CN101643876B - Super-pure smelting method for industrially producing Incone1690 alloy - Google Patents

Abstract

The invention belongs to the technical field of vacuum induction smelting, and relates to the improvement of the industrial production of Incone1690 alloy smelting process, specifically an ultra-pure smelting process for industrial production of Incone1690 alloy, which uses high purity (CaO>98.5%) and good thermodynamic stability The CaO refractory material is used as the crucible material for vacuum induction melting; the specific melting process is: charging → melting period → refining period → condensation → deoxidation, desulfurization period → pouring; in the refining period, by increasing the refining temperature, the thermodynamics and thermodynamics of deoxidation and sulfur are strengthened. Under dynamic conditions, effective deoxidation and desulfurization can be carried out on the crucible wall and molten steel surface; strong deoxidation and desulfurization agents are added during the deoxidation and desulfurization period to carry out final deoxidation and desulfurization of the alloy, further reducing the oxygen and sulfur content in the alloy, so that The capital is below 10ppm.wt. The invention effectively improves the high-temperature plasticity of the alloy, improves the thermal processing performance of the alloy, and obtains a high-quality alloy.

Description

An ultra-pure smelting method for industrialized production of Incone1690 alloy

technical field

The invention relates to the field of vacuum induction smelting, in particular to an ultra-pure smelting process for industrial production of I-690 alloy.

Background technique

Inconel690 alloy is an American brand, and its main components range as follows:

Usually industrial vacuum induction smelting production of Inconel690 alloys uses MgO or MgO-Al ₂ O ₃ crucibles as refractory materials, which cannot achieve high-temperature deoxidation and desulfurization during the refining period, and no strong deoxidation and desulfurization agents are added at the end of the smelting period. The oxygen and sulfur content of the generally produced alloy is about 20ppm.wt (weight), which cannot be ultra-pure. Therefore, the high-temperature plasticity of the alloy is low, and ideal hot-working of the alloy cannot be carried out, so that the yield of the hot-working alloy is low.

Contents of the invention

The purpose of the present invention is to provide a kind of ultra-pure smelting process for industrial production of I-690 alloy, which can produce ultra-pure Inconel 690 alloy with oxygen and sulfur content less than 10ppm, improves the high-temperature plasticity of the alloy, and improves the thermal processing of the alloy performance.

Technical scheme of the present invention is:

An ultra-pure smelting process method for industrialized production of Inconel690 alloy (hereinafter referred to as I-690 alloy), using high-purity (CaO>98.5wt%), CaO refractory material with good thermodynamic stability as the melting crucible material; vacuum induction melting The specific smelting process is: charging → melting period → refining period → condensation → deoxidation, desulfurization period → pouring;

Refining period: take advantage of the advantages of the calcareous crucible to effectively increase the refining temperature. Refining can be carried out at 1650°C to 1730°C and kept for 10 to 30 minutes, which is 50°C to 100°C higher than the traditional crucible, creating better deoxidation 1. The thermodynamic and kinetic conditions of desulfurization make I-690 alloy deoxidize and desulfurize through the crucible wall and molten steel surface.

The alloy is condensed to cool down the I-690 alloy to the melting point. Through the principle that the solubility of oxygen and nitrogen in the alloy decreases with the decrease of temperature, a certain deoxidation and denitrification effect can be achieved during the condensation process.

In the deoxidation and desulfurization period, the final deoxidation and desulfurization of the alloy is carried out by adding strong deoxidation and desulfurization agents to further reduce the oxygen and sulfur content in the alloy.

In the present invention, the deoxidizer is Ni-Ca or Ni-Mg master alloy, and the desulfurizer is Ni-Ca master alloy.

In the vacuum induction smelting process method provided by the present invention, the mechanism of the process is as follows:

(1) Alloy melting period: the main elements are smelted under vacuum, and through the good carbon-oxygen reaction in this stage, the purpose of deoxidation and denitrification of the alloy is achieved.

(2) Alloy refining period: adopt high-temperature, high-vacuum refining system, use good stirring of induction melting, increase the diffusion rate of oxygen and sulfur in molten steel, strengthen the thermodynamics and kinetics of deoxidation and desulfurization, and pass through the crucible wall and steel Deoxidation and desulfurization of the liquid surface.

(3) Alloy condensation period: As the temperature of the alloy liquid decreases, the solubility of oxygen and nitrogen in the alloy decreases, achieving a certain deoxidation and denitrification effect.

(4) Deoxidation and desulfurization period: under the protective atmosphere of argon gas, strong deoxidation and desulfurization agents are added to the molten steel to further realize the enhanced deoxidation and desulfurization of the alloy.

Advantages of the present invention:

1. The present invention uses high-purity (CaO>98.5wt%) CaO refractory material with good thermodynamic stability as the crucible material for vacuum induction melting, which ensures the realization of ultra-purified melting process.

