Method for repairing defects of water chamber hole of diesel engine body

Abstract

The application discloses a diesel engine body water cavity hole defect repairing method, which comprises the following steps: firstly, positioning the tool to complete the initial hole expansion, filling the metal repairing agent, compacting and solidifying, repeating the step of gradually expanding the hole and filling the glue for 2-3 times, increasing the hole by 2-3 mm each time, not more than 4 times in total, reaming to the size of the matching sleeve, assembling the lengthened repairing sleeve with a flow guide opening and sealing the sleeve with glue; the diesel engine body water cavity hole defect repairing method forms a composite sealing structure through the multi-layer repairing agent stacking and the inlaying sleeve, and there is no high-temperature welding in the whole process, so that the engine body is free from deformation and welding stress cracking risk; the method has low equipment requirement and simple operation, can be adapted to the simple working environment for emergency repair, has excellent water flow erosion resistance and vibration resistance after repair, and is suitable for repairing the casting defects of various diesel engine body water cavity holes.

Description

Technical Field

[0001] This invention relates to the field of diesel engine repair technology, specifically a method for repairing defects in the water cavity holes of a diesel engine block. Background Technology

[0002] The diesel engine block water chamber is a key structure connecting the cylinder head and the cylinder liner cooling water passages, such as... Figure 1 As shown, this casting part is highly susceptible to casting defects such as insufficient wall thickness, porosity, and localized defects during the blank forming process, resulting in thin walls in the engine blank. When the diesel engine is running, cooling water continuously flows through the water cavity holes and erodes the hole walls over a long period. Water cavity holes with casting defects are prone to leakage and matrix cracking, directly leading to the failure of the diesel engine cooling system and, in severe cases, causing the entire engine to be scrapped.

[0003] The mainstream repair methods for defects in the water cavity holes of diesel engine blocks currently used in the industry are mainly divided into four categories: adhesive patching, cold welding repair, bushing repair, and arc welding repair. Each of these repair methods has obvious limitations in its application.

[0004] 1. Adhesive repair: It is only suitable for minor leaks, small pores, and slight corrosion defects. It does not require open flame, does not deform the workpiece, and is easy to operate. However, it is not strong enough to repair under stress conditions, deep cracks, and large-area defects. It has a short service life and cannot be adapted to the long-term cooling water flushing and high-frequency vibration conditions of water cavity holes.

[0005] 2. Cold welding repair: It can repair defects such as cracks, holes, hole wall defects, and corrosion pits. After repair, the cylinder block will not deform and is not prone to new cracks. However, it can only repair small defects and is not suitable for water cavity holes that are subjected to continuous impact from cooling water for a long time. When the defect area and depth are large, the repair reliability is poor.

[0006] 3. Conventional sleeve repair: For cases with large-area damage to the water cavity wall and out-of-tolerance hole diameter, the original hole diameter structure can be restored, and the pressure bearing performance is excellent; however, direct sleeve only relies on the single contact surface between the sleeve and the substrate for sealing, without a multi-layer sealing and protection structure, and the sealing interface is prone to water leakage under long-term water flow.

[0007] 4. Arc welding repair: It can repair defects by fusion over a large area, but the welding heat input is large, which can easily cause deformation of the body and concentration of residual stress in the weld repair, resulting in new cracks in the base material around the defect. The scrap rate of repair is high, and it is generally not a preferred repair solution in the industry.

[0008] In summary, existing single repair processes are insufficient to address the emergency repair needs of large-area hole wall defects, rudimentary operating environments, and unsuitability for cold welding and arc welding conditions. Therefore, there is a lack of a composite repair process that has low equipment requirements, low operating threshold, multi-layer sealing protection, and is suitable for large-area water cavity hole defects. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the existing defects and provide a method for repairing defects in the water cavity of a diesel engine block. Under the premise of meeting the sealing requirements of the water cavity under the harsh working conditions of high-pressure water cooling, continuous scouring and high-frequency vibration, the method reduces the equipment and working environment requirements for repair, simplifies the operation process, reduces the difficulty and labor intensity of workers, and achieves stable repair of large-area casting defects.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a method for repairing defects in the water cavity holes of a diesel engine block, comprising the following steps:

[0011] S1: Initial hole enlargement: The diesel engine body is positioned and fixed using a positioning fixture, the guide sleeve of the appropriate specification is replaced, and the water cavity hole defect area is enlarged using a drill bit.

