Additive repairing method for interlayer heterogeneous part

Abstract

The invention belongs to the technical field of additive manufacturing and repairing, and particularly relates to an additive repairing method for interlayer heterogeneous parts. Comprising the following steps that (1) a model is obtained, interlayer heterogeneous damaged parts are provided, the damaged parts are machined into regular areas to be repaired, a repairing model of the repairing areas is obtained, and the needed material adding technology is reasonably arranged according to needs; (2) repairing preparation is conducted, specifically, a corresponding welding wire is selected according to heterogeneous materials of the heterogeneous parts, the additive material path of each layer is planned according to a repairing model, and a robot walking program is written; and (3) repairing is started, the optimal technological parameters are matched according to the planned additive material path, and additive material repairing of the structural part is started. By means of the method, repairing of most interlayer heterogeneous parts can be met, through diversified adjustment of repairing parameters, the comprehensive mechanical property needed by original parts can be met or even exceeded after repairing, and a new thought of a heterogeneous part additive repairing mode is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing and repair, and in particular relates to an additive repair method for interlayer heterogeneous and heterogeneous components. Background Art

[0002] With the progress of industry and the development of additive manufacturing technology, the requirements for some parts are constantly increasing. Traditional homogeneous components are difficult to meet the requirements for diversified material performance. For high-strength and high-hardness materials, their plasticity is often low, and materials with good plasticity often have difficulty meeting the strength requirements. In heterogeneous and heterogeneous material parts, different parts have different properties. The superposition of different properties maximizes the comprehensive performance of heterogeneous and heterogeneous parts, thereby overcoming certain defects of materials. The more typical bionic shell layered structure can obtain advanced metals with excellent "strength-plasticity" synergy through the interlayer heterogeneous structure design with strong outer and tough inner strength. This complex heterogeneous component is usually produced by additive manufacturing. Metal additive manufacturing technology is also called "metal 3D printing technology". Unlike ordinary material cutting technology, metal additive manufacturing technology is a process of stacking materials by points, lines and surfaces after personalized customization of digital models to achieve flexible manufacturing.

[0003] Although heterogeneous and heterogeneous components have good mechanical properties, they will inevitably suffer damage such as breakage, cracking, and holes under harsh working conditions and long service time. The cost of directly producing and replacing parts through additive manufacturing will be very huge. Therefore, repairing key damaged parts will not only improve the service life of the equipment and enable it to quickly restore its operating capacity, but also maximize the potential value of the damaged parts and obtain huge economic and social benefits.

[0004] Additive repair technology is developed from additive manufacturing technology. It performs inverse modeling, forming layering, path planning on defective parts, and uses intelligent control software and appropriate laser, arc, plasma and other energy beam additive processes to stack layer by layer, ultimately achieving size restoration and performance improvement of damaged parts. At present, additive repair technology is mainly focused on the repair of the same material, and there is very little research on additive repair technology for heterogeneous and heterogeneous materials. Summary of the invention

[0005] The purpose of the present invention is to provide a method for additive repair of interlayer heterogeneous and heterogeneous components.

[0006] The technical solution to achieve the purpose of the present invention is: a method for additive repair of interlayer heterogeneous and heterogeneous components, comprising the following steps:

[0007] Step (1): obtain a model, provide a damaged part with heterogeneous and heterogeneous layers, process the damaged part into a regular area to be repaired, obtain a repair model of the repair area, and reasonably arrange the required additive process according to needs;

[0008] Step (2): Repair preparation: select the corresponding welding wire according to the heterogeneous materials of the heterogeneous components, plan the additive path of each layer according to the repair model, and write the robot walking program;

[0009] Step (3): Start repairing by matching the optimal process parameters according to the planned additive path and starting additive repair of the structural parts.

[0010] Furthermore, interlayer heterogeneity and heterogeneous components, heterogeneity refers to two or more materials, and isomerism refers to interlayer heterogeneity, including but not limited to: such as soft and hard interwoven layered bionic shell structures with excellent comprehensive mechanical properties, ultra-high strength steel and stainless steel, high strength steel and stainless steel, high nitrogen steel and stainless steel, etc., which are harder on the outside and have better toughness on the inside.

[0011] Furthermore, in step (1), the method for obtaining the model of the area to be repaired is, for the damaged area, preferably using a three-dimensional scanner to scan the damaged part to construct its three-dimensional image; for the damaged area with limited scanning, X-ray non-destructive testing, ultrasonic non-destructive testing, etc. can be used to obtain the geometric information of the damaged part.

