A method for establishing material standards and verifying airworthiness of civil aviation engine castings

Abstract

The present application discloses a method for establishing a standard for civil aviation engine casting materials and verifying airworthiness, including the following steps: S1, establishing a standard for casting materials: establishing a first draft of the standard for casting materials, and completing the revision of the first draft of the standard for casting materials by obtaining the relationship between the structure, defects and mechanical properties of castings through casting simulation production and small-batch production of castings; S2, obtaining a model diagram for the mechanical properties of castings: inputting the chemical composition, process parameters and other components of the castings into the optimized casting simulation production software based on the relationship to obtain a model diagram for the mechanical properties of castings; S3, evaluating the simulated production of castings: comparing the mechanical properties model diagram of castings with the force diagram of castings, and improving the process or replacing the materials if the strength design requirements cannot be met; otherwise, conducting the first batch and batch production trials, verifying the locations with weak mechanical properties and high stress, and passing the material standard identification. The present application ensures that castings meet actual requirements and provides support for the airworthiness verification of civil aviation engine casting materials.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular, to a method for establishing a material standard for civil aviation engine castings and verifying their airworthiness. Background Art

[0002] The standard mechanical properties of materials in castings are generally characterized by single-cast test bars or attached test bars. Due to the different crystallization rates and cooling rates at various positions during the casting process, the microstructure and mechanical properties at different positions of the castings are quite different. Moreover, castings with the same material but different structures also have quite different performances. Single-cast test bars or attached test bars are difficult to characterize the mechanical properties of each position of castings with different structures. In addition, due to the simple structure of single-cast / attached test bars, the test bars contain fewer defects, while actual castings often have complex structures. Due to the uneven cooling rate, castings have certain defects. Safety is the primary requirement for civil aviation engines. The current strength design often uses the index values ​​specified in the material standard to evaluate whether the strength and life of the parts meet the requirements. This brings certain hidden dangers to the strength and life evaluation results, mainly including:

[0003] (1) The mechanical properties in the current casting material standards are single values, but the mechanical properties of castings with different structures and at different positions of castings with the same structure are not the same;

[0004] (2) Single-cast / attached-cast test bars contain fewer defects, resulting in higher strength than the mechanical properties of some parts of the casting body with more defects. The current strength design often uses the index values ​​specified in the material standard to evaluate whether the strength and life of the parts meet the requirements, which brings certain hidden dangers to the strength and life evaluation results. Summary of the invention

[0005] The present application provides a method for establishing a standard for civil aviation engine casting materials and verifying their airworthiness, in order to solve the technical problem that the existing casting material standards have single values ​​for mechanical properties, which makes it difficult to characterize the mechanical properties of each position of castings with different structures, and brings certain hidden dangers to the strength and life assessment results.

[0006] This application is implemented through the following scheme:

[0007] A method for establishing a material standard for civil aviation engine castings and verifying airworthiness, comprising the steps of:

[0008] S1. Establishment of casting material standards: Establish the first draft of casting material standards, and obtain the relationship between casting structure, defects and mechanical properties through casting simulation production and small batch production of castings. Use the obtained relationship between casting structure, defects and mechanical properties to complete the revision of the first draft of casting material standards;

[0009] S2. Acquisition of a model diagram of mechanical properties of castings: Inputting the relationship into casting simulation production software to obtain optimized casting simulation production software that can simulate mechanical properties of different casting structures and positions, and inputting casting chemical composition, production process parameters, and gating system data into the optimized casting simulation production software to obtain a model diagram of mechanical properties of castings;

[0010] S3. Casting simulation production evaluation: Compare the obtained casting mechanical property model diagram with the existing casting force diagram. If it cannot meet the strength design requirements, improve the process or replace the material; if it can meet the strength design requirements, conduct the first batch and batch production trial, and conduct multiple batches of verification for locations with weak mechanical properties and high stress. After completion, pass the material standard identification.

[0011] Furthermore, in step S1, when establishing the first draft of the casting material standard, the first draft of the casting material standard is established by collecting casting material standards of multiple manufacturers at home and abroad.

