Steel for bearing outer ring of super-power wind generating set and manufacturing process of steel

Abstract

The invention discloses steel for a bearing outer ring of a super-power wind generating set and a manufacturing process of the steel, and belongs to the technical field of wind power equipment manufacturing. The invention discloses steel for a bearing outer ring of a super-power wind generating set. The steel comprises the following components in percentage by mass: 0.48%-0.52% of C, 0.28%-0.33% of Si, 0.62%-0.66% of Mn, 0.97%-1.04% of Cr, 0.16%-0.21% of Mo, 0.005%-0.01% of Ti, 0.003%-0.008% of Zr, 0.0007%-0.001% of Ba and the balance of Fe. According to the method, alloy elements such as Ti, Zr and Ba are used for refining the sizes of grains and inclusions, meanwhile, the crushing degree and uniform distribution of the blank tissue and the inclusions are enhanced through extrusion and torsion, a fine and uniform metal flow line can be obtained after ring rolling, and the mechanical property of a forged piece is improved.

Description

Technical Field

[0001] The invention relates to steel for an outer ring of a bearing of an ultra-high-power wind power generator set and a manufacturing process thereof, and belongs to the technical field of wind power equipment manufacturing. Background Art

[0002] With the implementation of the national "dual carbon" policy, the wind power market has experienced explosive growth. As the core component of wind turbines, bearings need to withstand huge loads and complex torque changes brought by wind during operation, which places high demands on the strength and stability of bearings. As the main component supporting the rolling elements, the quality and performance of the outer ring of the bearing directly affect the overall performance and service life of the bearing.

[0003] At present, the outer rings of bearings are mainly made by free forging and rolling. However, the diameter of the workpiece manufactured by free forging is generally ≤7500mm, and the free forging process has many forging times and a long cycle, the internal structure of the forging is poorly homogenized, and the overall production cost is high. Ring rolling is currently a popular forming process for the manufacture of bearing outer rings. Chinese Patent No. CN202110008625 has announced a manufacturing process for ultra-large wheel forgings. It uses a radial-axial rolling process instead of the traditional free forging process to manufacture ultra-large wheel forgings. It has the characteristics of energy saving, high efficiency, and high material utilization, and the metal streamlines are retained inside. In order to solve the problem of elliptical or warping deformation during ring rolling, Chinese Patent No. CN202010749403 has announced a process for rolling and shaping ultra-large integral ring forgings. By optimizing the rolling process parameters, the elliptical shape can be controlled to ≤15mm. Chinese patent number CN202210019834.1 discloses a forging process for 100CrMo7-3 steel wind turbine bearing rings. Wind turbine bearing rings with excellent plasticity, toughness and low-temperature impact resistance are obtained by forging, ring rolling and heat treatment. As wind turbines develop towards ultra-high power (≥8MW), the size of wind turbine gears and their outer rings also tends to be larger. Due to the limited deformation force of ring rolling, the core structure of the outer ring of large-size (≥20m) gears cannot be fully broken, resulting in uneven distribution of its internal structure and metal streamlines, and defects such as dendrites and inclusions in the core cannot be eliminated or reduced, and cannot meet the use requirements and life requirements of harsh service environments. Therefore, it is now urgent to develop a new method for manufacturing the outer ring of bearings for wind turbines to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a steel for the outer ring of a bearing of an ultra-high-power wind turbine generator set, which has fine grains (8 to 9 grades), uniform structure, and dense metal streamlines, in view of the above problems in the prior art.

[0005] At the same time, the present invention provides a manufacturing process for steel for the outer ring of the bearing of an ultra-high-power wind turbine generator set, through which a large-scale wind turbine generator set bearing outer ring with fine grains (8 to 9 levels) and uniform structure can be obtained, and the metal streamlines are dense.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A steel for an outer ring of a bearing of an ultra-high-power wind turbine generator set, comprising the following alloy components: C 0.48%-0.52%, Si 0.28%-0.33%, Mn 0.62%-0.66%, Cr 0.97%-1.04%, Mo 0.16%-0.21%, Ti 0.005%-0.01%, Zr 0.003%-0.008%, Ba 0.0007%-0.001% and the balance Fe.

[0008] The maximum power is ≥8MW.

