A bionic multilayer structure repair method for metal mold with crack arrest and wear-resistant reinforcement and application

Abstract

The application discloses a kind of bionic multilayer structure repair methods for metal mould with crack arrest, wear-resistant reinforcement, and relates to metal mould repair technical field.Repair uses laser fusion and laser cladding processing method, and special three-layer bionic structure is formed in repair site, including firm layer, recovery layer and strengthening layer;Wherein recovery layer is processed using laser cladding method, and firm layer and strengthening layer are processed using laser fusion method.After repair, mould failure site crack is healed, size is recovered, and surface has the same height bionic reinforcement structure with mould working surface.Firm layer and strengthening layer have bionic unit body structure with different structure, different distance and different angle, and the angle between different unit body structure type, distance and structure determines the healing effect of original mould crack, and the wear resistance of new repaired mould surface.

Description

Technical Field

[0001] This invention relates to the field of metal mold repair technology, and more specifically to a biomimetic multilayer structure repair method and application for metal molds with crack prevention, wear resistance and reinforcement. Background Technology

[0002] Metal molds, used under complex conditions such as high pressure and cyclic cooling for extended periods, are prone to crack initiation and propagation, as well as dimensional failures due to surface wear, severely impacting mold lifespan and product machining accuracy. Traditional repair methods often employ single cladding or welding processes, which suffer from defects such as weak bonding between the repaired area and the substrate, easy crack recurrence, and insufficient wear resistance, failing to meet the requirements for long-term stable mold operation. This invention addresses these pain points by proposing a biomimetic multi-layered structure repair scheme. Through layered design, it achieves integrated repair of crack arrest, dimensional restoration, and wear resistance enhancement. Summary of the Invention

[0003] In view of this, and in view of the shortcomings of the existing technology, the purpose of this invention is to provide a biomimetic multi-layer structure repair method for metal molds that combines the principle of biomimetic reinforcement and has the functions of crack prevention and wear resistance reinforcement. When repairing the mold, a three-layer structure repair layer is constructed by overlapping a stabilizing layer, a recovery layer and a reinforcing layer. According to the different functional characteristics of each layer, laser melting or laser cladding methods are selectively used to process the mold, forming a repair structure that can prevent the generation and propagation of internal cracks, has a surface hardness that is comparable to or slightly higher than that of the mold substrate surface, and has stronger wear resistance after repair.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A biomimetic multilayer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement is proposed. The repair adopts laser melting and laser cladding processing methods to form a special three-layer biomimetic structure in the repair area, including a stabilizing layer, a recovery layer and a reinforcing layer. The stabilizing and reinforcing layers are processed using laser melting and solidification, while the recovery layer is processed using laser cladding.

[0006] After repair, the cracks in the failed part of the mold were healed, the dimensions were restored, and the surface had a biomimetic reinforcement structure at the same height as the working surface of the mold. The stabilizing layer and the reinforcement layer have biomimetic unit structures with different structures, spacings, and angles. The different unit structure types, spacings, and the angles between the structures and the direction of force determine the repair effect of the original mold cracks and the wear resistance of the newly repaired mold surface.

[0007] Preferably, the stabilizing layer is located from the surface of the original mold crack to the interior of the mold crack, and is a composite structure formed by a biomimetic structure of bainitic or martensitic structure and the mold matrix material, with a thickness of 0.5-3mm; The recovery layer is located above the stabilizing layer, and is composed of extremely fine pearlite or martensite with a thickness of 0-8 mm and an average hardness of 50-65 HRC. The reinforcing layer is located from the surface to below the recovery layer. It is a composite structure consisting of a biomimetic structure of martensite or troostite and the recovery layer matrix, with a thickness of 0.15-1.5 mm and an average hardness of 55-75 HRC.

[0008] Preferably, the biomimetic structure of the stabilizing layer is composed of multiple simple biomimetic structures through superposition and calculation; the simple biomimetic structure includes parallel line type, grid type, ring type or wave type; The reinforcing layer biomimetic structure is composed of one or more simple biomimetic structures II through superposition and calculation; the simple biomimetic structure II includes parallel line type, flat grid type, flat spiral line type or wavy line type; The biomimetic structure processing area of ​​the stabilizing layer is a rectangular area 2mm away from the mold crack area. As needed, a composite structure composed of two simple biomimetic structures A1 and B1 is set up. A1 is a straight line or wave shape; B1 is a grid shape or a ring shape. The processing area of ​​the biomimetic structure of the reinforcement layer is the area 2mm outside the surface of the recovery layer and the junction with the mold substrate. As needed, a simple biomimetic structure C1 can be set alone, or two simple biomimetic structures C1 and A1 can be set overlapping. C1 can be grid-shaped, circular, or spiral-shaped. The spacing and angle parameters of the simple biomimetic structure with respect to the direction of force are simulated and optimized based on the mold base material and the required hardness.

