Local low-hardness control device for carburizing and quenching part
By designing the casing structure on the carburizing and quenching parts, a gap can be passed through by the active carburizing and quenching parts is achieved, and the problem of uneven hardness during carburizing and quenching is solved, which reduces production costs and avoids the risk of cracking.
Patent Information
- Application Number
- CN202422023214.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-20
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-08-20
AI Technical Summary
During carburizing and quenching, it is difficult to control the hardness in the local area of the product, so that it is greater than the hardness of the core but does not increase the brittleness.
A local low hardness control device including a sleeve is designed. The sleeve is arranged outside the carburizing control section, and the inner hole is a blind hole structure with an upper opening, with a radial size greater than the carburizing control section, forming an axial gap through which the active carburizing medium can pass, realizing local hardness control.
Through the design of the casing structure, the local hardness of the carburized quenched parts is controlled so that the surface hardness after quenching is lower than other positions, but greater than the hardness of the core, which solves the problem of uneven hardness, and avoids the risk of cracking and additional costs of induction of local high-temperature tempering.
Smart Images
Figure CN222948440U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of heat treatment equipment and relates to a local low hardness control device for a carburized and quenched part. Background Art
[0002] Carburizing and quenching is a commonly used process to increase the hardness of products. However, carburizing and quenching will increase brittleness while increasing hardness. Some parts of the product that do not require high hardness still want to maintain a certain toughness. In actual production, anti-seepage tooling will be used to protect these places.
[0003] For some special products, the local surface hardness needs to be greater than the core hardness during carburizing and quenching, but it cannot be too high to increase the brittleness. At this time, simple surface anti-seepage will make the surface hardness almost equal to the core hardness, which cannot meet the technical requirements. The usually feasible method is to use induction local high-temperature tempering on the surface after carburizing and quenching, but induction local high-temperature tempering will first have the risk of cracking, and secondly will increase the production cost. Therefore, for these special products, it is necessary to develop a local low hardness control device to control its hardness. Utility Model Content
[0004] The utility model aims at the deficiencies of the prior art and provides a local low hardness control device for a carburized and quenched part, which can control the local hardness of the carburized and quenched part.
[0005] In order to solve the above technical problems, the purpose of the utility model is achieved through the following technical solutions:
[0006] A device for controlling local low hardness of a carburized and quenched part comprises a sleeve sleeved outside a carburizing control section of the carburized and quenched part, wherein the inner hole of the sleeve is a blind hole structure with an upper opening, and its radial dimension is larger than the radial dimension of the carburizing control section, and an axial gap through which an active carburizing medium can pass is formed between the sleeve and the carburizing control section, the surface of the carburized and quenched part within the sleeve forms a low hardness controlled carburized surface, and the surface of the carburized and quenched part outside the sleeve forms a high hardness fully carburized surface.
[0007] In the above-mentioned device for controlling local low hardness of carburized and quenched parts, the difference between the radial dimension of the inner hole of the sleeve and the radial dimension of the carburizing control section depends on the hardness required by the carburizing control section. The lower the required hardness, the smaller the difference in radial dimension, and vice versa. Generally speaking, the difference between the radial dimension of the inner hole of the sleeve and the radial dimension of the carburizing control section is 1-3mm.
[0008] In the above-mentioned local low hardness control device for carburized and quenched parts, the carburizing control section is cylindrical or elliptical, and the inner hole shape of the sleeve is the same as that of the carburizing control section; when the carburizing control section is installed into the inner hole of the sleeve, there is no centering requirement.
[0009] In the above-mentioned local low hardness control device for carburizing and quenching parts, a step structure is formed between the carburizing control section and the complete carburizing section of the carburizing and quenching part, and a radial gap through which active carburizing medium can pass is formed between the upper end surface of the sleeve and the step structure.
[0010] In the above-mentioned device for controlling local low hardness of carburized and quenched parts, the sleeve is fixedly connected to the material tray, a coaxial external threaded joint is provided at the bottom of the sleeve, a mounting hole is provided on the material tray, and the external threaded joint passes through the mounting hole from top to bottom and is screwed and fixed with a locking nut.
[0011] In the above-mentioned device for controlling local low hardness of carburized and quenched parts, the material tray is a mesh plate structure, including a plurality of horizontal bars and vertical bars arranged at intervals, and the mounting holes are arranged at the intersections of the horizontal bars and the vertical bars.
[0012] In the above-mentioned device for controlling local low hardness of carburized and quenched parts, the material tray is sleeved on the column, spacers are arranged between adjacent material trays, the spacers are sleeved on the column and each column is sleeved with the same spacer.
