A method for preparing a wear-resistant layer on the surface of a cryogenic rotating shaft

Abstract

The application discloses a preparation method of a super-low-temperature rotating shaft surface wear-resistant layer in the technical field of rotating shaft wear prevention, and comprises the following steps: S10, cleaning the outer circumferential surface of the rotating shaft; S20, performing penetration inspection on the outer circumferential surface of the rotating shaft; S30, forming a surfacing layer on the outer circumferential surface of the rotating shaft that passes the penetration inspection by means of welding; S40, performing stress relief heat treatment on the surfacing layer; S50, rough turning the surfacing layer and performing nondestructive flaw detection; S60, fine turning the surfacing layer that passes the nondestructive flaw detection into a wear-resistant layer; and S70, performing rolling treatment on the wear-resistant layer. The surfacing layer is formed on the outer circumferential surface of the rotating shaft by means of the welding process, the hardness of the wear-resistant layer on the rotating shaft exceeds 300HV, the wear-resistant layer is compressed and deformed by means of the rolling process, and the hardness and service life of the wear-resistant layer are improved, so that the wear-resistant requirement of the rotating shaft under a super-low-temperature environment is met, the wear risk of the outer circumferential surface of the super-low-temperature rotating shaft is effectively reduced, and the service life of the super-low-temperature rotating shaft is prolonged.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant technology for rotating shafts, and specifically to a method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft. Background Technology

[0002] Cryogenic operating environments require materials with excellent low-temperature strength and toughness. 9Ni steel possesses excellent low-temperature toughness and can be used at -196℃, making it a relatively ideal cryogenic material. For rotating shaft components, their surfaces often require wear resistance. However, due to the insufficient hardness of 9Ni steel, if it is used directly as a rotating shaft, the surfaces of the contacting friction points will experience a certain degree of wear during long-term use, thus affecting the service life and rotational stability of the rotating shaft in cryogenic environments. Therefore, selecting a wear-resistant layer that maintains the excellent low-temperature toughness of the rotating shaft substrate while also possessing good wear resistance is a pressing issue that needs to be addressed for cryogenic rotating shafts. Under normal room temperature or high-temperature conditions, commonly used wear-resistant materials are cobalt-based alloys or ordinary martensitic steels; however, these materials have poor low-temperature toughness and cannot be used in cryogenic environments. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a wear-resistant layer on the surface of an ultra-low temperature rotating shaft to solve the technical problem of wear risk on the outer circumferential surface of an ultra-low temperature rotating shaft.

[0004] The technical solution adopted in this invention is: a method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft, comprising the following steps:

[0005] S10: Clean the outer circumference of the rotating shaft;

[0006] S20: Perform a penetrant test on the outer circumferential surface of the rotating shaft;

[0007] S30: A weld overlay is formed on the outer circumferential surface of the rotating shaft that has passed the penetration test by welding;

[0008] S40: Perform stress-relief heat treatment on the weld overlay layer;

[0009] S50: Rough machining of the weld overlay and performing non-destructive testing;

[0010] S60: The weld overlay layer that has passed non-destructive testing is precision machined into a wear-resistant layer;

[0011] S70: The wear-resistant layer is subjected to a rolling process.

[0012] Preferably, the chemical composition and weight percentage of the weld overlay in S30 are as follows: C: ≤0.04, Si: 0.3~0.6, Mn: 0.4~0.6, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu: ≤0.2, and the balance Fe.

[0013] The welding methods in S30 include submerged arc welding, argon arc welding, plasma arc welding, and laser welding.

[0014] Preferably, the welding method in S30 is submerged arc welding, and its welding process parameters are as follows: the diameter of the first layer of welding wire is 2.0 mm, the welding current is 300A to 350A, the welding voltage is 20V to 25V, and the welding speed is 30cm / min to 40cm / min; the diameter of the remaining layers of welding wire is 3.0 mm, the welding current is 350A to 400A, the welding voltage is 22V to 30V, and the welding speed is 40cm / min to 50cm / min; and the interpass temperature is not higher than 120℃.

[0015] Preferably, the chemical composition and weight percentage of the welding wire used in welding in S30 are as follows: C: ≤0.05, Si: ≤0.5, Mn: ≤0.5, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu≤0.2, and the balance Fe.

[0016] Preferably, the chemical composition and weight percentage of the flux used in welding in S30 are as follows: SiO2+TiO2: 15, CaO+MgO: 35, Al2O3+MnO: 21, CaF2: 26, and the balance is K2O+Na2O.

[0017] Preferably, the stress-relieving heat treatment temperature in S40 is 500℃~550℃, and the holding time is 6h~8h.

