Hob cutter ring and preparation process thereof, disc cutter and TMB (Tetramethylbenzidine) shield equipment

Abstract

The invention discloses a ZJ-09 type shield disc cutter ring, a preparation process of the ZJ-09 type shield disc cutter ring, a disc cutter and TMB shield equipment, and belongs to the technical field of tunneling equipment. The preparation process comprises the following steps: regulating and controlling metal components to prepare molten steel, pouring a steel ingot, carrying out electromagnetic oscillation ingot stripping and electroslag remelting, carrying out multi-directional forging, carrying out high-temperature homogenization treatment, and upsetting and drawing the steel ingot. The method comprises the following steps: blanking, upsetting and die forging, performing ring grinding and trepanning treatment on a forged cutter ring blank, performing ultrafine treatment, performing quenched-tempered heat treatment on the cutter ring, performing vacuum quenching on the cutter ring, performing cryogenic treatment at 120 DEG C, performing tempering for three times, emptying the cutter ring to normal temperature after cryogenic treatment, performing tempering for three times, performing tempering at 540 DEG C for two times for 5 hours, performing tempering at 530 DEG C for 5 hours, and performing high-frequency induction inner hole softening after discharging from a furnace; wherein the forged cutter ring blank is subjected to ring grinding and trepanning treatment, the radial pressure is controlled to be larger than the axial pressure, the ratio of the radial pressure to the axial pressure is (1.2-1.5), and the maximum radial pressure does not exceed 15 Mpa.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunneling equipment, and more specifically, relates to a ZJ-09 shield disc cutter ring and a preparation process thereof, a disc cutter and a TMB shield equipment. Background Art

[0002] Shield tunneling is widely used in tunnel construction. It is not only highly efficient and safe, but also economical and environmentally friendly, making it the optimal choice for modern tunnel construction. The shield tunneling machine (TBM) is the most modern and specialized equipment for this purpose. The disc-shaped single-edge cutter is a specialized tool used on a shield tunneling machine for cutting rock and soil. Mounted on the cutterhead, the disc-shaped single-edge cutter ring penetrates the rock and soil during tunnel construction. Simultaneously, the cutterhead, driven by a rotating mechanism, drives the disc-shaped single-edge cutter structure in both orbital and rotational motion, continuously rolling and crushing the rock and soil.

[0003] TBM disc cutters are rock-breaking tools that crush rock by rolling and crushing it with a cutter ring. The quality of a TBM disc cutter directly determines the machine's rock-breaking efficiency. The standard structure of a TBM disc cutter, widely used in the market, as shown in Patent No. CN201820995719.7, features two sets of tapered roller bearings mounted back-to-back on a roller shaft, separated by a spacer ring. The cutter ring is mounted on the outer diameter of the roller shaft. During operation, the roller shaft remains stationary, while the cutter ring rotates around the shaft along with the roller shaft and the outer ring of the bearing. Simultaneously, the cutter ring rotates with the cutter disc around the center of the cutter disc, crushing the rock.

[0004] To improve the performance of the existing cutter rings, a search revealed Chinese patent CN112080705A, which discloses a method for preparing a hob cutter ring. The method involves rolling and piercing the forged cutter ring, then using a double-guide roller horizontal ring rolling mill to roll the forged cutter ring to form the initial cutter ring blank. However, this technology utilizes conventional ring rolling and reaming processes, resulting in inconsistent stress levels on the inner and outer rings, which can lead to cracking and damage during use. Summary of the Invention

[0005] 1. Problem to be solved

[0006] In response to the technical problems existing in the prior art, the present invention provides a ZJ-09 shield disc cutter ring and its preparation process, so that the structure inside and outside the ring is uniform and consistent, meeting the performance requirements of heavy-duty shield disc cutters.

[0007] Another object of the present invention is to provide a heavy shield disc cutter having the above-mentioned shield disc cutter ring.

[0008] Another object of the present invention is to provide a TMB shield equipment having the above-mentioned heavy shield disc cutter.

[0009] 2. Technical solution

[0010] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0011] A first aspect of the present invention provides a process for preparing a shield disc cutter ring, comprising the following steps: controlling metal composition to prepare molten steel - pouring a steel ingot - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting, and die forging - rolling and drilling the forged cutter ring blank - ultrafine treatment - cutter ring quenching and tempering heat treatment - vacuum quenching the cutter ring - deep cooling at -120°C and tempering three times, after deep cooling, the cutter ring is cooled to room temperature and then tempered three times, including tempering at 540°C for two times for 5 hours and then tempering at 530°C for 5 hours, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to ensure that the inner hole hardness of the cutter ring is not less than HRC40;

[0012] The ring-rolling and hole-opening treatment of the forged cutter ring blank is as follows: radial pressure is controlled to be greater than axial pressure, the ratio of radial pressure to axial pressure is (1.2-1.5), and the maximum radial pressure does not exceed 15 MPa.