[0013] In the above-mentioned device for controlling local low hardness of a carburized and quenched part, the carburized and quenched part is a crankshaft, and the carburized control section is the front end shaft of the crankshaft.
[0014] Compared with the prior art, the utility model has the following beneficial effects:
[0015] 1. The utility model provides a local low hardness control device for carburized and quenched parts. A casing with a larger inner diameter is used to protect the carburized control section of the carburized and quenched parts. Since there is a gap between the casing and the carburized control section through which active carburizing medium can pass, a small amount of carbon will be added to the surface during carburizing. Due to the semi-shielding and protective effects, the carbon content at this location is significantly lower than that at other surface locations. Therefore, after quenching, its hardness is lower than the surface hardness at other locations. Due to the effect of partially diffused carbon, the surface hardness at this location will also be greater than the hardness of the core.
[0016] 2. The casing structure of the utility model can also well carry the carburized quenched parts, which is convenient for quenching. Since the inner diameter of the casing is larger and there is no need to center the carburized quenched parts with the casing, the carburized quenched parts can be easily inserted into the casing. Even if the carburized quenched parts are eccentrically placed on the casing or even contact the inner hole of the casing, since the contact surface is line contact, it does not have a great impact on its quenching area, and can still meet the technical requirements of local low hardness. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a three-dimensional diagram of the utility model;
[0018] Figure 2 It is the matching diagram of a single carburized and quenched part and a sleeve;
[0019] Figure 3 yes Figure 2 A cross-sectional view of
[0020] Figure numerals: 1. Carburized and quenched parts; 2. Carburized control section; 3. Sleeve; 4. Axial clearance; 5. Low hardness controlled carburized surface; 6. High hardness fully carburized surface; 7. Fully carburized section; 8. Step structure; 9. Radial clearance; 10. Feed tray; 11. Externally threaded joint; 12. Locking nut; 13. Horizontal bar; 14. Vertical bar; 15. Column; 16. Spacer. DETAILED DESCRIPTION
[0021] The present invention will be further described below with reference to the accompanying drawings. Figure 1-3 :
[0022] A device for controlling local low hardness of a carburized and quenched part, comprising a sleeve 3 sleeved outside a carburized and quenched part 1 carburized and quenched control section 2, wherein the inner hole of the sleeve 3 is a blind hole structure with an upper opening, and its radial dimension is larger than the radial dimension of the carburized and quenched section 2, and an axial gap 4 through which an active carburizing medium can pass is formed between the sleeve 3 and the carburized and quenched part 2, the surface of the carburized and quenched part 1 inside the sleeve 3 forms a low hardness controlled carburized surface 5, and the surface of the carburized and quenched part 1 outside the sleeve 3 forms a high hardness fully carburized surface 6.
[0023] The hardness control principle of this embodiment is: Figure 3 During carburizing and quenching, a part of the active carburizing medium will enter the axial gap 4 between the sleeve 3 and the carburizing control section 2, and the surface of the carburized and quenched part 1 inside the sleeve 3 will be carburized to a limited extent, so that its surface hardness is greater than the core hardness of the carburized and quenched part 1. However, due to the semi-shielding and protective effect of the sleeve 3, this part cannot be completely carburized, so its surface hardness is lower than the surface hardness of the carburized and quenched part 1 outside the sleeve 3.
[0024] It should be noted that, in the usual anti-seepage tooling, in order to facilitate assembly, a clearance is provided between the tooling and the workpiece, but the clearance is usually less than 0.2 mm, and a clearance of this size is not sufficient to allow the active carburizing medium to pass through, thereby achieving the purpose of anti-seepage; in the present embodiment, a larger axial clearance 4 is adopted to allow the active carburizing medium to pass through smoothly, and the standard for determining the size of the axial clearance 4 is: the difference between the radial dimension of the inner hole of the sleeve 3 and the radial dimension of the carburizing control section 2 depends on the hardness required by the carburizing control section 2, the lower the required hardness, the smaller the difference in radial dimension, and vice versa, the larger the difference in radial dimension; generally speaking, the difference between the radial dimension of the inner hole of the sleeve 3 and the radial dimension of the carburizing control section 2 is 1-3 mm.
[0025] This embodiment is particularly suitable for hardness control of arc surfaces: the carburizing control section 2 is cylindrical or elliptical, and the inner hole shape of the sleeve 3 is the same as that of the carburizing control section 2; when the carburizing control section 2 is installed into the inner hole of the sleeve 3, there is no centering requirement, and during assembly, the carburizing control section 2 can be directly inserted into the sleeve 3.