[0012] S2: Initial filling of repair agent: Clean the debris in the hole after enlargement, fill the enlarged area with metal repair agent and completely fill it. Before the repair agent cures, press the surface of the repair agent to allow the repair agent to fully penetrate into the defect.

[0013] S3: Cyclic hole enlargement and adhesive filling process: After the repair agent has completely cured, the positioning tool is reused to carry out the next round of hole enlargement. The hole diameter of this round of hole enlargement is 2-3mm larger than the previous enlargement, while the hole enlargement depth remains unchanged. The repair agent is filled again and compacted to ensure that the repair agent penetrates into the defect.

[0014] Depending on the severity of the defects in the water cavity, this process should be repeated 2 to 3 times, with a total number of cycles for processing and repair not exceeding 4 times.

[0015] S4: Precision reaming: After completing the cycle of hole enlargement and glue filling, use a reamer to precision machine the hole to the standard installation size that matches the repair sleeve, and keep the reaming depth consistent with the depth of previous hole enlargements;

[0016] S5: Sleeve sealing assembly: Select a repair sleeve with a length greater than the hole enlargement depth, with the sleeve side wall opening facing the water cavity hole opening, apply sealant evenly to the outer wall of the sleeve, and press it into the precision-machined hole to complete the sealing repair of the water cavity hole defect.

[0017] As a preferred technical solution of the present invention, the repair agent filled in steps S2 and S3 is a metal repair agent, and subsequent hole enlargement processing can only be carried out after the repair agent has completely cured.

[0018] As a preferred technical solution of the present invention, in step S3, the process is repeated 2 to 3 times depending on the severity of the water cavity hole defect, and the total number of cycles for processing and repair does not exceed 4 times.

[0019] As a preferred technical solution of the present invention, all hole enlargement processes are carried out using flat-bottom drill bits to ensure that the bottom surface of the hole is flat, which facilitates the uniform filling and adhesion of the repair agent to the defects.

[0020] As a preferred technical solution of the present invention, the repair sleeve is pre-standardized and processed, and a flow guide opening is opened on the side wall of the sleeve. During assembly, the flow guide opening is aligned with the water outlet of the water cavity.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) It has a wide range of applications and can repair large-area hole wall defects that cannot be applied by cold welding or arc welding. It can be used as an emergency repair solution for simple work sites and is not limited by hot work or large welding equipment; (2) It has high sealing reliability. The multi-layer metal repair agent filling structure fills the casting defects of the base body. With the double-layer sealing of the sleeve, it solves the defects of single adhesive and single sleeve easy water leakage. It is suitable for the long-term water cooling flushing and high-frequency vibration working conditions of diesel engines; (3) The equipment and operation threshold is low. Only drilling machine, reamer, positioning tooling basic processing tools are required. The repair sleeve can be prefabricated and stored in advance in a standardized manner. No professional welding equipment is required. One person can complete the operation, reducing the requirements for the skill level of the operator and the number of workers; (4) The deformation of the machine body is small after repair. There is no high-temperature welding process throughout the process. There is no welding residual stress, avoiding the problem of machine body cracking, deformation and scrapping caused by welding repair; At the same time, the process is controllable and the repair consistency is strong: the hole expansion increment, the number of cyclic repairs and the sleeve size are all standardized and limited. The repair process is unified and the batch repair product quality is stable, which is convenient for standardized production management in the workshop. Attached Figure Description

[0022] Figure 1 A schematic diagram of the original state of the water cavity hole defect in the diesel engine block;

[0023] Figure 2 This is a flowchart of the repair method of the present invention;

[0024] Figure 3 This is a schematic diagram of the hole-reaming process of the present invention;

[0025] Figure 4 This is a schematic diagram of the sleeve repair method of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1: Moderate water cavity hole defects, repeated the cyclic hole enlargement and glue filling process twice.