[0012] Furthermore, in step (1), the damaged parts of the interlayer heterogeneous and heterogeneous components are processed into regular areas to be repaired, and the processing ideas include but are not limited to: the areas to be repaired can be processed into inverted frustum shapes with matching sizes according to the location, shape, size and depth of the damaged parts.

[0013] Furthermore, during the processing of the damaged part, the upper base radius, lower base radius, and depth requirements can be obtained through the geometric model of the damaged area. The taper of the inverted cone obtained by milling is preferably 2:1. Under the condition of including the damaged part, the processing size of the repair area can be obtained.

[0014] Furthermore, in step (2), the selection of welding wire can be based on the requirements of the repair effect, and the same additive wire as the damaged additive part or other suitable wire with good metallurgical bonding with the damaged additive part can be selected.

[0015] Furthermore, in step (2), the idea of ​​planning the additive repair path for each layer includes but is not limited to concentric circle and zigzag additive paths.

[0016] Furthermore, when planning the repair path, the additive gun scans in real time whether it will hit a wall on the path, and adjusts the positioning of the additive gun in real time to control the additive position.

[0017] Furthermore, in step (3), during the additive repair process, if a higher repair accuracy needs to be ensured, the upper surface can be milled flat after each repair layer, and then subsequent additive repair can be performed.

[0018] Compared with the prior art, the present invention has the following significant advantages: At present, additive repair technology is mainly focused on the repair of the same material, and there is very little research on the additive repair technology of heterogeneous and heterogeneous materials. The present invention provides a flexible and changeable repair idea for the repair of heterogeneous and heterogeneous components. For heterogeneous and heterogeneous components with different damaged sizes and positions, the damaged area can be processed into different standard repair areas, and corresponding to different additive repair paths, the repair efficiency is higher and the repair effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the heterogeneous and heterogeneous components to be repaired in Example 1 of the present invention.

[0020] Figure 2 It is a schematic diagram of the concentric circle additive repair path of Example 1 of the present invention.

[0021] Figure 3 This is a photograph of the ultra-high strength steel-stainless steel interlayer heterogeneous component obtained before additive repair in Example 1 of the present invention.

[0022] Figure 4 This is a photograph of the ultra-high strength steel-stainless steel interlayer heterogeneous component obtained after additive repair in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with specific embodiments:

[0024] Example 1

[0025] This example requires repairing a pulse cold metal transition additively manufactured ultra-high strength steel-stainless steel interlayer heterogeneous component. The wire material in the repair area is required to be consistent with the wire material in the original component. For the damaged area, a 3D scanner is used to scan the damaged part to construct its 3D image to obtain the geometric information of the damaged part. Through processing planning, the required frustum of the repaired area is 60mm in upper diameter, 40mm in lower diameter, and 2:1 in taper. The damaged part has been processed into a regular frustum by a milling machine, and its bottom is flush with the bottom of the stainless steel layer. Figure 1 As shown, the repaired part is a 150*130*20mm rectangular block. The dark part is the ultra-high strength steel additive area, the light part is the ER316L stainless steel additive area, the frustum part is the repaired area, and the bottom is a 304 stainless steel plate.

[0026] According to the requirements, the same stainless steel material, ER316L, is used to repair the stainless steel area, and the wire diameter is 1.20mm. The same ultra-high-strength steel material is used to repair the ultra-high-strength steel area, and the wire diameter is 1.60mm. The ultra-high-strength steel wire and the stainless steel wire are installed in two VR7000-CMT wire feeders respectively. The chemical composition of the wire and the substrate is shown in Table 1.

[0027] Table 1 Chemical composition of wire and substrate

[0028]

[0029] The depth of the area to be repaired in the rounded table is 10mm and the taper is 2:1. The repair area model is sliced ​​and divided into 4 layers, that is, one layer of stainless steel is added and then 3 layers of ultra-high strength are added. Each layer is repaired by a concentric circle additive path. Figure 2 .

[0030] Both materials were repaired using the pulsed cold metal transition additive mode. The experimental equipment used was the CMT RCU5000i welding machine from Fronius. The CMT welding machine was automatically matched with the unified program in the corresponding material library. First, the CMT stainless steel welding program was used to build up a layer of stainless steel in the repair area. The stainless steel wire feeding speed was set to 5.00 m / min, the welding speed was 9.50 mm / s, the inward offset was 4.1 mm, and the shielding gas was 98.50% Ar+1.50% O 2 , the shielding gas flow rate is 20.00L / min, then select the CMT ultra-high strength steel welding program to weld 3 layers of ultra-high strength steel in the repair area, set the ultra-high strength steel wire feeding speed to 5.00m / min, the welding speed to 7.50mm / s, the inward offset to 5.2mm, the shielding gas to 99.99%Ar, the shielding gas flow rate to 25.00L / min, and the additive repair is completed. Figure 4 .

