Search

CN-115709261-B - Single crystal casting and preparation method thereof

CN115709261BCN 115709261 BCN115709261 BCN 115709261BCN-115709261-B

Abstract

The invention discloses a single crystal casting and a preparation method thereof, and in the preparation method of the single crystal casting, the seed crystal and a seed crystal cavity of a mould shell are designed into a matched frustum shape, the height of the seed crystal is designed to be larger than that of the seed crystal cavity, the mould shell assembled with the seed crystal is arranged on a chilling chassis of a vacuum directional solidification furnace, the mould shell is supported by the seed crystal, the mould shell is not contacted with the chilling chassis, the conicity of the seed crystal and the seed crystal cavity is the same, the whole mould shell is fully pressed on the seed crystal, the seed crystal is tightly attached to the mould shell, no gap exists, casting metal liquid cannot flow into the mould shell to form a drape, and therefore, a drape mixed crystal cannot be formed.

Inventors

  • MA DEXIN
  • ZHAO YUNXING
  • WEI JIANHUI
  • XU WEITAI
  • XU FUZE
  • LI LV
  • DENG YANGPI

Assignees

  • 深圳市万泽中南研究院有限公司
  • 深圳市万泽航空科技有限责任公司

Dates

Publication Date
20260512
Application Date
20221114

Claims (9)

  1. 1. A preparation method of a single crystal casting is characterized by comprising the steps of designing a seed crystal (1) and a seed crystal cavity (10) of a mould shell (2) into a matched frustum shape, designing the height of the seed crystal (1) to be larger than that of the seed crystal cavity (10), installing the mould shell (2) assembled with the seed crystal (1) on a chilling chassis (3) of a vacuum directional solidification furnace, supporting the mould shell (2) by using the seed crystal (1), and preventing the mould shell (2) from being contacted with the chilling chassis (3), wherein the seed crystal (1) is identical with the taper of the seed crystal cavity (10), the whole mould shell (2) is fully pressed on the seed crystal (1), the seed crystal is tightly attached with the mould shell (2) without a gap (4), and casting molten metal (5) cannot flow into the mould shell (6) so as not to form a drape gap miscellaneous crystal (7); When the vacuum directional solidification furnace is used for preparing the single crystal casting, a chilling chassis (3) is used for lifting most of a mould shell (2) into a hot chamber of the directional solidification furnace, the furnace chamber is preheated after vacuumizing, but a seed crystal cavity (10) and the seed crystal (1) are still kept in a cold region, the furnace chamber is preheated to a set temperature, the seed crystal cavity (10) of the mould shell (2) is lifted into the hot chamber to enable part of the seed crystal (1) to enter the hot region, then heat preservation and pouring are carried out, finally the chilling chassis (3) is slowly lowered to enable the mould shell (2) to be lowered into the cold chamber according to a set speed, and the seed crystal (1) is upwards subjected to epitaxial growth to obtain the single crystal casting.
  2. 2. The method for preparing single crystal castings according to claim 1, wherein the preheating temperature of the mold shell (2) is more than or equal to 1500 degrees, the preheating temperature rise time of the mold shell (2) is more than or equal to 1 hour, and the heat preservation time of the seed crystal cavity (10) and the seed crystal (1) after being lifted into a hot chamber is 12-18 minutes.
  3. 3. The method for preparing the single crystal casting according to claim 1, wherein the original chilling chassis (3) is split into two sets of formwork chassis (11) and seed crystal chassis (12) which can move up and down independently through modifying a vacuum directional solidification furnace, when the casting is prepared, the whole formwork (2) is lifted into a hot chamber of the directional solidification furnace by the formwork chassis (11) to be preheated, the seed crystal (1) remains in a cold area of the vacuum directional solidification furnace in the preheating process of the formwork (2), then the seed crystal (1) is lifted into the heated formwork (2) by the seed crystal chassis (12) and tightly supported, the formwork (2) is slightly lifted and separated from the formwork chassis (11), then heat preservation and pouring are carried out, finally the seed crystal chassis (12) and the formwork chassis (11) are slowly lowered together, the formwork (2) is lowered into a cold chamber, and the seed crystal (1) is grown upwards to obtain the single crystal casting.
  4. 4. The method for preparing a single crystal casting according to claim 3, wherein a plurality of through holes distributed in a circumferential array are formed in the mold shell chassis, each through hole is internally provided with a seed crystal chassis (12) in a corresponding manner, a plurality of seed crystal cavities (10) in one-to-one correspondence with the seed crystal chassis (12) are formed in the mold shell (2), each seed crystal cavity (10) is internally provided with a seed crystal (1), and each seed crystal (1) can be epitaxially grown upwards to obtain the single crystal casting.
  5. 5. A method of producing a single crystal casting according to claim 4 wherein the circumferential axis of distribution of the plurality of through holes coincides with the axis of the formwork base plate (11).
  6. 6. The method for preparing a single crystal casting according to claim 4, wherein the preheating temperature of the mold shell (2) is more than or equal to 1500 degrees, the preheating temperature rise time of the mold shell (2) is more than or equal to 1 hour, and the heat preservation time is 4-6 minutes after the seed crystal is lifted into the hot chamber.
  7. 7. The method for producing a single crystal casting according to any one of claims 1 to 6, wherein the seed crystal has a truncated cone shape or a right truncated pyramid shape.
  8. 8. A single crystal casting, characterized in that it is produced by the single crystal casting production method according to any one of claims 1 to 7.
  9. 9. The single crystal casting of claim 8 wherein the single crystal casting is a single crystal blade.

