Casting evaluation method

Abstract

The invention provides a casting evaluation method which comprises the following steps: S1, reducing the shrinkage porosity of a shrinkage cavity, and optimizing the structure and process of a part; s2, establishing a relationship between material-level shrinkage porosity and stress; s3, shrinkage porosity distribution of shrinkage cavities is obtained; s4, stress distribution is obtained according to service conditions; s5, based on the stress distribution in S4 from the working condition angle, according to the function relation in S2, evaluating each position to obtain the requirement for the shrinkage porosity distribution of the shrinkage cavity, comparing with S3, if the requirement is met, working under the working condition, and if the requirement is not met, optimizing; and from the angle of the shrinkage porosity of the shrinkage cavity, based on the shrinkage porosity of the S3 and according to the function relation of the S2, evaluating each position to obtain the limit of stress distribution of the cast part, comparing with the S4, if the stress is greater than the S4, working under the working condition, and if the stress is less than the S4, not working under the working condition. According to the casting evaluation method, the shrinkage cavity and the shrinkage porosity are included in the evaluation process of the casting part, and part failure caused by the shrinkage cavity and the shrinkage porosity is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of casting part evaluation, and in particular relates to a casting part evaluation method taking shrinkage cavities and porosity into consideration. Background Art

[0002] Before industrial application, parts must be evaluated, including mechanical properties, service conditions, etc., especially large and complex structural parts, which have complex manufacturing processes, long cycles, and high labor and material costs. They must be evaluated before industrial application. The common manufacturing method for complex structural parts is casting, such as diesel engine cylinder heads, fuselages, missile racks, etc. In the prior art, the location and size of shrinkage cavities and shrinkage porosity are predicted during the evaluation of the casting process of parts, and then the structure and process are optimized; when evaluating strength and fatigue properties, it is assumed that the parts are dense and evenly distributed, and the service conditions are only used as boundary conditions to evaluate and optimize the parts. It can be seen that in the prior art, shrinkage cavities and shrinkage porosity are not included in the evaluation process of cast parts. Shrinkage cavities and shrinkage porosity and part evaluation are two independent processes. First, shrinkage cavities and shrinkage porosity are evaluated, and the conditions that shrinkage cavities and shrinkage porosity cannot exceed are specified. Then, it is assumed that the parts are dense and evenly distributed, and the parts are evaluated. This leads to many parts failing due to shrinkage cavities and shrinkage porosity. In addition, many scholars have studied the influence of material-level defects on mechanical properties (such as fatigue strength, yield strength, etc.), but have not involved applying this influence to the part evaluation process. As we all know, even if the structure and process are optimized, it is difficult to ensure that there are no shrinkage cavities and shrinkage in the parts. The shrinkage cavities and shrinkage can only be controlled within a certain range. Therefore, it is of great significance to incorporate shrinkage cavities and shrinkage into the evaluation process of casting parts. Summary of the invention

[0003] In view of this, the present invention aims to provide a casting evaluation method to improve the accuracy of casting evaluation and reduce part failure caused by shrinkage cavities and porosity.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A casting evaluation method comprises the following steps:

[0006] S1. Minimize shrinkage and porosity, and optimize the structure and process of casting parts;

[0007] S2. Establishing the functional relationship between shrinkage and stress at the material level of the casting part body;

[0008] S3, simulating the casting parts to obtain the distribution of shrinkage cavities and porosity of the casting parts;

[0009] S4. According to the service conditions of the casting parts, the stress distribution of the casting parts is obtained by simulation;

[0010] S5. From the perspective of working conditions, based on the stress distribution obtained in S4 and the functional relationship obtained in S2, each position of the part is evaluated to obtain the requirements for shrinkage distribution of the casting part, and compared with the shrinkage distribution obtained in S3. If the requirements are met, the casting part can work under this service condition. If the requirements are not met, auxiliary means are taken to optimize the structure and process of the casting part.

[0011] S6. From the perspective of shrinkage and porosity, based on the shrinkage and porosity distribution of S3 and the functional relationship of S2, each position of the part is evaluated to obtain the limit of the stress distribution of the casting part, and compared with the stress distribution obtained by S4. If the stress is greater than S4, the casting part can work under this service condition. If the stress is less than S4, the casting part cannot work under this service condition, and auxiliary measures are taken to reduce the degree of the service condition.