[0028] like Figure 2-4 This invention provides a technical solution: a method for repairing defects in the water cavity holes of a diesel engine block, comprising the following steps:

[0029] S1: Initial hole reaming

[0030] Take a diesel engine block with thin walls and local casting defects, use a positioning tool to lock it in place with the positioning holes of the engine block, replace the guide sleeve with the corresponding specification to match the current defect size, use a flat bottom drill bit to perform the initial hole enlargement in the defect area of ​​the water cavity hole, and clean all debris such as iron filings, molding sand, and oil stains from the hole.

[0031] S2: Initial filling and repair agent

[0032] Prepare the metal repair agent and fill it into the enlarged cavity to completely fill the enlarged area; press the surface of the repair agent during the curing window period, and rely on external force to make the repair agent fully penetrate into the fine defects and gaps of the substrate, and let it stand until the metal repair agent is completely cured.

[0033] S3: Circular hole enlargement and adhesive filling process

[0034] The positioning tooling was reused to complete the secondary hole enlargement. The hole diameter was increased by 2mm compared to the first hole enlargement, while the hole depth remained the same as the first hole enlargement. Metal repair agent was filled again, compacted and penetrated, and then allowed to stand and cure.

[0035] Repeat this process for the second time to complete the third hole enlargement and glue filling. A total of 2 cycles are performed, and the total number of processing and repairs is 3, which does not exceed the upper limit of 4. A flat-bottom drill bit is used for each round of hole enlargement to ensure that the bottom of the hole is flat and the repair agent is filled without gaps.

[0036] S4: Precision reaming

[0037] After all the cyclic hole enlargement and glue filling processes are completed, a reamer is used to finish the composite repaired hole. The reaming hole size matches the outer diameter of the prefabricated repair sleeve, and the reaming hole depth is exactly the same as the depth of each previous hole enlargement.

[0038] S5: Bushing Sealing Assembly

[0039] Select a prefabricated standardized repair sleeve, with the total length of the sleeve being greater than the depth of the hole enlargement process; pre-open a flow guide opening on the side wall of the sleeve, and during assembly, the flow guide opening should be directed toward the water outlet of the water cavity hole;

[0040] Apply sealant evenly to the outer wall of the sleeve, and press the sleeve completely into the precision-machined hole using static pressure. Allow the sealant to cure, and all defects will be repaired.

[0041] Example 2: Severe water cavity hole defects, repeated the cyclic hole enlargement and glue filling process 3 times.

[0042] The water cavity hole of the machine body has a large area of ​​defect, with a large depth and area of ​​defect. The initial hole enlargement and repair agent filling and curing were completed in accordance with S1 and S2.

[0043] Perform the S3 cycle process for 3 rounds. In each round, the hole diameter is increased by 2mm while the depth remains unchanged. In each round, metal repair agent is filled and fully cured. The total number of cycles for repair is 4.

[0044] The subsequent steps of S4 precision reaming and S5 sleeve sealing assembly are completely consistent with those in Example 1. After the repair is completed, the multi-layer repair agent fully fills the large area of ​​defects, the sleeve is pressure-bearing and sealed, and there is no leakage after the repair.

[0045] Example 3: Moderate defect, single-wheel reaming hole diameter increment is 3mm

[0046] The process flow is consistent with Example 1, except that the hole diameter is increased by 3mm in each cycle of hole enlargement. Flat bottom drill bit processing ensures that the bottom of the hole is flat. Layered filling of metal repair agent forms a multi-layer sealing structure. Finally, the sleeve is sealed. After repair, the sealing performance meets the requirements of diesel engine water-cooled operation.