[0013] The metal components are as follows in percentage by mass: C: 0.5% to 0.55%, Si: 0.27% to 0.32%, Mn: 0.40% to 0.45%, Cr: 5% to 7.5%, W: 0.5% to 0.8%, Mo: 2.0% to 2.8%, V: 0.6% to 0.8%, N: 0.007%, Nb: 0.06%, Ni: 0.2% to 0.35%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other unavoidable impurities.

[0014] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 5% to 7.5% of Cr elements can improve creep resistance and make δ yAt 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.0% to 2.8% of Mo elements can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.0% to 2.8%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0015] 1) Radial pressure: Install a pressure sensor on the support structure or hydraulic cylinder of the roller (such as the main roller or core shaft) that applies radial force; 2) Axial pressure: Install a sensor in the circuit of the side roller or hydraulic cylinder that applies axial pressure.

[0016] The above sensor selection: Use commercially available industrial-grade pressure sensors (such as strain gauge or piezoelectric sensors) that are resistant to high temperatures and vibrations. The range must cover the maximum radial pressure (such as 0-20MPa), and the dynamic response speed must match the pressure change frequency of the ring rolling process. Real-time calculation: Dynamically calculate the pressure ratio And set the alarm threshold (1.2-1.5); monitor whether the radial pressure exceeds 15MPa.

[0017] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the knife ring product at room temperature is not less than 8.4J and the average longitudinal impact energy is not less than 21J / cm 2 The average hardness is not less than 58 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0018] According to any embodiment of the first aspect of the present invention, the electromagnetic oscillation ingot extraction electroslag remelting: the steel ingot is subjected to bipolar series electroslag remelting, and during the ingot extraction process, the steel ingot is spray-cooled and the magnetic field oscillates synchronously.

[0019] According to any embodiment of the first aspect of the present invention, the steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability, and a synergistic effect occurs between the elements. Among them, a material with a C content of 0.5% to 0.55% is selected, taking into account both strength and toughness; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0020] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1130-1150℃, the final forging temperature is 900℃, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0021] According to any embodiment of the first aspect of the present invention, the high-temperature homogenization treatment: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0022] According to any embodiment of the first aspect of the present invention, the ultrafine treatment: step-by-step heating to 1050°C and heating and heat preservation for 3 hours, then water quenching and air cooling, repeated alternating operations, and cycled in sequence until the air cooling temperature after the last water discharge is 150°C-200°C, transferred to a trolley furnace set at 920°C, heated and heat-insulated so that the whole is heated evenly, and then heat-insulated for 5-7 hours, and then cooled to 765°C-720°C with the furnace, and after heat preservation for 6-7 hours, cooled to 350°C with the furnace and taken out of the furnace.

[0023] According to any embodiment of the first aspect of the present invention, the knife ring is subjected to tempering heat treatment: step-by-step heating to 1030°C and holding for 40 minutes; the knife ring is subjected to vacuum quenching: 1030°C*(3-5h), quenching; tempering at 350°C*3h+(530~540)°C*5h, and the overall hardness range after three temperings is HRC59-HRC60-HRC62.

[0024] The second aspect of the present invention provides a shield disc cutter ring obtained by the preparation process of the first aspect mentioned above.

[0025] A third aspect of the present invention provides a heavy shield disc cutter having the above-mentioned shield disc cutter ring, comprising:

[0026] A cutter shaft has a journal step and a thread is provided along the outer circumference of the cutter shaft;

[0027] The upper tapered roller bearing and the lower tapered roller bearing are sleeved on the cutter shaft. The two sets of tapered roller bearing inner sleeves are hot-fitted on the cutter shaft at 80°C. The upper tapered roller bearing and the lower tapered roller bearing are separated by a spacer ring. An elastic spacer ring is installed between the end faces of the upper tapered roller bearing and the lower tapered roller bearing inner sleeve. When the two sets of tapered roller bearings are installed and pre-tightened, the elastic performance of the spacer ring is used to adjust the bearing clearance to achieve the normal required pre-tightening force.

[0028] A cutter hub is sleeved on the outer portion of the upper tapered roller bearing and the lower tapered roller bearing; when the cutter rings are shrink-fitted on the cutter hub, the outer rings of the upper tapered roller bearing and the lower tapered roller bearing are quickly and steadily placed into the corresponding bearing outer ring positions of the cutter hub after the cutter hub has a suitable thermal expansion period;

[0029] At least one cutting ring (in some cases, more than two cutting rings may be provided) is sleeved on the outer circumference of the cutting hub, a retaining ring is provided on one side of the cutting ring, the retaining ring is fixed to the cutting hub (e.g., welded), and the inner hole hardness of the cutting ring is not less than HRC40;

[0030] And an upper cover assembly and a lower cover assembly are arranged at the axial ends of the knife shaft, an upper floating seal is provided between the upper cover assembly and the upper tapered roller bearing; a lower floating seal is provided between the lower cover assembly and the lower tapered roller bearing.

