitive materials, environmental protection, silver jewelry and craft products. With the development of the electronics industry and the aviation industry, the industrial demand for silver has been growing steadily and rapidly in recent years, and there is still a lot of room for improvement in the deep processing of silver and the application of high technology.

[0003] Silver and oxygen do not combine directly, but in the molten state, one volume of silver dissolves nearly 20 times the volume of oxygen, so it absorbs a large amount of oxygen during smelting. Although the oxygen dissolved in silver will precipitate when it solidifies, there will still be residues, leaving tiny pores, looseness and other defects in the casting. Oxygen in silver alloys will also cause a large amount of beneficial elements to be burned, reducing mechanical properties such as strength, plasticity, hardness, and impact toughness, causing casting defects in the alloy structure, and seriously affecting the reliability of the alloy. Reducing the oxygen content in silver alloys can improve the wettability and casting and wire drawing properties of the alloy, making it possible to produce high-cleanliness and high-reliability silver alloys. In addition, silver is also easy to react with sulfur to produce sulfides that affect the performance of silver alloys.

[0004] At present, the charcoal covering method can prevent oxygen from contacting silver during the smelting process and remove oxygen, but the deoxygenation capacity is limited, resulting in about 150ppm of oxygen still dissolved in the alloy. In addition, at high temperatures, silver is easy to volatilize, and "silver rain" is easily produced during the high-temperature cooling process, causing metallic silver loss, thereby making the alloy composition inaccurate and causing the alloy performance to be unstable. Although vacuum melting can attract oxygen in the alloy, the deoxygenation is not thorough. At the same time, for silver alloys containing high vapor pressure metal components, the alloy components are easy to volatilize, resulting in inaccurate alloy composition.

[0005] In view of this, this invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide an alloy smelting method, which solves the problem that non-metallic inclusions such as oxygen and sulfur are difficult to remove during alloy smelting, and can obtain high-purity and high-performance alloy products; in particular, it can reduce the oxygen and sulfur content in silver alloys, thereby improving the quality of silver alloys.

[0007] A second object of the present invention is to provide an apparatus for implementing the above alloy smelting method.

[0008] The third object of the present invention is to provide an alloy smelting method for use in preparing silver alloy parts.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides an alloy smelting method, comprising the following steps:

[0011] S1, conveying the mixed gas into the alloy raw material melt and stirring and reacting it;

[0012] S2, after the reaction, continue to transport the mixed gas to the alloy raw material melt and stir it, add the remaining alloy raw materials to the alloy raw material melt according to the alloy element composition to perform tempering, and obtain the alloy melt after smelting;

[0013] S3, continuously casting the alloy melt to obtain an alloy cast rod;

[0014] Wherein, the mixed gas includes reducing gas and inert gas.

[0015] Further, the reducing gas includes at least one of hydrogen, carbon monoxide and hydrocarbon gas;

[0016] And / or, the inert gas includes at least one of nitrogen, argon and helium.

[0017] Further, in step S1, the volume percentage of reducing gas in the mixed gas is 1% to 4%;

[0018] And / or, in step S1, the flow rate of the mixed gas is 0.1-0.6m 3 / h.

[0019] Further, in step S1, the stirring speed is 100 to 500 rpm / min;

[0020] And / or, the reaction time is 20 to 120 minutes.

[0021] Further, in step S2, the volume percentage of reducing gas in the mixed gas is 1% to 4%;

[0022] And / or, in step S2, the flow rate of the mixed gas is 0.1-0.6m 3 / h.

[0023] Further, step S2 includes at least one of the following features (1) to (3);

[0024] (1) The stirring speed is 100 to 500 rpm / min;

[0025] (2) The smelting includes: smelting under the action of electromagnetic stirring and mechanical stirring;

[0026] (3) The smelting time is 10 to 40 minutes.

[0027] Further, in step S3, at least one of the following features is included;

[0028] (1) The continuous casting speed is 100 to 600 mm / min;

[0029] (2) The oxygen content in the alloy casting rod is less than 20 ppm;

[0030] (3) The sulfur content in the alloy casting rod is less than 10 ppm.

[0031] In a second aspect, the present invention also provides an apparatus for implementing the alloy smelting method as described above, comprising: a smelting furnace, a hollow stirring paddle, a stop valve, a continuous casting furnace, a movable piston and a guide rod;

[0032] The smelting furnace is connected to the continuous casting furnace;

[0033] The melt in the smelting furnace flows into the continuous casting furnace through a stop valve;

[0034] The smelting furnace is provided with an air inlet and an air outlet;

[0035] The hollow stirring paddle is connected to the air inlet of the smelting furnace by a dynamic seal, and the hollow stirring paddle extends into the smelting furnace;

[0036] The movable piston is located in the continuous casting furnace and is used for squeezing the melt in the continuous casting furnace;

[0037] The guide rod extends into the continuous casting furnace through a continuous casting port of the continuous casting furnace.

