Thermal deformation control method for special-shaped plate body of special vehicle

Abstract

According to the thermal deformation control method for the special-shaped plate body of the special vehicle, a normalizing tool and a performance thermal treatment tool which are used for thermal treatment of the plate body are designed, the stacking mode of the plate body is optimized by combining the tools, it is guaranteed that the plate body can be vertically placed during thermal treatment, thermal treatment deformation is reduced, the flatness of the heated plate body is smaller than or equal to 1.0 mm, the leveling efficiency is improved, and the production cost is reduced. Precision guarantee can be provided for subsequent processing; a leveling process is added between normalizing and performance heat treatment, and a special leveling tool is used, so that the leveling efficiency and quality can be greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal deformation control of key parts of special vehicles, and in particular relates to a method for controlling thermal deformation of a special vehicle special-shaped plate. Background Art

[0002] The plate body is an important and complex structural part of the running part of special vehicles, and plays a decisive role in the mobility and reliability of the whole vehicle. Under the combined effect of the combined stress, the flatness of the heat-treated plate body is greatly deformed, and the high hardness increases the difficulty of leveling. The consistency of leveling quality is poor, which directly affects the pin hole processing on both sides of the plate body after heating, resulting in the minimum wall thickness exceeding the tolerance, and the reliability of the running part of the whole vehicle cannot be guaranteed.

[0003] The plate material used in special vehicles is 42CrMo, and its structure is different from other types of plates, such as Figure 1 As shown, the plate body takes into account the functions of track parts such as end couplers and induction teeth at the same time. It has a complex shape and large size. During heat treatment, the cross-sectional size changes greatly, resulting in uneven heating and large thermal stress, which leads to large deformation of its flatness after heat treatment. In addition, since the hardness required for the plate body is HRC37-42, the higher hardness increases the difficulty of leveling. With the existing performance heat treatment tooling, the plate body can only be placed flat, resulting in a flatness of more than 2.5mm after heat treatment, and the number of furnaces loaded is small, and the production efficiency is low; after performance heat treatment, the plate body has high hardness and poor leveling effect. It takes 20 to 30 minutes to level a single piece. Even if part of the plate body cannot meet the flatness requirement of ≤1.0mm after leveling, there is still a risk of crushing, and the subsequent processing accuracy cannot be guaranteed. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The present invention proposes a method for controlling thermal deformation of a special vehicle irregular plate, so as to solve the technical problem of controlling plate deformation and providing precision guarantee for subsequent mechanical processing and product quality.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention proposes a method for controlling thermal deformation of a special vehicle special-shaped plate, which comprises the following steps:

[0008] S1. Normalizing the forged special vehicle special-shaped plate to eliminate the processing stress after forging and refine the grain;

[0009] S2. Use the plate leveling tool to level the special vehicle special-shaped plate after normalizing;

[0010] S3. Performing a performance heat treatment on the leveled special vehicle special-shaped plate body so that the plate body obtains the required performance indicators;

[0011] S4. Check the flatness of the special vehicle special-shaped plate after quenching and tempering, and perform secondary leveling on the plate with excessive flatness. The leveling method is the same as step S2, so that the flatness of the plate meets the requirements; temper the special vehicle special-shaped plate that meets the flatness requirements to eliminate the leveling stress.

[0012] Furthermore, in step S1, the normalizing heating temperature is 860±10°C, the temperature is kept for 120-150 minutes, and the steel is air-cooled after being taken out of the furnace.

[0013] Furthermore, in step S1, when the boards are loaded into the basket, they are placed upright with their long sides facing downward, and there are gaps between the boards when they are stacked.

[0014] Furthermore, in step S2, the plate leveling tooling includes a conical pressure head, a pad, a pad and bolts. The conical pressure head is installed on the slide of the press by bolts, and the pad is placed on the platform surface of the press by eye bolts; the position of the pad is consistent with the position of the grounding ribs of the plate, the long pad among the pads is placed on the pad, and the short pad among the pads is fixed to the pad with bolts.

[0015] Furthermore, in step S2, when the leveling process is performed, the grounding surface of the grounding ribs of the plate body is placed on the pad, and a conical pressure head is used to apply pressure to the position of the plate body with greater deformation.

[0016] Furthermore, in step S2, the diameter of the pressing head surface where the conical pressing head contacts the plate body is 50-60 mm, the pressure during the leveling process is less than 60 kN, and the flatness after leveling is no greater than 0.6 mm.

