Method for rapidly removing aluminum from aluminum-containing high-titanium nickel-based alloy molten steel

Abstract

The invention belongs to the field of steelmaking. In the LF furnace refining process of the aluminum-containing high-titanium nickel-based alloy, under the condition that the aluminum content of molten steel in an LF furnace exceeds the standard, a method for rapidly removing aluminum from the aluminum-containing high-titanium nickel-based alloy molten steel is designed, that is, when the aluminum content of the molten steel in the LF furnace is larger than 0.20%, lime and fluorite are added, and the purpose of rapid aluminum removal is achieved through steel ladle bottom blowing and strong stirring in combination with a corresponding power transmission system. Through practice of the invention, corresponding lime addition amount, fluorite addition amount, steel ladle bottom blowing stirring strength, steel ladle bottom blowing stirring time, electrode power transmission voltage and electrode power transmission current are determined under the condition that different molten steel aluminum superscales are determined, and a set of technological parameters for rapid dealumination of aluminum-containing high-titanium nickel-based molten alloy steel are designed. After the method is implemented, under the condition that the aluminum content of the molten steel in the LF exceeds the standard, the aluminum content of the molten steel can be reduced to below 0.20% after rapid dealumination is carried out on the aluminum-containing high-titanium nickel-based alloy, the purpose of rapid dealumination of the aluminum-containing high-titanium nickel-based alloy molten steel is achieved, and the production accident of steel billet waste judgment is avoided.

Description

Technical Field

[0001] The invention belongs to the field of steelmaking, and in particular relates to a method for rapidly dealuminizing aluminum-containing high-titanium nickel-based alloy molten steel. Background Art

[0002] Nickel-based alloys, especially precipitation-strengthened alloys containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), have excellent heat resistance, corrosion resistance and good comprehensive mechanical properties. They are widely used in petrochemical, energy and power, industrial and household heating elements and other fields.

[0003] A domestic steel company has successfully developed a manufacturing process for this kind of nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), which is smelted in a stainless steel refining furnace and cast by a continuous casting machine. The titanium content of the finished product needs to be precisely controlled within 0.60-0.70%. To achieve precise control of the titanium content, the premise is to accurately control the aluminum content in the molten steel within the range of 0.10-0.20%. In the actual production process, due to the differences in the composition, temperature, oxygen blowing operation and the amount of lime and fluorite auxiliary materials added to the molten steel entering the furnace, the weight and composition of the slag in the refining process fluctuate. After adding aluminum according to the empirical value, some furnaces have an aluminum content exceeding the standard (> 0.20%), resulting in a production accident in which the steel billet is judged to be scrapped.

[0004] The present invention is aimed at the LF furnace refining process of aluminum-containing high-titanium nickel-based alloy (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), when the aluminum content of the LF furnace molten steel exceeds the standard (> 0.20%), and designs a method for rapid dealuminization of aluminum-containing high-titanium nickel-based alloy molten steel, that is, when the aluminum content of the LF refining furnace molten steel is > 0.20%, lime and fluorite are added, and strong stirring is performed by bottom blowing of the ladle, combined with the corresponding power supply system, to achieve the purpose of rapid dealuminization. Through the practice of the invention, the corresponding amount of lime added, the amount of fluorite added, the intensity of bottom blowing stirring of the ladle, the stirring time of bottom blowing stirring of the ladle, the electrode power supply voltage, and the electrode power supply current are determined under different conditions of excessive aluminum in the molten steel, and a set of process parameters for rapid dealuminization of aluminum-containing high-titanium nickel-based alloy molten steel is designed. After the implementation of the invention, when the aluminum content of molten steel in the LF furnace exceeds the standard (>0.20%), the aluminum content of the nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%) can be reduced to below 0.20% after rapid dealumination, thereby achieving the purpose of rapid dealumination of molten steel containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%) and avoiding production accidents in which the steel billet is judged as scrapped. Summary of the invention

[0005] The purpose of the present invention is to provide a method for rapidly dealuminating aluminum-containing high-titanium nickel-based alloy molten steel in view of the above problems.

[0006] The object of the present invention is achieved in this way: a method for quickly dealuminating aluminum-containing high-titanium nickel-based alloy molten steel, comprising the following steps: step one: for every 0.01% excess of aluminum content in the molten steel, 0.8-1.2 kg / t of lime and 0.4-0.6 kg / t of fluorite are added; step two: after adding lime and fluorite, the ladle bottom blowing stirring intensity is 4-6 Nl / min / t, and the ladle bottom blowing stirring time is 0.8-1.2 min for every 0.01% excess of aluminum content in the molten steel; step three: after adding lime and fluorite, the electrode power transmission voltage is 320-360 V, the electrode power transmission current is 20 KA-24 KA, and the power transmission time is 0.8-1.2 min for every 0.01% excess of aluminum content in the molten steel.