[0009] The grains of the edge and the core of the steel obtained by the invention are both of level 8-9, and the structure is uniform and the metal streamline is dense.

[0010] The steel obtained by the invention has a tensile strength of 1057-1152 MPa, an elongation of 15.8-18.1%, and an impact toughness of 41-44 J / cm at -40°C. 2 , the corrosion current density is 1.39~2.26μA / cm 2 .

[0011] A manufacturing process for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following steps:

[0012] 1) Billet heating: Heat the billet to 1200℃~1250℃ and keep it warm for 1.5~2h;

[0013] 2) Strong magnetic field assisted torsion blanking: first place the blank in a die for rough forging, with a forging ratio of 2.1 to 2.4; then apply a strong magnetic field to the rough forged blank and perform torsional deformation treatment, with a magnetic field strength of 12 to 15T, a working temperature of 900 to 1050°C, a torsional speed of 3 to 6° / s, and a torsional time of 60 to 90s.

[0014] 3) Magnetic + electric + ultrasonic multi-field coupling assisted ring rolling:

[0015] The primary ring rolling temperature is 1200-1250℃, the main roller linear speed is 900-1000mm / s, the core roller radial feed speed is 0.5-0.6mm / s, the cone roller rotation speed is 8.0-9.0rad / s, the ultrasonic frequency is 20-25kHz, the ultrasonic amplitude is 12-15μm, the pulse current frequency is 800-1000Hz, and the peak current density is 12-15A / mm2 , the total time of a single pulse is 1500-2000μs, the pulse interval is 1800-2000ms, and the magnetic field intensity is 9-12T;

[0016] The secondary ring rolling temperature is 1000-1050℃, the main roller linear speed is 850-950mm / s, the core roller radial feed speed is 0.3-0.4mm / s, the cone roller rotation speed is 8.0-8.5rad / s, the ultrasonic frequency is 10-15kHz, the ultrasonic amplitude is 8-10μm; the pulse current frequency is 500-700Hz, and the peak current density is 8-10A / mm 2 The total time of a single pulse is 800-1000μs, and the pulse interval is 400-500ms.

[0017] The invention discloses an application of steel for outer ring of bearing of super-high-power wind turbine generator set in outer ring of bearing of large-size wind turbine generator set.

[0018] Large specifications include inner diameter ≥20m.

[0019] The invention discloses an application of steel for outer ring of bearing of super-high power wind turbine generator set in super-high power wind turbine generator set.

[0020] The outer ring of a large-size wind turbine generator set bearing is prepared by using the steel for the outer ring of a super-large-power wind turbine generator set bearing of the present invention.

[0021] Alloying effect: C is a strengthening element; Si is a deoxidizing and strengthening element; Mn is an element for deoxidation and improving the hardenability of steel, and plays a role in solid solution strengthening and fixing sulfides in steel; Cr is a carbide-forming element and improves tempering stability; Mo is a grain refining element, which improves the hardenability and thermal strength of steel, prevents tempering brittleness, and increases remanence and coercivity; Ti is a deoxidizing and grain refining element; Zr is an element for grain refining, deoxidation, nitrogen removal, and sulfur removal, and can inhibit the growth of austenite grains at high temperatures; Ba is an element for refining inclusions and optimizing their distribution.

[0022] The basic principle of strong magnetic field assisted torsion billet making: the use of strong magnetic field and torsion can fully break up the billet structure under the action of extrusion and shear deformation, which can not only refine the grains, but also break up and disperse the inclusions in the billet; in addition, under the action of strong magnetic field, the grain recrystallization process can be slowed down and the grains can be refined.

[0023] The basic principle of magnetic + electric + ultrasonic multi-field coupling assisted ring rolling forming: ultrasonic vibration is used to reduce the yield strength and flow stress of the material, and the thermal and non-thermal effects of pulse current are used to improve the metal flow ability and enhance the radial and axial deformation depth, which is beneficial to the deformation of the core structure of the blank. At the same time, the strong magnetic field is used to slow down the recrystallization of grains and refine the grains.