[0031] The repair effect was tested by using a universal tensile testing machine for tensile testing at a tensile loading speed of 1 mm / min. The tensile strength of the original ultra-high strength steel additive area was between 994.40 and 1081.39 MPa, and the tensile strength of the ultra-high strength steel in the repair area was between 781.15 and 873.01 MPa. The average tensile strength of the repair area tensile test can reach 80% of the original. The impact test of the Charpy U-notch specimen was carried out using a drop hammer impact testing machine with a pre-lift angle of 150°, and the impact test of the original ultra-high strength steel additive area was obtained. The average absorbed energy of the sample is 116.40J, and the average absorbed energy of the impact sample of the ultra-high strength steel in the repaired area is 98.33J. The average absorbed energy of the impact sample in the repaired area can reach 84% of the original part. The hardness test using a Vickers hardness tester obtained that the average hardness of the original ultra-high strength steel additive area is 280.6HV, and the average hardness of the ultra-high strength steel in the repaired area is 282.2HV; the average hardness of the original stainless steel additive area is 189.8HV, and the average hardness of the stainless steel in the repaired area is 187HV. It can be seen that the hardness of the repaired area has reached the hardness level of the original part.

Claims

1. A method for additive repair of interlayer heterogeneous and heterogeneous components, characterized in that: The steps include: Step (1): obtain a model, provide a damaged part with heterogeneous and heterogeneous layers, process the damaged part into a regular area to be repaired, obtain a repair model of the repair area, and reasonably arrange the required additive process according to needs; Step (2): Repair preparation: select the corresponding welding wire according to the heterogeneous materials of the heterogeneous components, plan the additive path of each layer according to the repair model, and write the robot walking program; Step (3): Start repairing by matching the optimal process parameters according to the planned additive path and starting additive repair of the structural parts.

2. The additive repair method for interlayer heterogeneous components according to claim 1 is characterized in that: The heterogeneity mentioned above indicates two or more materials, and heterogeneity refers to interlayer heterogeneity, including but not limited to: such as soft and hard interwoven layered bionic shell structures with excellent comprehensive mechanical properties, ultra-high strength steel and stainless steel, high strength steel and stainless steel, high nitrogen steel and stainless steel, etc., which are harder on the outside and have better toughness on the inside.

3. The additive repair method for interlayer heterogeneous components according to claim 1 is characterized in that: In step (1), the method for obtaining the model of the area to be repaired is, for the damaged area, preferably using a three-dimensional scanner to scan the damaged part and construct its three-dimensional image; for the damaged area with limited scanning, X-ray non-destructive testing, ultrasonic non-destructive testing, etc. are used to obtain the geometric information of the damaged part.

4. The additive repair method for interlayer heterogeneous components according to claim 1, characterized in that: In step (1), the damaged part of the interlayer heterogeneous and heterogeneous components is processed into a regular area to be repaired, and the processing ideas include but are not limited to: the area to be repaired can be processed into an inverted frustum of a cone with matching size according to the position, shape, size and depth of the damaged part.

5. The additive repair method for interlayer heterogeneous components according to claim 4 is characterized in that: During the processing of the damaged parts, the upper base radius, lower base radius, and depth requirements can be obtained through the geometric model of the damaged area. The taper of the frustum obtained by milling is 2:

1. Under the condition of including the damaged parts, the processing dimensions of the repair area can be obtained.

6. The additive repair method for interlayer heterogeneous components according to claim 1, characterized in that: In step (2), the selection of welding wire can be based on the requirements of the repair effect, and the same additive wire as the damaged additive part or other suitable wire with good metallurgical bonding with it can be selected.

7. The additive repair method for interlayer heterogeneous and heterogeneous components according to claim 1 is characterized in that: In step (2), the idea of ​​planning the additive repair path for each layer includes but is not limited to concentric circle and zigzag additive paths.

8. The additive repair method for interlayer heterogeneous components according to claim 7 is characterized in that: When planning the repair path, the additive gun scans in real time whether it will hit a wall on the path, and adjusts the positioning of the additive gun in real time to control the additive position.

9. The additive repair method for interlayer heterogeneous components according to claim 1, characterized in that: In step (3), during the additive repair process, if a higher repair accuracy needs to be ensured, the upper surface can be milled flat after each repair layer, and then subsequent additive repair can be performed.

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