[0007] The upper limit of aluminum content in molten steel is 0.20%.

[0008] The method relates to an aluminum-containing high-titanium nickel-based alloy, wherein the alloy components are C≤0.050%, Si≤0.50%, Mn≤1.0%, P≤0.030%, S≤0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al≤0.20%, Ti: 0.60-1.20%, and the rest are Fe and unavoidable impurities.

[0009] The beneficial effect of the present invention is that in the LF furnace refining process of the aluminum-high-titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%) nickel-based alloy, when the aluminum content of the LF furnace molten steel exceeds the standard (> 0.20%), after the implementation of the present invention, the aluminum content of the molten steel can be reduced to below 0.20%, thereby achieving the purpose of rapid dealuminization of the aluminum-high-titanium nickel-based alloy molten steel and avoiding production accidents in which the steel billet is judged as scrapped. DETAILED DESCRIPTION

[0010] The finished product titanium content of the nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%) needs to be precisely controlled within the range of 0.60-0.70%. To achieve precise control of the titanium content, the premise is to precisely control the aluminum content in the molten steel within the range of 0.10-0.20%. In the actual production process, due to the differences in the composition, temperature, oxygen blowing operation and the amount of lime and fluorite auxiliary materials added to the molten steel entering the furnace, the weight and composition of the slag in the refining process fluctuate. After adding aluminum according to the empirical value, some furnaces have an aluminum content exceeding the standard (> 0.20%), resulting in a production accident in which the steel billet is judged to be scrapped. Therefore, it is necessary to invent a method for quickly dealuminizing molten steel containing aluminum and high titanium nickel-based alloy.

[0011] The purpose of the present invention is to design a method for rapidly dealuminizing aluminum-containing high-titanium nickel-based alloy steel, that is, when the aluminum content of LF refining furnace steel is greater than 0.20%, lime and fluorite are added, and strong stirring is performed by bottom blowing of the ladle, combined with the corresponding power supply system, to achieve the purpose of rapid dealuminization. Through the practice of the invention, the corresponding amount of lime added, the amount of fluorite added, the stirring intensity of the bottom blowing of the ladle, the stirring time of the bottom blowing of the ladle, the electrode power supply voltage, and the electrode power supply current are determined under different conditions of excessive aluminum in the steel, and a set of process parameters for rapid dealuminization of aluminum-containing high-titanium nickel-based alloy steel is designed. After the implementation of the invention, the aluminum-containing high-titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%) nickel-based alloy, when the aluminum content of LF furnace steel exceeds the standard (> 0.20%), after rapid dealuminization, the aluminum content of the steel can be reduced to less than 0.20%, achieving the purpose of rapid dealuminization of aluminum-containing high-titanium nickel-based alloy steel, and avoiding the production accident of steel billet scrapping.

[0012] The invention relates to an aluminum-containing and high-titanium (aluminum content ≤0.20%, titanium content ≥0.60%) nickel-based alloy, wherein the alloy components are C≤0.050%, Si≤0.50%, Mn≤1.0%, P≤0.030%, S≤0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al≤0.20%, and Ti: 0.60-1.20%.

[0013] In the LF furnace refining process of aluminum-containing high-titanium nickel-based alloy, when the aluminum content of LF furnace molten steel exceeds the standard (>0.20%), a set of process parameters for rapid dealuminization of aluminum-containing high-titanium (aluminum content ≤0.20%, titanium content ≥0.60%) nickel-based alloy molten steel is designed. The embodiment steps are as follows: The present invention relates to the LF furnace refining process of aluminum-containing high-titanium (aluminum content ≤0.20%, titanium content ≥0.60%) nickel-based alloy. When the aluminum content of LF furnace molten steel exceeds the standard (>0.20%), for every 0.01% excess of the aluminum content of the molten steel (the upper limit of the standard is 0.20%), 0.8-1.2kg / t of lime and 0.4-0.6kg / t of fluorite are added. After adding lime and fluorite, the stirring intensity of the bottom blowing of the ladle is 4-6Nl / min / t, and the stirring time of the bottom blowing of the ladle is 0.8-1.2min for every 0.01% excess of the aluminum content of the molten steel (the upper limit of the standard is 0.20%). After adding lime fluorite, the electrode power supply voltage is 320-360V, the electrode power supply current is 20KA-24KA, and the power supply time is 0.8-1.2min for every 0.01% excess of aluminum content in molten steel (the upper limit of the standard is 0.20%). Example

[0014] The steel type in this example is a nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), and its alloy composition is C ≤ 0.050%, Si ≤ 0.50%, Mn ≤ 1.0%, P ≤ 0.030%, S ≤ 0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al ≤ 0.20%, Ti: 0.60-1.20%, and the aluminum content of LF furnace molten steel exceeds the standard by 0.25%. The steps of the embodiment are as follows: (1) Add 5.1 kg / t of lime and 2.6 kg / t of fluorite.