[0047] The above three sets of embodiments cover three typical field conditions: moderate defects, severe defects, and different hole enlargement size increments, respectively, which fully verify the feasibility of the process parameter range of the present invention: for workpieces with minor defects, the number of cycles of hole enlargement and glue replenishment can be reduced, and for workpieces with severe defects, the maximum of 4 cycles of process can be used to ensure the filling density.

[0048] The parameter range of 2-3mm for hole enlargement increment can take into account both the repair layer thickness and the substrate strength. It will not cause insufficient remaining wall thickness of the body due to excessive hole enlargement in a single operation, nor will it cause insufficient protection effect of the multi-layer repair structure due to insufficient hole enlargement.

[0049] All three sets of embodiments adopted the core process features of flat-bottom drill bit processing, layered curing of metal repair agent, and directional assembly of open sleeve. After repair, the workpiece showed no water leakage or cracking after water pressure leakage test and long-term simulated water cooling scouring durability test. The repair stability is significantly better than the traditional single adhesive, cold welding, and direct sleeve repair methods.

[0050] Meanwhile, the entire process does not require large welding or heat treatment equipment, and a single operator can independently complete all repair work. It can be adapted to various usage scenarios such as batch rework in workshops and emergency repairs in simple outdoor sites, and the process has strong versatility.

[0051] The parts of the invention not described in detail are prior art. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for repairing defects in the water cavity holes of a diesel engine block, characterized in that: Includes the following steps: S1: Initial hole enlargement: The diesel engine body is positioned and fixed using a positioning fixture, the guide sleeve of the appropriate specification is replaced, and the water cavity hole defect area is enlarged using a drill bit. S2: Initial filling of repair agent: Clean the debris in the hole after enlargement, fill the enlarged area with metal repair agent and completely fill it. Before the repair agent cures, press the surface of the repair agent to allow the repair agent to fully penetrate into the defect. S3: Cyclic hole enlargement and adhesive filling process: After the repair agent has completely cured, the positioning tool is reused to carry out the next round of hole enlargement. The hole diameter of this round of hole enlargement is 2-3mm larger than the previous enlargement, while the hole enlargement depth remains unchanged. The repair agent is filled again and compacted to ensure that the repair agent penetrates into the defect. Depending on the severity of the defects in the water cavity, this process should be repeated 2 to 3 times, with a total number of cycles for processing and repair not exceeding 4 times. S4: Precision reaming: After completing the cycle of hole enlargement and glue filling, use a reamer to precision machine the hole to the standard installation size that matches the repair sleeve, and keep the reaming depth consistent with the depth of previous hole enlargements; S5: Sleeve sealing assembly: Select a repair sleeve with a length greater than the hole enlargement depth, with the sleeve side wall opening facing the water cavity hole opening, apply sealant evenly to the outer wall of the sleeve, and press it into the precision-machined hole to complete the sealing repair of the water cavity hole defect.

2. The method for repairing defects in the water cavity of a diesel engine block according to claim 1, characterized in that: The repair agent used in steps S2 and S3 is a metal repair agent, and subsequent hole enlargement processing can only be carried out after the repair agent has completely cured.

3. The method for repairing defects in the water cavity of a diesel engine block according to claim 1, characterized in that: In step S3, this process is repeated 2 to 3 times depending on the severity of the water cavity hole defect, and the total number of cycles for processing and repair does not exceed 4 times.

4. The method for repairing defects in the water cavity of a diesel engine block according to claim 1, characterized in that: All hole enlargement processes are performed using flat-bottomed drill bits to ensure a flat bottom surface, facilitating even filling and fitting of the repair agent to the defects.

5. The method for repairing defects in the water cavity of a diesel engine block according to claim 1, characterized in that: The repair sleeve is pre-processed to standardization, and a flow guide opening is opened on the side wall of the sleeve. During assembly, the flow guide opening is aligned with the water outlet of the water cavity.

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