GH5188 alloy steel smelting process

Abstract

According to the GH5188 alloy steel smelting process, a cobalt raw material is subjected to dehydrogenation treatment, specifically, the cobalt raw material is put into an electric heating drying furnace, and heat preservation is conducted for 8 hours after the temperature is increased to 600 DEG C; the steps can effectively reduce the content of hydrogen (H), nitrogen (N) and oxygen (O) elements in the finished alloy, and prolong the service life of the alloy; in the process, the temperature is reduced to 1480-1530 DEG C, the lanthanum (La) is wrapped by the aluminum foil and then is independently added, and the volatilization of the lanthanum (La) can be reduced by a method of cooling and wrapping by the aluminum foil, so that the content of the lanthanum (La) in the product meets the requirement, and the cost is greatly reduced under the condition of meeting the product quality.

Description

Technical Field

[0001] This invention relates to the field of metal smelting technology, specifically a smelting process for GH5188 alloy steel. Background Technology

[0002] GH5188 alloy steel is a cobalt-nickel-chromium based reinforced high-temperature alloy that combines high-temperature mechanical properties with excellent ductility and is commonly used in the aerospace field.

[0003] The material requirements for high-quality GH5188 alloy steel necessitate controlling the lanthanum (La) content to between 0.03% and 0.12% to ensure excellent oxide film adhesion. However, in existing conventional GH5188 alloy steel smelting processes, a significant amount of the rare earth element lanthanum (La) volatilizes during production, resulting in substandard quality of the final GH5188 alloy steel. To address this issue, current technologies typically employ the addition of a higher proportion of lanthanum (La) to meet the requirements, but this significantly increases production costs. Summary of the Invention

[0004] The purpose of this invention is to provide a smelting process for GH5188 alloy steel to solve the above-mentioned problems.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a GH5188 alloy steel smelting process, comprising the following steps: (1) Prepare raw materials according to the required amount of each element, including carbon (C), chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), lanthanum (La), silicon (Si), manganese (Mn), boron (B), aluminum (Al), and cobalt (Co); (2) The cobalt raw material is dehydrogenated by placing it in an electric heating drying furnace, heating it to 600°C and holding it for 8 hours. This step can effectively reduce the content of hydrogen (H), nitrogen (N) and oxygen (O) elements in the finished alloy and extend the service life of the alloy. (3) Use an electric heating drying oven to dry the moisture of other raw materials; (4) Load the raw materials into the vacuum induction melting furnace; wherein, chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), and cobalt (Co) are loaded into the crucible of the vacuum induction melting furnace; tungsten (W) and cobalt (Co) are loaded into the upper middle part of the crucible; Carbon (C) is added in three stages. The first stage is placed on top of chromium (Cr) in the crucible, the second stage is placed below nickel (Ni) in the crucible, and the third stage is placed in the small hopper of the vacuum induction melting furnace with carbon (C) and aluminum (Al) and added to the molten steel in two stages. (5) The raw materials are melted in a vacuum induction melting furnace to obtain molten steel; specifically, after the furnace is closed, the slide valve vacuum pump, the Roots pump and the oil diffusion vacuum pump are started in stages to achieve a vacuum effect. After vacuuming, a melting operation is carried out. After the melt is cleared, the temperature is raised to 1560℃-1590℃ and completely melted. After refining for 50 minutes, the temperature is lowered to 1520℃-1550℃, and silicon (Si), manganese (Mn), boron (B), and aluminum (Al) are added in sequence. Then the temperature is raised to 1570℃-1590℃ while stirring to achieve deoxidation. Afterwards, the mixture is cooled to 1480℃-1530℃, and lanthanum (La) is added after being wrapped in aluminum foil. The mixture is then stirred to obtain molten steel. Cooling and wrapping the steel in aluminum foil can reduce the volatilization of lanthanum (La) and ensure that the lanthanum (La) content in the product meets the requirements.

[0006] (6) The molten steel is immediately cast to obtain steel bars.

[0007] (7) The steel bar obtained in step six is ​​remelted in a remelting electroslag furnace to obtain GH5188 alloy steel ingot.