[0009] Preferably, the specific steps of the above repair method are as follows: S1. Analysis and Design The biomimetic structure type and spacing of the stabilizing layer are designed based on the length and number of cracks in the mold; the biomimetic structure type and spacing of the reinforcing layer are designed based on the crack direction and the surface area of ​​the repair structure. S2. Preprocessing The surface of the mold to be repaired is cleaned and pre-ground. S3. Construct a stable layer First, laser cladding is used to fill the cracks on the mold surface. Then, laser melting is used to process the B1 biomimetic structure. On this basis, laser melting is used to process the A1 biomimetic structure to form a stable layer biomimetic structure. S4. Construct the recovery layer Laser cladding is used to fill the mold with lost dimensions and structures due to wear. After processing, the surface of the restored layer is machined to be smooth. S5. Construct a reinforcement layer Using laser melting and solidification, the C1 biomimetic structure is first processed, and then the A1 biomimetic structure is processed on this basis to form a reinforcing layer.

[0010] Preferably, laser cladding and laser condensation use a fiber continuous laser with a power of 2000W-6000W.

[0011] Preferably, the laser cladding (crack repair) parameters in step S3 are: laser output power of 800W-1500W, defocusing amount of -15±3mm, scanning speed of 3-12mm / s, and cladding material of iron-based powder or welding wire. The parameters for laser melting and coagulation (crack arrest structures A1 and B1) are as follows: laser output power is 650W-1750W, defocusing amount is -20±10mm, and scanning speed is 3-12mm / s.

[0012] Preferably, the laser cladding (size recovery) parameters in step S4 are: laser output power of 1200W-6000W, defocusing amount of -15±5mm, scanning speed of 7-30mm / s, and cladding material of iron-based powder or welding wire.

[0013] Preferably, the laser melting and coagulation (wear-resistant and crack-resistant C1, A1) parameters in step S5 are: laser output power of 650W-1200W, defocusing amount of -25±10mm, and scanning speed of 7-35mm / s.

[0014] Another objective of this invention is to provide the application of the above-mentioned biomimetic multilayer structure repair method for metal molds with crack arrest and wear resistance reinforcement in the repair of cracks and dimensional failures of iron-based metal molds under high pressure and cooled by internal circulating cooling water, and it can also be used for the repair of other types of metal molds.

[0015] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical effects: 1. Thorough crack repair: The biomimetic structure of the stabilizing layer can effectively close the original cracks, while inhibiting the initiation and expansion of new cracks, resulting in a significant crack-stopping effect.

[0016] 2. Precise Dimension Restoration: The restoration layer is precisely clad and machined to ensure that the mold dimensions return to the design standards and meet assembly and processing requirements.

[0017] 3. Excellent wear resistance: The biomimetic structure and high hardness design of the reinforced layer greatly improve the wear resistance of the mold surface and extend its service life.

[0018] 4. High bonding strength: The layered process and the design of suitable materials and parameters ensure that each layer forms a metallurgical bond with the substrate and between layers, eliminating the risk of detachment. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a multi-layer repair structure; Figure 2 This is a schematic diagram of a typical A1 structure; Figure 3 This is a schematic diagram of a typical B1 structure; Figure 4 This is a schematic diagram of a typical C1 structure; Figure 5 This is a schematic diagram of the stabilizing layer composite structure; Figure 6 This is a schematic diagram of the reinforced composite structure; Figure 7 It is a typical microstructure of cladding structure; Figure 8 It is a typical fused solid unit cell structure; Figure 9 It is a typical fused composite unit cell structure. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0022] Example 1 This embodiment provides a biomimetic multilayer structure repair method for H13 metal molds with crack-stopping and wear-resistant reinforcement. The repair employs laser melting and laser cladding processes, including the following steps: 1. Analysis and Design: Based on the crack density per unit area of ​​the mold surface: within a unit area of ​​30mm × 30mm, crack length × number / 20mm = crack density (L). When L ≤ 1.5, it is a light cracking state, and the stabilizing layer A1 should preferably be a straight structure, and B1 should preferably be a circular structure; when L > 1.5, it is a severe cracking state, and the stabilizing layer A1 should preferably be a wavy line structure, and B1 should preferably be a grid structure.

[0023] 2. Pre-treatment: Clean and remove dirt from the surface of the mold to be repaired, and pre-grind it to ensure that there are no impurities or oxide layers on the surface.

[0024] 3. Constructing a Stabilizing Layer: First, major cracks or through cracks with a width b > 0.5 mm are filled using laser cladding. Then, B1 and A1 type biomimetic structures are sequentially processed using laser melting to form a crack-arresting and crack-preventing composite layer. During cladding, the laser power is 860W, the defocusing amount is -17mm, and the scanning speed is 7mm / s. The cladding material is the same material welding wire. For laser melting, the power is 780W, the defocusing amount is -15mm, and the scanning speed is 5mm / s.

