Grinding method of high-strength steel

Abstract

The invention provides a high-strength steel grinding method, and relates to the technical field of metal material machining. The grinding method comprises the following steps that a high-strength steel workpiece is provided, and the high-strength steel workpiece comprises a clamping area and a machining area; first grinding is conducted on the machining area in the radial direction of the high-strength steel workpiece, and a concave part is formed in the high-strength steel workpiece; and second grinding is conducted on the machining area in the radial direction of the high-strength steel workpiece, meanwhile third grinding is conducted on the machining area in the axial direction of the high-strength steel workpiece, and a chamfer is formed on the edge of the machining area. The depth of the grinding crack is adjusted by adjusting the cutting process and the chamfer size, the relation between the grinding process and the chamfer size and grinding crack failure is established, and therefore the machining process is fed back, and the machining quality of parts in practical application is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing, and in particular to a grinding method for high-strength steel. Background Art

[0002] Fatigue-induced metal failure is one of the primary modes of mechanical component failure. Fatigue fracture is driven by numerous factors, typically related to the component's shape, size, surface condition, operating conditions, external environment, and microstructure. As the service life of various power plants increases, surface cracks generated during the forming process are increasingly responsible for fatigue-induced fractures in mechanical components. Among these, grinding-induced cracks, primarily found in rotating components (shafts and fasteners), are attracting increasing attention. Advances in detection technology have revealed that grinding-induced cracks typically range from 10 to 500 μm in size. This small size has led to limited understanding of the cross-sectional morphology of grinding cracks. This inadequate understanding of the microscopic morphology of the crack initiation zone within these fractures can reduce the accuracy of failure analysis and risk preventing fundamental component repair. Therefore, research into the causes of grinding cracks and their resulting fatigue behavior can help improve targeted repair strategies for sensitive mechanical components and is crucial for enhancing the safety and economic efficiency of power plants. Summary of the Invention

[0003] The present invention provides a high-strength steel grinding method, establishes the relationship between grinding cracks and processing technology, and improves the processing quality of components in practical applications.

[0004] The present invention provides a high-strength steel grinding method, which comprises the following steps:

[0005] Providing a high-strength steel workpiece, wherein the high-strength steel workpiece includes a clamping area and a processing area;

[0006] performing a first grinding on the processing area along the radial direction of the high-strength steel workpiece to form a recessed portion on the high-strength steel workpiece;

[0007] The processing area is subjected to a second grinding along the radial direction of the high-strength steel workpiece, and the processing area is subjected to a third grinding along the axial direction of the high-strength steel workpiece to form a chamfer at the edge of the processing area.

[0008] In one embodiment of the present invention, the diameter of the high-strength steel workpiece is 12-20 mm.

[0009] In one embodiment of the present invention, the feed speed of the first grinding is 0.8-1.2 mm / min.

[0010] In one embodiment of the present invention, the feed speed of the second grinding is 0.8-1.2 mm / min.

[0011] In one embodiment of the present invention, the diameter of the recess is 9.8-10.2 mm.

[0012] In one embodiment of the present invention, the indentation of the chamfer is 0.4-0.6 mm, and the radius of the chamfer is 0.4-0.6 mm.

[0013] In one embodiment of the present invention, after the edge of the processing area is chamfered, the grinding method further includes performing a fourth grinding on the clamping area.

[0014] In one embodiment of the present invention, the feed speed of the fourth grinding is 8-12 mm / min.

[0015] In one embodiment of the present invention, when the edge of the processing area is chamfered, the instantaneous grinding heat of the chamfered area is 800°C.

[0016] In one embodiment of the present invention, before performing the first grinding on the processing area along the radial direction of the high-strength steel workpiece, the grinding method further includes: determining a grinding speed of a lathe.

[0017] The beneficial effects of the present invention are as follows: The present invention proposes a method for grinding high-strength steel. First, a first grinding operation is performed on the workpiece's machining area along the workpiece's radial direction, forming a recess. A second grinding operation is then performed along the workpiece's radial direction. Simultaneously, a third grinding operation is performed along the workpiece's axial direction, forming a chamfer at the edge of the machining area. The present invention adjusts the depth of grinding cracks by adjusting the cutting process and chamfer size. This establishes a relationship between the grinding process, chamfer size, and grinding crack failure, thereby providing feedback on the machining process and improving the machining quality of components in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be derived from these drawings without inventive effort.

[0019] In the attached figure:

[0020] Figure 1 A flow chart of high-strength steel grinding provided by one embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a high-strength steel workpiece provided in one embodiment of the present invention;

[0022] Figure 3 A schematic diagram of a high-strength steel workpiece after the first grinding provided in one embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a high-strength steel workpiece chamfered after grinding provided in one embodiment of the present invention;

[0024] Figure 5 The macroscopic morphology of a high-strength steel workpiece after grinding provided in one embodiment of the present invention;

[0025] Figure 6 This is the microscopic morphology of a high-strength steel workpiece after grinding provided in one embodiment of the present invention;

[0026] Figure 7 This is another microscopic morphology of a high-strength steel workpiece after grinding provided in one embodiment of the present invention.

