CN-115921787-B - Multi-point thermal control feeding method and device for large complex thin-wall superalloy castings

CN115921787BCN 115921787 BCN115921787 BCN 115921787BCN-115921787-B

Abstract

The invention provides a multipoint heat control feeding method and device for a large complex thin-wall high-temperature alloy casting, wherein all hot spots are classified in a grading way, solidification hot spot positions in sequence from bottom to top are formed on the whole, secondly, a long bar-shaped wax rod is adopted to prepare a large complex thin-wall casting shell with a complex multipoint heat control runner based on the classified hot spots, finally, high-temperature alloy master alloy is smelted and poured into the large complex thin-wall casting shell, and in one or more grades, a heat control pipeline formed by the long bar-shaped wax rods corresponding to the hot spots is connected into a temperature control part to form temperature gradients among the hot spots in different heights in the same grade, so that solidification is performed in sequence from bottom to top according to the hot spot positions in each grade. The invention carries out graded thermal control management on all the thermal knots, can change the thermal control intensity of each grade thermal knot in an isolated way, not only can reduce the tendency of shrinkage cavity shrinkage porosity formation, but also can adjust the grain size of each part of the casting.

Inventors

KANG MAODONG
WANG JUN
WANG GUOXIANG
GAO HAIYAN
DONG ANPING
SUN BAODE

Assignees

上海交通大学
江苏中超航宇精铸科技有限公司

Dates

Publication Date: 20260508
Application Date: 20221207

Claims (9)