[0008] Preferably, the slide valve vacuum pump is started first, and the vacuum degree reaches 1950pa-2010pa under the action of the slide valve vacuum pump; then the Roots pump is started, and the vacuum degree reaches 10pa-12pa under the action of the Roots pump; finally, the oil diffusion vacuum pump is started, and the vacuum degree reaches 2.3pa-4.2pa under the action of the oil diffusion vacuum pump.

[0009] Preferably, the steel rod obtained in step (6) needs to be polished to remove the surface oxide layer before it can be used in step (7).

[0010] In summary, the present invention has the following beneficial effects: 1. This invention performs dehydrogenation treatment on cobalt raw materials by placing them in an electrically heated drying furnace, heating them to 600°C, and holding them at that temperature for 8 hours. This step can effectively reduce the content of hydrogen (H), nitrogen (N), and oxygen (O) elements in the finished alloy, and extend the service life of the alloy.

[0011] 2. After the furnace is closed, three pumps are started in stages to achieve a vacuum effect. The first pump to be started is the slide valve vacuum pump, which achieves a vacuum of 1950 Pa to 2010 Pa. Next, the Roots pump is started, which achieves a vacuum of 10 Pa to 12 Pa. Finally, the oil diffusion vacuum pump is started, which achieves a vacuum of 0 Pa to 5 Pa. The three-stage pump setup ensures that the internal vacuum environment temperature is suitable for the smooth melting of the raw materials.

[0012] 3. In this process, the temperature is first lowered to 1480℃-1530℃, and lanthanum (La) is added separately after being wrapped in aluminum foil. The cooling and aluminum foil wrapping methods can reduce the volatilization of lanthanum (La), so that the lanthanum (La) content in the product meets the requirements. This greatly reduces the cost while meeting product quality requirements. Detailed Implementation

[0013] The present invention will be further described below through specific embodiments.

[0014] A GH5188 alloy steel smelting process includes the following steps: Step 1: Prepare the raw materials according to the required amounts of each element. The raw materials include carbon (C), chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), lanthanum (La), silicon (Si), manganese (Mn), boron (B), aluminum (Al), and cobalt (Co). The percentages of each component are as follows: carbon (C) 0.93%-0.11%, chromium (Cr) 22.5%-23.3%, nickel (Ni) 21.9%-23.4%, iron (Fe) 1.3-2.1%, tungsten (W) 14.1%-15.2%, lanthanum (La) 0.15%-0.22%, silicon (Si) 0.2%-0.5%, manganese (Mn) 0.74%-0.99%, boron (B) 0.01%, aluminum (Al) 0.13%-0.21%, and the remainder is cobalt (Co).

[0015] Step 2: Dehydrogenation treatment of cobalt raw materials. Specifically, the cobalt raw materials are placed in an electric heating drying furnace, heated to 600℃ and held at that temperature for 8 hours. This step can effectively reduce the content of hydrogen (H), nitrogen (N), and oxygen (O) elements in the finished alloy and extend the service life of the alloy.

[0016] Step 3: Dry the other raw materials using an electric heating drying oven. Bake carbon (C), chromium (Cr), nickel (Ni), tungsten (W), silicon (Si), manganese (Mn), and boron (B) in the electric oven for 3-4 hours, with the baking temperature controlled at 340℃-410℃.

[0017] Step 4: Load the raw materials into the vacuum induction melting furnace; wherein, chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), and cobalt (Co) are loaded into the crucible of the vacuum induction melting furnace; tungsten (W) and cobalt (Co) are loaded into the upper middle part of the crucible; It should be noted that carbon (C) is added in three stages. The first stage is placed on top of chromium (Cr) in the crucible, the second stage is placed below nickel (Ni) in the crucible, and the third stage is placed in the small hopper of the vacuum induction melting furnace with carbon (C) and aluminum (Al) and added to the molten steel in two separate stages.