[0027] The reference numerals are as follows:

[0028] 100. High-strength steel workpiece; 110. Processing area; 111. Recess; 112. Chamfer; 120. Clamping area. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments. The details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. The following embodiments and features therein may be combined with one another without conflict.

[0030] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The drawings only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0031] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0032] Failure analysis is a discipline that studies when a product fails to reliably perform its intended function. By analyzing each stage of a product's development and design, incoming material inspection, processing and assembly, testing and screening, and usage, failure modes are identified, failure mechanisms analyzed, and causes of failure clarified. Ultimately, preventative measures are developed to reduce or avoid the recurrence of failure. Failure modes serve as a blueprint guiding the entire failure analysis process and play an indispensable role in the entire analysis process. With the continuous development of failure analysis of metal materials, our understanding of common failure modes such as overload, corrosion, fatigue, wear, and hydrogen embrittlement has continued to deepen. However, with advances in manufacturing processes and testing technologies, more and more new failure modes have been discovered and proposed, and a deeper understanding of these new failure modes is urgently needed. Currently, domestic and foreign scholars have conducted in-depth research on mechanical components in various operating environments, microstructural states, vibration conditions, and fit types, but have paid less attention to surface cracks introduced during the molding process of mechanical components.

[0033] Grinding cracks are thermal cracks generated during the grinding (turning) process. Grinding (turning) refers to the use of abrasives (tools) to cut the surface of a material and is generally divided into the sliding, scoring, and cutting stages. During the sliding stage, the workpiece undergoes only elastic deformation, which intensifies as the friction generated during the sliding stage increases. The metal surface is heated to a critical point by friction, and the normal force applied to the workpiece exceeds the material's yield strength, which decreases with increasing temperature. The plastically deformed metal is pushed to the sides and front of the abrasive, forming a scoring zone, and grinding enters the scoring stage. When the cutting edge enters the plastic zone, stress increases until the maximum shear energy of the workpiece material is reached, leaving a furrow on the grinding surface aligned with the grinding direction. This is the cutting stage. When the grinding heat and temperature are high, structural changes will occur on the material surface, accompanied by harmful residual tensile stresses. Severe overheating can cause grinding cracks.

[0034] With the continuous improvement of detection technology, it has been found in practice that the cracks generated by grinding processing are usually 10 to 500 μm. Because their size is too small, the understanding of the cross-sectional morphology of grinding cracks is not high. In the face of insufficient understanding of the microscopic morphology of the crack initiation source area of ​​special fractures, there is a risk of reducing the accuracy of failure analysis and failing to fundamentally treat related components. Therefore, the study of the causes of grinding cracks and the fatigue behavior caused by them will help to improve the pertinence of the treatment strategy for sensitive mechanical components, which is of great significance to improving the safety and economy of power plants. Therefore, this application provides a method for grinding high-strength steel, establishes the relationship between grinding cracks and processing technology, and improves the processing quality of components in practical applications.

[0035] See Figure 1 , Figure 1 A flow chart of high-strength steel grinding provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the grinding method includes the following steps:

[0036] S1. Provide a high-strength steel workpiece 100, wherein the high-strength steel workpiece 100 includes a clamping area 120 and a processing area 110;

[0037] S2, performing a first grinding on the processing area 110 along the radial direction of the high-strength steel workpiece 100 to form a recessed portion 111 on the high-strength steel workpiece 100;

[0038] S3 , performing a second grinding on the processing area 110 along the radial direction of the high-strength steel workpiece 100 , and simultaneously performing a third grinding on the processing area 110 along the axial direction of the high-strength steel workpiece 100 to form a chamfer 112 at the edge of the processing area 110 .

[0039] In step S1, Figure 2 As shown, the high-strength steel workpiece 100 is in the shape of a round rod, and the high-strength steel workpiece 100 includes a processing area 110 and a clamping area 120. Exemplarily, the diameter of the high-strength steel workpiece 100 is 12 to 20 mm, for example, any value within the range of 12 to 20 mm, such as 12 mm, 15 mm, or 20 mm. The length of the high-strength steel workpiece 100 can be adjusted according to actual needs. Exemplarily, the length of the high-strength steel workpiece 100 is 120 mm. The middle area of ​​the high-strength steel workpiece 100 is selected as the processing area 110 of the high-strength steel workpiece 100, and the remaining area is selected as the clamping area 120 of the high-strength steel workpiece 100 to fix and clamp the high-strength steel workpiece 100 during processing.