[0024] Compared with the prior art, the invention has the following beneficial effects: alloy elements such as Ti, Zr, and Ba are used to refine the grain and inclusion size, and the billet organization and the degree of inclusion crushing and uniform distribution are enhanced through extrusion and torsion, which is conducive to obtaining fine and uniform metal streamlines after ring rolling. Electric pulses and ultrasound are used to improve the fluidity of the metal, enhance the deformation depth during ring rolling, solve the problem of insufficient deformation of the traditional core organization, and significantly optimize the rolling quality; Zr elements and strong magnetic fields are used to slow down the growth of grains at high temperatures, maintain fine grains, and improve the mechanical properties of forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The strong magnetic field assisted twisting device of the present invention comprises: 1-upper pressure head, 2-electromagnetic coil, 3-core rod, 4-blank, 5-lower die head;

[0026] Figure 2 Metal streamlines at different parts of the outer ring of the bearing of the present invention and the comparative bearing: (a) the outer edge of the sample of Example 1 of the present invention, (b) the core of the sample of Example 1 of the present invention, (c) the inner edge of the sample of Example 1 of the present invention, (d) the outer edge of the sample of Comparative Example 5, (e) the core of the sample of Comparative Example 5, (f) the inner edge of the sample of Comparative Example 5;

[0027] Figure 3 Grain sizes at different parts of the outer ring of the bearing of the present invention and the comparative bearing: (a) edge of the sample of Example 1 of the present invention, (b) core of the sample of Example 1 of the present invention, (c) edge of the sample of Comparative Example 5, (d) core of the sample of Comparative Example 5. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0029] Example 1

[0030] A steel for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following chemical components: 0.48% C, 0.28% Si, 0.62% Mn, 0.97% Cr, 0.16% Mo, 0.005% Ti, 0.003% Zr, 0.0007% Ba and the balance Fe.

[0031] A manufacturing process for steel for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following steps:

[0032] 1) Billet heating: Heat the billet to 1200°C and keep it warm for 1.5h;

[0033] 2) Strong magnetic field assisted torsion blanking: First, the blank is placed in the mold for rough forging, such as Figure 1As shown, the forging ratio is 2.1; then a strong magnetic field is applied to the rough forged billet, and a torsional deformation treatment is performed, with a magnetic field intensity of 12T, a working temperature of 900°C, a torsional speed of 3° / s, and a torsional time of 60s.

[0034] 3) Magnetic + electric + ultrasonic multi-field coupling assisted ring rolling: the ring rolling temperature is 1200℃, the main roller linear speed is 900mm / s, the core roller radial feed speed is 0.5mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 20kHz, the ultrasonic amplitude is 12μm, the pulse current frequency is 800Hz, and the peak current density is 12A / mm 2 , the total time of a single pulse is 2000μs, the pulse interval is 2000ms, the magnetic field intensity is 9T; the secondary rolling ring temperature is 1000℃, the main roller linear speed is 850mm / s, the core roller radial feed speed is 0.3mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 10kHz, the ultrasonic amplitude is 8μm; the pulse current frequency is 500Hz, and the peak current density is 8A / mm 2 , the total time of a single pulse is 1000μs, and the pulse interval is 500ms.

[0035] The invention discloses an application of steel for outer ring of bearing of super-high-power wind turbine generator set in outer ring of bearing of large-size wind turbine generator set.

[0036] The largest specification is 20m inner diameter.

[0037] The invention discloses an application of steel for outer ring of bearing of super-high power wind turbine generator set in super-high power wind turbine generator set.

[0038] Maximum power is 8MW

[0039] The outer ring of the large-sized wind turbine bearing is prepared by using the steel for the outer ring of the super-large-power wind turbine bearing of the embodiment.

[0040] Figure 1 In the figure, the mold consists of an upper ram 1 and a lower die 5 that are matched with each other. The lower surface of the upper ram 1 is integrally connected with a core rod 3 extending downward. The upper surface of the lower die 5 is provided with a groove for placing a blank 4. A hole is provided in the center of the blank 4. The core rod 3 is located in the center hole of the blank 4. Both the upper ram 1 and the lower die 5 are provided with an electromagnetic coil 2 for providing a strong magnetic field. The blank 4 is placed in the mold for rough forging, and then a strong magnetic field is applied to the rough forged blank, and a torsional deformation treatment is performed. The torsional deformation treatment is to twist the lower die 5.