1. The preparation method of the large complex thin-wall casting shell with the complex multipoint thermal control runner is characterized by comprising the following steps: S201, determining a solidification hot joint part and N grades of average hot joint diameters, namely N different diameter values, by adopting a large complex thin-wall casting control solidification hot joint classification determination method; the method for determining the classification of the solidification hot joint of the large complex thin-wall casting comprises the following steps: S101, calculating the thermophysical properties of the alloy to be poured based on a designed pouring system of a high-temperature alloy large-scale complex thin-wall casting, introducing the alloy to be poured into casting simulation software, performing mold filling and solidification simulation, and extracting hot joint parts with large shrinkage cavity shrinkage porosity formation tendency; S102, dividing all extracted heat sections into N grades from large to small, dividing all heat sections of the whole casting into N according to the heat sections from a riser at the top end of a pouring system of a high-temperature alloy large complex thin-wall casting to the bottom part of the casting, and marking all heat sections according to the grades and the height levels respectively so as to divide all heat sections of the whole casting into N N major classes, each major class has x heat joints, and the solidification heat joint parts are formed in sequence from bottom to top as a whole; S202, performing wax pressing and riser and sprue assembling according to a designed pouring system of a high-temperature alloy large complex thin-wall casting, and respectively pressing wax rods with the diameters of N different diameter values; And S203, in the process of sizing and sand spraying of the large complex thin-wall casting, the wax rods are respectively connected to hot sections with the same diameter value, the hot sections with the same grade and different heights are connected by adopting the wax rods with the same diameter, sizing sand spraying is completed, sizing drying is performed, and roasting treatment is performed to obtain the large complex thin-wall casting shell with the complex multi-point thermal control runner.
2. The method for preparing a large complex thin-wall casting shell with a complex multipoint thermal control runner according to claim 1, wherein in S101, the design-based pouring system of the high-temperature alloy large complex thin-wall casting is designed by adopting a shape-following design principle.
3. The method for preparing a large complex thin-wall casting shell with a complex multi-point thermal control runner according to claim 1, wherein in S102, all the hot spots are marked according to the grade and the height level respectively, comprising: Each hotlink is represented using a three-bit code, wherein: A first bit code represents the level N of each hot node; a second bit code representing the level n of height at which each hot spot is located; a third bit code representing the number x of different height horizontal hotspots in each level; by the method, all the hot joints of the whole casting are divided into N N major classes, each major class having x hotspots.
4. The method of claim 1, wherein in S102, further comprising calculating N levels of average hot spot diameters, respectively, for subsequent design of the large complex thin-wall casting shell with the complex multipoint thermal control runner.
5. The method of manufacturing a large complex thin-walled cast shell with complex multi-point thermal control runners of claim 1, wherein when S201, all hot segments are classified into N grades from large to small, labeled A, B, c.; n height levels from the topmost riser to the bottom of the casting, labeled G, Z and d., respectively, according to the hot junction; all hotspots are marked according to grades and height levels, respectively AGx, AZx and ADx, BGx, BZx and BDx, CGx, CZx and CDx, and the like, wherein x represents the number. The average hot-spot diameters of N grades are Φa, Φb, Φc, and the pressed diameters are Φa, Φb, Φc, respectively, in S202.
6. The method for preparing a large complex thin-wall casting shell with a complex multipoint thermal control runner according to claim 5, wherein in S203, the large complex thin-wall casting is subjected to slurry bonding and sand showering, and when the slurry is bonded to a designated layer: the thermal joints AGx, AZx and ADx with different heights in the first grade are connected by adopting a phi A long-strip wax rod phi Ax; adopting phi B strip wax bars phi Bx connection among all heat joints BGx, BZx and BDx of different heights of the second grade. The Φc elongated wax bars Φcx connection is adopted between all third grades of hot joints CGx, CZx, cdx. According to the mode, the connection of the long-strip-shaped wax bars with the corresponding diameters among all N grades of heat sections with different heights is completed; And continuing to perform slurry bonding and sand spraying until the number of layers is set, sealing slurry, drying, and roasting to obtain the large complex thin-wall casting shell with the complex multi-point thermal control flow channel.
7. A multipoint thermal control feeding method for a large complex thin-wall superalloy casting is characterized by comprising the following steps of: s301, smelting a superalloy master alloy, and pouring the superalloy master alloy into a large complex thin-wall casting shell with a complex multipoint thermal control runner obtained by any one of the claims 1-6 after the design pouring temperature is reached; S302, in one or more grades, a thermal control pipeline formed by the long-strip-shaped wax rods corresponding to the hot joints is connected into a temperature control part, and a temperature gradient between the horizontal hot joints with different heights in the same grade is formed, so that solidification is carried out according to the hot joint parts in each grade from bottom to top.
8. The multipoint heat control feeding method of a large complex thin-wall superalloy casting according to claim 7, wherein in S302, comprising one or more of the following options: The bottom of a thermal control pipeline formed by a long-strip wax rod phi Ax of a thermal joint in the first grade A is connected with an air outlet of an air compressor, a temperature gradient from ADx to AGx is forced to be formed from AZx to AGx, the probability of shrinkage cavity shrinkage porosity is reduced, and/or, An opening is formed at the bottom of a thermal control pipeline formed by the long-strip-shaped wax bars phi Bx of the thermal joints in the second grade B, a temperature gradient from BDx to BGx is automatically formed by utilizing the principle that hot air flows from bottom to top, so that the probability of shrinkage cavity shrinkage porosity is reduced, and/or, In S302, magnesium powder is added to the top of a thermal control pipeline formed by the long-strip wax bars Φcx of the thermal joints in the third grade C, and the magnesium powder is added to a temperature gradient from CDx to CZx to cgx.
9. A multipoint heat control feeding device for a large complex thin-wall superalloy casting, for realizing the multipoint heat control feeding method for the large complex thin-wall superalloy casting according to claim 7 or 8, comprising: the pouring system is provided with a riser and a sprue, and the riser is positioned above the sprue; a plurality of heat segments, all the heat segments of the whole casting are divided into N grades from large to small, and the heat segments are divided into N height levels from the top riser to the bottom of the casting, thereby dividing all the heat segments of the whole casting into N N major classes, each major class has x heat joints, and the solidification heat joint parts are formed from the bottom of the casting to the riser from bottom to top in sequence; at least one long-strip-shaped wax rod connected with the same grade of heat sections with different heights in the N grades of heat sections, wherein each long-strip-shaped wax rod forms a thermal control pipeline; And the temperature control part is used for controlling the heat sections with different heights in the same grade in the N grades to form a required temperature gradient through each thermal control pipeline.