[0017] Furthermore, in step S3, the performance heat treatment includes quenching and tempering. The plate body is quenched and tempered, and the basket is loaded with a layered structure, with the long side facing downward and placed upright. The protruding induced tooth top is stuck in the groove under the previous plate body, trapezoidal baffles are added on both sides of the tray, and a mouth-shaped square basket is added to ensure that the plate body can be placed vertically.

[0018] Furthermore, in step S3, the quenching heating temperature is 840±10°C, the temperature is kept for 90 to 120 minutes, and the steel is oil-cooled after being taken out of the furnace; the tempering heating temperature is 460±20°C, the temperature is kept for 150 to 180 minutes, and the steel is water-cooled after being taken out of the furnace.

[0019] Furthermore, in step S4, the flatness of the plate should satisfy ≤1.0 mm.

[0020] (III) Beneficial effects

[0021] The present invention proposes a method for controlling thermal deformation of special vehicle special-shaped plate bodies. By designing normalizing tooling and performance heat treatment tooling used for plate body heat treatment, and optimizing the plate body stacking method in combination with the tooling, it is ensured that the plate body can be placed vertically during heat treatment, and the heat treatment deformation is reduced, so that the flatness of the plate body after heating is ≤1.0mm, the leveling efficiency is improved, and the accuracy guarantee can be provided for subsequent processing; adding a leveling process between normalizing and performance heat treatment, and using a special leveling tooling can greatly improve the leveling efficiency and quality.

[0022] The beneficial effects of the method for controlling thermal deformation of a special-shaped plate of the present invention include:

[0023] 1. When the plates are heat treated, the long side is placed upright on the side. Compared with other stacking methods, such as flat placement and oblique placement, this can avoid lateral bending and twisting of the plates and reduce the difficulty of leveling. Combined with the plate basket stacking method, the number of plates loaded into the furnace can be increased by 1 to 2 times through special heat treatment tooling, while also meeting the requirements of side-standing placement of the plates to avoid the safety hazard of sliding.

[0024] 2. Combined with the special-shaped structure and thermal deformation law of the plate, a dedicated leveling tool is used to facilitate the leveling operation and improve the leveling efficiency; by optimizing the leveling process settings, a leveling process is added between normalizing and performance heat treatment, so that the number of plate flatness deviations after performance heat treatment is reduced by 70-80%, that is, only 20%-30% of the plate needs to be leveled after quenching + tempering, and the leveling efficiency of the plate can be increased by nearly 70%. In addition, when leveling a plate under high hardness, in order to ensure the leveling effect, force will be applied to the plate to cause excessive deformation, which is prone to the risk of fracture. Reducing the number of quenching + tempering plate leveling can reduce the safety hazards of leveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the plate structure of a special vehicle targeted by the present invention;

[0026] Figure 2 A schematic diagram of a leveling tool used in a method for controlling thermal deformation of a special vehicle special-shaped plate of the present invention;

[0027] Figure 3a This is a front view of a performance heat treatment tool used in the method for controlling thermal deformation of a special vehicle special-shaped plate of the present invention. Figure 3b It is a side view. DETAILED DESCRIPTION

[0028] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0029] This embodiment provides a method for controlling thermal deformation of a special vehicle irregular plate, and the method specifically includes the following steps:

[0030] S1. Normalizing treatment of forged special vehicle special-shaped plates

[0031] In order to eliminate the processing stress after forging and refine the grains, the forged special vehicle special-shaped plate body is normalized. The normalizing heating temperature is 860±10℃, and the temperature is kept for 120-150min. After leaving the furnace, it is air-cooled. When the plate body is loaded into the basket, the long side is placed upright with a certain gap between the plates, so as to ensure that there is no obvious shaking between the plates when the basket is transferred, and to minimize the deformation of the plate flatness caused by the normalizing treatment, and to improve the leveling efficiency after the normalizing treatment.

[0032] S2. Leveling of special vehicle special-shaped plates after normalizing

[0033] Use the plate leveling tool to level the special vehicle special-shaped plate after normalizing. Figure 2 As shown, the plate leveling tool consists of a conical pressure head 1, a pad 2, a pad 3 and a bolt 4, wherein the conical pressure head 1 is installed on the slider of the press by means of bolts 4, and the pad 2 is placed on the platform surface of the press by means of eyebolts. The position of the pad 3 is consistent with the position of the grounding ribs of the plate, wherein the long pad in the pad 3 is placed on the pad 2, and the short pad (length ≤ 70mm) in the pad 3 is fixed to the pad 2 by means of bolts. The purpose of fixing the short pad is to prevent the conical pressure head 1 from flying out and injuring people during the process of applying pressure to the plate. During the leveling process, the grounding surface of the plate grounding rib is placed on the pad 3, and the conical pressure head 1 is used to apply pressure to the position of the plate with greater deformation. The diameter of the pressure head surface of the conical pressure head 1 in contact with the plate is 50-60mm, the pressure during the leveling process is less than 60kN, and the flatness after leveling is not greater than 0.6mm.