[0041] like Figure 2As shown, the steel for the outer ring of the bearing of the ultra-high power wind turbine generator set obtained in this embodiment has metal streamlines in various regions (outer edge, core and inner edge) that are similar and small. However, the sample in comparative example 5 has insufficient deformation depth in the core, so the streamlines in the core region are coarser than those in the edge region.

[0042] like Figure 3 The figure shows the grain map of the edge and core of the steel for the outer ring of the bearing of the super-high-power wind turbine generator obtained in this embodiment. The grain level of this embodiment is all level 8, and the structure is uniform. However, since the external field is not applied to the sample of comparative example 5, the grain size of the edge is slightly larger, and the deformation force in the core area is insufficient and the force is uneven, so that the grains in the core are coarse and uneven, and the local grains are seriously coarsened.

[0043] Example 2

[0044] A steel for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following chemical components: 0.49% C, 0.30% Si, 0.64% Mn, 0.99% Cr, 0.18% Mo, 0.007% Ti, 0.006% Zr, 0.0008% Ba and the remainder Fe.

[0045] The manufacturing process includes the following steps:

[0046] 1) Billet heating: Heat the billet to 1250°C and keep it warm for 2 hours;

[0047] 2) Strong magnetic field assisted torsion blanking: First, the blank is placed in the mold for rough forging, such as Figure 1 As shown, the forging ratio is 2.3; then a strong magnetic field is applied to the rough forged billet, and a torsional deformation treatment is performed, with a magnetic field intensity of 14T, a working temperature of 1050°C, a torsional speed of 4° / s, and a torsional time of 90s.

[0048] 3) Magnetic + electric + ultrasonic multi-field coupling assisted ring rolling: the ring rolling temperature is 1250℃, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.55mm / s, the cone roller rotation speed is 8.5rad / s, the ultrasonic frequency is 22kHz, the ultrasonic amplitude is 13μm, the pulse current frequency is 900Hz, and the peak current density is 13A / mm 2 , the total time of a single pulse is 1500μs, the pulse interval is 1800ms, the magnetic field intensity is 10T; the secondary rolling ring temperature is 1050℃, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.35mm / s, the cone roller rotation speed is 8.3rad / s, the ultrasonic frequency is 13kHz, the ultrasonic amplitude is 9μm; the pulse current frequency is 550Hz, and the peak current density is 9A / mm 2 , the total time of a single pulse is 800μs, and the pulse interval is 400ms.

[0049] The invention discloses an application of steel for outer ring of bearing of super-high-power wind turbine generator set in outer ring of bearing of large-size wind turbine generator set.

[0050] The largest specification is 25m inner diameter.

[0051] The invention discloses an application of steel for outer ring of bearing of super-high power wind turbine generator set in super-high power wind turbine generator set.

[0052] The maximum power is 10MW.

[0053] The outer ring of the large-sized wind turbine bearing is prepared by using the steel for the outer ring of the super-large-power wind turbine bearing of the embodiment.

[0054] Example 3

[0055] A steel for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following chemical components: 0.51% C, 0.31% Si, 0.65% Mn, 1.0% Cr, 0.21% Mo, 0.01% Ti, 0.007% Zr, 0.0008% Ba and the balance Fe.

[0056] The manufacturing process includes the following steps:

[0057] 1) Billet heating: Heat the billet to 1220°C and keep it warm for 1.8h;

[0058] 2) Strong magnetic field assisted torsion blanking: First, the blank is placed in the mold for rough forging, such as Figure 1 As shown, the forging ratio is 2.4; then a strong magnetic field is applied to the rough forged billet, and a torsional deformation treatment is performed, with a magnetic field intensity of 15T, a working temperature of 1000°C, a torsional speed of 5° / s, and a torsional time of 70s.

[0059] 3) Magnetic + electric + ultrasonic multi-field coupling assisted ring rolling: the ring rolling temperature is 1225℃, the main roller linear speed is 970mm / s, the core roller radial feed speed is 0.6mm / s, the cone roller rotation speed is 9.0rad / s, the ultrasonic frequency is 25kHz, the ultrasonic amplitude is 15μm, the pulse current frequency is 900Hz, and the peak current density is 14A / mm 2 , the total time of a single pulse is 2000μs, the pulse interval is 2000ms, the magnetic field intensity is 11T; the secondary rolling ring temperature is 1020℃, the main roller linear speed is 875mm / s, the core roller radial feed speed is 0.4mm / s, the cone roller rotation speed is 8.5rad / s, the ultrasonic frequency is 12kHz, the ultrasonic amplitude is 9μm; the pulse current frequency is 700Hz, and the peak current density is 9A / mm 2 , the total time of a single pulse is 1000μs, and the pulse interval is 500ms.