[0015] (2) After adding lime and fluorite, the ladle bottom blowing stirring intensity is 4.8Nl / min / t, and the ladle bottom blowing stirring time is 5.4min.

[0016] (3) After adding lime fluorite, the electrode power supply voltage is 348V, the electrode power supply current is 23KA, and the power supply time is 5.6min.

[0017] After rapid dealumination, the aluminum content of the molten steel was 0.18%, and no production accident of the steel billet being scrapped occurred.

[0018] Another example steel is a nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), with alloy components C ≤ 0.050%, Si ≤ 0.50%, Mn ≤ 1.0%, P ≤ 0.030%, S ≤ 0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al ≤ 0.20%, Ti: 0.60-1.20%, and the aluminum content of LF furnace molten steel exceeds the standard: 0.30%. The steps of the embodiment are as follows: (1) Add 10.6 kg / t of lime and 4.8 kg / t of fluorite.

[0019] (2) After adding lime and fluorite, the ladle bottom blowing stirring intensity is 5.2Nl / min / t, and the ladle bottom blowing stirring time is 11.0min.

[0020] (3) After adding lime fluorite, the electrode power supply voltage is 332V, the electrode power supply current is 22KA, and the power supply time is 11.2min.

[0021] After rapid dealumination, the aluminum content of the molten steel was 0.17%, and no production accident resulting in the scrapping of the steel billet occurred.

[0022] Another example steel is a nickel-based alloy containing aluminum and high titanium (aluminum content ≤ 0.20%, titanium content ≥ 0.60%), with alloy components C ≤ 0.050%, Si ≤ 0.50%, Mn ≤ 1.0%, P ≤ 0.030%, S ≤ 0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al ≤ 0.20%, Ti: 0.60-1.20%, and the aluminum content of LF furnace molten steel exceeds the standard by 0.40%. The steps of the embodiment are as follows: (1) Add 21.3 kg / t of lime and 9.7 kg / t of fluorite.

[0023] (2) After adding lime and fluorite, the ladle bottom blowing stirring intensity is 4.9Nl / min / t, and the ladle bottom blowing stirring time is 21.2min.

[0024] (3) After adding lime fluorite, the electrode power supply voltage is 341V, the electrode power supply current is 23KA, and the power supply time is 21.5min.

[0025] After rapid dealumination, the aluminum content of the molten steel was 0.18%, and no production accident of the steel billet being scrapped occurred.

[0026] The above description is only a specific embodiment of the present invention, but the structural features of the protection scope of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are all covered by the patent scope of the present invention.

Claims

1. A method for rapidly dealuminating aluminum-containing high-titanium nickel-based alloy molten steel, characterized in that: The following steps are involved: Step 1: For every 0.01% excess of aluminum content in molten steel, add 0.8-1.2kg / t of lime and 0.4-0.6kg / t of fluorite; Step 2: After adding lime and fluorite, the ladle bottom blowing stirring intensity is 4-6Nl / min / t, and the ladle bottom blowing stirring time is 0.8-1.2min for every 0.01% excess of aluminum content in molten steel; Step 3: After adding lime and fluorite, the electrode power supply voltage is 320-360V, the electrode power supply current is 20KA-24KA, and the power supply time is 0.8-1.2min for every 0.01% excess of aluminum content in molten steel.

2. The method for rapidly dealuminating aluminum-containing high-titanium nickel-based alloy steel according to claim 1, characterized in that: The upper limit of aluminum content in molten steel is 0.20%.

3. The method for rapidly dealuminating aluminum-containing high-titanium nickel-based alloy steel according to claim 1, characterized in that: The method relates to an aluminum-containing high-titanium nickel-based alloy, wherein the alloy components are C≤0.050%, Si≤0.50%, Mn≤1.0%, P≤0.030%, S≤0.030%, Cr: 19.5-23.5%, Ni: 38.0-46.0%, Mo: 2.5-3.5%, Cu: 1.5-3.0%, Al≤0.20%, Ti: 0.60-1.20%, and the rest are Fe and unavoidable impurities.