[0012] Furthermore, in S5, the auxiliary means for optimizing the structure and process of the casting parts include ultrasonic casting and low-pressure casting.

[0013] Furthermore, in said S6, the auxiliary means for reducing the degree of service conditions include reducing the consumption of the performance of the parts themselves by reducing weight, friction, vibration, etc.;

[0014] Furthermore, in S2, the functional relationship between the bulk material level shrinkage and stress is established as follows:

[0015]

[0016] Among them, σ represents stress, S represents the area of ​​shrinkage cavity, x represents the distance from the center of shrinkage cavity to the surface of the sample, and d represents the diameter of shrinkage cavity.

[0017] Compared with the prior art, the casting evaluation method of the present invention has the following advantages:

[0018] (1) The casting evaluation method of the present invention incorporates shrinkage cavities and shrinkage porosity into the evaluation process of cast parts, thereby improving the reference value of the evaluation results and reducing part failures caused by shrinkage cavities and shrinkage porosity.

[0019] (2) The casting evaluation method described in the present invention explains the evaluation of casting parts from two perspectives: working conditions and shrinkage and porosity, which greatly increases the reference value of the method. In some cases, the working conditions cannot be changed, and only shrinkage and porosity can be optimized. In some cases, shrinkage and porosity have been optimized to a certain extent, and further optimization requires a lot of manpower and material resources, or even no further optimization is possible, and the degree of service conditions can only be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 This is a flow chart of the casting evaluation method described in an embodiment of the present invention; Draw the flow chart yourself

[0022] Figure 2 A schematic diagram of a principle block diagram of a casting evaluation method according to an embodiment of the present invention;

[0023] Figure 3 This is a distribution diagram of shrinkage cavities and porosity of an aluminum-silicon alloy cylinder head according to an embodiment of the present invention;

[0024] Figure 4 This is a stress distribution diagram of the aluminum-silicon alloy cylinder head described in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0029] A method of evaluating castings, such as Figures 1 to 4 As shown, the following steps are included:

[0030] S1. To maximize the reduction of shrinkage cavities and porosity, the structure and process of the casting parts are optimized to obtain the final structure and process of the casting parts;

[0031] S2. Establishing the functional relationship between shrinkage and stress at the material level of the casting part body;

[0032] S3, using commercial software to simulate the final casting part of step S1 to obtain the distribution of shrinkage cavities and porosity of the casting part;

[0033] S4. According to the service conditions of the casting parts, the stress distribution of the casting parts is obtained by simulation;

[0034] S5. From the perspective of working conditions, based on the stress distribution obtained in step S4 and according to the functional relationship obtained in step S2, each position of the part is evaluated to obtain the requirements for the shrinkage distribution of the casting part, and compared with the shrinkage distribution obtained in step S3. If the requirements are met, the casting part can work under this service condition and the casting part can proceed to the next process. If the requirements are not met, the casting part cannot work under this service condition, and auxiliary means can be taken to optimize the structure and process of the casting part.

[0035] In step S5, the auxiliary means for reducing the degree of service conditions include means such as lightening, reducing friction, vibration, etc. to reduce the consumption of performance of the parts themselves.

[0036] In step S5, the auxiliary means for optimizing the structure and process of the casting parts include ultrasonic casting, low pressure casting and other means.

[0037] S6. From the perspective of shrinkage cavities and shrinkage, based on the shrinkage cavities and shrinkage obtained in step S3 and according to the functional relationship obtained in step S2, each position of the part is evaluated to obtain the limit of the stress distribution of the casting part, and compared with the stress distribution obtained in step S4. If the stress is greater than S4, the casting part can work under this service condition and the casting part can proceed to the next process. If the stress is less than S4, the casting part cannot work under this service condition and auxiliary measures can be taken to reduce the degree of the service condition.

[0038] In one or more embodiments, the casting part is selected as a diesel engine cylinder head with a complex structure and uneven wall thickness. The main body material of the casting part is selected as an aluminum silicon alloy with a grade of ZL118 alloy. The specific evaluation method is as follows:

[0039] S1. To minimize shrinkage and porosity, the structure and process of the aluminum-silicon alloy cylinder head were optimized to obtain the final structure and process of the aluminum-silicon alloy cylinder head.

