CN-121072273-B - Sheath step-by-step compensation design method based on hot isostatic pressing powder densification process

CN121072273BCN 121072273 BCN121072273 BCN 121072273BCN-121072273-B

Abstract

The application relates to a sheath step-by-step compensation design method based on a densification process of hot isostatic pressing powder, and belongs to the field of advanced manufacturing. A sheath step-by-step compensation design method based on a hot isostatic pressing powder densification process comprises the following steps of S1, processing shape, size and surface information of a target part through a surface bias method, creating a conformal sheath which is attached to the surface of the target part and has uniform thickness, S2, simulating a hot isostatic pressing process of a powder body of the conformal sheath and the target part by using FEM software, collecting deformation data, S3, processing the deformation data, automatically identifying a plurality of deformation stages in the hot isostatic pressing process, S4, obtaining deformation characteristics of the plurality of deformation stages of the hot isostatic pressing obtained in the step S3, respectively applying different compensation coefficients to the plurality of deformation stages, and carrying out reverse compensation design on the conformal sheath and the powder body. The method provided by the application overcomes the problem of insufficient design precision of the traditional sheath.

Inventors

CAI CHAO
ZHANG CHENGJIAN
Cai jili
SHI YUSHENG

Assignees

华中科技大学

Dates

Publication Date: 20260505
Application Date: 20251107

Claims (9)

1. The sheath step-by-step compensation design method based on the hot isostatic pressing powder densification process is characterized by comprising the following steps of: S1, acquiring shape, size and surface information of a target part, processing the shape, size and surface information of the target part by a surface bias method, creating a conformal sheath which is attached to the surface of the target part and has uniform thickness, and establishing a finite element model for analyzing the target part and the conformal sheath in the hot isostatic pressing process; S2, simulating the hot isostatic pressing process of the conformal coating and the powder body of the target part by using FEM software, and collecting deformation data of the conformal coating and the powder body in the hot isostatic pressing process; s3, processing the deformation data, and automatically identifying a plurality of deformation stages in the hot isostatic pressing process; s4, obtaining deformation characteristics of the hot isostatic pressing at a plurality of deformation stages obtained in the step S3, respectively applying different compensation coefficients to the deformation stages, and carrying out reverse compensation design on the conformal sheath; The plurality of deformation stages comprises: a thermal expansion stage, wherein the thermal expansion stage is an initial compaction stage, the conformal wrap is thermally expanded due to the temperature rise, and the pressure does not reach the degree of plastic deformation of the conformal wrap at the moment, so that the conformal wrap expands outwards, the inner cavity volume increases, the powder flows outwards, and the relative density of the powder is reduced; A plastic deformation stage, wherein when external pressure exceeds thermal expansion effect and yield strength of the conformal wrap, shielding effect of the conformal wrap is weakened, most of pressure is effectively transmitted to the powder, and the powder is softened and plastically deformed at high temperature to form a closed pore; And the diffusion creep stage is that the powder which is bonded preliminarily is further densified through grain boundary diffusion and grain recrystallization along with the prolonging of the time of heat preservation and pressure maintaining, and creep deformation is carried out to shrink inwards under the continuous pressure.
2. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 1, wherein the specific steps of the step S1 are as follows: S11, acquiring the shape and the size of a target part, and constructing a three-dimensional model of the powder body and the conformal wrap according to the shape and the size of the target part, wherein the thickness of the conformal wrap is consistent, and the shape and the size of a cavity of the conformal wrap are matched with the model of the powder body; S12, establishing a finite element model, wherein the finite element model comprises a powder material parameter, the conformal wrap material parameter, a constitutive model, a grid model, a contact relation and a load curve which are set for the target part.
3. The sheath step-wise compensation design method based on the hot isostatic pressing powder densification process according to claim 2, wherein the powder bulk material parameters in step S12 comprise: a general parameter including density, poisson's ratio, and initial relative density; Thermophysical parameters including specific heat capacity, thermal conductivity, and coefficient of thermal expansion; temperature dependent mechanical parameters including Young's modulus and yield stress.
4. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 1, wherein the specific steps of the step S2 are as follows: S21, simulating the whole process of the hot isostatic pressing of the powder body and the conformal coating by using an implicit thermal coupling module of the FEM software according to the finite element model established in the step S1; S22, defining required output variables including node coordinates, displacement, temperature, stress strain and relative density of the powder body and the conformal sheath, and recording deformation data of the whole hot isostatic pressing process of the powder body and the conformal sheath in an output database Odb file.
5. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 4, wherein the specific steps of the step S3 are as follows: s31, calling the Odb file by using a data processing module, and acquiring node and unit information of the powder body and the conformal wrap from a grid object of the Odb file; S32, calculating and obtaining coordinate data of nodes of the powder body and coordinate data of nodes of the conformal wrap; S33, outputting coordinate data of nodes of the powder body and coordinate data of nodes of the conformal sheath, tracking deformation tracks of the nodes of the conformal sheath by using the data processing module, researching a curve of the material densification progress of the powder body changing with time, and automatically identifying a plurality of deformation stages in the hot isostatic pressing process.
6. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 5, wherein the specific steps of S4 are as follows: S41, obtaining coordinates and displacement sizes of the nodes of the conformal coating and the nodes of the powder body at each time point by using the data processing module, and calculating displacement amounts of the nodes of the powder body and the nodes of the conformal coating in a plurality of deformation stages of the hot isostatic pressing; s42, calculating the anti-deformation compensation quantity of each node of the powder body and each node of the conformal wrap in each deformation stage, wherein the anti-deformation compensation quantity is equal to the displacement quantity of the deformation stage multiplied by the compensation coefficient of the corresponding deformation stage.
7. The sheath step-by-step compensation design method based on a hot isostatic pressing powder densification process according to claim 6, wherein the compensation coefficients of the step S42 are different in a plurality of deformation phases, and the determination method of the compensation coefficients of different deformation phases is based on data fitting and multi-physical field coupling analysis.
8. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 1, wherein the step S4 further comprises the following steps: S5, performing finite element simulation verification on the conformal wrap after the compensation of the S4.
9. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder according to claim 8, wherein the specific step of S5 is as follows: s51, repeating the finite element simulation methods of the S1 and the S2 according to the compensated conformal wrap automatically generated in the step S4; S52, verifying the design accuracy of the shape-following sheath after compensation by comparing the simulation result with the target part.