[0012] Further, in step S1, the relationship between the structure, defects and mechanical properties of the castings is obtained through casting simulation production and small batch production of castings, and the obtained relationship between the structure, defects and mechanical properties of the castings is used to complete the revision of the first draft of the casting material standard, which specifically includes the steps of:

[0013] S11, inputting casting chemical composition, production process parameters, and gating system data into casting simulation production software, the casting simulation production software obtains the structure and defects at different positions of the casting by simulating the casting temperature field, the crystallization position of the casting, and the dendrite growth rate of different chemical components, the production process parameters include pouring time, pouring temperature, and the pouring system data include casting structure, core structure, cooling system structure and material;

[0014] S12. For castings put into production in small batches, samples are taken from locations with typical structures and defects in the castings to conduct mechanical property tests. Then, the mechanical properties in the draft of the casting material standard are used as initial values, the structures and defects are used as independent variables, and the tested mechanical properties are used as dependent variables. The initial values, independent variables, and dependent variables are input into the data processing software to obtain the relationship between the structure, defects, and mechanical properties of the castings;

[0015] S13. Use the obtained relationship to replace the single mechanical property value in the material standard, so that the mechanical property value in the first draft of the casting material standard is replaced by a single unchanging value related to the casting structure and defects, and the revision of the first draft of the casting material standard is completed.

[0016] Furthermore, in step S12, the locations of the structures and defects with typical characteristics are selected in the casting for sampling, specifically, the locations of the largest grains, the smallest grains, the locations with the most defects, and the locations with the least defects in the casting are sampled, and the defects include microscopic looseness and harmful phases.

[0017] Furthermore, in step S12, the data processing software includes MATLAB and ORINGIN.

[0018] Furthermore, in step S3, the casting force diagram is obtained by finite element strength calculation.

[0019] Furthermore, in step S3, multiple batches of verification are performed for locations with weak mechanical properties and high stress. After completion, the material standard identification is passed. Specifically, at least 30 sub-samples from 3 batches are verified for locations with weak mechanical properties and high stress. After completion, the material standard identification is passed.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] (1) The present application provides a method for establishing mechanical property indicators for different casting structures and different positions of castings, which can more accurately obtain the mechanical properties at various positions of different casting structures, ensuring that the actual strength and life of the castings meet the requirements;

[0022] (2) This application obtains a mechanical performance model diagram through the structure, organization, and defects of the casting, and establishes a relationship between the casting organization, defects, and mechanical performance indicators, which is convenient for a simple and quick evaluation of whether the casting material and process meet the strength design requirements, and provides support for the airworthiness verification of civil aviation engine casting materials.

[0023] In addition to the above-described purposes, features and advantages, the present application also has other purposes, features and advantages. The present application will be further described in detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0025] Figure 1 It is a flow chart of the method for establishing material standards and airworthiness verification of civil aviation engine castings according to the preferred embodiment of the present application.

[0026] Figure 2 It is a schematic diagram of the sub-step flow of step S1 of the preferred embodiment of the present application. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below in conjunction with the accompanying drawings, but the present application can be implemented in a variety of different ways defined and covered below.

[0028] Embodiment 1

[0029] like Figure 1As shown, the preferred embodiment of the present application provides a method for establishing a material standard for civil aviation engine castings and verifying airworthiness, comprising the steps of:

[0030] S1. Establishment of casting material standards: Establish the first draft of casting material standards, and obtain the relationship between casting structure, defects and mechanical properties through casting simulation production and small batch production of castings. Use the obtained relationship between casting structure, defects and mechanical properties to complete the revision of the first draft of casting material standards;

[0031] S2. Acquisition of a model diagram of mechanical properties of castings: Inputting the relationship into casting simulation production software to obtain optimized casting simulation production software that can simulate mechanical properties of different casting structures and positions, and inputting casting chemical composition, production process parameters, and gating system data into the optimized casting simulation production software to obtain a model diagram of mechanical properties of castings;

[0032] S3. Casting simulation production evaluation: Compare the obtained casting mechanical property model diagram with the existing casting force diagram. If it cannot meet the strength design requirements, improve the process or replace the material; if it can meet the strength design requirements, conduct the first batch and batch production trial, and conduct multiple batches of verification for locations with weak mechanical properties and high stress. After completion, pass the material standard identification.

[0033] In view of the technical problem that the existing technology may bring certain hidden dangers to the strength and life assessment results, on the one hand, this embodiment provides a method for establishing mechanical performance indicators for different casting structures and different positions of castings, which can more accurately obtain the mechanical properties at various positions of different casting structures, ensuring that the actual strength and life of the castings meet the actual engineering requirements. On the other hand, this embodiment obtains a mechanical performance model diagram through the structure, organization, and defects of the casting, and establishes a relationship between the organization, defects, and mechanical performance indicators of the casting, which is convenient for simple and rapid judgment of whether the casting materials and processes meet the actual strength design requirements, and provides support for the airworthiness verification of civil aviation engine casting materials.