[0018] Preferably, the non-destructive testing in S50 includes ultrasonic testing and surface crack testing.

[0019] Preferably, the wear-resistant layer in S60 has a thickness of 2mm to 10mm and a surface hardness exceeding 300HV.

[0020] Preferably, the rolling process in S70 uses an elastic rolling tool and the pressure is 100 bar to 150 bar.

[0021] Preferably, the rotating shaft is a 9Ni steel forging.

[0022] The beneficial effects of this invention are:

[0023] This invention forms a weld overlay layer on the outer circumference of a rotating shaft using submerged arc welding, which alters the composition of the surface layer of the rotating shaft, making the wear-resistant layer on the rotating shaft surface have a hardness exceeding 300HV, meeting the wear resistance requirements in ultra-low temperature environments. Then, the weld overlay layer is compressed and deformed through a rolling process, which can not only effectively reduce the wear risk on the outer circumference of the rotating shaft and extend the service life of the rotating shaft in ultra-low temperature environments, but also has the advantages of simple process, easy operation, high production efficiency and low cost. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the manufacturing process of the wear-resistant layer on the surface of the ultra-low temperature rotating shaft according to the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] Examples, such as Figure 1 As shown, a method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft includes the following steps:

[0030] S10: Clean the outer circumference of the rotating shaft.

[0031] Specifically, the outer circumferential surface of the rotating shaft is first degreased and derusted, and then acetone is used to clean the outer circumferential surface of the rotating shaft to ensure its cleanliness; the rotating shaft is a 9Ni steel forging.

[0032] S20: Perform a penetrant test on the outer circumferential surface of the rotating shaft to ensure it is free of defects.

[0033] S30: A weld overlay is formed on the outer circumferential surface of a rotating shaft that has passed the penetration test by welding.

[0034] Specifically, a rotating shaft that has passed the penetration test is selected, and a submerged arc welding process is used to build up a 9mm to 12mm thick weld overlay on the outer circumference of the rotating shaft, and the weld overlay covers all contact and friction parts of the rotating shaft.

[0035] During the surfacing process, a submerged arc welding machine is preferred for surfacing the outer circumference of the rotating shaft. For the first layer, the welding wire diameter is 2.0 mm, the welding current is 300A to 350A, the welding voltage is 20V to 25V, and the welding speed is 30cm / min to 40cm / min, using a lower heat input and controlling a lower dilution rate. For the remaining layers, the welding wire diameter is 3.0 mm, the welding current is 350A to 400A, the welding voltage is 22V to 30V, and the welding speed is 40cm / min to 50cm / min. The interpass temperature should not exceed 120℃.

[0036] The chemical composition and weight percentage of the submerged arc welding wire are as follows: C: ≤0.05, Si: ≤0.5, Mn: ≤0.5, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu≤0.2, and balance Fe. The chemical composition and weight percentage of the submerged arc welding flux are as follows: SiO2+TiO2: 15, CaO+MgO: 35, Al2O3+MnO: 21, CaF2: 26, and balance K2O+Na2O.

[0037] This design is based on the following: By selecting different welding wires and fluxes during the welding process, a weld overlay layer with a chemical composition different from that of the rotating shaft can be formed on the outer circumference of the rotating shaft. When the chemical composition and weight percentage of the weld overlay layer are: C: ≤0.04, Si: 0.3~0.6, Mn: 0.4~0.6, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu: ≤0.2, and the balance Fe, the weld overlay layer can not only ensure that the contact parts of the rotating shaft maintain the low-temperature toughness of 9Ni steel, but also improve the surface hardness of the rotating shaft.

[0038] S40: Stress-relieving heat treatment is applied to the weld overlay.

[0039] Specifically, the weld overlay on the rotating shaft is heated to 500℃~550℃, held for 6h~8h and then cooled to remove the stress generated during welding, while ensuring that the hardness of the weld overlay reaches above 300HV and has virtually no impact on the excellent low-temperature performance of the substrate.

[0040] S50: Rough machining of the weld overlay layer, followed by non-destructive testing.

[0041] Specifically, the surface of the weld overlay on the rough-machined rotating shaft is made to meet the requirements of non-destructive testing, and ultrasonic testing and surface crack testing are used to perform non-destructive testing on the weld overlay.

[0042] S60: The weld overlay that has passed non-destructive testing is precision machined into a wear-resistant layer with a thickness of 7mm to 10mm.

[0043] S70: The wear-resistant layer is rolled to form compressive stress on the surface of the wear-resistant layer, thereby improving the hardness and service life of the wear-resistant layer.