[0060] The invention discloses an application of steel for outer ring of bearing of super-high-power wind turbine generator set in outer ring of bearing of large-size wind turbine generator set.

[0061] The largest specification is an inner diameter of 23m.

[0062] The invention discloses an application of steel for outer ring of bearing of super-high power wind turbine generator set in super-high power wind turbine generator set.

[0063] The maximum power is 10MW.

[0064] The outer ring of the large-sized wind turbine bearing is prepared by using the steel for the outer ring of the super-large-power wind turbine bearing of this embodiment.

[0065] Example 4

[0066] A steel for an outer ring of a bearing of an ultra-high power wind turbine generator set comprises the following chemical components: 0.52% C, 0.33% Si, 0.66% Mn, 1.04% Cr, 0.21% Mo, 0.01% Ti, 0.008% Zr, 0.001% Ba and the balance Fe.

[0067] The manufacturing process includes the following steps:

[0068] 1) Billet heating: Heat the billet to 1235°C and keep it warm for 1.9h;

[0069] 2) Strong magnetic field assisted torsion blanking: First, the blank is placed in the mold for rough forging, such as Figure 1 As shown, the forging ratio is 2.4; then a strong magnetic field is applied to the rough forged billet, and a torsional deformation treatment is performed, with a magnetic field intensity of 15T, a working temperature of 1050°C, a torsional speed of 6° / s, and a torsional time of 80s.

[0070] 3) Magnetic + electric + ultrasonic multi-field coupling assisted ring rolling: the ring rolling temperature is 1250℃, the main roller linear speed is 1000mm / s, the core roller radial feed speed is 0.6mm / s, the cone roller rotation speed is 9.0rad / s, the ultrasonic frequency is 20-25kHz, the ultrasonic amplitude is 15μm, the pulse current frequency is 1000Hz, and the peak current density is 15A / mm 2 , the total time of a single pulse is 2000μs, the pulse interval is 2000ms, the magnetic field intensity is 12T; the secondary rolling ring temperature is 1050℃, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.4mm / s, the cone roller rotation speed is 8.5rad / s, the ultrasonic frequency is 15kHz, the ultrasonic amplitude is 10μm; the pulse current frequency is 700Hz, and the peak current density is 10A / mm 2 , the total time of a single pulse is 1000μs, and the pulse interval is 500ms.

[0071] The invention discloses an application of steel for outer ring of bearing of super-high-power wind turbine generator set in outer ring of bearing of large-size wind turbine generator set.

[0072] The largest specification is 28m inner diameter.

[0073] The invention discloses an application of steel for outer ring of bearing of super-high power wind turbine generator set in super-high power wind turbine generator set.

[0074] The maximum power is 12MW.

[0075] The outer ring of the large-sized wind turbine bearing is prepared by using the steel for the outer ring of the super-large-power wind turbine bearing of the embodiment.

[0076] Comparative Example 1

[0077] The only difference between this comparative example and Example 1 is that there is no Zr in the alloy composition.

[0078] Comparative Example 2

[0079] The only difference between this comparative example and Example 1 is that there is no Ba in the alloy composition.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that: Step 2) an ultra-strong magnetic field is used to assist torsion, an ultra-strong magnetic field is applied to the rough forged billet, and a torsional deformation treatment is performed, and the magnetic field strength is 20T.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 1 is only that: Step 3) only adopts ultrasonic assisted ring rolling, and the specific process is: the primary ring rolling temperature is 1250°C, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.55mm / s, the cone roller rotation speed is 8.5rad / s, the ultrasonic frequency is 22kHz, the ultrasonic amplitude is 13μm, and the ultrasonic time is 4000μs; the secondary ring rolling temperature is 1050°C, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.35mm / s, the cone roller rotation speed is 8.3rad / s, the ultrasonic frequency is 13kHz, the ultrasonic amplitude is 9μm, and the ultrasonic time is 2000μs.

