CN104788106A - Manufacturing method of crucible for vacuum induction melting of high-temperature alloy - Google Patents

Abstract

The invention provides a method for manufacturing a crucible for vacuum induction smelting superalloys. The steps are: 1) The raw material consists of zirconium corundum with a particle size of 1-4mm, zirconium corundum with a particle size of 0.1-1mm, zirconium corundum with a particle size of less than 0.1mm, and bimodal activity α-alumina and nanocrystalline α-alumina are mixed at a mass percentage of 15-40: 15-40: 15-40: 3-8: 3-8, and then the raw materials are mixed with ammonium polyacrylate and a binder to obtain Slurry, wherein ammonium polyacrylate and binder are added in amounts of 0.5-2% and 5-15% of the total mass of the raw materials respectively; 2) adding 0.1-0.3% of the total mass of the slurry to the water-soluble azo or piperidine initiator, mix at 2-30°C for 3-10min; 3) After the slurry obtained in step 2) is vacuum degassed at 2-30°C for 5min, immediately pour it into the crucible forming mold; 4) together with the mold Heating to 45-55°C for 5-35min, demoulding, and drying the crucible body at room temperature; 5) Put the crucible body at 1500-1650°C for more than 3 hours, then cool to room temperature to obtain the target product. The crucible prepared by the invention has low content of impurity elements when melting high-temperature alloys.

Description

Manufacturing method of crucible for vacuum induction melting superalloy

technical field

The invention relates to a method for manufacturing a crucible for vacuum induction melting high-temperature alloys, belonging to the technical field of metallurgy.

Background technique

The crucible is a key component in vacuum induction melting superalloys. Under high temperature and vacuum conditions, various physical and chemical interactions will occur between the crucible and the superalloy melt, resulting in erosion of the crucible material and contamination of the melt. Therefore, the crucible material should have good chemical stability. At the same time, the crucible is periodically subjected to heating and cooling during use, causing expansion and contraction stress inside the crucible, resulting in cracks and melt leakage. Therefore, the crucible material is required to have good thermal shock stability.

Oxygen, nitrogen, sulfur, phosphorus and other impurity elements have a significant impact on the mechanical properties of superalloys. Nitrogen usually exists in the form of nitrides or carbonitrides in superalloys. These compounds are very stable and will not melt into the melt at normal melting temperatures. In order to reduce the nitrogen content in superalloys, higher The melting temperature further intensifies the physical and chemical interaction between the crucible and the melt, resulting in a greater degree of pollution to the melt.

At present, the crucible materials used in vacuum induction melting superalloys are mainly magnesia crucibles, but because magnesia will be reduced and polluted by active elements such as carbon, aluminum, titanium, niobium and chromium in superalloys under the action of high temperature and high vacuum alloy, it is difficult to further reduce the purity of superalloys. In order to overcome the shortcomings of magnesia crucibles, a calcia crucible with higher high-temperature chemical stability was tested for melting superalloys. However, due to the shortcomings of calcium oxide, such as easy hydration, difficult molding and high cost, it has not been applied industrially. The pure corundum (alumina) crucible has good chemical stability and will not react chemically with the superalloy melt at high temperature, so it can be used to melt high-purity superalloys. However, because the existing pure corundum crucible has poor thermal shock stability and is easy to crack, it cannot be used as a crucible for vacuum induction melting superalloys. In order to overcome the shortcomings of pure corundum crucible, Chinese patent (ZL 201210440801.0) discloses a corundum spinel crucible and its preparation method, because the high temperature volume stability and thermal shock stability of magnesium aluminum spinel are better than magnesia material , thermal shock resistance is better than corundum, corrosion resistance and redox resistance are better than mullite, the crucible prepared with it has excellent high-temperature performance, but its composition still contains components with poor high-temperature chemical stability compared with pure corundum exist.