[0031] According to any embodiment of the third aspect of the present invention, the elastic spacer is made of high-quality spring steel and has an H-shaped profile. The elastic spacer undergoes a roughing process, followed by heat treatment and tempering, and fine machining and configuration. To the inventor's surprise, both the upper and lower tapered roller bearings rest against the H-shaped elastic spacer, effectively ensuring the end face strength of the elastic spacer and exhibiting excellent elastic deformation mechanical properties. Extensive testing and operational analysis have shown that, while ensuring the upper and lower tapered roller bearings are secured to the upper and lower end caps, the H-shaped elastic spacer can adjust the preload, thereby regulating the clearance between the upper and lower tapered roller bearings. This configuration achieves reasonable starting torque and rotational torque for the hob, according to varying geological requirements.

[0032] According to any embodiment of the third aspect of the present invention, the upper cover assembly includes an upper end cover, an upper oil seal bracket, a locking plate, an upper sealing dust ring, a pressure relief valve and a plurality of O-rings A;

[0033] The upper end cover is pre-tightened on the large end face of the upper tapered roller bearing with the cutter shaft by means of an internal thread. During the process of pre-tightening the upper tapered roller bearing, an O-ring A is installed between the upper end cover and the large end face of the inner sleeve of the upper tapered roller bearing to perform end face sealing.

[0034] The upper end cover is pre-tightened on the large end face of the upper tapered roller bearing by means of an internal thread and the cutter shaft, and the upper tapered roller bearing, the lower tapered roller bearing and the elastic spacer ring in the middle are simultaneously pre-tightened to adjust the surrounding rock strength corresponding to the cutter torque;

[0035] The upper oil seal bracket is arranged on the inner side of the upper end cover, and the upper floating seal is arranged on the upper oil seal bracket; the end surface between the upper oil seal bracket and the cutter hub is sealed by at least two O-rings A;

[0036] The upper oil seal bracket is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the quenched and tempered parts are rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are finely machined to achieve the designed dimensions;

[0037] During the assembly process, the upper end cover and the upper oil seal bracket are sealed by the upper sealing dust ring in a static friction gap type step seal, which enhances the sealing effect and blocks the erosion of mud and sand to the greatest extent without affecting the starting torque. An O-ring A is also added between the two and sealed below the upper sealing dust ring.

[0038] The L-shaped upper sealing dust ring is made of high-molecular ultra-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub, strictly prevents the erosion of the cutter hub by sediment particles, and further protects the safe use of the upper floating seal and upper tapered roller bearing in the cutter hub, which has practical significance for extending the service life of heavy-duty hobs.

[0039] After the upper end cover is pre-tightened into place, the locking piece is inserted into the upper end of the cutter shaft for peripheral groove welding, and is positioned on the cutter shaft and the upper end cover for welding stop to prevent the upper end cover thread from loosening and affecting the overall preload of the upper tapered roller bearing;

[0040] The upper end cover is provided with two symmetrically distributed ZG1 / 4 holes for oil filling and gas measurement, and is equipped with a single-hole pressure relief valve, which automatically discharges the internal pressure when the internal pressure of the cutter hub is greater than the external pressure by 3 bar, thereby balancing the internal pressure of the cutter hub and protecting the safe use of the floating seal inside the cutter hub.

[0041] According to any embodiment of the third aspect of the present invention, the lower cover assembly includes a bearing support seat, a lower end cover, a lower oil seal bracket, a lower sealing dust ring, and a plurality of O-rings B;

[0042] The bearing support seat is heat-fitted on the bottom of the cutter shaft and abuts against the shaft neck step. The bearing support seat and the shaft neck step are sealed with an O-ring B. The bearing support seat and the inner ring of the lower tapered roller bearing are sealed with an O-ring B. The outer circumferential surface of the bearing support seat is provided with a thread. The lower end cover is pre-tightened in a threaded connection manner, and an O-ring B is configured at the end face contact portion.

[0043] The lower oil seal bracket is arranged on the inner side of the lower end cover, and the lower floating seal is arranged on the lower oil seal bracket; the end surface between the lower oil seal bracket and the cutter hub is sealed by at least two O-rings B;

[0044] The lower oil seal bracket is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface. Alternatively, the quenched and tempered parts are rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are finely machined to achieve the designed dimensions.

[0045] During the assembly process, the lower end cover and the lower oil seal bracket are sealed with a static friction gap type stepped seal by the lower sealing dust ring, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring B is also added between the two to seal above the lower sealing dust ring.

[0046] The L-shaped lower sealing dust ring is made of high-molecular super-wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance and corrosion resistance. It can better stabilize the sealing performance of the cutter hub, strictly prevent the erosion of the cutter hub by mud and sand particles, further protect the safe use of the lower floating seal and lower tapered roller bearing in the cutter hub, and extend the service life of the heavy-duty hob.