[0018] Step 5: Melt the raw materials in a vacuum induction melting furnace to obtain molten steel; specifically, after the furnace is closed, start three pumps in stages to achieve a vacuum effect; The first pump to be started is the slide valve vacuum pump, which achieves a vacuum level of 1950 Pa to 2010 Pa. Next, the Roots pump is started, which achieves a vacuum level of 10 Pa to 12 Pa. Finally, the oil diffusion vacuum pump is started, which achieves a vacuum level of 0 Pa to 5 Pa. After vacuuming, a melting operation is performed. After the melt is cleared, the temperature is raised to 1560℃-1590℃ for complete melting, which takes about 2 hours. After refining for 50 minutes, the temperature is lowered to 1520℃-1550℃, and silicon (Si), manganese (Mn), boron (B), and aluminum (Al) are added in sequence to facilitate deoxidation. Then the temperature is raised to 1570℃-1590℃ while stirring to achieve deoxidation. Afterwards, the temperature is cooled to 1480℃-1530℃, and lanthanum (La) is added separately after being wrapped in aluminum foil and stirred to obtain molten steel. Cooling and wrapping with aluminum foil can reduce the volatilization of lanthanum (La), so that the lanthanum (La) content in the product meets the requirements, and the cost is greatly reduced while meeting the product quality requirements.

[0019] Step 6: Immediately pour the obtained molten steel into a steel bar.

[0020] Step 7: Remelt the steel bar obtained in Step 6 in a remelting electroslag furnace to obtain GH5188 alloy steel ingot.

[0021] It should be noted that the steel plate obtained in step six needs to be polished to remove the surface oxide layer before it can be used in step seven.

Claims

1. A smelting process for GH5188 alloy steel, characterized in that: Includes the following steps: (1) Prepare raw materials according to the required amount of each element. The raw materials include carbon (C), chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), lanthanum (La), silicon (Si), manganese (Mn), boron (B), aluminum (Al), and cobalt (Co). (2) Dehydrogenation treatment of cobalt (Co) raw materials: Specifically, cobalt raw materials are placed in an electric heating drying furnace, heated to 600℃ and held for 8 hours; This step can effectively reduce the content of hydrogen (H), nitrogen (N) and oxygen (O) elements in the finished alloy and extend the service life of the alloy. (3) Use an electric heating drying oven to dry the moisture of other raw materials; (4) Load the raw materials into the vacuum induction melting furnace; wherein, chromium (Cr), nickel (Ni), iron (Fe), tungsten (W), and cobalt (Co) are loaded into the crucible of the vacuum induction melting furnace; tungsten (W) and cobalt (Co) are loaded into the upper middle part of the crucible; Carbon (C) is added in three stages. The first stage is placed on top of chromium (Cr) in the crucible, the second stage is placed below nickel (Ni) in the crucible, and the third stage is placed in the small hopper of the vacuum induction melting furnace with carbon (C) and aluminum (Al) and added to the molten steel in two stages. (5) The raw materials are melted in a vacuum induction melting furnace to obtain molten steel; specifically, after the furnace is closed, the slide valve vacuum pump, the Roots pump and the oil diffusion vacuum pump are started in stages to achieve a vacuum effect. After vacuuming, a melting operation is carried out. After the melt is cleared, the temperature is raised to 1560℃-1590℃ and completely melted. After refining for 50 minutes, the temperature is lowered to 1520℃-1550℃, and silicon (Si), manganese (Mn), boron (B), and aluminum (Al) are added in sequence. Then the temperature is raised to 1570℃-1590℃ while stirring to achieve deoxidation. Afterwards, the temperature is cooled to 1480℃-1530℃, and lanthanum (La) is added separately after being wrapped in aluminum foil and stirred to obtain molten steel. Cooling and wrapping with aluminum foil can reduce the volatilization of lanthanum (La) and ensure that the lanthanum (La) content in the product meets the requirements. (6) The molten steel obtained is immediately cast to obtain steel bars; (7) The steel bar obtained in step six is ​​remelted in a remelting electroslag furnace to obtain GH5188 alloy steel ingot.

2. The GH5188 alloy steel smelting process according to claim 1, characterized in that: The first pump to be started is the slide valve vacuum pump, which achieves a vacuum level of 1950 Pa to 2010 Pa. Next, the Roots pump is started, which achieves a vacuum level of 10 Pa to 12 Pa. Finally, the oil diffusion vacuum pump is started, which achieves a vacuum level of 0 Pa to 5 Pa.

3. The smelting process for GH5188 alloy steel according to claim 1, characterized in that: The steel rod obtained in step (6) is polished and used in step (7) after the surface oxide layer is removed.