阅读说明：本技术 一种提升镍锭质量的熔炼工艺 (Smelting process for improving quality of nickel ingot ) 是由 武会宾 刘金旭 于 2020-12-01 设计创作，主要内容包括：本发明提供一种提升镍锭质量的熔炼工艺,适用200公斤以上的镍锭制备,各组分的化学成分质量百分数为Ni≥99.5%,C 0.002-0.01%,Si 0.02-0.1%,Mn 0.01-0.05%,Mg 0.01-0.03%,Ti 0.01-0.1%,Al 0.01-0.1%、S≤0.005%,P≤0.002%,Fe 0.01-0.1%,上述重量百分比之和为100%,应用该工艺能有效提高熔铸镍锭的质量,铸坯合格率在97%以上。(The invention provides a smelting process for improving the quality of a nickel ingot, which is suitable for preparing more than 200 kilograms of nickel ingots, and comprises the following chemical components of more than or equal to 99.5 percent of Ni, 0.002-0.01 percent of C, 0.02-0.1 percent of Si, 0.01-0.05 percent of Mn, 0.01-0.03 percent of Mg, 0.01-0.1 percent of Ti, 0.01-0.1 percent of Al, less than or equal to 0.005 percent of S, less than or equal to 0.002 percent of P, and 0.01-0.1 percent of Fe, wherein the sum of the weight percentages is 100 percent.)

1. A smelting process for improving the quality of a nickel ingot is characterized by comprising the following steps: the method comprises the following steps:

(1) adding raw materials into a vacuum smelting furnace for the first time, covering a furnace cover, vacuumizing to-0.1 MPa, starting the smelting furnace, stepping up to full power for smelting, after the raw materials are completely molten, closing the power of the smelting furnace and a vacuum pump, waiting for the cylinder liquor in the furnace to solidify and cake, closing the vacuum pump, breaking the vacuum, and recovering the atmospheric pressure;

(2) opening a furnace cover, adding the raw materials again, vacuumizing to-0.1 MPa, starting the power of the smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) shaking the furnace body for 4-6 times to perform semi-refining to maximize the liquid level, reducing the power of the smelting furnace to 60-80KW after the liquid level is not abnormal, and turning off the Roots pump and the vacuum pump after waiting for 3-5 min;

(4) filling argon and adding a deoxidizing agent, starting a vacuum pump and starting a smelting furnace to increase the full power, starting a roots pump to strengthen the vacuum when the vacuum degree reaches-0.1 MPa, reducing the power to 60-80KW for refining after 1-3min, adjusting the temperature of the casting furnace after 15min, and closing the roots pump and the vacuum pump;

(5) and introducing argon gas for nickel water casting, feeding after casting to obtain a complete cast ingot, and restoring atmospheric pressure.

2. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 3, the amplitude of the furnace body shaking is controlled until the nickel water does not overflow from the edge of the casting opening.

3. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 4, the deoxidizer is composed of a nickel-magnesium alloy, carbon, titanium, aluminum and rare earth, and is added in the order of C → AL → Ti → Ni + Mg → rare earth.

4. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 4, the nickel water is electromagnetically stirred for 4-6 times while argon is filled and a deoxidizer is added.

5. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 5, the nickel water casting is charged casting, and the casting process is slow firstly and then fast;

the casting power is controlled between 50KW and 150KW, and the whole casting process is controlled within 5 min.

6. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 5, after the shrinkage cavity contour is shrunk, nickel water is sequentially supplemented until the shrinkage cavity is completely complemented, and the shrinkage cavity time is not less than 10 min.

7. The smelting process for upgrading nickel ingot quality as set forth in claim 1, wherein: in the step 5, the ingot is kept in the smelting furnace for 1-3min and then is opened and lifted out.

Technical Field

The invention relates to a nickel ingot smelting process, in particular to a smelting process for improving the quality of a nickel ingot.

Background

Nickel is a silver-white metal, with magnetic properties and good plasticity. A metal element having good corrosion resistance, being hard and ductile and having ferromagnetism, which is highly polished and corrosion resistant. After dissolving in nitric acid, it is green.

At present, the weight of a nickel ingot blank produced by a domestic nickel strip production enterprise is basically about 200 kg, which is mainly limited by the most key core technology in a nickel strip production process, namely a vacuum melting casting blank; because the technical content of the vacuum melting casting blank is high, the quality of the blank ingot is determined by the tightness of the process and procedure process control, the quality of the casting blank produced by the domestic nickel strip is deeply concerned for many years, and the quality of the ingot blank directly influences the subsequent production procedures of rolling, heat treatment, stripping and the like.