[0040] S2. The functional relationship between shrinkage and stress of the aluminum-silicon alloy cylinder head body material level is established as follows:

[0041]

[0042] Among them, σ represents stress, S represents the area of ​​shrinkage cavity, x represents the distance from the center of shrinkage cavity to the surface of the sample, and d represents the diameter of shrinkage cavity.

[0043] S3, using ProCAST software to simulate the aluminum-silicon alloy cylinder head in step S1, and obtain the distribution of shrinkage cavities and porosity of the aluminum-silicon alloy cylinder head (such as Figure 2 As shown), the shrinkage cavity equivalent area at position 1 is 1mm 2 , The equivalent shrinkage area of ​​shrinkage cavity at position 2 is 1.2mm 2 ,

[0044] S4. According to the service conditions of the aluminum-silicon alloy cylinder head, the stress distribution of the aluminum-silicon alloy cylinder head is simulated (such as Figure 3 shown).

[0045] S5. From the perspective of working conditions, based on the stress distribution obtained in step S4 and according to the functional relationship obtained in step S2, each position of the aluminum-silicon alloy cylinder head is evaluated to obtain the requirements for the shrinkage porosity distribution of the aluminum-silicon alloy cylinder head.

[0046] Figure 2 The defect area at position 1 should be less than 1.2mm 2 , meet the requirements, Figure 2 The defect area at position 2 should be less than 0.8mm 2 , does not meet the requirements and needs to be optimized using auxiliary means.

[0047] S6. From the perspective of shrinkage porosity, based on the shrinkage porosity obtained in step S3 and according to the functional relationship obtained in step S2, each position of the aluminum-silicon alloy cylinder head is evaluated to obtain the limit of stress distribution of the aluminum-silicon alloy cylinder head.

[0048] Figure 2 The stress at position 1 should be less than 16.1MPa, which meets the requirements. Figure 2 The stress at position 2 should be less than 19.1MPa, which does not meet the requirements and needs to be optimized using auxiliary means.

[0049] This application explains the evaluation of casting parts from two perspectives: working conditions and shrinkage and porosity, which greatly increases the reference value of this method. In some cases, the working conditions cannot be changed, and shrinkage and porosity can only be optimized. In some cases, shrinkage and porosity have been optimized to a certain extent, and further optimization requires huge manpower and material resources, or even no further optimization is possible, and the degree of service conditions can only be reduced.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A casting evaluation method, characterized in that: The following steps are involved: S1. Minimize shrinkage and porosity, and optimize the structure and process of casting parts; S2. Establishing the functional relationship between shrinkage and stress at the material level of the casting part body; S3, simulating the casting parts to obtain the distribution of shrinkage cavities and porosity of the casting parts; S4. According to the service conditions of the casting parts, the stress distribution of the casting parts is obtained by simulation; S5. From the perspective of working conditions, based on the stress distribution obtained in S4 and the functional relationship obtained in S2, each position of the part is evaluated to obtain the requirements for shrinkage distribution of the casting part, and compared with the shrinkage distribution obtained in S3. If the requirements are met, the casting part can work under this service condition. If the requirements are not met, auxiliary means are taken to optimize the structure and process of the casting part. S6. From the perspective of shrinkage and porosity, based on the shrinkage and porosity distribution of S3 and the functional relationship of S2, each position of the part is evaluated to obtain the limit of the stress distribution of the casting part, and compared with the stress distribution obtained by S4. If the stress is greater than S4, the casting part can work under this service condition. If the stress is less than S4, the casting part cannot work under this service condition, and auxiliary measures are taken to reduce the degree of the service condition.

2. A casting evaluation method according to claim 1, characterized in that: In step S5, auxiliary means for optimizing the structure and process of the casting part include ultrasonic casting and low-pressure casting.

3. A casting evaluation method according to claim 1, characterized in that: In step S6, auxiliary means to reduce the degree of service conditions include reducing weight, friction, vibration, etc. to reduce the consumption of performance of the parts themselves.

4. A casting evaluation method according to claim 1, characterized in that: In step S2, the functional relationship between bulk material level shrinkage and stress is established as follows: Among them, σ represents stress, S represents the area of ​​shrinkage cavity, x represents the distance from the center of shrinkage cavity to the surface of the sample, and d represents the diameter of shrinkage cavity.

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