[0038] Further, it includes at least one of the following features (1) to (3);

[0039] (1) The stop valve is located on the side where the smelting furnace is connected to the continuous casting furnace;

[0040] (2) The alloy smelting method further comprises a feeding pipe, wherein the feeding pipe is connected to a feeding port of the smelting furnace and extends into the smelting furnace;

[0041] (3) A slag outlet is provided at the bottom of the side of the furnace body of the smelting furnace.

[0042] In a third aspect, the present invention also provides the use of the alloy smelting method as described above in the preparation of silver alloy products.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The alloy smelting method of the present invention adopts a flowing gas reduction method, wherein a mixed gas of reducing gas and inert gas is transported into the melt, the flowing mixed gas is sprayed into the melt, and the melt is stirred, so that non-metallic inclusions (element such as O and S) react rapidly with hydrogen, and the generated gas product is discharged from the reaction zone along with the flowing mixed gas, thereby removing non-metallic inclusions in the melt and obtaining an alloy melt with uniform composition and high purity; then the alloy melt is continuously cast, so as to obtain an alloy cast rod with good surface quality.

[0045] 2. The device for implementing the above alloy smelting method of the present invention can transport the mixed gas to the melt in the smelting furnace through the hollow stirring paddle and stir it, thereby realizing double mechanical stirring of the melt and obtaining a highly clean and high-performance alloy melt; the smelting furnace is separated from the continuous casting furnace, and a movable piston is provided in the continuous casting furnace to ensure that the melt is efficiently and stably drawn downward during the continuous casting process.

[0046] 3. The alloy smelting method of the present invention is used in the preparation of silver alloy products, such as silver alloy bonding wires, silver alloy solders, etc., to avoid the problems of wire breakage, low processing efficiency, and reduced quality and reliability of products during subsequent processing due to high S or O content in the silver alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0049] Figure 2 The microstructure diagrams of the silver alloy ingot prepared in Comparative Example 1 of the present invention and the silver alloy cast rod prepared in Example 3 are shown.

[0050] Reference numerals:

[0051] 1- smelting furnace; 11- air inlet; 12- charging port; 13- air outlet; 14- slag outlet; 2- hollow stirring paddle; 3- stop valve; 4- continuous casting furnace; 41- continuous casting port; 5- moving piston; 6- guide rod. DETAILED DESCRIPTION

[0052] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0053] The following is a detailed description of an alloy smelting method, device and application of the present invention.

[0054] In some embodiments of the present invention, an alloy smelting method is provided, comprising the following steps:

[0055] S1, conveying the mixed gas into the alloy raw material melt and stirring and reacting it;

[0056] S2. After the reaction, the mixed gas is transported to the alloy raw material melt and stirred. According to the alloy element composition, the remaining alloy raw materials are added to the alloy raw material melt for tempering. After smelting, an alloy melt is obtained;

[0057] S3, continuously casting the alloy melt to obtain an alloy cast rod;

[0058] The mixed gas includes reducing gas and inert gas.

[0059] In the alloy smelting method of the present invention, a mixed gas is flushed into the molten pool, and the mixed gas can protect the alloy from oxidation; the reducing gas in the mixed gas can reduce non-metallic inclusions, thereby removing the non-metallic inclusions in the melt; the mixed gas can also play a stirring role, accelerate the reduction reaction, and mix the alloy raw material components.

[0060] In the alloy smelting method of the present invention, the mixed gas is transported to the bottom of the molten pool, the flowing mixed gas is sprayed on the melt, and the melt is stirred at the same time, so as to realize double stirring of the molten pool; the reducing gas in the mixed gas reacts with the non-metallic inclusions (element such as O, S) in the melt, and the stirring promotes the rapid contact between the reducing gas and the non-metallic inclusions, accelerates the reaction, shortens the reaction time, and the reaction product floats in the molten pool, and the generated gas product is discharged from the reaction zone with the flow of the mixed gas. The reducing gas, taking hydrogen as an example, mainly undergoes the following reactions: 2H2(g)+O2(g)=2H2O(g); H2(g)+S=H2S(g). After the reaction is completed, the mixed gas is continuously transported, and the remaining alloy raw materials are added to the alloy raw material melt for quenching and tempering, and smelting, which is conducive to the full mixing of the alloy raw material components and the formation of an alloy melt with uniform composition and high purity. Then the alloy melt is continuously cast, so as to obtain an alloy casting rod with good surface quality. The alloy smelting method of the present invention can realize the continuous preparation of alloy casting rods with uniform composition and high purity.

[0061] The reducing gas reacts with non-metallic inclusions, such as elements such as O and S, to heat the molten pool, ensure thermal balance, fully utilize energy, and reduce overall energy consumption.

[0062] During the degassing process, the reducing gas can not only act as a reducing agent, but also act as a carrier to carry the reaction products out of the molten pool quickly and leave the smelting device along with the flow of inert gas. At the same time, due to the gas flow, a certain negative pressure is generated on the surface of the melt, which has a certain attraction effect on the reaction products, increases the floating and diffusion speed of the reaction products, and accelerates the smelting efficiency.