[0047] 3. Beneficial effects

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The preparation process of the shield disc cutter ring of the present invention adjusts the radial pressure and axial pressure during the ring opening process to make the structure inside and outside the ring uniform and consistent, so that the average transverse impact energy of the cutter ring product at room temperature is not less than 8.4J and the average longitudinal impact energy is not less than 21J, and the average hardness is not less than 58 / HRC, which meets the performance requirements of heavy-duty shield disc cutters;

[0050] (2) The preparation process of the shield disc cutter ring of the present invention, the initial forging temperature of the multi-directional forging is 1130-1150°C, the final forging temperature is 900°C, the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5%, and the thermoplastic is stabilized, which solves the problem that the forging strength of this component is higher and causes it to be more prone to cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, these drawings are intended only to conceptually illustrate the structures described herein and are not necessarily drawn to scale.

[0052] Figure 1 This is a schematic structural diagram of the heavy shield disc cutter of the present invention;

[0053] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of part A;

[0054] Figure 3 for Figure 1 A schematic diagram of the enlarged structure of part B;

[0055] Figure 4 This is a schematic diagram of the spacer ring installation structure of the heavy shield disc cutter of the present invention;

[0056] Figure 5-Figure 8 A test report on the hardness and impact energy of the shield disc cutter ring of the present invention;

[0057] Description of reference numerals:

[0058] 1. Cutter shaft; 1-1. Journal step; 2. Upper tapered roller bearing; 3. Lower tapered roller bearing; 4. Spacer ring; 5. Cutter hub; 6. Cutter ring; 7. Retaining ring;

[0059] 8. Upper cover assembly; 8-1. Upper end cover; 8-2. Upper oil seal bracket; 8-3. Locking plate; 8-4. Upper sealing dust ring; 8-5. Pressure relief valve; 8-6. O-ring A;

[0060] 9. Lower cover assembly; 9-1. Bearing support seat; 9-2. Lower end cover; 9-3. Lower oil seal bracket; 9-4. Lower sealing dust ring; 9-5. O-ring B;

[0061] 10. Upper floating seal;

[0062] 11. Bottom floating seal. DETAILED DESCRIPTION

[0063] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is merely for illustration and does not limit the description of the features and characteristics of the present invention, so as to propose the best way to perform the present invention and be sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0064] The following detailed description of the present invention and example embodiments may be better understood with reference to the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0065] When the TBM shield equipment operates in a stratum with relatively uniform rock structure, the load changes on the cutter are also relatively gentle; when the TBM shield equipment operates in a rock stratum with uneven hardness or the rock stratum structure suddenly hardens, it may cause the cutter ring 66 of the cutter to be locally and instantaneously overloaded and cause the cutter ring 66 to break. Therefore, it is necessary to improve the overall strength of the cutter ring 66. The preparation process of the shield disc cutter ring 6 of the present invention includes the following steps: regulating the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultrafine treatment - tempering heat treatment of the cutter ring 6 - vacuum quenching of the cutter ring 6 - deep cooling at -120°C + 3 temperings, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, the inner hole is softened by high-frequency induction, so that the hardness of the inner hole of the cutter ring 6 is not lower than HRC40, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered.

[0066] The hole opening treatment of the forged cutter ring 6 blank is as follows: radial pressure is controlled to be greater than axial pressure, the ratio of radial pressure to axial pressure is 1.2-1.5, and the maximum radial pressure does not exceed 15 MPa.

[0067] The metal components are as follows in percentage by mass: C: 0.5% to 0.55%, Si: 0.27% to 0.32%, Mn: 0.40% to 0.45%, Cr: 5% to 7.5%, W: 0.5% to 0.8%, Mo: 2.0% to 2.8%, V: 0.6% to 0.8%, N: 0.007%, Nb: 0.06%, Ni: 0.2% to 0.35%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other unavoidable impurities.

[0068] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 5% to 7.5% of Cr elements can improve creep resistance and make δ yAt 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.0% to 2.8% of Mo elements can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.0% to 2.8%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0069] The present invention adopts Kistler 601C piezoelectric sensor with a sampling rate of 2kHz, combined with LabVIEW to realize real-time proportional monitoring. By adjusting the radial pressure and axial pressure during the ring rolling hole opening process, the structure inside and outside the ring is made uniform and consistent, so that the average transverse impact energy of the cutter ring 6 product at room temperature is not less than 8.4J and the average longitudinal impact energy is not less than 21J, and the average hardness is not less than 58 / HRC, meeting the performance requirements of heavy-duty shield disc cutters.