[0026] Compare with Figure 2 For some special carburized and quenched parts 1, a step structure 8 is formed between the carburized control section 2 and the fully carburized section 7 of the carburized and quenched part 1. In order to allow the active carburizing medium to smoothly enter the axial gap 4, the sleeve 3 cannot contact the step structure 8; that is, referring to the attached Figure 3 A radial gap 9 is formed between the upper end surface of the sleeve 3 and the stepped structure 8, through which the active carburizing medium can pass.
[0027] In order to process multiple carburized and quenched parts 1 at the same time, refer to the attached Figure 1 , this embodiment further provides a material tray 10:
[0028] The sleeve 3 is fixedly connected to the material tray 10 , a coaxial external threaded joint 11 is provided at the bottom of the sleeve 3 , a mounting hole is provided on the material tray 10 , and the external threaded joint 11 passes through the mounting hole from top to bottom and is screwed and fixed with a locking nut 12 .
[0029] Furthermore, the material tray 10 is a mesh plate structure, including a plurality of horizontal bars 13 and vertical bars 14 arranged at intervals, and the mounting holes are arranged at the intersections of the horizontal bars 13 and the vertical bars 14 .
[0030] Furthermore, the material trays 10 are sleeved on the columns 15 , and spacers 16 are provided between adjacent material trays 10 . The spacers 16 are sleeved on the columns 15 , and the same spacers 16 are sleeved on each column 15 .
[0031] In this embodiment, the carburized and quenched part 1 is a crankshaft, and the carburized control section 2 is the front end shaft of the crankshaft. After the crankshaft is carburized and quenched, the surface hardness of the front end shaft is less than the surface hardness of other parts of the crankshaft, but greater than the hardness of the core of the crankshaft.
[0032] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A device for controlling local low hardness of carburized and quenched parts, characterized in that: The invention comprises a sleeve (3) sleeved outside a carburizing control section (2) of a carburizing and quenching part (1); the inner hole of the sleeve (3) is a blind hole structure with an upper opening, and its radial dimension is larger than the radial dimension of the carburizing control section (2); an axial gap (4) through which an active carburizing medium can pass is formed between the sleeve (3) and the carburizing control section (2); the surface of the carburizing and quenching part (1) inside the sleeve (3) forms a low-hardness controlled carburizing surface (5); and the surface of the carburizing and quenching part (1) outside the sleeve (3) forms a high-hardness fully carburized surface (6).
2. A device for controlling local low hardness of carburized and quenched parts according to claim 1, characterized in that: The difference between the radial dimension of the inner hole of the sleeve (3) and the radial dimension of the carburizing control section (2) is 1-3 mm.
3. A device for controlling local low hardness of carburized and quenched parts according to claim 1, characterized in that: The carburizing control section (2) is cylindrical or elliptical, and the inner hole shape of the sleeve (3) is the same as that of the carburizing control section (2).
4. A device for controlling local low hardness of carburized and quenched parts according to claim 1, characterized in that: A step structure (8) is formed between the carburizing control section (2) and the fully carburized section (7) of the carburized and quenched part (1), and a radial gap (9) through which an active carburizing medium can pass is formed between the upper end surface of the sleeve (3) and the step structure (8).
5. The device for controlling local low hardness of carburized and quenched parts according to claim 1, characterized in that: The sleeve (3) is fixedly connected to the material tray (10); a coaxial external threaded joint (11) is provided at the bottom of the sleeve (3); a mounting hole is provided on the material tray (10); the external threaded joint (11) passes through the mounting hole from top to bottom and is screwed and fixed with a locking nut (12).
6. A device for controlling local low hardness of a carburized and quenched part according to claim 5, characterized in that: The material tray (10) is a mesh plate-shaped structure, comprising a plurality of horizontal bars (13) and vertical bars (14) arranged at intervals, and the mounting holes are arranged at the intersections of the horizontal bars (13) and the vertical bars (14).
7. A device for controlling local low hardness of a carburized and quenched part according to claim 6, characterized in that: The material tray (10) is sleeved on the column (15), a spacer (16) is arranged between adjacent material trays (10), the spacer (16) is sleeved on the column (15), and each column (15) is sleeved with the same spacer (16).
8. A device for controlling local low hardness of a carburized and quenched part according to any one of claims 1 to 7, characterized in that: The carburized and quenched part (1) is a crankshaft, and the carburized control section (2) is a front end shaft of the crankshaft.