[0034] Specifically, in step S1, when establishing a preliminary draft of casting material standards, the preliminary draft of casting material standards is established by collecting casting material standards of multiple manufacturers at home and abroad.

[0035] Embodiment 2

[0036] like Figure 2 As shown, in another preferred embodiment of the present application, in step S1, the relationship between the structure, defects and mechanical properties of the castings is obtained through casting simulation production and small batch production of castings, and the obtained relationship between the structure, defects and mechanical properties of the castings is used to complete the revision of the first draft of the casting material standard, which specifically includes the steps of:

[0037] S11, inputting casting chemical composition, production process parameters, and gating system data into casting simulation production software, the casting simulation production software obtains the structure and defects at different positions of the casting by simulating the casting temperature field, the crystallization position of the casting, and the dendrite growth rate of different chemical components, the production process parameters include pouring time, pouring temperature, and the pouring system data include casting structure, core structure, cooling system structure and material;

[0038] S12. For castings put into production in small batches, samples are taken from locations with typical structures and defects in the castings to conduct mechanical property tests. Then, the mechanical properties in the draft of the casting material standard are used as initial values, the structures and defects are used as independent variables, and the tested mechanical properties are used as dependent variables. The initial values, independent variables, and dependent variables are input into the data processing software to obtain the relationship between the structure, defects, and mechanical properties of the castings;

[0039] S13. Use the obtained relationship to replace the single mechanical property value in the material standard, so that the mechanical property value in the first draft of the casting material standard is replaced by a single unchanging value related to the casting structure and defects, and the revision of the first draft of the casting material standard is completed.

[0040] In the present embodiment, when revising the first draft of the casting material standard, firstly, the chemical composition of the casting is input into the casting simulation production software, and the production process parameters and the pouring system data are simulated to obtain the structure and defects at different positions of the casting; then, the casting is put into production in small batches, and the positions of the structure and defects with typical characteristics are sampled in the casting to perform mechanical property tests; then, the mechanical properties in the first draft of the casting material standard are used as initial values, the structure and defects are used as independent variables, and the tested mechanical properties are used as dependent variables to input into the data processing software to obtain the relationship between the structure, defects and mechanical properties of the casting; finally, the obtained relationship is used to replace the single mechanical property value in the material standard, so that the mechanical property value in the first draft of the casting material standard is replaced by a single constant value related to the structure and defects of the casting, and the revision of the first draft of the casting material standard is completed. The purpose and benefits of revising the first draft of the casting material standard in the above manner include: obtaining mechanical properties that are strongly related to the structure and defects of the casting, and fully considering the problem that the internal structure and defects of the casting are uneven due to the solidification sequence and heat dissipation performance differences, and a single mechanical property index cannot represent the mechanical properties of different parts of the casting. The mechanical properties of castings of different sizes and different parts of castings can be judged more accurately based on the number of defects and organizational relationships.

[0041] Specifically, in step S12, the locations of the structures and defects with typical characteristics are selected in the casting for sampling, specifically, the locations of the largest grains, the smallest grains, the locations with the most defects, and the locations with the least defects in the casting, and the defects include microscopic looseness and harmful phases.

[0042] In this embodiment, when sampling the locations of the castings with typical structures and defects for mechanical property testing, including the locations with the largest grains, the smallest grains, the most defects, and the least defects, the purposes and benefits include: sampling for mechanical property testing at the locations with the best structure and the least defects and the worst structure and the most defects in the casting, the structure-defect-mechanical property relationship can be quickly constructed with fewer specimens, thereby reducing construction costs.

[0043] Preferably, in step S12, the data processing software includes MATLAB and ORINGIN.

[0044] Preferably, in step S3, the casting force diagram is obtained by finite element strength calculation.

[0045] Preferably, in step S3, multiple batches of verification are performed for locations with weak mechanical properties and high stress. After completion, when passing the material standard identification, specifically, at least 30 sub-samples from 3 furnace batches are verified for locations with weak mechanical properties and high stress. After completion, the material standard identification is passed.