[0070] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0071] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.5% to 0.55% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0072] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1130-1150℃, the final forging temperature is 900℃, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0073] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0074] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and the heat is kept for 3 hours, and then water quenching and air cooling are repeated, and the operation is cycled in sequence until the air cooling temperature after the last water discharge is 150°C-200°C, and then the steel is transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole steel is heated evenly, and then kept warm for 5-7 hours, and then cooled to 765°C-720°C with the furnace, kept warm for 6-7 hours, and then cooled to 350°C with the furnace and taken out of the furnace.

[0075] The above-mentioned knife ring 6 is subjected to tempering heat treatment: step-by-step heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*(3-5h), quenching; tempering at 350°C*3h+(530~540)°C*5h, and the overall hardness of the three temperings corresponds to not less than HRC59, not less than HRC60, and not less than HRC62, respectively.

[0076] In this embodiment, the heavy-duty shield disc cutter of the present invention includes: a cutter shaft 1 having a journal step 1-1 and a threaded outer circumferential surface of the cutter shaft 1; an upper tapered roller bearing 2 and a lower tapered roller bearing 3 sleeved on the cutter shaft 1, wherein the two sets of tapered roller bearing inner sleeves are heat-fitted onto the cutter shaft 1 at 80°C, and the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are separated by a spacer ring 4; wherein an elastic spacer ring 4 is installed between the end faces of the inner sleeves of the upper tapered roller bearing 2 and the lower tapered roller bearing 3, and when the two sets of tapered roller bearings are installed and preloaded, the elastic performance of the spacer ring 4 is used to adjust the bearing clearance to achieve the normal required preload force;

[0077] A cutter hub 5 is sleeved on the outer portion of the upper tapered roller bearing 2 and the lower tapered roller bearing 3; when the outer rings of the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are shrink-fitted on the cutter hub 5, the outer rings of the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are quickly and smoothly placed into the corresponding outer ring positions of the cutter hub 5 after the cutter hub 5 has a suitable thermal expansion period;

[0078] At least one cutting ring 6 (in some cases, more than two cutting rings 6 may be provided) is sleeved on the outer circumference of the cutting hub 5. A retaining ring 7 is provided on one side of the cutting ring 6. The retaining ring 7 is fixed to the cutting hub 5 (for example, by welding). The inner hole hardness of the cutting ring 6 is not less than HRC40.

[0079] An upper cover assembly 8 and a lower cover assembly 9 are arranged at the axial ends of the cutter shaft 1. An upper floating seal 10 is provided between the upper cover assembly 8 and the upper tapered roller bearing 2; a lower floating seal 11 is provided between the lower cover assembly 9 and the lower tapered roller bearing 3.

[0080] Furthermore, the elastic spacer ring 4 is made of high-quality spring steel and has an H-shaped profile. The elastic spacer ring 4 undergoes a rough initial processing, heat treatment and tempering, and fine processing and configuration molding process. To the inventor's surprise, the upper tapered roller bearing 2 and the lower tapered roller bearing 3 both rest on the H-shaped elastic spacer ring 4. The H-shaped structure effectively ensures the end face strength of the elastic spacer ring 4 and has good elastic deformation mechanical properties. Through extensive testing and usage analysis, it was found that while ensuring that the upper tapered roller bearing 2 and the lower tapered roller bearing 3 are in the upper end cover 8-1 and the lower end cover 9-2, the H-shaped elastic spacer ring 4 can adjust the preload force, thereby adjusting the clearance of the upper tapered roller bearing 2 and the lower tapered roller bearing 3. According to different geological requirements, the configuration can achieve reasonable starting torque and rotational torque of the hob.

[0081] In this embodiment, the upper cover assembly 8 includes an upper end cover 8-1, an upper oil seal bracket 8-2, a locking piece 8-3, an upper sealing dust ring 8-4, a pressure relief valve 8-5 and a plurality of O-rings A8-6;

[0082] 1) The upper end cover 8-1 is pre-tightened with the cutter shaft 1 at the large end face of the upper tapered roller bearing 2 using an internal thread. During the process of pre-tightening the upper tapered roller bearing 2, an O-ring A8-6 is installed between the upper end cover 8-1 and the large end face of the inner sleeve of the upper tapered roller bearing 2 to perform end face sealing;

[0083] 2) The upper end cover 8-1 is pre-tightened with the cutter shaft 1 at the large end surface of the upper tapered roller bearing 2 using an internal thread, and the upper tapered roller bearing 2, the lower tapered roller bearing 3 and the elastic spacer ring 4 in the middle are simultaneously pre-tightened to adjust the surrounding rock strength corresponding to the cutter torque;

[0084] 3) The upper oil seal bracket 8-2 is arranged on the inner side of the upper end cover 8-1, and the upper floating seal 10 is arranged on the upper oil seal bracket 8-2; the end surface between the upper oil seal bracket 8-2 and the blade hub 5 is sealed by at least two O-rings A8-6;

[0085] 4) The upper oil seal bracket 8-2 is made of 42CrMo quenched and tempered material, and then fine-machined and nitrided to a thickness of 0.7 mm on the surface. Alternatively, the quenched and tempered part is rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then fine-machined to the internal dimensions to achieve the designed dimensions.

