Laser cladding repairing method based on component regulation and control

Abstract

The invention provides a laser cladding repairing method based on component regulation and control, and relates to the technical field of laser cladding repairing. Calculating the yield strength difference between the as-cast substrate and the cladding layer based on a Hall-Pearch formula, the Hall-Pearch formula being sigma y = sigma 0 + k * d-0. 5, and sigma y being the yield strength of the material; sigma 0 is the yield strength when the grain boundary is not strengthened, k is the Hall-Pearch slope of the material, and d is the average grain size; according to the yield strength difference value, the content of strengthening elements in cladding alloy of the cladding layer is adjusted so as to adjust the sigma0 value of the cladding layer, and the yield strength of the adjusted cladding layer can be matched with the yield strength of the as-cast base material; and alloy powder is prepared according to the adjusted content of the strengthening elements, and the to-be-repaired area is subjected to laser cladding through the alloy powder. The method gives consideration to alloy structure regulation and repair performance matching, is suitable for high-performance remanufacturing repair of various as-cast copper alloy parts, and is also suitable for other alloy materials meeting the Hall-Pearch relationship.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser cladding repair, and particularly relates to a repair method based on laser cladding with component regulation. BACKGROUND

[0002] In a traditional laser cladding process, a material with the same component as a base material is usually used for repair. However, since the base material is usually in a cast state and has coarse grains, and the cladding layer has fine grains after rapid solidification, there is a significant difference in mechanical properties between the two. If an experimental method is used for trial, on the one hand, it is time-consuming and laborious, and on the other hand, in order to prepare a tensile sample, the thickness of the cladding layer must be more than 3 mm, while the thickness of a single cladding layer is usually about 1 mm, which means that at least 2-3 cladding layers need to be prepared to meet the sample preparation requirements of the tensile sample. In the process of preparing multiple cladding layers, the last cladding layer is continuously remelted by heat output, resulting in a change in grain size. Generally, the more layers of cladding layers, the larger the grain size, resulting in a change in tensile properties of the cladding layer. The performance of the tensile sample prepared in this way cannot truly reflect the actual performance of a single cladding layer, and the performance matching of the base material and the repair layer cannot be achieved.

[0003] Therefore, there is an urgent need to provide a repair method for laser cladding to solve the above problems. SUMMARY

[0004] The purpose of the present application is to provide a repair method for laser cladding based on component regulation to solve the above problems.

[0005] To achieve the above purpose, the present application provides a repair method for laser cladding based on component regulation, comprising: calculating a yield strength difference between a cast base material and a cladding layer based on a Hall-Petch formula, the Hall-Petch formula being: σ y =σ0+k×d -0.5 , wherein σ y is the yield strength of the material, σ0 is the yield strength when the grain boundary is not strengthened, k is the Hall-Petch slope of the material, and d is the average grain size; adjusting the content of a strengthening element in the cladding alloy of the cladding layer according to the yield strength difference, so as to adjust the σ0 value of the cladding layer, so that the yield strength of the adjusted cladding layer matches the yield strength of the cast base material; preparing an alloy powder according to the content of the adjusted strengthening element, and using the alloy powder to perform laser cladding on a region to be repaired.

[0006] Optionally, the cast base material and the cladding layer have the same element composition.

[0007] Optionally, the as-cast base material and the cladding layer comprise one or more of copper-based alloy, iron-based alloy, nickel-based alloy, aluminum-based alloy.

[0008] Optionally, the as-cast base material comprises ZCuAl8Mn 13 Fe3Ni2 copper alloy.

[0009] Optionally, the grain size of the as-cast base material is 0.05-1 mm.

[0010] Optionally, the grain size of the cladding layer is 0.001-0.05 mm.

[0011] Optionally, the strengthening element comprises one or more of Mn, Al, Fe and Ni.

[0012] Optionally, the mass content of the strengthening element in the alloy powder is lower than the content of the strengthening element in the cladding layer by 2.7%-4.06%.

[0013] Optionally, the thickness of the repair layer obtained by the laser cladding is less than or equal to 1.5 mm.

[0014] Optionally, the matching refers to that the difference between the yield strength of the adjusted cladding layer and the yield strength of the as-cast base material is less than or equal to 10%.

[0015] Compared with the prior art, the beneficial effects of the present application include: The repair method for laser cladding based on component regulation provided by the present application adjusts the content of the chemical element in the alloy powder to be cladded, and optimizes the content of other elements, so that the fine-grained structure formed by laser cladding is matched with the coarse-grained as-cast base material in terms of strength and hardness, thereby improving the repair bonding quality and service stability; the method takes into account alloy organization regulation and repair performance matching, is suitable for high-performance remanufacturing repair of various as-cast copper alloy parts, and is also suitable for other alloy materials satisfying the Hall-Petch relationship. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope of the present application.