Description

Single crystal casting and preparation method thereof Technical Field The invention belongs to the technical field of single crystal preparation, and particularly relates to a single crystal casting and a preparation method thereof. Background The existing seed crystal process has the problems that a gap 4 is inevitably formed when a cylindrical seed crystal 1 is arranged in a cylindrical seed crystal cavity of a mould shell 2, as shown in (a) of fig. 1, a molten metal 5 flows into the mould to form a coating gap 6 during casting, as shown in (c) of fig. 1, and the molten metal grows into a coating gap mixed crystal 7 during solidification, as shown in (d) of fig. 1. One method is to directly connect the seed crystal under the vane wax mold during the manufacture of the wax mold, the seed crystal is kept in the mold shell without gaps after dipping and sand spraying, but the surface of the seed crystal is oxidized by roasting for a long time (about one day) after dewaxing, so that the method is not practical, and the upper surface of the seed crystal 1 reacts with residual gas in a vacuum furnace after the mold shell is provided with the seed crystal in a preheating time (for a plurality of hours) before casting to generate an oxide film 8, as shown in (b) in fig. 1, the oxide film is kept in place or changed in position during the casting of the metal liquid 5, the crystal growth is blocked during the solidification thereafter, and the growth of the oxide film mixed crystal 9 is caused, as shown in (d) in fig. 1. Disclosure of Invention The invention mainly aims to provide a single crystal casting and a preparation method thereof, and aims to effectively solve the problem of mixed crystal caused by the existence of a mantling gap between a seed crystal and a mould shell. The monocrystalline casting preparation method comprises the steps of designing a seed crystal and a seed crystal cavity of a mould shell into a frustum shape matched with each other, designing the height of the seed crystal to be larger than that of the seed crystal cavity, installing the mould shell assembled with the seed crystal on a seed crystal chassis of a vacuum directional solidification furnace, and supporting the mould shell by utilizing the seed crystal to prevent the mould shell from being contacted with a chilling chassis. The method comprises the steps of preparing a single crystal casting by utilizing a vacuum directional solidification furnace, utilizing a chilling chassis to lift most of a mould shell into a hot chamber of the directional solidification furnace, vacuumizing a furnace chamber, preheating, keeping a seed crystal cavity and seed crystals in a cold region, preheating the furnace chamber to a set temperature, lifting the seed crystal cavity of the mould shell into the hot chamber to enable the seed crystals to enter the hot region, preserving heat and pouring, slowly descending the chilling chassis to enable the mould shell to be lowered into the cold chamber according to a set speed, and carrying out epitaxial growth on the seed crystals to obtain the single crystal casting. Specifically, the preheating temperature of the mould shell is more than or equal to 1500 degrees, the preheating temperature rise time of the mould shell is more than or equal to 1 hour, and the heat preservation time of the seed crystal cavity and the seed crystal after being lifted into the hot chamber is 12-18 minutes. Specifically, the original chilling chassis is split and designed into two sets of die shell chassis and seed crystal chassis which can independently move up and down by modifying the vacuum directional solidification furnace, when a casting is prepared, the die shell chassis is firstly utilized to lift the whole die shell into a hot chamber of the directional solidification furnace for preheating, seed crystals remain in a cold region of the vacuum directional solidification furnace in the die shell preheating process, then the seed crystals are lifted into the heated die shell by utilizing the seed crystal chassis and tightly supported, the die shell is slightly lifted and separated from the die shell chassis, then the heat preservation and the casting are carried out, finally the seed crystal chassis and the die shell chassis are slowly lowered together, the die shell is lowered into the cold chamber, and the seed crystals are upwards subjected to epitaxial growth to obtain the single crystal casting Specifically, a plurality of through holes distributed in a circumferential array are formed in the mould shell chassis, one seed crystal chassis is correspondingly arranged in each through hole, a plurality of seed crystal cavities corresponding to the seed crystal chassis one to one are formed in the mould shell, seed crystals are arranged in each seed crystal cavity, and each seed crystal can be epitaxially grown upwards to obtain a single crystal casting. Specifically, the distributed circumferential axes of the plur