[0063] By adopting the flowing gas reduction method, the mixed gas is transported to the bottom of the molten pool and the melt is stirred. The molten pool can be double mechanically stirred, which can realize the rapid reaction of non-metallic inclusions (S, O and other elements) with the reducing gas, and can also realize the uniform distribution of alloy elements in the melt to avoid component segregation.

[0064] The entire impurity removal and smelting process of the present invention is operated under normal pressure, so the alloy raw materials can be added at any time to ensure flexible control of the composition.

[0065] The smelting and continuous casting steps of the present invention are carried out separately, which can ensure that the melt is stably drawn downward during the continuous casting process and avoid the problem of increased pores in the casting rod due to melt vibration.

[0066] In some embodiments of the present invention, the mixed gas is delivered to the alloy raw material melt through a hollow stirring paddle and stirred.

[0067] Reduction and impurity removal is a chemical process, and the chemical reaction process is generally slow. The present invention can increase the reaction interface and improve the reaction efficiency through the mechanical stirring of the hollow stirring paddle blades and gas stirring. The mechanical stirring of the hollow stirring paddle blades can break up the bubbles generated by gas stirring, thereby increasing the reaction interface.

[0068] In some embodiments of the present invention, the reducing gas includes at least one of hydrogen, carbon monoxide and hydrocarbon gas; preferably, the hydrocarbon gas includes methane; more preferably, the reducing gas includes hydrogen. Oxygen is an oxidizing atmosphere, which can be removed by adding a reducing gas. Considering the safety of the gas, hydrogen is preferred.

[0069] In some embodiments of the present invention, the inert gas includes at least one of nitrogen (N2), argon (Ar) and helium (He).

[0070] In some embodiments of the present invention, in step S1, the alloy raw material is heated and completely melted to obtain an alloy raw material melt; preferably, the alloy raw material includes silver or a silver alloy, and the heating temperature is 1000-1250°C.

[0071] In some embodiments of the present invention, in step S1, the volume percentage of the reducing gas in the mixed gas is 1% to 4%; typically but not limitatively, for example, in step S1, the volume percentage of the reducing gas in the mixed gas can be 1%, 2%, 3%, 4% or a range consisting of any two of them.

[0072] During the reaction between the mixed gas and the non-metallic inclusions in the melt, if the content of reducing gas in the mixed gas is small, it will not be able to fully react with the non-metallic inclusions in the melt for reduction; if the content of reducing gas is large, it will easily cause safety hazards.

[0073] In some embodiments of the present invention, in step S1, the flow rate of the mixed gas is 0.1 to 0.6 m 3 / h; typically but not limiting, for example, in step S1, the flow rate of the mixed gas may be 0.1m 3 / h、0.2m 3 / h、0.3m 3 / h、0.4m 3 / h、0.5m 3 / h、0.6m 3 / h or a range consisting of any two of them.

[0074] If the flow rate of the mixed gas is small, the stirring effect on the molten pool will be weak; if the flow rate is large, it will cause serious heat loss and reduce the smelting temperature.

[0075] In some embodiments of the present invention, in step S1, the stirring speed is 100 to 500 rpm / min; typically but not limitatively, for example, in step S1, the stirring speed can be 100 rpm / min, 200 rpm / min, 300 rpm / min, 400 rpm / min, 500 rpm / min or a range of any two thereof.

[0076] In some embodiments of the present invention, in step S1, the reaction time is 20 to 120 min; typically but not limiting, for example, the reaction time can be 20 min, 40 min, 60 min, 80 min, 100 min, 120 min or a range consisting of any two thereof.

[0077] In some embodiments of the present invention, in step S2, the volume percentage of the reducing gas in the mixed gas is 1% to 4%; typically but not limitatively, for example, in step S2, the volume percentage of the reducing gas in the mixed gas can be 1%, 2%, 3%, 4% or a range consisting of any two of them.

[0078] In some embodiments of the present invention, in step S2, the flow rate of the mixed gas is 0.1 to 0.6 m 3 / h; typically but not limiting, for example, in step S2, the flow rate of the mixed gas may be 0.1m 3 / h、0.2m 3 / h、0.3m 3 / h、0.4m 3 / h、0.5m 3 / h、0.6m 3 / h or a range consisting of any two of them.

[0079] In some embodiments of the present invention, in step S2, the stirring speed is 100 to 500 rpm / min; typically but not limitatively, for example, the stirring speed can be 100 rpm / min, 200 rpm / min, 300 rpm / min, 400 rpm / min, 500 rpm / min or a range of any two thereof.

[0080] In some embodiments of the present invention, in step S2, the remaining alloy raw materials include one or more of Au element, Cu element, Pd element, Ce element, Ni element and Pt element.

[0081] In some embodiments of the present invention, in step S2, smelting includes: smelting under the action of electromagnetic stirring and mechanical stirring.