[0040] Before grinding a high-strength steel workpiece, determine the appropriate lathe grinding speed. Specifically, conduct a limit turning test on the intended high-strength steel material. Gradually increase the lathe grinding speed until stripes parallel to the grinding direction appear on the material surface. This determines the appropriate grinding speed. The grinding speed should not be too fast, and lathes should use worn tools whenever possible.

[0041] In step S2, in some embodiments, the shape of the high-strength steel workpiece 100 after the first grinding is as follows: Figure 3 As shown, for example, the feed rate of the first grinding is 0.8-1.2 mm / min, and the diameter of the recess 111 is 9.8-10.2 mm.

[0042] In step S3, two cutting heads are provided on the processing device, which can process the radial and axial directions of the processing area 110 at the same time. For example, the feed speed of the second grinding is 0.8-1.2 mm / min, and the feed speed of the third grinding is 0.8-1.2 mm / min. When the feed reaches 1 / 3 of the arc, it cuts along the tangent line. The schematic diagram of the chamfer 112 is shown in FIG. Figure 4 As shown, the concave of the chamfer 112 is 0.4 to 0.6 mm, and the radius of the chamfer 112 is 0.4 to 0.6 mm. When the chamfer 112 is formed on the edge of the processing area 110, the instantaneous grinding heat in the chamfer 112 area is 800°C.

[0043] In some embodiments of the present application, after the edge of the processing area 110 is chamfered 112, the grinding method further includes performing a fourth grinding on the clamping area 120. The feed rate of the fourth grinding is 8 to 12 mm / min. For example, the clamping area 120 of the high-strength steel workpiece 100 is ground to a diameter of 12 mm.

[0044] The technical solutions of the present invention are described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available.

[0045] Example 1

[0046] The high-strength steel grinding method of this embodiment includes the following steps: providing a high-strength steel workpiece, the high-strength steel workpiece including a clamping area and a processing area, performing a first grinding on the processing area at a speed of 0.8 mm / min along the radial direction of the high-strength steel workpiece to form a recess with a diameter of 10 mm on the high-strength steel workpiece, performing a second grinding on the processing area at a speed of 0.8 mm / min along the radial direction of the high-strength steel workpiece, and simultaneously performing a third grinding on the processing area at a speed of 0.8 mm / min along the axial direction of the high-strength steel workpiece to form a chamfer at the edge of the processing area, and performing a fourth grinding on the clamping area at a speed of 10 mm / min to a diameter of 12 mm.

[0047] In this embodiment, the diameter of the high-strength steel workpiece is 12 mm, the inner concave of the chamfer is 0.5 mm, and the radius of the chamfer is 0.5 mm.

[0048] Example 2

[0049] The high-strength steel grinding method of this embodiment includes the following steps: providing a high-strength steel workpiece, the high-strength steel workpiece including a clamping area and a processing area; performing a first grinding operation on the processing area at a speed of 1 mm / min along the radial direction of the high-strength steel workpiece to form a recess with a diameter of 10 mm on the high-strength steel workpiece; performing a second grinding operation on the processing area at a speed of 1 mm / min along the radial direction of the high-strength steel workpiece; and performing a third grinding operation on the processing area at a speed of 1 mm / min along the axial direction of the high-strength steel workpiece to form a chamfer at the edge of the processing area. The clamping area is then subjected to a fourth grinding operation at a speed of 8 mm / min to a diameter of 12 mm.

[0050] In this embodiment, the diameter of the high-strength steel workpiece is 16 mm, the inner concave of the chamfer is 0.4 mm, and the radius of the chamfer is 0.4 mm.

[0051] Example 3

[0052] The high-strength steel grinding method of this embodiment includes the following steps: providing a high-strength steel workpiece, the high-strength steel workpiece including a clamping area and a processing area; performing a first grinding operation on the processing area at a speed of 1.2 mm / min along the radial direction of the high-strength steel workpiece to form a recess with a diameter of 10 mm on the high-strength steel workpiece; performing a second grinding operation on the processing area at a speed of 1.2 mm / min along the radial direction of the high-strength steel workpiece; and performing a third grinding operation on the processing area at a speed of 1.2 mm / min along the axial direction of the high-strength steel workpiece to form a chamfer at the edge of the processing area. The clamping area is then subjected to a fourth grinding operation at a speed of 12 mm / min to a diameter of 12 mm.

[0053] In this embodiment, the diameter of the high-strength steel workpiece is 20 mm, the inner concave of the chamfer is 0.6 mm, and the radius of the chamfer is 0.6 mm.

[0054] In Examples 1 to 3, when the edge of the processing area is chamfered, the instantaneous grinding heat of the chamfered area is about 800°C.

