阅读说明：本技术 Gh5188合金电极锭及其制备方法 (GH5188 alloy electrode ingot and preparation method thereof ) 是由 蒋世川 张健 周扬 付建辉 于 2020-06-12 设计创作，主要内容包括：本发明涉及冶金技术领域,公开了一种GH5188合金电极锭及其制备方法,所述方法包括以下步骤：将合金原料根据GH5188合金成分控制要求,按质量百分比计算并配制各元素原材料用量,合金原料的金属镧元素按0.2-0.4质量％配入；将配好的原材料装入真空感应炉,对原材料进行熔化、精炼,得到合金溶液；调整出钢温度与液相线温度之间的温差；将所得的合金溶液在真空条件下浇铸到经烘烤的钢锭模里面,得到电极锭,钢锭模温度为500-800℃；冷却。本发明通过对GH5188合金在真空感应炉熔炼时镧元素加入量的控制,及对浇铸钢锭模进行烘烤,避免了电极开裂,且在满足产品对镧含量要求的条件下节约金属镧含量的使用量。(The invention relates to the technical field of metallurgy, and discloses a GH5188 alloy electrode ingot and a preparation method thereof, wherein the method comprises the following steps: calculating and preparing the dosage of each element raw material by mass percent according to the control requirement of GH5188 alloy components, wherein the metal lanthanum element of the alloy raw material is added according to the mass percent of 0.2-0.4; the prepared raw materials are put into a vacuum induction furnace, and the raw materials are melted and refined to obtain an alloy solution; adjusting the temperature difference between the tapping temperature and the liquidus temperature; casting the obtained alloy solution into a baked ingot mold under a vacuum condition to obtain an electrode ingot, wherein the temperature of the ingot mold is 500-800 ℃; and (6) cooling. According to the invention, by controlling the lanthanum addition amount of the GH5188 alloy during smelting in the vacuum induction furnace and baking the cast ingot mold, electrode cracking is avoided, and the usage amount of the lanthanum content is saved under the condition of meeting the lanthanum content requirement of the product.)

1. A preparation method of a GH5188 alloy electrode ingot is characterized by comprising the following steps:

(1) calculating and preparing the consumption of raw materials of each element according to the control requirement of GH5188 alloy components by mass percent, wherein the lanthanum element of the alloy raw material is added according to the mass percent of 0.2-0.4;

(2) putting the raw materials prepared in the step (1) into a vacuum induction furnace, and melting and refining the raw materials to obtain an alloy solution;

(3) determining a tapping temperature according to the liquidus temperature corresponding to the chemical composition of the alloy solution in the step (2), and adjusting the temperature difference between the tapping temperature and the liquidus temperature;

(4) casting the alloy solution obtained in the step (3) into a baked ingot mold under a vacuum condition to obtain an electrode ingot, wherein the temperature of the ingot mold is 500-;

(5) and (6) cooling.

2. The method of preparing a GH5188 alloy electrode ingot according to claim 1, wherein the mass of metallic lanthanum element in the alloy raw material is 0.25-0.4 mass% of the mass of the alloy raw material.

3. The method for preparing the GH5188 alloy electrode ingot according to claim 2, wherein the mass of the metallic lanthanum element in the alloy raw material is 0.3-0.35% by mass of the alloy raw material.

4. The preparation method of the GH5188 alloy electrode ingot according to claim 1, wherein the tapping temperature in step (3) is 60-80 ℃ higher than the liquidus temperature of the alloy.

5. The preparation method of the GH5188 alloy electrode ingot according to claim 4, wherein the tapping temperature in step (3) is 60-75 ℃ higher than the liquidus temperature of the alloy.

6. The preparation method of the GH5188 alloy electrode ingot of claim 5, wherein the tapping temperature in step (3) is 65-70 ℃ higher than the liquidus temperature of the alloy.