The patent number CN204747434U discloses a nickel ingot casting mold, and the patent number CN206832042U discloses a nickel ingot vacuum melting furnace, which are all applied to the melting process of the invention. Based on the improvement of the smelting equipment, the quality of the nickel ingot can be obviously improved by combining the smelting process disclosed by the invention.

Disclosure of Invention

The invention aims to overcome and supplement the defects in the prior art, provide a smelting process for improving the quality of a nickel ingot, achieve the aim of improving the quality of the nickel ingot and meet the current market demand on high-purity nickel strips. The technical scheme adopted by the invention is as follows:

a smelting process for improving the quality of a nickel ingot comprises the following steps:

(1) adding raw materials into a vacuum smelting furnace for the first time, wherein the raw materials added for the first time are scrap returns, then covering a furnace cover, vacuumizing to-0.1 MPa, starting the smelting furnace, increasing to full power according to steps of 180KW, 200KW and 257KW for smelting, after the raw materials are completely molten, closing the power of the smelting furnace and a vacuum pump, waiting for cylinder liquor in the furnace to be solidified and cake, closing the vacuum pump, breaking vacuum and recovering atmospheric pressure;

(2) opening the furnace cover, adding the raw materials again, vacuumizing to-0.1 MPa, starting the power of the smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) shaking the furnace body for 4-6 times to perform semi-refining to maximize the liquid level, reducing the power of the smelting furnace to 60-80KW after the liquid level is not abnormal, and turning off the Roots pump and the vacuum pump after waiting for 3-5 min;

(4) filling argon and adding a deoxidizing agent, starting a vacuum pump and starting a smelting furnace to increase the full power, starting a roots pump to strengthen the vacuum when the vacuum degree reaches-0.1 MPa, reducing the power to 60-80KW for refining after 1-3min, adjusting the temperature of the casting furnace after 15min, and closing the roots pump and the vacuum pump;

(5) and introducing argon gas for nickel water casting, feeding after casting to obtain a complete cast ingot, and restoring atmospheric pressure.

Further, in said step 3, the liquid level is not abnormal, which means that there is no more bubble on the liquid surface.

Further, in the step 3, the amplitude of shaking the furnace body should be controlled until the nickel water does not overflow to the edge of the casting gate.

Further, in the step 4, the deoxidizer is composed of a nickel-magnesium alloy, carbon, titanium, aluminum, and rare earth, and is added in the order of C → AL → Ti → Ni + Mg → rare earth. Carbon has very low solid solubility in nickel and can form a eutectic with nickel. When the carbon content in the nickel is less than 0.15%, the carbon is dissolved in the solid solution, the strength and the hardness of the nickel are slightly improved, the magnetic transition temperature of the nickel is reduced, and the recrystallization temperature of the nickel is improved. Carbon is a good deoxidizer, can improve the casting performance of nickel and nickel alloy, and can obtain high-quality cast ingots and semi-finished products, but when the carbon content in nickel exceeds 0.2%, carbon can be precipitated along grain boundaries in the form of graphite in the annealing process, so that the nickel generates cold brittleness. The solid solubility of aluminum in nickel is not great and decreases significantly with decreasing temperature. Aluminum is a strong deoxidizer, and when the content is small, the fluidity of nickel can be improved, and when the content is too large, the fluidity is reduced. Titanium has only a limited solid solution in nickel and the solubility decreases sharply with decreasing temperature. The trace titanium (0.1%) can refine the cast structure of nickel, eliminate intergranular cracks and improve the strength and thermoplasticity of nickel. Titanium can significantly improve the thermal strength, resistivity, thermoelectric force and recrystallization temperature of nickel. Titanium is a strong deoxidizer and can reduce the gas content in nickel. Magnesium is hardly dissolved in solid nickel. Magnesium has good desulfurization and deoxidation effects in nickel. A small amount of magnesium can increase the recrystallization temperature, resistivity and strength of nickel. A large amount of magnesium (0.7%) increases the heat strength of nickel, but decreases the fluidity, and the nickel becomes brittle when too much magnesium is contained therein. The rare earth elements such as lanthanum, praseodymium, gadolinium and the like are not substantially solid-soluble in nickel, and cerium and yttrium have extremely low solubility in solid nickel. A small amount of rare earth elements can improve the plasticity of the nickel in a hot brittleness temperature area, refine the crystalline structure and improve the strength. However, when their content is too high, nickel becomes brittle instead. Cerium forms with sulfur compounds with melting points above 2000 c, so it also desulfurizes in nickel.