[0034] S3.Perform heat treatment on the special vehicle special-shaped plate after leveling

[0035] The special vehicle special-shaped plate body after leveling is subjected to performance heat treatment, so that the plate body obtains the required performance indicators and meets the use requirements. Figure 3a and 3b As shown, the performance heat treatment includes quenching and tempering. The plate body is quenched and tempered. The basket adopts a layered structure, with the long side facing downward and placed upright. The protruding induction tooth top is stuck in the groove below the previous plate body. Trapezoidal baffles are added on both sides of the material tray, and a mouth-shaped square basket is added at the same time, which can ensure that the plate body can be placed vertically, reduce heat treatment deformation, and ensure that the plate body does not slip during the transfer process. The quenching heating temperature is 840±10℃, the heat preservation is 90~120min, and the oil cooling is carried out after the furnace; the tempering heating temperature is 460±20℃, the heat preservation is 150~180min, and the water cooling is carried out after the furnace.

[0036] S4. Flatness inspection of special vehicle special-shaped panels after performance heat treatment

[0037] After quenching and tempering, the special vehicle special-shaped plate body is checked for flatness, and the plate body with excessive flatness (≥1.0mm) is leveled twice, and the leveling method is the same as step S2, so that the plate body flatness satisfies ≤1.0mm. The special vehicle special-shaped plate body that meets the flatness requirements is tempered to eliminate the leveling stress.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling thermal deformation of special vehicle profiled plates, characterized in that: The thermal deformation control method comprises the following steps: S1. Normalizing the forged special vehicle special-shaped plate to eliminate the processing stress after forging and refine the grain; S2. Use the plate leveling tool to level the special vehicle special-shaped plate after normalizing; S3. Performing a performance heat treatment on the leveled special vehicle special-shaped plate body so that the plate body obtains the required performance indicators; S4. Check the flatness of the special vehicle special-shaped plate after quenching and tempering, and perform secondary leveling on the plate with excessive flatness. The leveling method is the same as step S2, so that the flatness of the plate meets the requirements; temper the special vehicle special-shaped plate that meets the flatness requirements to eliminate the leveling stress.

2. The method for controlling thermal deformation of a special vehicle special-shaped plate according to claim 1, characterized in that: In step S1, the normalizing heating temperature is 860±10°C, the temperature is kept for 120-150 minutes, and the product is air-cooled after being taken out of the furnace.

3. The method for controlling thermal deformation of a special vehicle special-shaped plate according to claim 1, characterized in that: In step S1, when the boards are loaded into the basket, they are placed upright with their long sides facing downward, and there are gaps between the boards when they are stacked.

4. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 1, characterized in that: In step S2, the plate leveling tooling includes a conical pressure head, a pad, a pad and bolts. The conical pressure head is installed on the slide of the press by bolts, and the pad is placed on the platform surface of the press by eye bolts; the position of the pad is consistent with the position of the grounding ribs of the plate, the long pad among the pads is placed on the pad, and the short pad among the pads is fixed to the pad with bolts.

5. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 4, characterized in that: In step S2, when leveling is performed, the grounding surface of the grounding ribs of the plate body is placed on the pad, and a conical pressure head is used to apply pressure to the position of the plate body with greater deformation.

6. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 5, characterized in that: In step S2, the diameter of the pressing head surface where the conical pressing head contacts the plate body is 50-60 mm, the pressure during the leveling process is less than 60 kN, and the flatness after leveling is no greater than 0.6 mm.

7. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 1, characterized in that: In step S3, the performance heat treatment includes quenching and tempering. The plate body is quenched and tempered. The basket is loaded with a layered structure, with the long side facing downward and placed upright. The protruding induced tooth top is stuck in the groove under the previous plate body. Trapezoidal baffles are added on both sides of the tray, and a mouth-shaped square basket is added to ensure that the plate body can be placed vertically.

8. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 7, characterized in that: In step S3, the quenching heating temperature is 840±10°C, the temperature is kept for 90 to 120 minutes, and the product is oil-cooled after being taken out of the furnace; the tempering heating temperature is 460±20°C, the temperature is kept for 150 to 180 minutes, and the product is water-cooled after being taken out of the furnace.

9. The method for controlling thermal deformation of a special vehicle irregular plate according to claim 1, characterized in that: In step S4, the flatness of the plate should satisfy ≤1.0 mm.

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