7. The preparation method of the GH5188 alloy electrode ingot of claim 1, wherein the ingot mold temperature is 550-800 ℃.

8. The preparation method of the GH5188 alloy electrode ingot of claim 7, wherein the ingot mold temperature is 600-750 ℃.

9. The method of preparing a GH5188 alloy electrode ingot according to claim 8, wherein the cooling in step (5) is natural cooling with a mold.

10. A GH5188 alloy electrode ingot made by the process of any one of claims 1 to 9.

Technical Field

The invention relates to the field of high-temperature alloy preparation, in particular to a GH5188 alloy electrode ingot and a preparation method thereof.

Background

The GH5188 alloy is a cobalt-based wrought high-temperature alloy with the largest use amount in domestic aeroengines, is used for manufacturing high-temperature components such as flame tubes, guide vanes and the like of combustion chambers of aeroengines, is widely used for high-temperature components of gas turbines and missiles at abroad, such as combustion chambers, tail nozzles and the like, and is also used as parts such as heat exchangers and the like in the nuclear energy industry. The GH5188 alloy is Co-Ni-Cr-based solid solution strengthening type deformation high-temperature alloy, the use temperature is less than 1100 ℃, and the alloy is added with 14 percent of W for solid solution strengthening, so that the alloy has good comprehensive performance; 0.02-0.12% of La and 20-24% of Cr are added, so that the alloy has good oxidation resistance and good technological properties such as cold and hot processing shaping and welding.

The vacuum induction electrode is a basic link of cobalt-based high-temperature alloy production, if the electrode cracks, the subsequent refining process of the alloy is seriously influenced, so that the process parameters such as voltage, current, droplet rate and the like in the electroslag remelting process are greatly fluctuated, various macroscopic metallurgical defects are caused, and the cast ingot product is judged to be useless.

In the industrial production of the GH5188 cobalt-based high-temperature alloy, a large amount of brittle phases which have smaller expansion coefficients and higher hardness than a matrix are easily precipitated on dendritic crystals or grain boundaries in the casting and solidification process of an electrode ingot, and a large temperature gradient exists in the electrode ingot in the casting process, so that the electrode ingot generates large thermal stress, and finally an electrode is cracked.

Disclosure of Invention

The invention aims to solve the problems that a GH5188 alloy is easy to separate out a brittle phase and an electrode is easy to crack in the solidification process in the prior art, and provides a GH5188 alloy electrode ingot and a preparation method thereof.

In order to achieve the above object, the present invention provides, in a first aspect, a method for preparing an GH5188 alloy electrode ingot, the method comprising the steps of:

(1) calculating and preparing the consumption of raw materials of each element according to the control requirement of GH5188 alloy components by mass percent, wherein the lanthanum element of the alloy raw material is added according to the mass percent of 0.2-0.4;

(2) putting the raw materials prepared in the step (1) into a vacuum induction furnace, and melting and refining the raw materials to obtain an alloy solution;

(3) determining a tapping temperature according to the liquidus temperature corresponding to the chemical composition of the alloy solution in the step (2), and adjusting the temperature difference between the tapping temperature and the liquidus temperature;

(4) casting the alloy solution obtained in the step (3) into a baked ingot mold under a vacuum condition to obtain an electrode ingot, wherein the temperature of the ingot mold is 500-;

(5) and (6) cooling.

Preferably, the mass of the metal lanthanum element in the alloy raw material is 0.25-0.4 mass% of the mass of the alloy raw material.

Preferably, the mass of the metal lanthanum element in the alloy raw material is 0.3-0.35% of the mass of the alloy raw material.

Preferably, in the step (3), the temperature of the steel is 60-80 ℃ higher than the temperature of the liquidus line of the alloy.

Preferably, in the step (3), the temperature of the steel is 60-75 ℃ higher than the temperature of the liquidus line of the alloy.

Preferably, the steel temperature in step (3) is 65-70 ℃ higher than the liquidus temperature of the alloy.

