CN-121976022-A - Wind power main shaft and surface strengthening layer microscopic defect control method thereof

CN121976022ACN 121976022 ACN121976022 ACN 121976022ACN-121976022-A

Abstract

The invention discloses a wind power main shaft and a method for controlling microscopic defects of a surface strengthening layer of the wind power main shaft, and belongs to the technical field of surface modification of metal materials. The method comprises the steps of carrying out heat treatment and surface purification treatment on a wind power main shaft matrix, then carrying out multi-energy field composite surface strengthening treatment, and then carrying out defect eliminating treatment and stress optimizing treatment, wherein the heat treatment comprises quenching treatment and high-temperature tempering treatment, the multi-energy field composite surface strengthening treatment comprises preheating and hydrogen trap setting, low-temperature ion nitriding and laser remelting-quenching composite treatment, and the defect eliminating treatment and stress optimizing treatment comprises low-temperature dehydrogenation and stabilizing treatment for eliminating defects and shot blasting treatment and polishing treatment for stress optimizing. The method can realize systematic control of microcracks, harmful phases, hydrogen content and unfavorable residual stress in the strengthening layer, so that a high-quality strengthening layer with compact microstructure, few defects and optimized stress state is obtained, and the fatigue resistance and service life of the wind power main shaft are greatly improved.

Inventors

GAN CHUNLEI
CHEN LIJIE
ZHOU NAN
LI JILIN
LI XIAOHUI
LIU LIANHAO
KANG YUEHUA

Assignees

广东省科学院新材料研究所
佛山大学
中集海洋工程有限公司

Dates

Publication Date: 20260505
Application Date: 20260214

Claims (10)