[0086] 5) During assembly, the upper end cover 8-1 and the upper oil seal bracket 8-2 are sealed by the upper sealing dust ring 8-4 in a static friction gap-type stepped seal, which enhances the sealing effect and minimizes sediment erosion without affecting the starting torque. An O-ring A8-6 is also provided between the two and seals below the upper sealing dust ring 8-4.

[0087] 6) The L-shaped upper sealing dust ring 8-4 is made of a high-molecular wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance. It better stabilizes the sealing performance of the cutter hub 5, strictly prevents the erosion of the cutter hub 5 by sediment particles, and further protects the upper floating seal 10 and the upper tapered roller bearing 2 in the cutter hub 5 for safe use, which has practical significance for extending the service life of heavy-duty hobs;

[0088] 7) After the upper end cover 8-1 is pre-tightened into place, the locking piece 8-3 is inserted into the upper end of the cutter shaft 1 for peripheral groove welding, and positioned on the cutter shaft 1 and the upper end cover 8-1 for welding to prevent the upper end cover 8-1 thread from loosening and affecting the overall preload of the upper tapered roller bearing 2;

[0089] 8) The upper end cover 8-1 is provided with two symmetrically distributed ZG1 / 4 holes for oil injection and gas measurement, and is equipped with a single-hole pressure relief valve 8-5, which automatically discharges the internal pressure when the internal pressure of the cutter hub 5 is greater than the external pressure by 3 bar, thereby balancing the internal pressure of the cutter hub 5 and protecting the safe use of the upper floating seal 10 in the cutter hub 5.

[0090] like Figure 3 As shown, the lower cover assembly 9 includes a bearing support seat 9-1, a lower end cover 9-2, a lower oil seal bracket 9-3, a lower sealing dust ring 9-4, and several O-rings B9-5; the bearing support seat 9-1 is heat-fitted on the bottom of the cutter shaft 1 and abuts against the journal step 1-1, and the bearing support seat 9-1 and the journal step 1-1 are sealed with an O-ring B9-5; the bearing support seat 9-1 and the inner ring of the lower tapered roller bearing 3 are sealed with an O-ring B9-5, the outer circumferential surface of the bearing support seat 9-1 is provided with a thread, the lower end cover 9-2 is pre-tightened in a threaded connection manner, and an O-ring B9-5 is configured at the end face contact portion;

[0091] The lower oil seal bracket 9-3 is arranged on the inner side of the lower end cover 9-2, and the lower floating seal 11 is arranged on the lower oil seal bracket 9-3; the end surface between the lower oil seal bracket 9-3 and the blade hub 5 is sealed by at least two O-rings B9-5;

[0092] The lower oil seal bracket 9-3 is made of 42CrMo quenched and tempered parts, finely machined, and then subjected to a 0.7mm nitriding process on the surface, or the quenched and tempered parts are rough-turned and then induction hardened on the outer bevel to improve the surface wear resistance, and then the internal dimensions are finely machined to achieve the designed dimensions;

[0093] During the assembly process, the lower end cover 9-2 and the lower oil seal bracket 9-3 are sealed with a static friction gap type step seal by the lower sealing dust ring 9-4, which enhances the sealing effect and blocks the erosion of mud and sand to the maximum extent without affecting the starting torque; an O-ring B9-5 is also added between the two to seal above the lower sealing dust ring 9-4.

[0094] In order to strictly prevent the erosion of mud and sand particles on the cutter hub 5, further protect the safe use of the lower floating seal 11 and the lower tapered roller bearing 3 in the cutter hub 5, and extend the service life of the heavy-duty hob, the L-shaped lower sealing dust ring 9-4 is made of a polymer super wear-resistant polyimide TPI material, which has the advantages of dimensional stability, high rigidity, good toughness, wear resistance, high temperature resistance, and corrosion resistance, and can better stabilize the sealing performance of the cutter hub 5.

[0095] Example 1

[0096] The preparation process of the shield disc cutter ring 6 of this embodiment includes the following steps: regulating the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultra-fine treatment - cutter ring 6 quenching and tempering heat treatment - cutter ring 6 vacuum quenching - -120°C deep cooling + 3 tempering, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to make the inner hole hardness of the cutter ring 6 HRC42, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered here;

[0097] The hole opening process of the forged cutter ring 6 blank is as follows: radial pressure>axial pressure, the ratio of radial pressure to axial pressure is 1.2, the radial pressure is 12 MPa, and the axial pressure is 10 MPa;

[0098] The metal components are as follows in percentage by mass: C: 0.5%, Si: 0.27%, Mn: 0.40%, Cr: 5%, W: 0.5%, Mo: 2.0%, V: 0.6%, N: 0.007%, Nb: 0.06%, Ni: 0.2%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other inevitable impurities.