[0082] Mechanical stirring is provided by a hollow stirring paddle, which transports the mixed gas into the molten pool and stirs the melt; during the smelting process, the alloy elements can be fully mixed under the action of electromagnetic stirring and mechanical stirring (gas blowing and stirring by the blades of the hollow stirring paddle), thereby forming an alloy melt with uniform composition and high purity.

[0083] In some embodiments of the present invention, in step S2, the smelting time is 10 to 40 minutes; typically but not limiting, for example, the smelting time can be 10 minutes, 20 minutes, 30 minutes, 40 minutes or a range of any two thereof.

[0084] In some embodiments of the present invention, in step S3, the continuous casting initiation speed is 100-600 mm / min; typically but not limitatively, for example, the continuous casting initiation speed can be 100 mm / min, 200 mm / min, 300 mm / min, 400 mm / min, 500 mm / min, 600 mm / min or a range of any two thereof.

[0085] In some embodiments of the present invention, the oxygen content in the alloy casting rod is less than 20 ppm; preferably, the oxygen content in the alloy casting rod is ≤15 ppm.

[0086] In some embodiments of the present invention, the sulfur content in the alloy casting rod is less than 10 ppm; preferably, the sulfur content in the alloy casting rod is ≤8 ppm.

[0087] See also Figure 1 In some embodiments of the present invention, there is also provided an apparatus for implementing the above alloy smelting method, comprising: a smelting furnace 1, a hollow stirring paddle 2, a stop valve 3, a continuous casting furnace 4, a movable piston 5 and a guide rod 6;

[0088] The smelting furnace 1 is connected to the continuous casting furnace 4;

[0089] The melt in the smelting furnace 1 flows into the continuous casting furnace 4 through the stop valve 3;

[0090] The smelting furnace 1 is provided with an air inlet 11 and an air outlet 13;

[0091] The hollow stirring paddle 2 is connected to the air inlet 11 of the smelting furnace 1 by a dynamic seal, and the hollow stirring paddle 2 extends into the smelting furnace 1;

[0092] The movable piston 5 is located in the continuous casting furnace 4 and is used to squeeze the melt in the continuous casting furnace 4;

[0093] The guide rod 6 extends into the continuous casting furnace 4 through the continuous casting port 41 of the continuous casting furnace 4 .

[0094] The device of the present invention can transport a mixed gas of reducing gas and inert gas to the bottom of the molten pool in the smelting furnace through a hollow stirring paddle. The flowing mixed gas and the rotating hollow stirring paddle spray and stir the melt, which can not only remove elements such as oxygen and sulfur, but also stir, accelerate reduction and mix the alloy components, thereby removing non-metallic inclusions in the melt and obtaining an alloy melt with uniform composition and high purity.

[0095] During the alloy smelting process, a mixed gas of reducing gas and inert gas is introduced from the gas inlet, and the mixed gas is transported to the bottom of the molten pool by a hollow stirring paddle, and the melt is stirred by a hollow stirring paddle. The reducing gas in the mixed gas reacts with the non-metallic inclusions in the melt to produce a reduction reaction, and the generated gas product is discharged from the gas outlet along with the flow of the mixed gas. After the reaction is completed, the required alloy raw materials are added from the feed for tempering and smelting to obtain an alloy melt.

[0096] The alloy melt in the smelting furnace enters the continuous casting furnace for continuous casting through the stop valve under the suction force generated by the upward movement of the moving piston. The downward movement of the moving piston generates pressure to pressurize the alloy melt, so that the alloy melt can be discharged through the continuous casting port and directly cast, achieving efficient and stable casting, thereby obtaining alloy casting rods with good surface quality. The device of the present invention can realize the continuous preparation of high-purity alloy casting rods with uniform composition.

[0097] In some embodiments of the present invention, the smelting furnace 1 comprises an induction smelting furnace.

[0098] In some embodiments of the present invention, the blades of the hollow stirring paddle are hollow structures; the mixed gas enters from the center of the hollow stirring rod and is exhausted from the blades, thereby transporting the mixed gas into the melt.

[0099] In some embodiments of the present invention, the hollow stirring blade 2 is made of graphite.

[0100] In some embodiments of the present invention, the stop valve 3 is located at the side where the smelting furnace 1 is connected to the continuous casting furnace 4 .

[0101] In some embodiments of the present invention, the vertical distance between the stop valve 3 and the bottom of the furnace body of the smelting furnace 1 is equal to the thickness of the slag layer in the smelting furnace 1 .

[0102] The stop valve is located at a distance H between the side of the furnace body and the bottom of the smelting furnace. H is determined according to the height of the slag layer in the molten pool. The height of the slag layer is equal to the height of the stop valve position.

[0103] In some embodiments of the present invention, the device further comprises a feeding pipe, which is connected to a feeding port 12 of the smelting furnace 1 and extends into the smelting furnace 1 .

[0104] In some embodiments of the present invention, the gas inlet 11 is located at the top of the furnace body of the smelting furnace 1 .

[0105] In some embodiments of the present invention, the gas outlet 13 is located at the top of the furnace body of the smelting furnace 1 .