[0025] 4. Constructing the restoration layer: The defect is filled using laser cladding, followed by surface smoothing through machining. The laser power is 960W, the defocusing distance is -15mm, and the scanning speed is 5mm / s. The cladding material is the same material welding wire.

[0026] 5. Constructing the Reinforcement Layer: C1 and A1 type biomimetic structures are sequentially processed using laser melting to form a wear-resistant reinforced surface layer. The degree of wear (light or heavy) is determined based on the depth D of the recovery layer. When D ≤ 1mm, it is considered light wear; C1 uses a flat helical structure with the short axis of the helix parallel to the friction direction during operation, and A1 uses a straight structure. When D > 1mm, it is considered heavy wear; C1 uses a flat mesh structure with the obtuse angles of the mesh parallel to the friction direction, and A1 uses a wavy structure. During melting, the C1 type structure is processed first, followed by the A1 type structure. The coverage area of ​​the biomimetic structure should be 5-10mm larger than the cladding layer.

[0027] During laser melting and solidification, the laser power is 820W, the defocusing distance is -18mm, and the scanning speed is 5 / s.

[0028] Example 2 Repairing low-pressure die-casting molds made of ductile iron includes the following steps: 1. Structural Selection and Design: Based on the specific gravity of cracks per unit area on the mold surface caused by erosion and thermal fatigue: Within a unit area of ​​30mm × 30mm, crack length × number / 20mm = specific gravity of cracks (L). When L ≥ 4 and the crack width is less than 0.2mm, the stabilizing layer A1 should preferably have a wavy structure, and B1 should preferably have a grid structure, with an angle of 60° between the two structures. The surface strengthening layer A1 structure remains unchanged, while C1 should preferably have a flat grid structure, with a 15° angle between the obtuse angle direction and the melt flow direction. When L < 4, the stabilizing layer only needs to use the B1 annular structure, without needing to process the A1 structure; the surface strengthening layer only needs to process the C1 flat spiral structure, with a 30° angle between the short axis direction and the melt flow direction.

[0029] 2. Pre-treatment: Clean and remove dirt from the surface of the mold to be repaired, and pre-grind it to ensure that there are no impurities or oxide layers on the surface.

[0030] 3. Constructing a stabilizing layer: Crack-arresting structures A1 and B1 are sequentially processed using laser melting and solidification. Laser power: 780W; scanning speed: 4mm / s; defocusing distance: -15mm.

[0031] 4. Constructing the restoration layer: Laser cladding is used to fill dimensional defects, followed by surface smoothing through machining. The laser power is 860W, the defocusing distance is -15mm, and the scanning speed is 5mm / s. The cladding material is Fe30 powder.

[0032] 5. Constructing the reinforcement layer: C1 and A1 type biomimetic structures are sequentially processed using laser melting and solidification. The coverage area of ​​the biomimetic structure should be 5-10 mm larger than the cladding layer. The laser power is 795W, the scanning speed is 7 mm / s, and the defocusing amount is -16 mm.

[0033] Example 3 Repair of steel molds without wear and cracks 1. Structural Design: Since there are no underlying cracks, there is no need to process the underlying stabilization layer; the dimensional restoration layer can be processed directly. The surface strengthening layer only requires the processing of the C1 structural biomimetic unit. The restoration layer is processed using laser cladding, and the strengthening layer is processed using laser melting.

[0034] 2. Pre-treatment: Clean and remove dirt from the surface of the mold to be repaired, and pre-grind it to ensure that there are no impurities or oxide layers on the surface.

[0035] 3. Constructing the restoration layer: Laser cladding is used to fill dimensional defects, followed by surface smoothing through machining. The laser power is 870W, the defocusing distance is -12mm, and the scanning speed is 5mm / s. The cladding material is Fe30 powder.

[0036] 4. Constructing the reinforcement layer: A C1-type biomimetic structure is fabricated using laser melting. The biomimetic structure should cover an area 5-10 mm larger than the cladding layer. The laser power is 785W, the scanning speed is 6 mm / s, and the defocusing amount is -14 mm.

[0037] Compared with direct cladding repair without processing the bottom stabilizing layer, the mold with the added biomimetic structure of the bottom stabilizing layer reduced the tendency of bottom crack propagation by more than 90% (the crack propagation length per 10mm is about 1.8-3.6mm after cladding repair alone; the crack propagation length per 10mm is about 0.18mm after processing the stabilizing layer and cladding repair).