1. A method for controlling microscopic defects of a wind power main shaft surface strengthening layer is characterized by comprising the following steps of carrying out heat treatment and surface purification treatment on a wind power main shaft substrate, then carrying out multi-energy field composite surface strengthening treatment, and then carrying out defect elimination treatment and stress optimization treatment; Wherein, the heat treatment comprises quenching treatment and high-temperature tempering treatment; the multi-energy field composite surface strengthening treatment comprises preheating and hydrogen trap setting, low-temperature ion nitriding, laser remelting and quenching composite treatment; The defect removal process and the stress optimization process include a low-temperature dehydrogenation and stabilization process for defect removal, and a shot blasting process and a polishing process for stress optimization.
2. The method for controlling microscopic defects of a wind power main shaft surface strengthening layer according to claim 1, wherein the quenching treatment is carried out for 1.5-2.5 hours under the condition of 850-870 ℃; and/or carrying out oil quenching for 2.5-3.5 hours under the condition of 570-580 ℃ in high-temperature tempering treatment; Preferably, the hardness of the wind power main shaft matrix after heat treatment is 28-35 HRC.
3. The method for controlling microscopic defects of a surface strengthening layer of a wind power spindle according to claim 1, wherein the surface purification treatment comprises the steps of firstly mechanically polishing or precisely grinding the surface of a region to be strengthened of a wind power spindle base body to ensure that the surface roughness Ra of the corresponding region is less than or equal to 0.4 mu m, and then carrying out ultrasonic cleaning and low-temperature plasma bombardment cleaning to remove grease, oxide and adsorbate existing on the corresponding surface.
4. The method for controlling microscopic defects of a surface strengthening layer of a wind power spindle according to claim 1, wherein the preheating and hydrogen trap arrangement comprises the steps of performing low-energy ion bombardment at a temperature of 250-400 ℃ to introduce hydrogen traps on the surface of a wind power spindle substrate; Preferably, the conditions of low-energy ion bombardment include a gas pressure of 0.8X10 -3 Pa~1.2×10 -3 Pa、Ar + ion gas particles energy of 0.8 Kev-1.2 Kev and an ion beam current density of 0.4mA/cm 2 ~0.6mA/cm 2 ; preferably, the hydrogen traps are introduced into a region with the depth of 5-20 mu m on the surface of the wind power main shaft matrix.
5. The method for controlling microscopic defects of a surface strengthening layer of a wind power spindle according to claim 1, wherein the low-temperature ion nitriding comprises pulse plasma nitriding in a nitrogen-hydrogen mixed atmosphere; Preferably, the nitrogen-hydrogen mixed atmosphere comprises nitrogen and hydrogen in a volume ratio of 2:1 to 4:1; Preferably, the temperature of the pulse plasma nitriding is 480-520 ℃ and the treatment time is 24-26 hours; Preferably, the nitrogen potential Kn value of pulse plasma nitridation is 1-5; preferably, the low-temperature ion nitriding treatment is performed to form a reinforcing layer with the thickness of 0.3 mm-0.6 mm.
6. The method for controlling microscopic defects of the surface strengthening layer of the wind power spindle according to claim 1, wherein the laser remelting-quenching treatment comprises the steps of carrying out multi-lap scanning on the surface of the workpiece subjected to the low-temperature ion nitriding treatment under the protection of inert gas; Preferably, the laser power of multi-pass lap joint scanning is 2 kW-4 kW, the diameter of a light spot is 2 mm-4 mm, the scanning speed is 10 mm/s-25 mm/s, and the lap joint rate is 25% -35%.
7. The method for controlling microscopic defects of a surface strengthening layer of a wind power spindle according to claim 1, wherein the low-temperature dehydrogenation and stabilization treatment comprises the steps of preserving heat for 8-12 hours at 180-220 ℃ in a vacuum furnace or an inert atmosphere furnace.
8. The method for controlling microscopic defects of the surface strengthening layer of the wind power spindle according to claim 1, wherein the shot blasting comprises the steps of performing ultrasonic shot blasting on a strengthening area by adopting high-strength ceramic shots, and introducing a residual compressive stress layer; and/or polishing treatment comprises performing microparticle blasting or abrasive particle stream polishing with low-strength glass or ceramic shots; Preferably, the high strength ceramic pellets comprise zirconia ceramic pellets; preferably, the diameter of the high-strength ceramic pellet is 0.2 mm-0.4 mm; preferably, the ultrasonic intensity of ultrasonic shot blasting treatment is 0.3-0.4 mmA, and the coverage rate is 180-220%; Preferably, the diameter of the low-strength glass pellets or ceramic pellets is 0.04 mm-0.06 mm; preferably, the surface roughness Ra of the workpiece after the polishing treatment is reduced to not more than 0.2 μm.
9. The wind power main shaft is characterized by being prepared by the method for controlling microscopic defects of the surface strengthening layer of the wind power main shaft according to any one of claims 1-8.
10. A wind power spindle according to claim 9, characterized in that the wind power spindle has at least one of the following features: The method is characterized in that the surface hardness of the strengthening layer of the wind power main shaft is more than or equal to 700Hv0.3; the characteristic 2 is that the depth of the strengthening layer of the wind power main shaft is more than or equal to 0.5mm; The characteristic 3 is that the surface roughness Ra of the wind power main shaft is less than or equal to 0.2 mu m; The hydrogen content in the strengthening layer of the wind power main shaft is less than or equal to 2ppm; The characteristic 5 is that the surface residual compressive stress of the wind power main shaft is less than or equal to 150MPa, and the residual compressive stress at the depth of 0.1mm inwards of the surface is less than or equal to 300MPa; And 6, in an acceleration bench fatigue test equivalent to a 20-year service load spectrum, the fatigue life of the wind power main shaft is more than 5 multiplied by 10 7 times.