Further, in the step 4, the nickel water is electromagnetically stirred for 4-6 times while argon is filled and a deoxidizer is added.

Further, in the step 5, the nickel water casting is charged casting, and the casting process is slow firstly and then fast;

the casting power is controlled between 50KW and 150KW, and the whole casting process is controlled within 5 min.

In the step 5, after the shrinkage cavity contour is shrunk, nickel water is sequentially supplemented until the shrinkage cavity is completely complemented, and the shrinkage cavity time is not less than 10 min.

Further, in the step 5, the ingot is kept in the smelting furnace for 1-3min and then is opened and lifted out.

The invention has the advantages that:

1. the quality of the cast nickel ingot can be effectively improved by applying the process to be matched with a vacuum smelting furnace and a casting die, the qualified rate of the cast ingot is more than 97 percent, wherein the chemical components comprise, by mass, not less than 99.5 percent of Ni, 0.002-0.01 percent of C, 0.02-0.1 percent of Si, 0.01-0.05 percent of Mn, 0.01-0.03 percent of Mg, 0.01-0.1 percent of Ti, 0.01-0.1 percent of Al, not more than 0.005 percent of S, not more than 0.002 percent of P and 0.01-0.1 percent of Fe, the sum of the weight percentages is 100 percent, and the process is suitable for preparing the nickel ingot with more than 200 kilograms;

2. smelting is carried out in a step-type power increasing mode, the smelting is carried out layer by layer, and the smelting effect is better;

2. the raw materials put into the smelting furnace for the first time are leftover materials, so that the nickel ingot is high in recovery rate and low in cost;

3. the nickel water is cast in a mode of first quick casting and then slow casting, so that the nickel water is prevented from splashing in the early stage, and the feeding efficiency and the nickel ingot quality are improved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments further describe the present invention in detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The first embodiment is as follows:

a smelting process for improving the quality of a nickel ingot comprises the following steps:

(1) adding 80kg of corner feed back into a vacuum melting furnace for the first time, then covering a furnace cover, vacuumizing to-0.1 MPa, starting the melting furnace, melting according to the step increase of 180KW, 200KW and 257KW to 257KW full power, after the materials are completely melted, closing the power of the melting furnace and a vacuum pump, waiting for the cylinder liquid in the furnace to be solidified and cake-formed, closing the vacuum pump, breaking the vacuum and recovering the atmospheric pressure;

(2) opening a furnace cover, adding 150kg of electrolytic pure nickel plate again, vacuumizing to-0.1 MPa, starting the power of a smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) semi-refining for 4-6 times to maximize the liquid level, reducing the power of the smelting furnace to 70KW after the liquid level is free from abnormity, namely no bubbles, and turning off the Roots pump and the vacuum pump after waiting for 3-5 min;

(4) argon is filled, a deoxidizing agent is added, a vacuum pump is started, a smelting furnace is started to be heated to 257KW full power, when the vacuum degree reaches-0.1 MPa, a roots pump is started to strengthen vacuum pumping, after 1-3min, the power is reduced to 70KW for refining, after 15min, the temperature of the casting furnace is adjusted, and the roots pump and the vacuum pump are closed;

(5) and introducing argon gas to carry out nickel water casting, wherein the nickel water casting is carried out slowly and then quickly, the fine water flows long, the nickel water is cast in an electrified mode, the casting power is controlled to be 50-150KW, the whole casting process is controlled within 5min, feeding is carried out after casting to obtain 230kg of complete cast ingot, and the atmospheric pressure is restored.

Example two:

(1) adding 90kg of corner feed back into a vacuum melting furnace for the first time, then covering a furnace cover, vacuumizing to-0.1 MPa, starting the melting furnace, melting according to the step increase of 180KW, 200KW and 257KW to 257KW full power, after the materials are completely melted, closing the power of the melting furnace and a vacuum pump, waiting for the cylinder liquid in the furnace to be solidified and cake-formed, closing the vacuum pump, breaking the vacuum and recovering the atmospheric pressure;

(2) opening a furnace cover, adding 160kg of electrolytic pure nickel plate again, vacuumizing to-0.1 MPa, starting the power of a smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) shaking the furnace body for 4-6 times to perform semi-refining, maximizing the liquid level, reducing the power of the smelting furnace to 80KW after the liquid level is free from abnormity, namely no bubbles, and turning off the Roots pump and the vacuum pump after waiting for 3-5 min;