[0055] Obtain the high-strength steel workpiece after grinding and perform crack morphology detection. Specifically, open the fracture by means of a rotational fatigue test. Rotational fatigue test is a test method used in mechanical processing to evaluate the fatigue performance of materials or parts under rotating alternating loads. The specimen is mounted on a rotary testing machine, subjected to rotational motion and subjected to alternating stresses such as bending and torsion to simulate the fatigue process under actual working conditions. By observing the crack propagation, deformation and final fracture of the specimen after multiple stress cycles under certain speed, load and environmental conditions, the fatigue strength, fatigue life and other performance indicators of the material or part are determined, providing an important basis for mechanical design, material selection and quality control. Furthermore, a scanning electron microscope and an optical microscope are used to observe the surface morphology and cross-sectional morphology of the fracture to obtain the macroscopic and microscopic features of the components caused by abnormal processing technology.

[0056] The crack depths in Examples 1-3 were 60 μm, 80 μm, and 110 μm, respectively. These results indicate that the larger the diameter of the high-strength steel workpiece, the deeper the grinding cracks. When machining high-strength steel components, faster feed rates are more likely to cause defects such as grinding cracks. Slower turning feed rates produce better surface finishes, emphasizing the importance of carefully controlling the relationship between feed rate and turning speed.

[0057] The high-strength steel grinding parts obtained in Example 1 were selected for macromorphology and micromorphology characterization. The characterization results are as follows: Figures 5 to 7 shown. Figure 5 This is the macroscopic morphology of high-strength steel after grinding. Figure 6 and Figure 7 The microstructure of high-strength steel after grinding is shown in Figure 2. Figure 5 It can be seen from the figure that the chamfer after grinding has the appearance of vibration marks. Figure 6and Figure 7 It can be seen from the figure that the surface of the matrix near the crack has the characteristics of organizational stratification. After the crack is opened, the fracture morphology is seen to be intergranular + dimple characteristics, and plastic radial edges can be seen in some intergranular areas.

[0058] The beneficial effects of the present invention are as follows: The present invention proposes a method for grinding high-strength steel. First, a first grinding operation is performed on the workpiece's machining area along the workpiece's radial direction, forming a recess. A second grinding operation is then performed along the workpiece's radial direction. Simultaneously, a third grinding operation is performed along the workpiece's axial direction, forming a chamfer at the edge of the machining area. The present invention adjusts the depth of grinding cracks by adjusting the cutting process and chamfer size. This establishes a relationship between the grinding process, chamfer size, and grinding crack failure, thereby providing feedback on the machining process and improving the machining quality of components in practical applications.

[0059] This high-strength steel grinding method utilizes non-standard cutting processes and chamfer dimensions, allowing for the artificial introduction of grinding cracks of varying depths. This allows for the establishment of a relationship between the grinding process and chamfer dimensions and grinding crack failure, thereby establishing a system for evaluating grinding crack failure. Furthermore, by generating defects through abnormal contact, feedback is provided to the engineering process, improving the machining quality of components in practical applications.

[0060] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for grinding high-strength steel, characterized in that: The steps include: Providing a high-strength steel workpiece, wherein the high-strength steel workpiece includes a clamping area and a processing area; performing a first grinding on the processing area along the radial direction of the high-strength steel workpiece to form a recessed portion on the high-strength steel workpiece; The processing area is subjected to a second grinding along the radial direction of the high-strength steel workpiece, and the processing area is subjected to a third grinding along the axial direction of the high-strength steel workpiece to form a chamfer at the edge of the processing area.

2. The grinding method according to claim 1, wherein: The diameter of the high-strength steel workpiece is 12-20 mm.

3. The grinding method according to claim 1, wherein: The feed speed of the first grinding is 0.8-1.2 mm / min.

4. The grinding method according to claim 1, wherein: The feed speed of the second grinding is 0.8-1.2 mm / min, and the feed speed of the third grinding is 0.8-1.2 mm / min.

5. The grinding method according to claim 1, wherein: The diameter of the recess is 9.8 to 10.2 mm.

6. The grinding method according to claim 1, wherein: The indentation of the chamfer is 0.4 to 0.6 mm, and the radius of the chamfer is 0.4 to 0.6 mm.

7. The grinding method according to claim 1, wherein: After the edge of the processing area is chamfered, the grinding method further includes performing a fourth grinding on the clamping area.

8. The grinding method according to claim 7, wherein: The feed speed of the fourth grinding is 8-12 mm / min.

9. The grinding method according to claim 1, wherein: When the edge of the processing area is chamfered, the instantaneous grinding heat of the chamfered area is 800°C.

10. The grinding method according to claim 1, wherein Before performing the first grinding on the processing area along the radial direction of the high-strength steel workpiece, the grinding method further includes: determining a grinding speed of a lathe.

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