[0084] Comparative Example 5

[0085] The difference between this comparative example and Example 1 is that: Step 3) only uses electric + ultrasonic multi-field coupling to assist the ring rolling;

[0086] The specific process is as follows: the primary ring rolling temperature is 1200℃, the main roller linear speed is 900mm / s, the core roller radial feed speed is 0.5mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 20kHz, the ultrasonic amplitude is 12μm, the pulse current frequency is 800Hz, and the peak current density is 12A / mm 2 , the total time of a single pulse is 2000μs, the pulse interval is 2000ms; the secondary ring rolling temperature is 1000℃, the main roller linear speed is 850mm / s, the core roller radial feed speed is 0.3mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 10kHz, the ultrasonic amplitude is 8μm; the pulse current frequency is 500Hz, and the peak current density is 8A / mm 2 , the total time of a single pulse is 1000μs, and the pulse interval is 500ms.

[0087] like Figure 2 As shown, the steel for the outer ring of the wind turbine bearing obtained in this comparative example has large differences in the metal streamlines of each area (outer edge, core and inner edge). Since the deformation depth of the core is not enough, the streamlines in the core area are coarser than those in the edge area.

[0088] like Figure 3 The figure shows the grain map of the edge and core of the steel for the outer ring of the wind turbine bearing obtained in this comparative example. The grain level of this comparative example is: the edge is level 8, the core is level 7, and the organization is uneven. Since the external field is not applied to the sample of this comparative example, the grain size of the edge is slightly larger, and the deformation force in the core area is insufficient and the force is uneven, making the core grains coarse and uneven, and the local grains are seriously coarsened.

[0089] Comparative Example 6

[0090] The difference between this comparative example and Example 1 is that: Step 3) only uses magnetic + ultrasonic multi-field coupling to assist the ring rolling;

[0091] The specific process is: the primary ring rolling temperature is 1200℃, the main roller linear speed is 900mm / s, the core roller radial feed speed is 0.5mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 20kHz, the ultrasonic amplitude is 12μm, the ultrasonic time is 4000μs, and the magnetic field intensity is 9T; the secondary ring rolling temperature is 1000℃, the main roller linear speed is 850mm / s, the core roller radial feed speed is 0.3mm / s, the cone roller rotation speed is 8.0rad / s, the ultrasonic frequency is 10kHz, the ultrasonic amplitude is 8μm; the ultrasonic time is 2000μs.

[0092] Comparative Example 7

[0093] The difference between this comparative example and Example 1 is that: Step 3) only uses magnetic + electric assisted ring rolling forming;

[0094] The specific process is: primary ring rolling temperature 1200℃, main roller linear speed 900mm / s, core roller radial feed speed 0.5mm / s, cone roller rotation speed 8.0rad / s, pulse current frequency 800Hz, peak current density 12A / mm 2 , the total time of a single pulse is 2000μs, the pulse interval is 2000ms, the magnetic field intensity is 9T; the secondary rolling ring temperature is 1000℃, the main roller linear speed is 850mm / s, the core roller radial feed speed is 0.3mm / s, the cone roller rotation speed is 8.0rad / s, the pulse current frequency is 500Hz, and the peak current density is 8A / mm 2 , the total time of a single pulse is 1000μs, and the pulse interval is 500ms.

[0095] Comparative Example 8

[0096] The difference between this comparative example and Example 1 is that: during the second ring rolling in step 3), a magnetic field is also used, and the magnetic field strength is 7T.

[0097] Comparative Example 9

[0098] A steel for an outer ring of a wind turbine generator set bearing comprises the following chemical components: C 0.45%, Si 0.37%, Mn 0.68%, Cr 1.05%, Mo 0.19%, Ni 0.13%, and Cu 0.18%.

[0099] The manufacturing process includes the following steps:

[0100] 1) Billet heating: Heat the billet to 1200°C and keep it warm for 2 hours;

[0101] 2) Forging: The blanks are upset at forging ratios of 1.78, 2.1 and 2.3, and then punched.

[0102] 3) Ring rolling forming: the primary ring rolling temperature is 1200℃, the main roller linear speed is 900mm / s, the core roller radial feed speed is 0.6mm / s, the cone roller rotation speed is 9.0rad / s, the secondary ring rolling temperature is 1000℃, the main roller linear speed is 950mm / s, the core roller radial feed speed is 0.25mm / s, and the cone roller rotation speed is 7.0rad / s.