(4) argon is filled, a deoxidizing agent is added, a vacuum pump is started, a smelting furnace is started to be heated to 257KW full power, when the vacuum degree reaches-0.1 MPa, a roots pump is started to strengthen vacuum pumping, after 1-3min, the power is reduced to 80KW for refining, after 15min, the temperature of the casting furnace is adjusted, and the roots pump and the vacuum pump are closed;

(5) and introducing argon gas to carry out nickel water casting, wherein the nickel water casting is carried out slowly and then quickly, the fine water flows long, the nickel water is cast in an electrified way, the casting power is controlled to be 50-150KW, the whole casting process is controlled within 5min, feeding is carried out after casting to obtain 250kg of complete cast ingot, and the atmospheric pressure is restored.

Example three:

a smelting process for improving the quality of a nickel ingot comprises the following steps:

(1) adding 80kg of corner feed back into a vacuum melting furnace for the first time, then covering a furnace cover, vacuumizing to-0.1 MPa, starting the melting furnace, melting according to the step increase of 180KW, 200KW and 257KW to 257KW full power, after the materials are completely melted, closing the power of the melting furnace and a vacuum pump, waiting for the cylinder liquid in the furnace to be solidified and cake-formed, closing the vacuum pump, breaking the vacuum and recovering the atmospheric pressure;

(2) opening a furnace cover, adding 150kg of electrolytic pure nickel plate again, vacuumizing to-0.1 MPa, starting the power of a smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) shaking the furnace body for 6 times to perform semi-refining, maximizing the liquid level, reducing the power of the smelting furnace to 75KW after the liquid level is free from abnormity, namely no bubbles, and turning off the Roots pump and the vacuum pump after waiting for 3-5 min;

(4) argon is filled, a deoxidizing agent is added, a vacuum pump is started, a smelting furnace is started to be heated to 257KW full power, when the vacuum degree reaches-0.1 MPa, a roots pump is started to strengthen vacuum pumping, after 1-3min, the power is reduced to 75KW for refining, after 18min, the temperature of the casting furnace is adjusted, and the roots pump and the vacuum pump are closed;

(5) and introducing argon gas to carry out nickel water casting, wherein the nickel water casting is carried out slowly and then quickly, the fine water flows long, the nickel water is cast in an electrified mode, the casting power is controlled to be 50-150KW, the whole casting process is controlled within 5min, feeding is carried out after casting to obtain 230kg of complete cast ingot, and the atmospheric pressure is restored.

Example four:

a smelting process for improving the quality of a nickel ingot comprises the following steps:

(1) adding 90kg of corner feed back into a vacuum melting furnace for the first time, then covering a furnace cover, vacuumizing to-0.1 MPa, starting the melting furnace, melting according to the step increase of 180KW, 200KW and 257KW to 257KW full power, after the materials are completely melted, closing the power of the melting furnace and a vacuum pump, waiting for the cylinder liquid in the furnace to be solidified and cake-formed, closing the vacuum pump, breaking the vacuum and recovering the atmospheric pressure;

(2) opening a furnace cover, adding 160kg of electrolytic pure nickel plate again, vacuumizing to-0.1 MPa, starting the power of a smelting furnace for smelting, starting a roots pump to enhance vacuumizing after the raw materials are completely molten, and entering a semi-refining state;

(3) the furnace body is shaken for 5 times for semi-refining, so that the liquid level is maximized, after the liquid level is free of abnormity, namely, no bubbles exist, the power of the smelting furnace is reduced to 72KW, and after 3-5min, the Roots pump and the vacuum pump are turned off;

(4) argon is filled, a deoxidizing agent is added, a vacuum pump is started, a smelting furnace is started to be heated to 257KW full power, when the vacuum degree reaches-0.1 MPa, a roots pump is started to strengthen vacuum pumping, after 1-3min, the power is reduced to 72KW for refining, after 15min, the temperature of the casting furnace is adjusted, and the roots pump and the vacuum pump are closed;

(5) and introducing argon gas to carry out nickel water casting, wherein the nickel water casting is carried out slowly and then quickly, the fine water flows long, the nickel water is cast in an electrified way, the casting power is controlled to be 50-150KW, the whole casting process is controlled within 5min, feeding is carried out after casting to obtain 250kg of complete cast ingot, and the atmospheric pressure is restored.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.