2. The present invention effectively reduces the content of oxygen and sulfur in the alloy by combining the refining period with the deoxidation and desulfurization period to ensure the super-purity of the alloy.

3. The appearance of the present invention can effectively improve the purity of the I-690 alloy, further improve the high-temperature plasticity of the alloy, and improve the hot workability of the alloy.

Detailed ways

Example 1

A crucible knotted with high-purity, thermodynamically stable CaO refractory material is used to melt the I-690 alloy for industrial production. The melting process includes: charging → melting period → refining period → condensation → deoxidation and desulfurization period → pouring; among them, charging , melting period, and pouring are conventional techniques. The specific process is:

(1) The crucible for smelting is a 500kg crucible knotted with CaO, and the purity of CaO is ≥98.5wt%;

(2) Alloy raw materials: According to the composition requirements, take Ni plate, pure Fe, metal Cr, C and other alloy elements, deoxidizer and desulfurizer.

In this step, the deoxidizer is a Ni-Ca master alloy: Ni 80wt%, Ca 20wt%; or, the deoxidizer is a Ni-Mg master alloy: Ni 80wt%, Mg 20wt%; the desulfurizer is a Ni-Ca master alloy: Ni 80wt%, Ca 20wt%.

(3) Alloy charging: put the main raw materials Ni, Cr, C, and Fe into the crucible, and put Ti, Al and deoxidizing and desulfurizing agents into different compartments of the alloy feeding hopper;

(4) Alloy melting: Vacuumize the furnace to less than 0.8Pa and start power transmission, first at 200KW for 20 minutes, and then at 360KW to melt and clear;

(5) Alloy refining: After alloying and clearing, heat up to 1710°C for 5 minutes at 360KW, keep it warm for 20 minutes and refine;

(6) Alloy condensation: After refining, power off and freeze to below the melting point of the alloy (the surface of the molten steel solidifies, and there is no molten steel flow when the crucible is turned);

Both Ti and Al are added before adding the final deoxidizer and final desulfurizer, titanium sponge is added in granular form, and aluminum is added in block form.

(7) Final deoxidation and desulfurization of the alloy: close the vacuum valve, pass in argon protection, send the frozen molten steel to 360KW to Huaqing, reduce the power to 80KW and add deoxidation and desulfurization agents, stir at 280KW for one minute, continue to keep warm at 80KW, At the same time, vacuumize (vacuum degree less than 1Pa) for 10 minutes to remove excess deoxidizing and desulfurizing agents (the oxide film on the surface of the molten steel is completely washed away to reach a film-free state).

In this step, the deoxidizer is a Ni-Ca master alloy: Ni 80wt%, Ca 20wt%; or, the deoxidizer is a Ni-Mg master alloy: Ni 80wt%, Mg 20wt%; the desulfurizer is a Ni-Ca master alloy: Ni 80wt%, Ca 20wt%. (8) Alloy pouring: power off to cool down, and when the molten steel stops flowing, power on 360KW to adjust the temperature for pouring. The Inconel690 alloy composition of present embodiment melting sees the following table:

Table 1 vacuum induction melting Inconel690 alloy composition (wt%)

Smelting furnace number C Cr Fe Al Ti P S o Ni 06-261 0.015 29.55 10.4 0.43 0.36 0.0035 0.0005 0.0003 Surplus 06-262 0.020 29.59 9.84 0.46 0.33 0.0033 0.0006 0.0004 Surplus

It can be seen that the content of oxygen and sulfur in the 500 kg I-690 alloy ingot smelted by the present invention is less than 10 ppm, and high purity is obtained.

Claims (1)

1. the ultrapure clean melting method of a suitability for industrialized production Inconel690 alloy, it is characterized in that, use the crucible material of CaO refractory materials as melting, CaO purity 〉=98.5wt%, adopt the method for vacuum induction melting, obtain oxygen, sulphur content all less than the ultrapure clean Inconel690 alloy of 10ppm;

Vacuum induction melting comprises: charging → melting period → refining period → condensation → deoxidation, desulfurization the phase → cast;

The refining period of described alloy: utilize the advantage of calcareous crucible self, carry out refining, be incubated 10-30 minute, make the Inconel690 alloy by the surface deoxidation of sidewall of crucible and molten steel, desulfurization at 1650 ℃～1730 ℃;

The condensation of described alloy: the Inconel690 alloy is cooled to fusing point, realizes deoxidation, denitrogenation in the condensation process along with temperature reduces the principle that reduces by oxygen, nitrogen solubility in the alloy;

The deoxidation of described alloy, desulfurization phase, by adding strong deoxidation, sweetening agent, alloy is carried out the final deoxygenation desulfurization, further reduce oxygen, nitrogen content in the alloy; Wherein, reductor is Ni-Ca or Ni-Mg master alloy, and sweetening agent is the Ni-Ca master alloy.