Preferably, the ingot mold temperature is 550-.

Preferably, the ingot mold temperature is 600-.

Preferably, the cooling in step (5) is natural cooling with the mold.

In order to solve the technical problems, the invention provides a GH5188 alloy electrode ingot prepared by any one of the methods.

According to the technical scheme, the alloy raw materials are mixed according to the GH5188 alloy component control requirement, the consumption of each element raw material is calculated according to the mass percent, metal lanthanum is mixed according to 0.2-0.4 mass%, the mixed raw materials are put into a vacuum induction furnace to be melted and refined, alloy solution with gas and chemical components meeting the GH5188 alloy component control requirement is obtained, then the temperature difference between the tapping temperature and the alloy liquid phase line temperature is adjusted, and the alloy solution is cast into a steel ingot mold which is baked and has the temperature of 500-800 ℃ under the vacuum condition, so that an electrode ingot is generated. According to the invention, by controlling the addition of lanthanum element during smelting of the GH5188 cobalt-based high-temperature alloy vacuum induction furnace and baking the cast ingot mould, electrode cracking is avoided, and the usage amount of rare metal lanthanum content is saved under the condition of meeting the requirement of the product on the lanthanum content.

Drawings

FIG. 1 is a schematic view of a coagulated structure of an electrode ingot in example 1;

FIG. 2 is a schematic view of a coagulated structure of an electrode ingot in example 2;

FIG. 3 is a schematic view of a coagulated structure of an electrode ingot in example 3;

FIG. 4 is a schematic representation of the brittle phase of lanthanides at the cracks of the electrode ingot in comparative example 1;

FIG. 5 is a schematic representation of the brittle phase of lanthanides at the cracks of the electrode ingot in comparative example 2.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a preparation method of a GH5188 alloy electrode ingot, which comprises the following steps:

(1) calculating and preparing the consumption of raw materials of each element according to the control requirement of GH5188 alloy components by mass percent, wherein the lanthanum element of the alloy raw material is added according to the mass percent of 0.2-0.4;

(2) putting the raw materials prepared in the step (1) into a vacuum induction furnace, and melting and refining the raw materials to obtain an alloy solution;

(3) determining a tapping temperature according to the liquidus temperature corresponding to the chemical composition of the alloy solution in the step (2), and adjusting the temperature difference between the tapping temperature and the liquidus temperature;

(4) casting the alloy solution obtained in the step (3) into a baked ingot mold under a vacuum condition to obtain an electrode ingot, wherein the temperature of the ingot mold is 500-;

(5) and (6) cooling.

According to the technical scheme, the alloy raw materials are mixed according to the GH5188 alloy component control requirement, the consumption of each element raw material is calculated according to the mass percent, metal lanthanum is mixed according to 0.2-0.4 mass%, the mixed raw materials are put into a vacuum induction furnace to be melted and refined, alloy solution with gas and chemical components meeting the GH5188 alloy component control requirement is obtained, then the temperature difference between the tapping temperature and the alloy liquid phase line temperature is adjusted, and the alloy solution is cast into a steel ingot mold which is baked and has the temperature of 500-800 ℃ under the vacuum condition, so that an electrode ingot is generated. According to the invention, by controlling the addition of lanthanum element during smelting of the GH5188 cobalt-based high-temperature alloy vacuum induction furnace and baking the cast ingot mould, electrode cracking is avoided, and the usage amount of rare metal lanthanum content is saved under the condition of meeting the requirement of the product on the lanthanum content.

Preferably, the mass of the metal lanthanum element in the alloy raw material is 0.25 to 0.4 mass%, and more preferably 0.3 to 0.35 mass% of the mass of the alloy raw material. The mass ratio of the metal lanthanum element to the alloy raw material may be 0.2 mass%, 0.25 mass%, 0.3 mass%, 0.35 mass%, or 0.4 mass%, but is not limited thereto as long as the mass ratio of the metal lanthanum element to the alloy raw material is 0.2 to 0.4 mass%.