[0044] Specifically, an elastic rolling tool is used to apply a pressure of 100 bar to 150 bar to the surface of the wear-resistant layer, so as to cause compression deformation of the surface of the wear-resistant layer, thereby further improving the hardness of the wear-resistant layer and extending the service life of the rotating shaft.

[0045] Comparison table of mechanical properties of wear-resistant layer on rotating shaft surface and 9Ni steel in this application

[0046] category room temperature tensile strength Tensile strength at -196℃ Room temperature surface hardness The wear-resistant layer on the rotating shaft surface of this application ≥950MPa ≥1050MPa ≥300HV 9Ni steel ≤820MPa ≤240HV

[0047] Compared with the prior art, this application has at least the following beneficial technical effects:

[0048] 1. This application employs a welding process to form a weld overlay layer on the outer circumference of the rotating shaft, preferably submerged arc welding. This alters the chemical composition of the surface layer of the rotating shaft, resulting in a wear-resistant layer of low-carbon martensitic steel. Low-carbon martensitic steel possesses good low-temperature toughness and hardness, making it suitable not only for low-temperature environments but also enabling the rotating shaft to achieve the required surface hardness for wear resistance. Furthermore, a rolling process generates compressive stress on the outer circumference of the wear-resistant layer, further hardening the surface and extending its lifespan. This effectively reduces the risk of wear on the outer surface of the rotating shaft in ultra-low temperature environments, significantly extending the service life of the rotating shaft in ultra-low temperature environments and maintaining the smoothness of the transmission shaft's rotation.

[0049] 2. This application uses welding to deposit a wear-resistant layer on the surface of the rotating shaft, which can ensure a high bonding force between the rotating shaft substrate and the wear-resistant layer under low temperature conditions. The life of the wear-resistant layer is improved by rolling process. Compared with other process methods, this preparation method has the advantages of strong bonding force of wear-resistant layer, good wear resistance, long service life, simple process, easy operation, high production efficiency and low cost.

[0050] 3. The production of ultra-low temperature rotating shafts using the preparation method of this application can effectively enhance the wear resistance of the rotating shaft surface, thereby enabling long-term and safe operation of shaft components in ultra-low temperature environments.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft, characterized in that, Includes the following steps: S10: Clean the outer circumferential surface of the rotating shaft; S20: Perform a penetrant test on the outer circumferential surface of the rotating shaft; S30: A weld overlay is formed on the outer circumferential surface of the rotating shaft that has passed the penetration test by welding; S40: Perform stress-relief heat treatment on the weld overlay layer; S50: Rough machining of the weld overlay and performing non-destructive testing; S60: The weld overlay layer that has passed non-destructive testing is precision machined into a wear-resistant layer; S70: The wear-resistant layer is subjected to a rolling process; The chemical composition and weight percentage of the weld overlay in S30 are as follows: C: ≤0.04, Si: 0.3~0.6, Mn: 0.4~0.6, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu: ≤0.2, and the balance is Fe; The chemical composition and weight percentage of the welding wire used in S30 are as follows: C: ≤0.05, Si: ≤0.5, Mn: ≤0.5, P: ≤0.02, S: ≤0.02, Cr: 11.5~13.0, Ni: 4.0~5.0, Mo: 0.4~0.7, Cu≤0.2, and the balance Fe; the chemical composition and weight percentage of the flux used in welding are as follows: SiO2+TiO2: 15, CaO+MgO: 35, Al2O3+MnO: 21, CaF2: 26, and the balance K2O+Na2O.

2. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The welding methods in S30 include submerged arc welding, argon arc welding, plasma arc welding, and laser welding.

3. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1 or 2, characterized in that, The welding method in S30 is submerged arc welding, and its welding process parameters are as follows: the diameter of the first layer of welding wire is 2.0 mm, the welding current is 300A~350A, the welding voltage is 20V~25V, and the welding speed is 30cm / min~40cm / min; the diameter of the welding wire for the remaining layers is 3.0 mm, the welding current is 350A~400A, the welding voltage is 22V~30V, and the welding speed is 40cm / min~50cm / min; and the interpass temperature does not exceed 120℃.

4. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The stress-relief heat treatment temperature in S40 is 500℃~550℃, and the holding time is 6h~8h.

5. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The non-destructive testing in S40 includes ultrasonic testing and surface crack detection.

6. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The wear-resistant layer in the S60 has a thickness of 2mm to 10mm and a surface hardness exceeding 300HV.

7. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The rolling process in S70 uses an elastic rolling tool with a pressure of 100 bar to 150 bar.

8. The method for preparing a wear-resistant layer on the surface of an ultra-low temperature rotating shaft according to claim 1, characterized in that, The rotating shaft is a 9Ni steel forging.

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