Description

Sheath step-by-step compensation design method based on hot isostatic pressing powder densification process Technical Field The invention relates to the advanced manufacturing field, in particular to a sheath step-by-step compensation design method based on a hot isostatic pressing powder densification process. Background Hot isostatic pressing (Hot Isostatic Pressing, HIP) technology plays an important role in the field of high-performance complex structural part manufacturing, especially in high-end applications such as aerospace, nuclear industry and biomedical. During hot isostatic pressing of powders, the powder undergoes a transition from loose to dense, accompanied by shrinkage deformation on a macroscopic scale. However, the prior art does not compensate the sheath for the shrinkage deformation, and finally causes larger errors between the actual size and the preset size when the powder is completely formed in the sheath to form the target part, which causes the problems of insufficient design precision of the sheath and low efficiency of the design process. This problem severely hampers the high precision manufacturing process of the part, and presents a number of inconveniences and challenges for the associated production. Disclosure of Invention Based on the above, it is necessary to provide a sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder, aiming at the problem of insufficient sheath design precision of the hot isostatic pressing. A sheath step-by-step compensation design method based on a hot isostatic pressing powder densification process comprises the following steps: S1, acquiring shape, size and surface information of a target part, processing the shape, size and surface information of the target part by a surface bias method, creating a conformal sheath which is attached to the surface of the target part and has uniform thickness, and establishing a finite element model for analyzing the target part and the conformal sheath in the hot isostatic pressing process; S2, simulating the hot isostatic pressing process of the conformal coating and the powder body of the target part by using FEM software, and collecting deformation data of the conformal coating and the powder body in the hot isostatic pressing process; s3, processing the deformation data, and automatically identifying a plurality of deformation stages in the hot isostatic pressing process; s4, obtaining deformation characteristics of the hot isostatic pressing at a plurality of deformation stages obtained in the step S3, respectively applying different compensation coefficients to the deformation stages, and performing reverse compensation design on the conformal sheath. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder is disclosed, and the development of manufacturing industry is restrained for a long time due to insufficient precision and low efficiency in the traditional sheath design field. The sheath step-by-step compensation design method based on the densification process of the hot isostatic pressing powder solves the problems in a targeted way. Firstly, a surface bias technology is applied, a sheath model which is closely attached to the surface of a part and has uniform thickness is constructed according to the shape, the size and detailed surface information of a target part, and a corresponding finite element model is constructed. The measure ensures the effective contact between the sheath and the powder grid, ensures the full transfer of heat and force in the hot isostatic pressing process, and can accurately reflect the cooperative deformation relation between the compaction deformation of the powder and the sheath. Second, FEM software with leading edge was introduced to simulate the overall process of hot isostatic pressing. By means of simulation, technicians can accurately know the deformation conditions of the powder body and the conformal coating of the part in a plurality of stages of hot isostatic pressing in advance, and key deformation data are obtained. The data provides a reliable calculation basis for the subsequent compensation design, and ensures that the compensation strategy has scientificity and effectiveness. The core bright point of the application is to adopt a multi-stage compensation strategy which is highly adaptive to the stage characteristics of the powder hot isostatic pressing forming process. By accurately identifying the deformation characteristics of the powder bodies of the conformal sheath and the target part in each stage of hot isostatic pressing, applying different compensation coefficients in a targeted manner according to the collected deformation data of the conformal sheath and the target part, reversely optimizing a sheath model, and reversely compensating the powder bodies at the same time, the reliability of the method can be verif