Description

Multi-point thermal control feeding method and device for large complex thin-wall superalloy castings Technical Field The invention relates to the technical field of precision casting of high-temperature alloy, in particular to a multipoint thermal control feeding method and device for a large complex thin-wall high-temperature alloy casting. Background Aeroengines and hypersonic aircraft are heavy machines in the country and are important markers for measuring the comprehensive technological level, industrial basis and capability of a country. The development of advanced aeroengines and high-performance hypersonic vehicles promotes the selection of alloy materials with higher temperature bearing capacity for high-temperature alloy castings, the heat-resistant strengthening phase content of the alloy materials is even more than 60%, the content of loose elements is easy to form, the cracking tendency is large, the casting process performance and weldability of the materials are extremely poor, loose defects and cracking phenomena are extremely easy to occur in the forming process, and the alloy materials cannot be repaired through later repair welding. Meanwhile, the structural design is enlarged, complicated and thinned, the discrete hot spots of the casting are more, hot spot interference in the casting and pouring system becomes a common phenomenon, and the loosening caused by the hot spots shows a dynamic behavior due to the disturbance of the external process environment. How to realize the large-scale molding size of the extremely high temperature resistant superalloy, and the internal zero porosity is a key technical problem of integral precise molding of large-scale complex thin-wall castings. According to the document search of the prior art, the Chinese patent application No. 201811636648.2 discloses that the high-temperature alloy liquid rises into a preheated casting mould through a liquid lifting pipe under the pressure of inert gas and fills a cavity, a heater moves downwards at a certain speed to separate from the casting mould, and the high-temperature alloy liquid is gradually crystallized and fed under the pressure of the inert gas and the sequential solidification condition to obtain a compact structure. To a certain extent, the method has the characteristic of single thermal control feeding, and although the method can better solve the problem of defect control of castings with simple structures, aerospace key castings often have complex structural characteristics, a plurality of scattered heat joints exist, and the single thermal control feeding is difficult to realize internal metallurgical defect control of large complex thin-wall high-temperature castings. Disclosure of Invention According to the research of the invention, the key to solve the loose control is to form a sequential solidification mode at all hot joints, and the development of a multi-hot joint oriented thermal control feeding technology is one of effective ways to solve the difficult problem of controlling the metallurgical defects of the aerospace superalloy key castings. Aiming at the defects of the existing single heat control feeding technology design, the invention provides a multipoint heat control feeding method and device for controlling metallurgical defects of large complex thin-wall superalloy castings. The invention provides a method for classifying and determining solidification heat joints of large complex thin-wall castings, which comprises the following steps: S101, calculating the thermophysical properties of the alloy to be poured based on a designed pouring system of a high-temperature alloy large-scale complex thin-wall casting, introducing the alloy to be poured into casting simulation software, performing mold filling and solidification simulation, and extracting hot joint parts with large shrinkage cavity shrinkage porosity formation tendency; S102, dividing all extracted heat sections into N grades from large to small, dividing the top riser of a casting system of a high-temperature alloy large complex thin-wall casting into N height levels from the top riser to the bottom of the casting according to the heat sections, and marking all the heat sections according to the grades and the height levels, so that all the heat sections of the whole casting are divided into N x N major categories, each major category comprises x heat sections, and the solidification heat section positions in sequence from bottom to top are integrally formed. In a possible implementation mode of the invention, in S101, the design-based pouring system of the high-temperature alloy large-scale complex thin-wall casting is designed by adopting a conformal design principle. In one possible embodiment of the present invention, the marking of all hotspots according to the level and the height level, respectively, comprises: Each hotlink is represented using a three-bit code, wherein: A first bit code represents the level N of