[0046] In this embodiment, when multiple batches of verification are performed for locations with weak mechanical properties and high stress, and after passing the material standard identification, at least 3 batches of 30 sub-samples are verified for locations with weak mechanical properties and high stress to pass the material standard identification. Its purpose and benefits include: through this method, the weak mechanical properties and locations with high stress, that is, dangerous points, can be quickly identified. Through this method, the performance verification of the dangerous points of the casting can be focused on, without the need to dissect multiple locations of multiple castings for performance verification. By verifying whether the dangerous points meet the strength and life requirements through multiple batches of verification, it can accurately determine whether the casting can be used safely while reducing the identification cost.

[0047] The present invention proposes a method for establishing material standards and verifying airworthiness of civil aviation engine castings. The method involves optimization of casting simulation production software, acquisition of casting mechanical property model diagrams, establishment of relationship between mechanical property indicators and organizations and defects, and proposes methods for establishing mechanical properties of castings with different structures and at different positions of castings. The material standards are preliminarily verified by simulation methods, which has engineering practical significance.

[0048] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0049] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for establishing material standards for civil aviation engine castings and verifying airworthiness, characterized in that: Includes steps: S1. Establishment of casting material standards: Establish the first draft of casting material standards, and obtain the relationship between casting structure, defects and mechanical properties through casting simulation production and small batch production of castings. Use the obtained relationship between casting structure, defects and mechanical properties to complete the revision of the first draft of casting material standards, including: S11, inputting the chemical composition of the casting, production process parameters, and pouring system data into the casting simulation production software, the casting simulation production software obtains the structure and defects at different positions of the casting by simulating the casting temperature field, the crystallization position of the casting, and the dendrite growth rate of different chemical components, the production process parameters include pouring time and pouring temperature, and the pouring system data includes the casting structure, core structure, cooling system structure and material; S12. For castings put into production in small batches, samples are taken from locations with typical structures and defects in the castings to conduct mechanical property tests. Then, the mechanical properties in the draft of the casting material standard are used as initial values, the structures and defects are used as independent variables, and the tested mechanical properties are used as dependent variables. The initial values, independent variables, and dependent variables are input into the data processing software to obtain the relationship between the structure, defects, and mechanical properties of the castings; S13. Use the obtained relationship to replace the single mechanical property value in the material standard, so that the mechanical property value in the first draft of the casting material standard is replaced by a single constant value related to the casting structure and defects, and the revision of the first draft of the casting material standard is completed; S2. Acquisition of a model diagram of mechanical properties of castings: Inputting the relationship into casting simulation production software to obtain optimized casting simulation production software that can simulate mechanical properties of different casting structures and positions, and inputting casting chemical composition, production process parameters, and gating system data into the optimized casting simulation production software to obtain a model diagram of mechanical properties of castings; S3. Casting simulation production evaluation: Compare the obtained casting mechanical property model diagram with the existing casting force diagram. If it cannot meet the strength design requirements, improve the process or replace the material; if it can meet the strength design requirements, conduct the first batch and batch production trial, and conduct multiple batches of verification for locations with weak mechanical properties and high stress. After completion, pass the material standard identification.

2. The method for establishing material standards and verifying airworthiness of civil aviation engine castings according to claim 1, characterized in that: In step S1, when establishing a preliminary draft of casting material standards, the preliminary draft of casting material standards is established by collecting casting material standards of multiple manufacturers at home and abroad.

3. The method for establishing material standards and verifying airworthiness of civil aviation engine castings according to claim 1, characterized in that: In step S12, the locations of the structures and defects with typical characteristics are selected in the casting for sampling, specifically, the locations of the largest grains, the smallest grains, the locations with the most defects, and the locations with the least defects in the casting, wherein the defects include microscopic looseness and harmful phases.

4. The method for establishing material standards and verifying airworthiness of civil aviation engine castings according to claim 1, characterized in that: In step S12, the data processing software includes MATLAB and ORINGIN.

5. The method for establishing material standards and verifying airworthiness of civil aviation engine castings according to claim 1, characterized in that: In step S3, the casting force diagram is obtained by finite element strength calculation.

6. The method for establishing material standards and verifying airworthiness of civil aviation engine castings according to claim 1, characterized in that: In step S3, multiple batches of verification are performed for locations with weak mechanical properties and high stress. After completion, the material standard identification is passed. Specifically, at least 30 sub-samples of 3 batches are verified for locations with weak mechanical properties and high stress. After completion, the material standard identification is passed.

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