[0017] Figure 1 SEM image of the as-cast base material provided for Example 1; Figure 2 SEM image of the repaired cladding layer provided for Example 1; Figure 3 SEM image of the repaired cladding layer provided for Comparative Example 1. DETAILED DESCRIPTION

[0018] As used herein the terms "about" and "substantially" mean approximately or nearly, as in "about 90%," "substantially similar," or "substantially identical." "Made by" is synonymous with "comprising." The terms "comprising," "including," "having," "containing," or any other similar term are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0019] When expressing a value or parameter, such as an equivalent weight, concentration, or other value or parameter, as a range, preferably a range, or a series of upper preferred values and lower preferred values, it should be understood that all ranges formed by any pair of an upper or preferred value and a lower or preferred value, whether or not the range is expressly disclosed, are specifically disclosed. For example, when a range "1-5" is disclosed, the described range should be interpreted to include ranges "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," and the like. When numerical ranges are described herein, unless otherwise stated, the range is intended to include the end values and all integers and fractions within that range.

[0020] In these examples, the parts and percentages are by mass unless otherwise indicated.

[0021] "Mass parts" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass of component A is a parts, and the mass of component B is b parts, it means that the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, representing a multiple factor). It should not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0022] "and / or" is used to indicate one or both of the stated circumstances can occur, for example, A and / or B includes (A and B) and (A or B).

[0023] The present application provides a repair method based on ingredient regulation of laser cladding, comprising: The yield strength difference between the as-cast base material and the cladding layer is calculated based on the Hall-Petch formula, and the Hall-Petch formula is: σ y =σ0+k×d -0.5 , wherein σ y is the yield strength of the material, σ0 is the yield strength when the grain boundary is not strengthened, k is the Hall-Petch slope of the material, and d is the average grain size; It should be noted that the k value of the Hall-Petch slope of the as-cast base material and the cladding layer can be obtained by experiment or literature; According to the yield strength difference, the content of the strengthening element in the cladding alloy of the cladding layer is adjusted to adjust the σ0 value of the cladding layer, so that the yield strength of the adjusted cladding layer and the yield strength of the as-cast base material match; According to the content of the adjusted strengthening element, an alloy powder is prepared, and the alloy powder is used for laser cladding on the repaired area.

[0024] It should be noted that since the laser cladding forms fine-grained structure (smaller than the grain size of the base material), the σ y of the cladding layer is obviously higher than that of the as-cast material; in order to match the yield strength of the as-cast base material after repair, the σ y熔覆层 of the cladding layer needs to be y铸态基体 , that is, σ0+k·d 熔覆层 -0.5 ≈σ0+k·d 铸态基体 -0.5 .

[0025] Since the grain size (d) is known (which can be tested by experiment), k is an inherent value of the alloy, and therefore σ0 can be adjusted, that is, the yield strength of the cladding layer is reduced by reducing the Mn in the cladding material; for example, for ZCuAl8Mn 13 Fe3Ni2 alloy, k≈4MPa·mm 0.5 , by substitution, the difference between the cladding layer and the as-cast base material is: σ y熔覆层 -σ y铸态基体 =σ0+k·d 熔覆层 -0.5 -σ0+k·d 铸态基体 -0.5 =(0.01 -0.5 -0.28 -0.5 )k=32.44MPa; For ZCuAl8Mn 13 Fe3Ni2 alloy, for every 1wt% increase in Mn, the yield strength increases by about 8-12 MPa, so it is necessary to reduce 2.70-4.06wt% of Mn to achieve the matching of the yield strength of the cladding layer and the base material.

[0026] In some embodiments, the as-cast base material and the cladding layer have the same element composition.

[0027] In some embodiments, the as-cast base material and the cladding layer comprise one or more of a copper-based alloy, an iron-based alloy, a nickel-based alloy, and an aluminum-based alloy.

[0028] In some embodiments, the as-cast substrate comprises ZCuAl8Mn 13 Fe3Ni2 copper alloy.

[0029] In some embodiments, the as-cast substrate has a grain size of 0.05-1 mm.

[0030] Optionally, the grain size of the as-cast substrate can be 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, or any value between 0.05-1 mm.

[0031] In some embodiments, the cladding layer has a grain size of 0.001-0.05 mm.

[0032] Optionally, the grain size of the cladding layer can be 0.001 mm, 0.005 mm, 0.01 mm, 0.05 mm, or any value between 0.001-0.05 mm.

[0033] In some embodiments, the strengthening element comprises one or more of Mn, Al, Fe, and Ni.

[0034] In some embodiments, the mass content of the strengthening element in the alloy powder is 2.7%-4.06% lower than the content of the strengthening element in the cladding layer.