Contents of the invention

The object of the present invention is to provide a kind of manufacture method that can overcome above-mentioned defective, the crucible of vacuum induction melting superalloy with excellent working performance, its technical scheme is:

A method for manufacturing a crucible for vacuum induction melting superalloy, characterized in that it comprises the following steps:

1) The raw material components are calculated by mass percentage: 15-40% of zirconium corundum with a particle size of 1-4mm, 15-40% of zirconium corundum with a particle size of 0.1-1mm, and 15-40% of zirconium corundum with a particle size of 0.1mm or less. 40%, bimodal active α-alumina 3-8% and nanocrystalline α-alumina 3-8%; dispersant is ammonium polyacrylate; binder is acrylamide and N,N′-methylenebisacrylamide The mixed aqueous solution, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%; the raw material, dispersant, and binding agent are mixed uniformly with a mass ratio of 100:0.5-2:5-15 to obtain a slurry material;

2) Add an initiator to the slurry obtained in step 1), mix at 2-30°C for 3-10min, the initiator is a water-soluble azo or piperidine initiator, and the amount added is 0.1- 0.3%;

3) After the slurry obtained in step 2) is degassed in vacuum at 2-30°C for 5 minutes, it is immediately poured into a crucible forming mold, wherein the degassing vacuum degree is less than 10Pa;

4) Heating together with the mold to 45-55°C for 5-35min, demoulding, and drying the crucible body at room temperature;

5) Place the dried crucible body in a kiln for sintering at a sintering temperature of 1500-1650° C., hold for more than 3 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Compared with the prior art, the present invention has the advantages that zirconium corundum is used as the raw material for the vacuum induction melting superalloy crucible disclosed in the present invention, and it is casted and formed by a special process, and the composition phase of the finished crucible is α-Al2O3, The tetragonal phase t-ZrO2 with square structure and the monoclinic phase m-ZrO2 with monoclinic structure have good high temperature chemical stability and thermal shock resistance; Volume increase of sulfur and phosphorus; bimodal active α-alumina and nanocrystalline α-alumina are added, and fired at a high temperature of 1500-1650°C, with high bonding strength and strong melt erosion resistance. Using the crucible of the invention to smelt high-temperature alloys can carry out high-temperature treatment of melts above 1700° C., and the smelted alloys have low content of impurity elements such as O, N, S, and P.

Detailed ways

Below in conjunction with embodiment the present invention is further described.

The mass ratio of raw materials in each embodiment is shown in Table 1.

Example 1

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 0.5% of the total mass of raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 5% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), and mix at 30°C for 3 minutes. The initiator is water-soluble 2,2'-azo hydrochloride, and the amount added is 0.3% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 30°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 9Pa;

4) Heating together with the mold to 45°C for 30 minutes, demoulding, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1650° C., hold for 3.5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 2

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 1.5% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 10% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 25° C. for 6 minutes, the initiator is piperidine hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum-degassed at 25° C. for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassing vacuum degree was 8 Pa;

4) Heating together with the mold to 50°C for 35 minutes to release the mold, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1600° C., hold for 4 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 3

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 2% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 15% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 20°C for 8 minutes, the initiator is 2,2'-azo hydrochloride, and the amount added is 0.15% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum-degassed at 20° C. for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassing vacuum degree was 7 Pa;

4) Heating together with the mold to 55°C for 35 minutes to remove the mold, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1500° C., hold for 5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 4

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 1% of the total mass of the raw materials. The binder is acrylamide and N. The mixed aqueous solution of N′-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition amount of the binder is 8% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 15°C for 10 minutes, the initiator is piperidine hydrochloride, and the amount added is 0.1% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 15°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 6Pa;

4) Heating together with the mold to 55°C for 35 minutes to remove the mold, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1550° C., hold for 5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 5

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 1.5% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylene bisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 12% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), and mix at 15°C for 10 minutes. The initiator is 2,2'-azo hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 15°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 6Pa;

4) Heating together with the mold to 50°C for 20 minutes to release the mold, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1580° C., hold for 5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 6

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 2% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 10% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 25°C for 5 minutes, the initiator is piperidine hydrochloride, and the amount added is 0.25% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum-degassed at 25° C. for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassing vacuum degree was 9 Pa;

4) Heating together with the mold to 45°C for 30 minutes to release the mold, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1650° C., hold for 5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 7

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 2% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N′-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition amount of the binder is 8% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 30°C for 8 minutes, the initiator is 2,2'-azo hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 30°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 9Pa;

4) Heating together with the mold to 50°C for 15 minutes, demoulding, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1600° C., hold for 3.5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 8

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 1.5% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 10% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 2°C for 3 minutes, the initiator is piperidine hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was degassed in vacuum at 2°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 5Pa;