[0038] Compared with direct cladding repair without processing the surface reinforcement layer, the wear resistance can be improved by about 58% after processing the surface reinforcement biomimetic structure (under high-speed friction conditions, the weight loss per unit area (30x30mm) is about 0.12g every 15 minutes; after processing the reinforcement layer, the weight loss is about 0.05g every 15 minutes).

[0039] Based on the overall usage of the mold, adopting a multi-layer repair method can increase the service life after repair by approximately 35%-50% or more.

[0040] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biomimetic multi-layer structure repair method for metal molds, characterized by crack arrest and wear resistance enhancement, wherein... The repair process employs laser melting and laser cladding to create a unique three-layer biomimetic structure at the repair site, including a stabilizing layer, a recovery layer, and a reinforcing layer. The recovery layer is processed using laser cladding, while the stabilizing and reinforcing layers are processed using laser melting.

2. The biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 1, characterized in that, The stabilizing layer is located from the surface of the original mold crack to the inside of the mold crack. It is a composite structure formed by the biomimetic structure of pearlite or martensite and the mold matrix material, with a thickness of 0.5-3mm. The recovery layer is located above the stabilizing layer, and is made of extremely fine pearlite with a thickness of 0-8 mm and an average hardness of 50-65 HRC. The reinforcing layer is located from the surface to below the recovery layer. It is a composite structure consisting of a biomimetic structure of martensite or troostite and the recovery layer matrix, with a thickness of 0.15-1.5 mm and an average hardness of 55-75 HRC.

3. The biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 2, characterized in that, The stabilizing layer biomimetic structure is composed of multiple simple biomimetic structures through superposition and calculation; the simple biomimetic structures include parallel line type, grid type, ring type or wave type; The reinforcing layer biomimetic structure is composed of one or more simple biomimetic structures II through superposition and calculation; the simple biomimetic structure II includes parallel line type, flat grid type, flat spiral line type or wavy line type; The biomimetic structure processing area of ​​the stabilizing layer is a rectangular area 2mm away from the mold crack area. As needed, a composite structure composed of two simple biomimetic structures A1 and B1 is set up. A1 is a straight line or wave shape; B1 is a grid shape or a ring shape. The processing area of ​​the biomimetic structure of the reinforcement layer is the area 2mm outside the surface of the recovery layer and the junction with the mold base. As needed, a simple biomimetic structure C1 can be set alone, or two simple biomimetic structures C1 and A1 can be set overlapping. C1 is a flat grid type or a flat spiral type. The spacing and angle parameters between the simple biomimetic structure and the direction of force are simulated and optimized based on the mold matrix material and the required hardness.

4. A biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 3, characterized in that, The specific steps are as follows: S1. Analysis and Design The biomimetic structure type and spacing of the stabilizing layer are designed based on the length and number of cracks in the mold; the biomimetic structure type and spacing of the reinforcing layer are designed based on the crack direction and the surface area of ​​the repair structure. S2. Preprocessing The surface of the mold to be repaired is cleaned and pre-ground. S3. Construct a stable layer First, laser cladding is used to fill the cracks on the mold surface. Then, laser melting is used to process the B1 biomimetic structure. On this basis, laser melting is used to process the A1 biomimetic structure to form a stable layer biomimetic structure. S4. Construct the recovery layer Laser cladding is used to fill the mold with lost dimensions and structures due to wear. After processing, the surface of the restored layer is machined to be smooth. S5. Construct a reinforcement layer Using laser melting and solidification, the C1 biomimetic structure is first processed, and then the A1 biomimetic structure is processed on this basis to form a reinforcing layer.

5. A biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 4, characterized in that, Laser cladding and laser melting use fiber continuous lasers with a power of 2000W-6000W.

6. A biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 5, characterized in that, The laser cladding parameters in step S3 are: laser output power of 800W-1500W, defocusing amount of -15±3mm, scanning speed of 3-12mm / s, and cladding material of iron-based powder or welding wire. The laser melting and coagulation parameters are: laser output power of 650W-1750W, defocusing amount of 20±10mm, and scanning speed of 3-12mm / s.

7. A biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 5, characterized in that, The laser cladding parameters in step S4 are: laser output power of 1200W-6000W, defocusing amount of -15±5mm, scanning speed of 7-30mm / s, and cladding material of iron-based powder or welding wire.

8. A biomimetic multi-layer structure repair method for metal molds with crack-stopping and wear-resistant reinforcement as described in claim 5, characterized in that, The laser melting parameters in step S5 are: laser output power of 650W-1200W, defocusing amount of -20±10mm, and scanning speed of 7-35mm / s.

9. The application of the biomimetic multi-layer structure repair method for metal molds with crack arrest and wear resistance as described in any one of claims 1-8 in the repair of cracks and dimensional failures in iron-based metal molds under high pressure and cooled by internal circulating cooling water.

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