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Method for realizing fine crystal solidification by controlling spherical crystal stabilization

A fine-grain and spherulite technology, applied in the field of manufacturing high-temperature alloy ingots or castings, can solve problems such as uneven distribution of carbides and second phases, coarse grains in columnar grain areas, and sensitivity to billet deformation, and achieve improved The effect of billet opening success rate, small micro-segregation, and small micro-shrinkage

Inactive Publication Date: 2013-06-05
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] In order to overcome the problems existing in the prior art, such as coarse grains in the columnar grain region, uneven distribution of carbides and second phases, serious microsegregation, easy cracking in the subsequent billeting, and sensitivity to billet deformation, the present invention proposes a Fine-grain solidification method through controlled spherulite stabilization

Method used

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  • Method for realizing fine crystal solidification by controlling spherical crystal stabilization
  • Method for realizing fine crystal solidification by controlling spherical crystal stabilization
  • Method for realizing fine crystal solidification by controlling spherical crystal stabilization

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Embodiment 1

[0026]This embodiment is a method for realizing fine-grain solidification by controlling the stabilization of spherulites. The material involved is Ni-22Cr-18W-1Mo superalloy, Ni-22Cr-18W-1Mo superalloy is a kind of nickel-based deformation superalloy with solid solution strengthening and carbide dispersion strengthening, Bai Guanghai et al. in 2009 in " Secondary M23C6 Precipitation Behavior of Ni-Cr-W-Based Superalloys" reports the Ni-22Cr-18W-1Mo superalloy. Figure 1 The total mass of 60Kg superalloy fine-grained ingot with riser poured by this process, the specific size of the ingot is: φ110×370mm, and the grain size grade is ASTM4.

[0027] The concrete process of this embodiment is:

[0028] Step 1, vacuuming. Put 60Kg Ni-22Cr-18W-1Mo superalloy raw material into the quartz crucible, -2 Argon protection is passed at Pa, and heat treatment begins when the pressure of argon is 0.5Pa.

[0029] Step 2, repeated overheating. Raise the temperature of the Ni-22Cr-18W-1Mo ...

Embodiment 2

[0037] Embodiment two adopts Ni-22Cr-18W-1Mo superalloy material, Figure II In order to use this process to cast a slab with a size of 150×220×20mm, the overall grain size of the slab reaches ASTM2-3.

[0038] The concrete process of this embodiment is:

[0039] Step 1, vacuuming. Put 60Kg Ni-22Cr-18W-1Mo superalloy raw material into the quartz crucible, -2 Argon protection is passed at Pa, and heat treatment begins when the pressure of argon is 0.5Pa.

[0040] Step 2, repeated overheating. Raise the Ni-22Cr-18W-1Mo superalloy raw material to 100°C above the liquidus line under a 3KHz intermediate frequency power supply and then keep it warm for 1min. In this embodiment, the Ni-22Cr-18W-1Mo superalloy raw material is heated up to 1490° C. and cooled down to 1440° C. Repeat the above Ni-22Cr-18W-1Mo superalloy raw material heating-insulation-cooling process for a total of 3 times, and repeatedly overheat the Ni-22Cr-18W-1Mo superalloy raw material to obtain Ni-22Cr-18W-1M...

Embodiment 3

[0048] Embodiment three adopts Hayness230 superalloy, Figure three It is an anatomical diagram of a 30Kg fully equiaxed superalloy fine-grained ingot poured by this process after removing the riser, ( figure 2 The a and b in the figure are the comparison chart of ordinary ingot and fine grain ingot respectively), the specific size of the ingot is: φ100×280mm, and the grain size grade is ASTM5.

[0049] The concrete process of this embodiment is:

[0050] Step 1, vacuuming. Put 30Kg Hayness230 superalloy raw material into the quartz crucible, -2 Argon protection is passed at Pa, and heat treatment begins when the pressure of argon is 0.5Pa.

[0051] Step 2, repeated overheating. Under the 3KHz intermediate frequency power supply, raise the temperature of the Hayness230 superalloy raw material to 100°C above the liquidus line and then keep it warm for 1min. After the heat preservation is over, cool the Hayness230 superalloy raw material to 50°C above the liquidus line. 14...

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Abstract

The invention discloses a method for realizing fine crystal solidification by controlling spherical crystal stabilization. A method of combining oxide crucible, glass purifying, circulating and overheating, medium-frequency electromagnetic induction is adopted under vacuum environment, so that melt which is circulated and overheated by multiple times is slowly cooled to the liquid-phase line temperature. Temperature-equalizing and stirring are carried out by utilizing electromagnetic fields, so that temperature and solute of the whole melt are almost uniformly distributed, wherein the whole melt is enabled to be uniformly cooled integrally during the cooling process. According to the method disclosed by the invention, high-temperature alloy fine-grained structure, which is free of a tricrystal region of the conventional solidified ingot, small in microporosity, provided with fine equiaxed grains with grain size level of about ASTM (American Society for Testing Material) 5 level, small in microsegregation and high in density, can be obtained by the method disclosed by the invention. The grain size of the obtained fully equiaxed ingot is close to that of the spherical crystal and is very beneficial to the subsequent deformation, therefore, the billeting success rate of the high-temperature alloy is effectively improved.

Description

technical field [0001] The invention relates to the field of metal solidification manufacturing, in particular to a method for realizing fine-grain solidification by controlling the stabilization of spherulites, which is applicable to high-temperature alloy ingots or castings whose crystallization temperature range is greater than 10°C and does not react or reacts weakly with ceramic crucibles manufacture. Background technique [0002] The traditional high-temperature alloy ingots obtained by ordinary smelting methods have obvious three-crystal regions, and the grains in the columnar crystal regions are coarse, the carbides and the second phase are unevenly distributed, and the micro-segregation is serious. Warp sensitive. For this reason, it is usually necessary to homogenize the solidified ingot for a long time. The superalloy fine-grain casting method obtains fully equiaxed crystal ingots, and the refined equiaxed grains can significantly improve the forging power of hi...

Claims

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Application Information

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IPC IPC(8): C22F1/18B22D1/00B22D27/20
Inventor 胡锐寇宏超张绪虎李金山张铁邦高中堂
Owner NORTHWESTERN POLYTECHNICAL UNIV
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