[0106] In some embodiments of the present invention, the charging port 12 is located at the top of the furnace body of the smelting furnace 1 .

[0107] The charging port can be located at any position on the top of the furnace, including the center of the gas outlet, and the charging pipe connected to the charging port extends to the bottom of the furnace. Alloy raw materials can be added directly from the charging port; or alloy elements can be sprayed into the furnace by inert gas.

[0108] In some embodiments of the present invention, a slag outlet 14 is provided at the bottom of the side surface of the smelting furnace 1 .

[0109] The slag outlet is located at the bottom of the side of the smelting furnace body, so that the slag can be scraped out from the slag outlet when the continuous casting is completed.

[0110] In some embodiments of the present invention, the maximum moving distance of the movable piston 5 is the vertical distance between the stop valve 3 and the top of the continuous casting furnace 4 .

[0111] The upward movement of the movable piston generates suction, which allows the melt in the smelting furnace to enter the continuous casting furnace through the stop valve under the action of suction; the downward movement of the movable piston generates pressure, which can pressurize the melt and allow the melt to be discharged through the continuous casting port; the movable piston can move between the position of the continuous casting furnace corresponding to the stop valve and the top of the continuous casting furnace.

[0112] In some embodiments of the present invention, the application of the above alloy smelting method in the preparation of silver alloy parts is also provided.

[0113] In some embodiments of the present invention, the silver alloy part includes silver alloy solder and / or silver alloy bonding wire.

[0114] High S or O content in silver alloys may cause problems in subsequent processing. For example, the silver alloy bonding wire may break easily during processing, thereby reducing processing efficiency. The wire may also break easily during bonding, thereby reducing the quality of use and device reliability. The alloy smelting method of the present invention is used in the preparation of silver alloy products to avoid the above problems.

[0115] Example 1

[0116] The device provided in this embodiment includes: an induction melting furnace, a hollow stirring paddle 2, a stop valve 3, a feeding pipe, a continuous casting furnace 4, a movable piston 5 and a guide rod 6;

[0117] The induction melting furnace is connected to the continuous casting furnace 4;

[0118] The stop valve 3 is located at the side where the induction melting furnace is connected to the continuous casting furnace, and the melt in the induction melting furnace flows into the continuous casting furnace 4 through the stop valve 3; the vertical distance between the stop valve 3 and the bottom of the furnace body of the induction melting furnace is equal to the thickness of the slag layer in the induction melting furnace;

[0119] The top of the induction melting furnace is provided with an air inlet 11, an air outlet 13 and a feed port 12;

[0120] The hollow stirring paddle 2 includes a hollow stirring rod and a paddle. The hollow stirring paddle 2 is connected to the air inlet 11 of the induction melting furnace by a dynamic seal, and the hollow stirring paddle 2 extends into the induction melting furnace.

[0121] The feeding pipe is connected to the feeding port 12 of the induction melting furnace, and the feeding pipe extends into the induction melting furnace;

[0122] A slag outlet 14 is provided at the bottom of the side of the induction melting furnace;

[0123] The movable piston 5 is located in the continuous casting furnace 4 and is used to squeeze the melt in the continuous casting furnace 4. The maximum moving distance of the movable piston 5 is the vertical distance between the stop valve 3 and the top of the continuous casting furnace 4.

[0124] The guide rod 6 extends into the continuous casting furnace 4 through the continuous casting port 41 of the continuous casting furnace 4 .

[0125] The silver alloy smelting method provided in this embodiment is implemented by using the above-mentioned device, and comprises the following steps:

[0126] S1. Silver or a silver-copper alloy containing 10 wt% copper is completely melted in an induction melting furnace, and the current of the induction melting furnace is adjusted to 43.8 A; then a mixed gas is continuously introduced from the gas inlet 11, wherein the mixed gas is hydrogen and nitrogen, the volume percentage of hydrogen in the mixed gas is 4%, and the flow rate of the mixed gas is 0.1 m 3 / h; the molten pool temperature is 1050°C; the mixed gas is transported to the molten pool through the hollow stirring paddle 2 and stirred and reacted, the stirring speed is 100rpm / min, and the reaction time is 20min; the reaction product floats in the molten pool, and the gas product is discharged from the gas outlet 13 along with the mixed gas;

[0127] S2. After the reaction is completed, a mixed gas is introduced from the gas inlet 11. The mixed gas is hydrogen and nitrogen. The volume percentage of hydrogen in the mixed gas is 1%. The flow rate of the mixed gas is 0.5m 3 / h; continue to convey the mixed gas to the molten pool through the hollow stirring paddle 2 and stir it at a speed of 100rpm / min, add the required alloying elements (Pd and at least one of Au, Pt, Rh, Cu, In, Ce, Si, Zn, Sn, Be and La) through the feeding port 12 to perform alloying component tempering, and after smelting for 10 minutes under the action of electromagnetic stirring and mechanical stirring (gas blowing and blade stirring), a silver alloy melt is obtained;

[0128] S3. The silver alloy melt flows into the continuous casting furnace 4 through the stop valve 3 under the action of the suction force generated by the upward movement of the moving piston 5 in the continuous casting furnace 4. When the cavity of the continuous casting furnace 4 is filled with the silver alloy melt, the moving piston 5 moves downward to squeeze the silver alloy melt and start the continuous casting process. The casting speed is 100 mm / min to obtain a silver alloy cast rod. In the silver alloy cast rod, the mass percentage of Pd is 1% to 30%.