[0103] The metallurgical qualities of the steel for the outer ring of the wind turbine bearing obtained in Examples 1 to 4 and Comparative Examples 1 to 9 are shown in Table 1 below, and the mechanical properties are shown in Table 2 below.

[0104] Table 1 Metallurgical quality of examples and comparative samples

[0105]

[0106]

[0107] Table 2 Mechanical properties of examples and comparative samples

[0108]

[0109] Grain rating refers to GB / T 6394-2002, non-metallic inclusion detection refers to GB / T 10561-2005, tensile strength and elongation detection refers to GB / T 228.1-2021, impact toughness detection refers to GB / T229-2020, and corrosion current density test refers to GB / T 24196-2009.

[0110] It should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the previously disclosed embodiments. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0111] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

[0112] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A steel for outer ring of bearing of super high power wind turbine generator set, characterized in that: The invention comprises the following components in mass percentage: C 0.48%-0.52%, Si 0.28%-0.33%, Mn 0.62%-0.66%, Cr 0.97%-1.04%, Mo 0.16%-0.21%, Ti 0.005-0.01%, Zr 0.003-0.008%, Ba 0.0007-0.001% and the balance Fe.

2. The steel for outer ring of bearing of super high power wind turbine generator set according to claim 1, characterized in that: The maximum power is ≥8MW.

3. The steel for outer ring of bearing of super high power wind turbine generator set according to claim 1, characterized in that: The grains at the edge and center of the steel are both level 8 to 9, with uniform structure and dense metal streamlines.

4. The steel for outer ring of bearing of super high power wind turbine generator set according to claim 1, characterized in that: The tensile strength of the steel is 1057-1152MPa, the elongation is 15.8-18.1%, and the impact toughness at -40℃ is 41-44J / cm 2 , the corrosion current density is 1.39~2.26μA / cm 2 .

5. A manufacturing process for the steel for the outer ring of the bearing of a super-high-power wind turbine generator set according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, billet heating: heat the billet to 1200℃~1250℃, keep warm for 1.5~2h; S2, strong magnetic field assisted torsion blanking: firstly, the heated blank is placed in a die for rough forging, with a forging ratio of 2.1 to 2.4; then, a strong magnetic field is applied to the blank after rough forging, and a torsion deformation treatment is performed, with a magnetic field strength of 12 to 15T, a working temperature of 900 to 1050°C, a torsion speed of 3 to 6° / s, and a torsion time of 60 to 90s; S3, magnetic + electric + ultrasonic multi-field coupling assisted ring rolling: The primary ring rolling temperature is 1200-1250℃, the main roller linear speed is 900-1000mm / s, the core roller radial feed speed is 0.5-0.6mm / s, the cone roller rotation speed is 8.0-9.0rad / s, the ultrasonic frequency is 20-25kHz, the ultrasonic amplitude is 12-15μm, the pulse current frequency is 800-1000Hz, and the peak current density is 12-15A / mm 2 , the total time of a single pulse is 1500-2000μs, the pulse interval is 1800-2000ms, and the magnetic field intensity is 9-12T; The secondary ring rolling temperature is 1000-1050℃, the main roller linear speed is 850-950mm / s, the core roller radial feed speed is 0.3-0.4mm / s, the cone roller rotation speed is 8.0-8.5rad / s, the ultrasonic frequency is 10-15kHz, the ultrasonic amplitude is 8-10μm; the pulse current frequency is 500-700Hz, and the peak current density is 8-10A / mm 2 The total time of a single pulse is 800-1000μs, and the pulse interval is 400-500ms.

6. Application of the steel for outer ring of bearing of super high power wind turbine generator set according to any one of claims 1 to 4 in outer ring of bearing of large-sized wind turbine generator set.

7. The use according to claim 6, characterized in that: Large specifications include inner diameter ≥20m.

8. Use of the steel for outer ring of a bearing of a super-high power wind generator set according to any one of claims 1 to 4 in a super-high power wind generator set.

9. Large-sized wind turbine bearing outer ring, characterized in that: The outer ring of the bearing of a super-high-power wind turbine generator set is prepared by using the steel for the outer ring of the bearing of any one of claims 1 to 4.

Images