[0035] Optionally, the mass content of the strengthening element in the alloy powder can be 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.06%, or any value between 2.7%-4.06% lower than the content of the strengthening element in the cladding layer.

[0036] In some embodiments, the thickness of the repair layer obtained by the laser cladding is less than or equal to 1.5 mm.

[0037] It should be noted that the repair layer is a single layer, and the thickness of the repair layer is less than or equal to 1.5 mm, to ensure that the grain size matches the theoretical calculation. Limiting the thickness of the laser cladding coating to not more than 1.5 mm can effectively reduce the substrate dilution rate, refine the grain structure, improve the coating density and uniformity, reduce the residual stress and the tendency of thermal cracks, and ensure the formation of stable metallurgical bonding between the coating and the substrate, thereby significantly improving the comprehensive service performance and process stability of the cladding coating.

[0038] In some embodiments, the matching refers to the difference between the yield strength of the adjusted cladding layer and the yield strength of the as-cast substrate being less than or equal to 10%.

[0039] Optionally, the difference between the yield strength of the adjusted cladding layer and the yield strength of the as-cast base material can be 0.01%, 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any value less than or equal to 10%.

[0040] It should be noted that in this application, by limiting the difference between the yield strength of the repair coating and the base material to be less than or equal to 10%, the problem of mismatching of the mechanical properties of the coating and the substrate commonly existing in traditional laser cladding repair can be effectively solved. If the difference in yield strength is too large, the load transfer is uneven during service, which can easily form a stress concentration zone at the coating / substrate interface, leading to interface peeling, crack initiation and propagation, and other failure behaviors. Controlling the difference in yield strength within 10% can achieve the following beneficial effects: Interface coordinated deformation: the repair layer and the substrate can produce plastic deformation under external load, significantly reducing the accumulation of interface discontinuous strain.

[0041] Stress distribution uniformization: reduces the stress concentration effect in the interface area, avoiding local stress exceeding the yield limit of the coating or substrate and inducing early failure.

[0042] Macroscopic mechanical property matching: ensures that the overall mechanical properties of the repaired parts are close to the original substrate state, meeting the long-term stable service requirements of engineering structures. Therefore, this design principle not only optimizes the mechanical matching of the cladding repair layer and the substrate, but also significantly improves the structural integrity and use reliability of the repaired parts, having obvious engineering application value.

[0043] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0044] Example 1 The present embodiment provides a repair method based on composition control laser cladding, the specific steps comprising: S1: The grain size of the as-cast base material (ZCuAl8Mn 13 Fe3Ni2 copper alloy) and the surface part of the intact cladding layer is measured by a gold hand segment, which is 0.28 mm and 0.01 mm respectively, and the element composition of the as-cast base material and the cladding layer is the same; S2: According to the Hall-Page formula σ y =σ0+k×d -0.5 , the theoretical yield strength difference is calculated, where σ y =σ0+k×0.01-0.5 ; cast base material σ y = σ0+ k x 0.28 -0.5 , so that the yield strength difference Δσ = σ y熔覆层 - σ y铸态基体 = σ0+ k x d 熔覆层 -0.5 - σ0+ k x d 铸态基体 -0.5 = (0.01 -0.5 - 0.28 -0.5 ) k ≈ 32.44 MPa; S3: Since Mn is a strengthening element, the experimentally measured effect of Mn on the increase of yield strength is 8-12 MPa / %, and accordingly, the Mn content needs to be reduced by about 2.7wt%-4.06wt%; S4: According to the element content of the modified alloy powder, the raw material is weighed according to the chemical formula ZCuAl8Mn 9.6 Fe3Ni2, and the powder is prepared by gas atomization method; S5: The powder prepared in the S4 step is used for laser cladding on the surface of the base material to be repaired to prepare a single-layer cladding layer sample.

[0045] The repaired cladding layer is subjected to microscopic structure analysis and tensile property test, and the yield strength of the repaired cladding layer is 405 MPa, and the difference ratio with the yield strength 389 MPa of the base material is 4.1%. The repaired cladding layer has a dense structure and good interface bonding with the base material.

[0046] The SEM of the cast base material in this embodiment is shown in Figure 1 .

[0047] The SEM of the repaired cladding layer in this embodiment is shown in Figure 2 .

[0048] Example 2 The difference from Example 1 is that in the S4 step, the raw material is weighed according to the chemical formula ZCuAl8Mn9Fe3Ni2.

[0049] Example 3 The difference from Example 1 is that in the S4 step, the raw material is weighed according to the chemical formula ZCuAl8Mn 10.3 Fe3Ni2.