[0129] Example 2

[0130] The silver alloy smelting method provided in this embodiment is implemented using the device of embodiment 1, and comprises the following steps:

[0131] S1. The silver-palladium alloy containing 20 wt% palladium is completely melted in an induction melting furnace, and the current of the induction melting furnace is adjusted to 44.5 A; then a mixed gas is continuously introduced from the gas inlet 11, wherein the mixed gas is hydrogen and argon, the volume percentage of hydrogen in the mixed gas is 6%, and the flow rate of the mixed gas is 0.3 m 3 / h; the molten pool temperature is 1100°C; the mixed gas is transported to the molten pool through the hollow stirring paddle 2 and stirred and reacted, the stirring speed is 100rpm / min, and the reaction time is 20min; the reaction product floats in the molten pool, and the gas product is discharged from the gas outlet 13 along with the mixed gas;

[0132] S2. After the reaction is completed, a mixed gas is introduced from the gas inlet 11. The mixed gas is hydrogen and argon. The volume percentage of hydrogen in the mixed gas is 2%. The flow rate of the mixed gas is 0.4m 3 / h; continue to transport the mixed gas to the molten pool through the hollow stirring paddle 2 and stir it at a speed of 100rpm / min, add the required alloying element Zn through the feeding port 12 to temper the alloying composition, and smelt for 10 minutes under the action of electromagnetic stirring and mechanical stirring (gas blowing and blade stirring) to obtain a silver alloy melt;

[0133] S3. The silver alloy melt flows into the continuous casting furnace 4 through the stop valve 3 under the action of the suction force generated by the upward movement of the moving piston 5 in the continuous casting furnace 4. When the cavity of the continuous casting furnace 4 is filled with the silver alloy melt, the moving piston 5 moves downward to squeeze the silver alloy melt and start the continuous casting process. The casting speed is 200 mm / min to obtain a silver alloy cast rod. The mass percentage of Zn in the silver alloy cast rod is 10%.

[0134] Example 3

[0135] The silver alloy smelting method provided in this embodiment is implemented using the device of embodiment 1, and comprises the following steps:

[0136] S1. The silver-gold alloy containing 2wt% gold is completely melted in an induction melting furnace, and the current of the induction melting furnace is adjusted to 44.5A; then a mixed gas is continuously introduced from the gas inlet 11, wherein the mixed gas is hydrogen and argon, the volume percentage of hydrogen in the mixed gas is 6%, and the flow rate of the mixed gas is 0.3m 3 / h; the molten pool temperature is 1100°C; the mixed gas is transported to the molten pool through the hollow stirring paddle 2 and stirred and reacted, the stirring speed is 500rpm / min, and the reaction time is 30min; the reaction product floats in the molten pool, and the gas product is discharged from the gas outlet 13 along with the mixed gas;

[0137] S2. After the reaction is completed, a mixed gas is introduced from the gas inlet 11. The mixed gas is hydrogen and argon. The volume percentage of hydrogen in the mixed gas is 2%. The flow rate of the mixed gas is 0.3m 3 / h; continue to transport the mixed gas to the molten pool through the hollow stirring paddle 2 and stir it at a speed of 500rpm / min, add the required alloying elements Cu and Zn through the feeding port 12 to perform alloying component tempering, and smelt for 10 minutes under the action of electromagnetic stirring and mechanical stirring (gas blowing and blade stirring) to obtain a silver alloy melt;

[0138] S3. The silver alloy melt flows into the continuous casting furnace 4 through the stop valve 3 under the action of the suction force generated by the upward movement of the moving piston 5 in the continuous casting furnace 4. When the cavity of the continuous casting furnace 4 is filled with the silver alloy melt, the moving piston 5 moves downward to squeeze the silver alloy melt and start the continuous casting process. The casting speed is 300 mm / min to obtain a silver alloy cast rod. In the silver alloy cast rod, the mass percentage of Cu is 5%, and the mass percentage of Zn is 5%.