[0099] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0100] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.5% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0101] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1130°C, the final forging temperature is 900°C, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0102] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0103] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and the heat is kept for 3 hours, and then water quenching and air cooling are repeated, and the operation is cycled in sequence until the air cooling temperature after the last water discharge is 150°C, and then the product is transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole product is heated evenly, and then kept warm for 5 hours, and then cooled to 765°C with the furnace, kept warm for 6 hours, and then cooled to 350°C with the furnace and taken out of the furnace.

[0104] As mentioned above, the knife ring 6 is subjected to tempering heat treatment: stepwise heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*5h, quenching; tempering at 350°C*3h+530°C*5h, and the overall hardness of the three temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0105] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 5% Cr element can improve creep resistance, making δ y At 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.0% Mo element can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.0%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0106] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the cutter ring 6 product at room temperature is 8.65J and the average longitudinal impact energy is 22J, and the average hardness is 59.3 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0107] Example 2

[0108] The preparation process of the shield disc cutter ring 6 of the present invention includes the following steps: regulating metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting, and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultrafine treatment - cutter ring 6 quenching and tempering heat treatment - cutter ring 6 vacuum quenching - -120°C deep cooling + 3 tempering, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to make the inner hole hardness of the cutter ring 6 HRC41, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered;

[0109] The forged cutter ring 6 blank is subjected to a hole-rolling process in which the radial pressure is controlled to be greater than the axial pressure, the ratio of the radial pressure to the axial pressure is 1.5, and the radial pressure is 12 MPa.

[0110] The metal components are as follows in percentage by mass: C: 0.55%, Si: 0.27%, Mn: 0.45%, Cr: 6%, W: 0.6%, Mo: 2.5%, V: 0.8%, N: 0.007%, Nb: 0.06%, Ni: 0.2%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other inevitable impurities.

[0111] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0112] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.55% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0113] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1150°C, the final forging temperature is 900°C, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0114] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0115] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and the heat is kept for 3 hours, and then water quenching and air cooling are repeated, and the operation is cycled in sequence until the air cooling temperature reaches 200°C after the last water discharge, and then the steel is transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole steel is heated evenly, and then kept warm for 7 hours, and then cooled to 765°C with the furnace, kept warm for 6 hours, and then cooled to 350°C with the furnace and taken out of the furnace.

[0116] As mentioned above, the knife ring 6 is subjected to tempering heat treatment: stepwise heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*4h, quenching; tempering at 350°C*3h+530°C*5h, and the overall hardness of the three temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0117] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 6% Cr element can improve creep resistance, making δ y At 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.5% Mo element can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.5%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0118] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the cutter ring 6 product at room temperature is 8.72J and the average longitudinal impact energy is 22.75J, and the average hardness is 60.5 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0119] Example 3

[0120] The preparation process of the shield disc cutter ring 6 of the present invention includes the following steps: regulating the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultrafine treatment - cutter ring 6 quenching and tempering heat treatment - cutter ring 6 vacuum quenching - -120°C deep cooling + 3 tempering, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to make the inner hole hardness of the cutter ring 6 not less than HRC40, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered;

[0121] The forged cutter ring 6 blank is subjected to a hole-rolling process in which the radial pressure is controlled to be greater than the axial pressure, the ratio of the radial pressure to the axial pressure is 1.5, and the radial pressure is 15 MPa;

[0122] The metal components are as follows in percentage by mass: C: 0.52%, Si: 0.3%, Mn: 0.42%, Cr: 5.5%, W: 0.75%, Mo: 2.3%, V: 0.75%, N: 0.007%, Nb: 0.06%, Ni: 0.26%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other inevitable impurities.

[0123] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0124] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.52% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0125] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1140°C, the final forging temperature is 900°C, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0126] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0127] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and kept warm for 3 hours, and then water quenched and air cooled, and the operation is repeated alternately, and the air cooling temperature is 200°C after the last water discharge, and then transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole is heated evenly, and then kept warm for 3 hours, and then cooled to 750°C with the furnace, kept warm for 6 hours, and then cooled to 350°C with the furnace and taken out of the furnace.

[0128] As mentioned above, the knife ring 6 is subjected to tempering heat treatment: stepwise heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*5h, quenching; tempering at 350°C*3h+530°C*5h, and the overall hardness of the three temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0129] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 5.5% Cr element can improve creep resistance, making δ y At 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.3% Mo element can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.3%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0130] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the cutter ring 6 product at room temperature is 8.49J and the average longitudinal impact energy is 21.625J, and the average hardness is 59.8 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0131] Example 4

[0132] The preparation process of the shield disc cutter ring 6 of the present invention includes the following steps: regulating the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultrafine treatment - cutter ring 6 quenching and tempering heat treatment - cutter ring 6 vacuum quenching - -120°C deep cooling + 3 tempering, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to make the inner hole hardness of the cutter ring 6 not less than HRC40, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered;

[0133] The forged cutter ring 6 blank is subjected to a hole-rolling process in which the radial pressure is controlled to be greater than the axial pressure, the ratio of the radial pressure to the axial pressure is 1.3, and the radial pressure is 13 MPa.