Because the solubility of lanthanum dissolved in a cobalt-based alloy solution is limited, excessive lanthanum is added, so that excessive lanthanum and matrix elements precipitate a large amount of lanthanum phases which have smaller expansion coefficients than the matrix and higher hardness than the matrix, namely brittle phases, together on dendrites or grain boundaries in the solidification process of the alloy, and the crack sensitivity of the alloy is greatly increased. According to the invention, by adding a proper amount of lanthanum, the generation of brittle phases in the solidification process is avoided, and meanwhile, the usage amount of rare metal lanthanum can be saved.

And (3) putting the prepared raw materials into a vacuum induction furnace, melting and refining to obtain an alloy solution with gas and chemical components meeting the GH5188 alloy component control requirement, and then adjusting the tapping temperature to be 60-80 ℃ above the alloy liquidus temperature.

The vacuum induction furnace is used for melting and refining raw materials, no air and slag pollution exists under the vacuum condition, metal is not easy to oxidize, and chemical components can be accurately adjusted and controlled; smelting under vacuum creates good degassing condition, carbon can be used for deoxidation, the deoxidation product is gas, and at the same time, electromagnetic stirring with a certain strength exists in a molten pool, so that molten steel components and temperature can be promoted to be uniform, and inclusions in steel are combined, grown and floated, thereby obtaining an alloy solution with high alloy purity, low gas content and chemical components meeting the control requirements of GH5188 alloy components.

The liquidus temperature (also called primary crystal temperature, which refers to the highest temperature at which an object begins to change from a liquid state to a solid state) of the alloy solution is not a constant value, is different according to the carbon content and the amount of various alloy trace elements, the liquidus temperature is generally higher when more alloys are added, and the liquidus temperature is lower. Preferably, the temperature difference is 65-70 ℃, and the specific temperature difference in the invention can be selected from 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 80 ℃, but is not limited to the temperature difference, as long as the temperature of the steel is 60-80 ℃ higher than the liquidus temperature of the alloy. The tapping temperature is determined according to the liquidus temperature corresponding to the actual steel smelting chemical composition of each furnace, the temperature difference between the tapping temperature and the alloy liquidus temperature is adjusted, so that the electrode ingot is prevented from generating large thermal stress due to large temperature gradient generated inside the electrode ingot in the casting process, and the electrode ingot is prevented from cracking due to internal thermal stress.

And casting the alloy solution into a baked ingot mould at the temperature of 500-800 ℃ under a vacuum condition to generate an electrode ingot, and finally cooling the mould to room temperature.

The invention adopts the ingot mould baked at high temperature to cast the alloy solution, reduces the larger temperature gradient existing inside and outside the ingot in the solidification process of the alloy, and reduces the solidification thermal stress of the ingot, thereby avoiding the electrode cracking phenomenon of the cast electrode ingot. The baking temperature of the ingot mold is preferably 550-.

The cooling mode of the electrode ingot is natural cooling (refers to a process of discharging heat from an object to an environment medium through heat transfer modes such as heat exchange, convection, heat radiation and the like, reducing the temperature of the object and finally achieving the spontaneity same as the environment temperature), and compared with a cooling mode of rapid heat exchange such as quenching and the like, the cooling mode of the electrode ingot can ensure that the electrode ingot does not crack in the cooling process.

In a second aspect of the present invention, there is provided a GH5188 alloy electrode ingot, where the GH5188 alloy electrode ingot is obtained by performing the steps of the method for preparing a GH5188 alloy electrode ingot, and the effect of the GH5188 alloy electrode ingot is consistent with the effect of the method for preparing a GH5188 alloy electrode ingot, which is not described herein again.

The present invention will be described in detail below by way of examples, but the scope of the present invention is not limited thereto.