4) Heating together with the mold to 50°C for 20 minutes, demoulding, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1620° C., hold for 4 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 9

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 2% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylenebisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 10% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 10°C for 5 minutes, the initiator is 2,2'-azo hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 10°C for 5 minutes, and immediately poured into a crucible molding mold, wherein the degassed vacuum degree was 9Pa;

4) Heating together with the mold to 50°C for 15 minutes, demoulding, and then drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1500° C., hold for 5 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

Example 10

The manufacture of a crucible for vacuum induction melting superalloys includes the following steps:

1) After weighing according to the ratio in Table 1, mix it with a dispersant and a binder to obtain a uniform slurry. The dispersant used is ammonium polyacrylate, and the amount added is 1.5% of the total mass of the raw materials. The binder is acrylamide and N, The mixed aqueous solution of N'-methylene bisacrylamide, the mass ratio of the two is 10:1, the total mass percentage concentration of the mixed aqueous solution is 14%, and the addition of the binder is 12% of the total mass of raw materials;

2) Add an initiator to the slurry obtained in step 1), mix at 15°C for 7 minutes, the initiator is piperidine hydrochloride, and the amount added is 0.2% of the total mass of the slurry;

3) The slurry obtained in step 2) was vacuum degassed at 15°C for 5 minutes, and immediately poured into a crucible forming mold, wherein the degassed vacuum degree was 8 Pa;

4) Heating together with the mold to 50°C for 5 minutes, demoulding, and drying at room temperature;

5) Place the dried crucible blank in a kiln for sintering at a sintering temperature of 1650° C., hold for 4 hours, and then cool to room temperature to obtain a crucible for vacuum induction melting superalloys.

The crucible made in the embodiment was used to conduct vacuum induction smelting and vacuum casting tests of nickel-based cast superalloy K417, and a high-temperature melt treatment at 1750° C. was adopted during the smelting process. Samples were taken from the cast alloy ingot, and the oxygen and nitrogen content was analyzed by TC-436 oxygen and nitrogen analyzer. The results are shown in Table 2. It can be seen that the gas content in the nickel-based cast superalloy smelted by the crucible of the present invention is very low.

The proportioning (mass percentage) of raw material in each embodiment of table 1

Table 2 Oxygen and nitrogen content (×0.0001%, mass percent) in nickel-based cast superalloy K417 using crucible vacuum induction melting of the present invention

Example oxygen nitrogen Example 1 4 3 Example 2 6 5 Example 3 5 4 Example 4 6 5 Example 5 5 4 Example 6 4 3 Example 7 6 5 Example 8 5 4 Example 9 6 5 Example 10 6 3

Claims (1)

1. a manufacture method for vacuum induction melting superalloy crucible, is characterized in that comprising the following steps:

1) feed composition is by mass percentage: the zircon corundum 15-40% that the zircon corundum 15-40% that particle size is 1-4mm, particle size are 0.1-1mm, particle size are zircon corundum 15-40%, the bimodal activity Alpha-alumina 3-8% of below 0.1mm and nanocrystalline Alpha-alumina 3-8%; Dispersion agent is ammonium polyacrylate; Bonding agent is the mixed aqueous solution of acrylamide and N, N '-methylene-bisacrylamide, and the mass ratio of the two is 10:1, and the total mass percent concentration of mixed aqueous solution is 14%; Raw material, dispersion agent, bonding agent are mixed with the mass ratio of 100:0.5-2:5-15 and obtains slurry;

2) by step 1) add initiator in the slurry that obtains, at 2-30 DEG C of mixing 3-10min, initiator is water-soluble azo class or piperidines initiator, and add-on is the 0.1-0.3% of slurry total mass;

3) by step 2) slurry that obtains is after 2-30 DEG C of vacuum outgas 5min, and pour into crucible forming mould immediately, wherein devolatilization vacuum degree is less than 10Pa;

4) be heated to 45-55 DEG C together with mould and keep the demoulding after 5-35min, by crucible base substrate drying at room temperature;

5) dried crucible base substrate is placed in kiln to sinter, sintering temperature is 1500-1650 DEG C, hold-time more than 3h, is then cooled to room temperature and obtains vacuum induction melting superalloy crucible.