Description

Wind power main shaft and surface strengthening layer microscopic defect control method thereof Technical Field The invention relates to the technical field of metal material surface modification, in particular to a wind power main shaft and a method for controlling microscopic defects of a surface strengthening layer of the wind power main shaft. Background The wind power main shaft is used as a core torque-bearing and force-bearing component of the wind generating set, and the surface quality and fatigue resistance of the wind power main shaft directly determine the safe operation life of the whole wind generating set. In order to improve the surface hardness, wear resistance and fatigue resistance, it is generally necessary to perform surface strengthening treatment on specific parts (such as bearing positions and sealing positions) of the main shaft. Common surface strengthening techniques include induction hardening, laser hardening, nitriding, shot peening, and the like. However, in the application process of the existing surface strengthening technology, various microscopic defects are very easy to introduce into the strengthening layer or cannot be effectively controlled, and the defects become preferential initiation sites of fatigue cracks, so that the strengthening effect is seriously restricted from being exerted, and even early failure of parts is caused. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a wind power main shaft and a method for controlling microscopic defects of a surface strengthening layer thereof so as to solve or improve the technical problems. The invention can be realized as follows: The invention provides a method for controlling microscopic defects of a wind power main shaft surface strengthening layer, which comprises the following steps of carrying out heat treatment and surface purification treatment on a wind power main shaft substrate, then carrying out multi-energy field composite surface strengthening treatment, and then carrying out defect elimination treatment and stress optimization treatment; Wherein, the heat treatment comprises quenching treatment and high-temperature tempering treatment; the multi-energy field composite surface strengthening treatment comprises preheating and hydrogen trap setting, low-temperature ion nitriding, laser remelting and quenching composite treatment; The defect removal process and the stress optimization process include a low-temperature dehydrogenation and stabilization process for defect removal, and a shot blasting process and a polishing process for stress optimization. In an alternative embodiment, the quenching treatment is carried out for 1.5 to 2.5 hours under the condition of 850 to 870 ℃; and/or carrying out oil quenching for 2.5-3.5 hours under the condition of 570-580 ℃ in the high-temperature tempering treatment. In an alternative embodiment, the hardness of the wind power main shaft matrix after heat treatment is 28-35 HRC. In an alternative embodiment, the surface cleaning treatment comprises the steps of firstly mechanically polishing or precisely grinding the surface of the area to be reinforced of the wind power main shaft matrix to ensure that the surface roughness Ra of the corresponding area is less than or equal to 0.4 mu m, and then carrying out ultrasonic cleaning and low-temperature plasma bombardment cleaning to remove grease, oxide and adsorbate existing on the corresponding surface. In an alternative embodiment, the preheating and hydrogen trap arrangement comprises low-energy ion bombardment at the temperature of 250-400 ℃ so as to introduce hydrogen traps on the surface of the wind power main shaft matrix. In an alternative embodiment, the conditions for low energy ion bombardment include a gas pressure of 0.8X10 -3Pa~1.2×10-3Pa、Ar+ ion gas particles energy of 0.8Kev to 1.2Kev and an ion beam density of 0.4mA/cm 2~0.6mA/cm2. In an alternative embodiment, hydrogen traps are introduced into a region of 5 μm to 20 μm depth of the wind power spindle substrate surface. In an alternative embodiment, low temperature ion nitridation comprises pulsed plasma nitridation in a nitrogen-hydrogen mixed atmosphere. In an alternative embodiment, the nitrogen-hydrogen mixed atmosphere comprises nitrogen and hydrogen in a volume ratio of 2:1 to 4:1. In an alternative embodiment, the temperature of the pulsed plasma nitridation is 480 ℃ to 520 ℃ and the treatment time is 24 hours to 26 hours. In an alternative embodiment, the nitrogen potential Kn of the pulsed plasma nitridation has a value of 1 to 5. In an alternative embodiment, the low temperature ion nitriding treatment is followed by forming the strengthening layer with a thickness of 0.3mm to 0.6 mm. In an alternative embodiment, the laser remelting-quenching treatment comprises carrying out multiple lap scans on the surface of the workpiece subjected to the low-temperature ion nitriding treatment under