Rapid evaluation method for tensile strength of electron beam pre-control shell

Abstract

A rapid assessment method for tensile strength of an electron beam pre-control shell is characterized in that the tensile strength sigma 1 of the electron beam pre-control shell is rapidly assessed through four parameters including the tensile strength sigma 0 of a shell base material, the defect length l, the shell thickness L and the included angle theta between the incident direction of an electron beam and the normal direction of the surface of the shell. The method can be used for quantitatively and rapidly evaluating the tensile strength of the electron beam pre-control shell, is high in accuracy, simple and practical, has important theoretical and economic values, can be used for guiding electron beam process design, and can be used for rapidly evaluating the tensile strength of the electron beam pre-control shell. The method is used for inspecting the electron beam pre-control shell and guiding the material structure design of the electron beam pre-control shell, and is worthy of large-scale popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of material property evaluation, and relates to a rapid evaluation method for the tensile strength of an electron beam pre-controlled shell. Background Art

[0002] The electron beam projectile pre-control technology is a new type of pre-controlled fragment forming technology that does not require cutting the projectile like mechanical grooving. It has the advantages of improving the fragment killing power of the projectile and ensuring the structural strength, and has extremely broad application prospects in the warhead of high-bore suppression guided projectiles.

[0003] After electron beam pre-control, a modified area grid will be formed on the projectile body, and holes will be reserved at the bottom of the modified area, resulting in a decrease in the overall strength, and there are certain potential safety hazards in the launch safety of high-bore suppression guided projectiles. To eliminate potential safety hazards and ensure launch safety, it is necessary to ensure that the designed strength of the pre-controlled projectile body is higher than the service strength.

[0004] However, at present, after electron beam pre-control, complex microstructure transformations occur in the projectile body, the microstructure distribution is non-linear and non-uniform, and the transformation law of mechanical properties is not clear. A large number of experiments are required to test the strength of the pre-controlled shell under each electron beam process to ensure that the designed strength of the pre-controlled projectile body is higher than the service strength, but there are problems of low R & D efficiency and high R & D costs.

[0005] Therefore, there is an urgent need to develop a rapid evaluation method for the tensile strength of an electron beam pre-controlled shell to accelerate the R & D efficiency of the electron beam pre-controlled shell and reduce the R & D cost. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a rapid evaluation method for the tensile strength of an electron beam pre-controlled shell, which can quantitatively and rapidly evaluate the tensile strength of the electron beam pre-controlled shell, and has the characteristics of being simple, practical, highly accurate, and low cost.

[0007] The technical solution adopted by the present invention to solve the above technical problem is as follows: A rapid evaluation method for the tensile strength of an electron beam pre-controlled shell, characterized in that: the tensile strength σ1 of the electron beam pre-controlled shell is rapidly evaluated by four parameters, namely, the tensile strength σ0 of the shell matrix material, the defect length l, the shell thickness L, and the angle θ between the electron beam incident direction and the shell surface normal direction. The tensile strength σ1 of the electron beam pre-controlled shell is:

[0008]

[0009] As an improvement, the defect length l refers to the average value of the defect lengths after actual electron beam processing, and the defect length l can be obtained by calculating the arithmetic mean of multiple defect lengths in the non-destructive testing CT image of the shell.

[0010] Furthermore, the defect is a hole defect formed due to the failure to timely backfill the shell material during electron beam modification. The hole defect shows an irregular long strip shape with an aspect ratio greater than 1 in the radial cross-section of the shell. The hole defect is located inside the shell, and the surrounding of the hole defect is the martensite modification zone structure, and the surrounding of the martensite modification zone structure is the tempered troostite structure of the steel matrix.

[0011] Preferably, the shell matrix material is 40CrMnSiB material.

[0012] Furthermore, the tensile strength σ0 of the shell matrix material is the self-strength of the shell before electron beam pre-control, which is generally used as the technical input document for the electron beam pre-control process and has been obtained through previous tensile experiments.

[0013] Finally, a grid-shaped modification zone is formed on the surface of the electron beam pre-controlled shell after electron beam pre-control. After the electron beam pre-controlled shell is processed by the defect length l, the error between the rapid evaluation result of the tensile strength of the electron beam pre-controlled shell and the actual detected average value is within 5%.