[0139] Example 4

[0140] The silver alloy smelting method provided in this embodiment is implemented using the device of embodiment 1, and comprises the following steps:

[0141] S1. The silver-palladium alloy containing 6wt% palladium is completely melted in an induction melting furnace, and the current of the induction melting furnace is adjusted to 45A; then a mixed gas is continuously introduced from the gas inlet 11, wherein the mixed gas is hydrogen and argon, the volume percentage of hydrogen in the mixed gas is 10%, and the flow rate of the mixed gas is 0.6m 3 / h; the molten pool temperature is 1150°C; the mixed gas is transported to the molten pool through the hollow stirring paddle 2 and stirred and reacted, the stirring speed is 500rpm / min, and the reaction time is 30min; the reaction product floats in the molten pool, and the gas product is discharged from the gas outlet 13 along with the mixed gas;

[0142] S2. After the reaction is completed, a mixed gas is introduced from the gas inlet. The mixed gas is hydrogen and argon. The volume percentage of hydrogen in the mixed gas is 3%. The flow rate of the mixed gas is 0.2m 3 / h; continue to transport the mixed gas to the molten pool through the hollow stirring paddle 2 and stir it at a speed of 500rpm / min, add the required alloying elements Zn and Mg through the feeding port 12 to temper the alloying components, and smelt for 10 minutes under the action of electromagnetic stirring and mechanical stirring (gas blowing and blade stirring) to obtain a silver alloy melt;

[0143] S3. The silver alloy melt flows into the continuous casting furnace 4 through the stop valve 3 under the action of the suction force generated by the upward movement of the moving piston 5 in the continuous casting furnace 4. When the cavity of the continuous casting furnace 4 is filled with the silver alloy melt, the moving piston 5 moves downward to squeeze the silver alloy melt and start the continuous casting process. The casting speed is 600 mm / min to obtain a silver alloy cast rod. In the silver alloy cast rod, the mass percentage of Zn is 1%, and the mass percentage of Mg is 2%.

[0144] Example 5

[0145] The silver alloy smelting method provided in this embodiment is implemented using the device of embodiment 1, and comprises the following steps:

[0146] S1. The silver-gold alloy containing 2 wt% gold is completely melted in an induction melting furnace, and the current of the induction melting furnace is adjusted to 44.5 A; then a mixed gas is continuously introduced from the gas inlet 11, wherein the mixed gas is CO and argon, the volume percentage of CO in the mixed gas is 6%, and the flow rate of the mixed gas is 0.3 m 3 / h; the molten pool temperature is 1100°C; the mixed gas is transported to the molten pool through the hollow stirring paddle 2 and stirred and reacted, the stirring speed is 500rpm / min, and the reaction time is 120min; the reaction product floats in the molten pool, and the gas product is discharged from the gas outlet 13 along with the mixed gas;

[0147] S2. After the reaction is completed, a mixed gas is introduced from the gas inlet 11. The mixed gas is CO and argon. The volume percentage of CO in the mixed gas is 2%. The flow rate of the mixed gas is 0.3m 3 / h; continue to transport the mixed gas to the molten pool through the hollow stirring paddle 2 and stir it at a speed of 500rpm / min, add the required alloying elements Cu and Zn through the feeding port 12 to perform alloying component tempering, and smelt for 40 minutes under the action of electromagnetic stirring and mechanical stirring (gas blowing and blade stirring) to obtain a silver alloy melt;

[0148] S3. The silver alloy melt flows into the continuous casting furnace 4 through the stop valve 3 under the action of the suction force generated by the upward movement of the moving piston 5 in the continuous casting furnace 4. When the cavity of the continuous casting furnace 4 is filled with the silver alloy melt, the moving piston 5 moves downward to squeeze the silver alloy melt and start the continuous casting process. The casting speed is 300 mm / min to obtain a silver alloy cast rod. In the silver alloy cast rod, the mass percentage of Cu is 5%, and the mass percentage of Zn is 5%.

[0149] Comparative Example 1

[0150] The silver alloy smelting method provided in this comparative example comprises the following steps:

[0151] S1. Silver or a silver-copper alloy containing 20 wt% copper is completely melted in an induction melting furnace. The current of the induction melting furnace is adjusted to 44.0 A, and the temperature of the molten pool is 1050° C. Then the gas inlet valve of the induction melting furnace is closed, and a layer of carbon powder is covered on the surface of the molten pool, and the reaction is carried out for 20 minutes.

[0152] S2. After the reaction is completed, the required alloying elements (Pd and at least one of Au, Pt, Rh, Cu, In, Ce, Si, Zn, Sn, Be and La) are added from the feeding port of the induction melting furnace to perform alloying component quenching and tempering, and the melting is continued under the action of electromagnetic stirring for 10 minutes to form a silver alloy melt;

[0153] S3. The silver alloy melt is discharged from the discharge port of the induction melting furnace and enters the solidification device for solidification to obtain a silver alloy ingot; the mass percentage of Pd in ​​the silver alloy cast rod is 1% to 30%.

[0154] Comparative Example 2

[0155] The silver alloy smelting method provided in this comparative example comprises the following steps:

[0156] Silver and palladium elements are completely melted in an induction melting furnace, the current of the induction melting furnace is adjusted to 45.2A, and then vacuum melting is performed, the vacuum degree is 10Pa, the molten pool temperature is 1150°C, and the time is 30min. The alloy elements are fully mixed under the action of electromagnetic stirring to obtain a silver alloy melt;

[0157] The silver alloy melt is solidified in a vacuum furnace to obtain a silver alloy ingot; in the silver alloy ingot, the mass percentage of Pd is 20%.