[0050] Comparative Example 1 This comparative example provides a repair method of laser cladding, and the difference from Example 1 is that the same material as the base material (ZCuAl8Mn 13 Fe3Ni2 copper alloy) is used for laser cladding.

[0051] The SEM of the repaired cladding layer in the present comparative example is shown in Figure 3

[0052] Comparative Example 2 The difference from Example 1 is that the amount of raw materials is weighed according to the chemical formula ZCuAl8Mn5Fe3Ni2 in the S4 step.

[0053] The repaired cladding layer and the base material of the above examples and comparative examples are subjected to performance testing, and the specific data are shown in Table 1.

[0054] Table 1 Performance Test

[0055] Analysis: As can be seen from the results in Table 1, the difference between the yield strength of the repaired cladding layer after composition control and the base material is controlled within 10%, and the difference ratio of Examples 1, 2 and 3 is 4.1%, 2.1% and 6.4% respectively, which are significantly lower than 10%. Compared with Comparative Example 1 (difference ratio of 13.9%) and Comparative Example 2 (difference ratio of 11.5%), the repaired cladding layer of the examples realizes good matching with the base material in mechanical properties. This result shows that by reducing the Mn content, the strength of the cladding layer is precisely adjusted, so that the yield strength is close to that of the base material. When the yield strength difference ratio is ≤10%, the repaired layer and the base material can realize synchronous deformation under external load, effectively reducing the stress concentration in the interface area, and ensuring good bonding state. The microstructure analysis results show that the repaired cladding layer has a dense structure without obvious defects, and is tightly combined with the base material, avoiding the risk of crack initiation and propagation caused by strength mismatch. When the strength difference ratio exceeds 10%, the yield strength of the cladding layer is too high (Comparative Example 1) or too low (Comparative Example 2), which will lead to stress imbalance between the base material and the cladding layer, thereby affecting the long-term service stability of the repaired layer.

[0056] In summary, the present application realizes precise matching of the yield strength of the laser cladding repaired layer and the base material based on composition control, effectively solves the problem of uneven mechanical properties in traditional repair, and significantly improves the structural integrity and service reliability of the repaired parts.

[0057] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present application.

[0058] ​Furthermore, to the extent that the terms "comprises", "comprising", "includes", "including" and "has" or any variation thereof are used in the following description and / or claims, such terms are intended to include a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, where appropriate to context, the above description and / or claims can refer to actions to be taken by a person or apparatus. Such actions are sometimes referred to as being taken "by the person" or "by the apparatus". Although some embodiments can be described in one preferred embodiment, it is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. A repair method based on compositionally regulated laser cladding, characterized in that, The method comprises the following steps: The yield strength difference between the as-cast base material and the cladding layer is calculated based on the Hall-Petch formula: σ y = σ0 + k x d -0.5 where σ y is the yield strength of the material; σ0 is the yield strength when the grain boundary is not strengthened, k is the Hall-Petch slope of the material, and d is the average grain size. According to the yield strength difference, the content of the strengthening element in the cladding alloy of the cladding layer is adjusted to adjust the σ0 value of the cladding layer, so that the yield strength of the adjusted cladding layer matches the yield strength of the as-cast base material; According to the content of the adjusted strengthening element, an alloy powder is prepared, and the laser cladding is performed on the repaired area using the alloy powder.

2. The compositionally regulated laser cladding repair method of claim 1, wherein, The as-cast base material and the cladding layer have the same element composition.

3. The compositionally regulated laser cladding repair method of claim 1, wherein, The as-cast base material and the cladding layer comprise one or more of copper-based alloy, iron-based alloy, nickel-based alloy, and aluminum-based alloy.

4. The compositionally regulated laser cladding repair method of claim 3, wherein, The as-cast base material comprises ZCuAl8Mn 13 Fe3Ni2 copper alloy.

5. The compositionally regulated laser cladding repair method of claim 1, wherein, The grain size of the as-cast base material is 0.05-1 mm.

6. The compositionally regulated laser cladding repair method of claim 1, wherein, The grain size of the cladding layer is 0.001-0.05 mm.

7. The compositionally regulated laser cladding repair method of claim 1, wherein, The strengthening element comprises one or more of Mn, Al, Fe, and Ni.

8. The compositionally regulated laser cladding repair method of claim 1, wherein, The mass content of the strengthening element in the alloy powder is 2.7%-4.06% lower than the content of the strengthening element in the cladding layer.

9. The compositionally regulated laser cladding repair method of claim 1, wherein, The thickness of the repaired layer obtained by the laser cladding is less than or equal to 1.5 mm.

10. The repair method by ingredient-regulated laser cladding according to any one of claims 1 to 9, characterized in that, The matching refers to that the yield strength difference between the adjusted cladding layer and the as-cast base material is less than or equal to 10%.

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