[0014] Compared with the prior art, the advantages of the present invention are as follows: the tensile strength σ1 of the electron beam pre-controlled shell is rapidly evaluated through four parameters, namely, the tensile strength σ0 of the shell matrix material, the defect length l, the shell thickness L, and the angle θ between the electron beam incident direction and the shell surface normal direction, so that the error between the rapid evaluation result and the actual detected average value is within 5%. The evaluation method of the present invention can quantitatively and rapidly evaluate the tensile strength of the electron beam pre-controlled shell, and at the same time has high accuracy, is simple and practical, can be used to guide the electron beam process design, for the inspection of the electron beam pre-controlled shell, and for guiding the material structure design of the electron beam pre-controlled shell, and has important theoretical and economic value and is worthy of large-scale popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the electron microscope image of the material structure after electron beam pre-control provided by the present invention;

[0016] Figure 2 is the CT diagram of the electron beam pre-controlled metal shells 1#, 2#, and 3#;

[0017] Figure 3 is the schematic diagram of the electron beam pre-controlled metal shell. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

[0019] As Figures 1 - 3As shown in the figure, a rapid evaluation method for the tensile strength of an electron beam pre-controlled shell. The tensile strength σ1 of the electron beam pre-controlled shell is rapidly evaluated by four parameters: the tensile strength σ0 of the shell matrix material, the defect length l, the shell thickness L, and the angle θ between the electron beam incident direction and the shell surface normal. The tensile strength σ1 of the electron beam pre-controlled shell is as follows:

[0020]

[0021] The defect length l refers to the average value of the defect lengths after the actual electron beam processing. The defect is a hole defect formed due to the failure of the shell material to be backfilled in time during electron beam modification. The hole defect shows an irregular long strip shape with an aspect ratio greater than 1 in the radial section of the shell. The hole defect is located inside the shell, and the martensite modification zone tissue surrounds the hole defect, and the tempered troostite tissue of the steel matrix surrounds the martensite modification zone tissue. The defect length l can be obtained by calculating the arithmetic mean of multiple defect lengths in the non-destructive testing CT images of the shell.

[0022] The shell matrix material is 40CrMnSiB material, and a grid-shaped modification zone is formed on the surface of the electron beam pre-controlled shell after electron beam pre-control.

[0023] The tensile strength σ0 of the shell matrix material is the self-strength of the shell before electron beam pre-control, which is generally used as the technical input document for the electron beam pre-control process and has been obtained through previous tensile experiments.

[0024] After the electron beam pre-controlled shell is processed with the defect length l, the error between the rapid evaluation result of the tensile strength of the electron beam pre-controlled shell and the actual detection average value is within 5%.

[0025] As shown in Table 1, through four parameters: the tensile strength σ0 (1423 MPa) of the shell matrix material, the average defect length l, the shell thickness L (7 mm), and the angle θ (30°) between the electron beam incident direction and the shell surface normal, according to The strengths of electron beam pre-controlled shells 1-3# were rapidly evaluated. The quantitative evaluation results were 1347 MPa, 1310 MPa, and 1240 MPa respectively. At the same time, wire cutting samples were taken from the electron beam pre-controlled shells and tensile experiments were carried out on a universal testing machine. The average values of the tensile strength experiments were 1358 MPa, 1316 MPa, and 1235 MPa respectively. The results show that the error between the rapid evaluation result and the actual detection average value is within 5%.

[0026] Table 1 Comparison table of tensile strength experimental values and rapid evaluation values under different defect design lengths

[0027]

[0028] As can be seen from the data in Table 1, the error between the rapid evaluation result of the tensile strength of the electron beam pre-controlled shell and the actual detected average value is within 5%, indicating a relatively high accuracy.

[0029] The rapid evaluation method of the present invention can be used to guide the electron beam process design, for the inspection of the electron beam pre-controlled shell, and for guiding the material structure design of the electron beam pre-controlled shell.

[0030] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A rapid evaluation method for the tensile strength of an electron beam pre-control housing, characterized in that: The tensile strength σ1 of the electron beam pre-controlled shell is rapidly evaluated by four parameters: the tensile strength σ0 of the shell matrix material, the defect length l, the shell thickness L, and the angle θ between the electron beam incident direction and the normal direction of the shell surface. The tensile strength σ1 of the electron beam pre-controlled shell is as follows:

2. The rapid evaluation method according to claim 1, wherein: The defect length l refers to the average value of the defect lengths after actual electron beam processing. The defect length l can be obtained by calculating the arithmetic mean of multiple defect lengths in the non-destructive testing CT image of the shell.

3. The rapid evaluation method according to claim 2, characterized in that: The defect is a hole defect formed due to the failure of timely backfilling of the shell material during electron beam modification. The hole defect shows an irregular long strip shape with an aspect ratio greater than 1 in the radial cross-section of the shell. The hole defect is located inside the shell, and the martensite modification zone tissue surrounds the hole defect, and the tempered troostite tissue of the steel matrix surrounds the martensite modification zone tissue.

4. The rapid evaluation method according to claim 1, characterized in that: The shell matrix material is 40CrMnSiB material.

5. The rapid evaluation method according to claim 1, wherein: The tensile strength σ0 of the shell matrix material is the self-strength of the shell before electron beam pre-control, which is generally used as the technical input document for the electron beam pre-control process and has been obtained through previous tensile experiments.

6. The rapid evaluation method according to claim 1, characterized in that: The surface of the electron beam pre-controlled shell forms a grid-like modification zone after electron beam pre-control. After processing the electron beam pre-controlled shell with the defect length l, the error between the rapid evaluation result of the tensile strength of the electron beam pre-controlled shell and the actual detection average value is within 5%.

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