[0158] Test example

[0159] The silver alloy ingots prepared in Example 1 and the silver alloy cast rods prepared in Example 3 were tested by scanning electron microscope. The results are as follows: Figure 2 shown. Figure 2 a is the silver alloy ingot prepared in Comparative Example 1, Figure 2 B is the silver alloy cast rod obtained in Example 3.

[0160] from Figure 1 It can be seen that the microstructure of the silver alloy ingot prepared in Comparative Example 1 is mixed with carbon particles, and the structure has defects; the microstructure of the silver alloy cast rod prepared in Example 3 is free of particle inclusions and has a uniform structure.

[0161] The parameters of the silver alloy smelting methods of Examples 1 to 5 and Comparative Examples 1 to 2 are shown in Table 1.

[0162] In Table 1, the gas content is the volume percentage of hydrogen or argon in the mixed gas in step S1 of Examples 1 to 5.

[0163] Flow rate is: the flow rate of the mixed gas in step S1 of Examples 1 to 5.

[0164] Table 1

[0165]

[0166]

[0167] The oxygen content and sulfur content in the silver alloy cast rods prepared in Examples 1 to 5 and the silver alloy ingots prepared in Comparative Examples 1 to 2, as well as the silver loss of the silver alloy smelting method are shown in Table 2.

[0168] Table 2

[0169] Oxygen content / ppm Sulfur content / ppm Silver loss / g Example 1 15 8 1.0 Example 2 10 6 1.1 Example 3 6 5 1.2 Example 4 3 ＜5 1.8 Example 5 2 ＜5 1.9 Comparative Example 1 380 20 0.9 Comparative Example 2 20 10 2

[0170] It can be seen from Table 2 that the alloy smelting method of the present invention can obtain a high-purity, high-performance silver alloy product, and the silver alloy product has low oxygen and sulfur contents.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An alloy smelting method, characterized in that: The steps include: S1, conveying the mixed gas into the alloy raw material melt and stirring and reacting it; S2, after the reaction, continue to transport the mixed gas to the alloy raw material melt and stir it, add the remaining alloy raw materials to the alloy raw material melt according to the alloy element composition to perform tempering, and obtain the alloy melt after smelting; S3, continuously casting the alloy melt to obtain an alloy cast rod; Wherein, the mixed gas includes reducing gas and inert gas.

2. The alloy smelting method according to claim 1, characterized in that: The reducing gas includes at least one of hydrogen, carbon monoxide and hydrocarbon gas; And / or, the inert gas includes at least one of nitrogen, argon and helium.

3. The alloy smelting method according to claim 2, characterized in that: In step S1, the volume percentage of reducing gas in the mixed gas is 1% to 4%; And / or, in step S1, the flow rate of the mixed gas is 0.1-0.6m 3 / h.

4. The alloy smelting method according to claim 2, characterized in that: In step S1, the stirring speed is 100-500 rpm / min; And / or, the reaction time is 20 to 120 minutes.

5. The alloy smelting method according to claim 3, characterized in that: In step S2, the volume percentage of reducing gas in the mixed gas is 1% to 4%; And / or, in step S2, the flow rate of the mixed gas is 0.1-0.6m 3 / h.

6. The alloy smelting method according to claim 5, characterized in that: In step S2, at least one of the following features (1) to (3) is included; (1) The stirring speed is 100 to 500 rpm / min; (2) The smelting includes: smelting under the action of electromagnetic stirring and mechanical stirring; (3) The smelting time is 10 to 40 minutes.

7. The alloy smelting method according to claim 5, characterized in that: In step S3, at least one of the following features is included; (1) The continuous casting speed is 100 to 600 mm / min; (2) The oxygen content in the alloy casting rod is less than 20 ppm; (3) The sulfur content in the alloy casting rod is less than 10 ppm.

8. An apparatus for implementing the alloy smelting method according to any one of claims 1 to 7, characterized in that: include: Melting furnace, hollow stirring paddle, stop valve, continuous casting furnace, moving piston and guide rod; The smelting furnace is connected to the continuous casting furnace; The melt in the smelting furnace flows into the continuous casting furnace through a stop valve; The smelting furnace is provided with an air inlet and an air outlet; The hollow stirring paddle is connected to the air inlet of the smelting furnace by a dynamic seal, and the hollow stirring paddle extends into the smelting furnace; The movable piston is located in the continuous casting furnace and is used for squeezing the melt in the continuous casting furnace; The guide rod extends into the continuous casting furnace through a continuous casting port of the continuous casting furnace.

9. The device according to claim 8, characterized in that The method comprises at least one of the following features (1) to (3); (1) The stop valve is located on the side where the smelting furnace is connected to the continuous casting furnace; (2) The device further comprises a feeding pipe, the feeding pipe is connected to a feeding port of the smelting furnace, and the feeding pipe extends into the smelting furnace; (3) A slag outlet is provided at the bottom of the side of the furnace body of the smelting furnace.

10. Use of the alloy smelting method according to any one of claims 1 to 7 in the preparation of silver alloy products.

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