[0134] The metal components are as follows in percentage by mass: C: 0.55%, Si: 0.32%, Mn: 0.45%, Cr: 7.5%, W: 0.8%, Mo: 2.8%, V: 0.8%, N: 0.007%, Nb: 0.06%, Ni: 0.35%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other inevitable impurities.

[0135] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0136] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.55% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0137] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1140°C, the final forging temperature is 900°C, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0138] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0139] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and the heat is kept for 3 hours, and then water quenching and air cooling are repeated, and the operation is cycled in sequence until the air cooling temperature reaches 180°C after the last water discharge, and then the steel is transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole steel is heated evenly, and then kept warm for 7 hours, and then cooled to 750°C with the furnace, kept warm for 6.5 hours, and then cooled to 350°C with the furnace and taken out of the furnace.

[0140] As mentioned above, the knife ring 6 is subjected to tempering heat treatment: stepwise heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*5h, quenching; tempering at 350°C*3h+530°C*5h, and the overall hardness of the three temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0141] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure is increased too quickly, the force difference of the blank will increase, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 7.5% Cr element can improve creep resistance, making δ y At 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.8% Mo element can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.8%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0142] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the cutter ring 6 product at room temperature is 8.58J and the average longitudinal impact energy is 24J, and the average hardness is 59.5 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0143] Example 5

[0144] The preparation process of the shield disc cutter ring 6 of the present invention includes the following steps: regulating the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingot, blanking and upsetting and die forging - ring rolling and opening treatment of the forged cutter ring 6 blank - ultrafine treatment - cutter ring 6 quenching and tempering heat treatment - cutter ring 6 vacuum quenching - -120°C deep cooling + 3 tempering, after deep cooling, the cutter ring 6 is emptied to room temperature and then tempered 3 times, including 2 temperings at 540°C * 5h, and then tempering at 530°C * 5h, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to make the inner hole hardness of the cutter ring 6 not less than HRC40, and the matching hardness requirements of the cutter ring 6 and the cutter hub 5 are fully considered;

[0145] The forged cutter ring 6 blank is subjected to a hole-rolling process in which the radial pressure is controlled to be greater than the axial pressure, the ratio of the radial pressure to the axial pressure is 1.4, and the radial pressure is 14 MPa;

[0146] The metal components are as follows in percentage by mass: C: 0.5%, Si: 0.27%, Mn: 0.40%, Cr: 5.4%, W: 0.59%, Mo: 2.6%, V: 0.65%, N: 0.007%, Nb: 0.06%, Ni: 0.28%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other inevitable impurities.

[0147] The electromagnetic oscillation ingot extraction and electroslag remelting method mentioned above: the steel ingot is subjected to bipolar series electroslag remelting, and the steel ingot is spray-cooled and synchronously oscillated in the magnetic field during the extraction process.

[0148] This type of steel achieves a balance between high strength and toughness through medium carbon + multi-element alloying (Cr-Ni-Mo), supplemented by strict control of harmful elements to ensure process stability. The elements act synergistically. Among them, materials with a C content of 0.5% are selected to take both strength and toughness into consideration; Cr-Ni-Mo work together to improve hardenability, high temperature performance and corrosion resistance; Mn-Si work together to optimize deoxidation, desulfurization and solid solution strengthening.

[0149] It should be noted that since the forging strength of this component is higher, it is more prone to cracking, so it is necessary to control the cracking of the blank during the multi-directional forging process. Therefore, the multi-directional forging: the initial forging temperature is 1130°C, the final forging temperature is 900°C, and the reduction rate is gradually reduced from 40% to 30% to 20% to 10% to 5% to stabilize the thermoplastic.

[0150] The high temperature homogenization treatment is as follows: the heating and holding temperature is 1265° C. and the holding time is 15 hours, the purpose of which is to dissolve the liquid carbides into the steel.

[0151] The ultrafine treatment is as follows: the temperature is stepped up to 1050°C and the heat is kept for 3 hours, and then water quenching and air cooling are repeated, and the operation is cycled in sequence until the air cooling temperature reaches 200°C after the last water discharge, and then the steel is transferred to a trolley furnace set at 920°C, heated and kept warm so that the whole steel is heated evenly, and then kept warm for 7 hours, and then cooled to 720°C with the furnace, and after keeping warm for 7 hours, cooled to 350°C with the furnace and taken out of the furnace.

[0152] As mentioned above, the knife ring 6 is subjected to tempering heat treatment: stepwise heating to 1030°C and holding for 40 minutes; the knife ring 6 is subjected to vacuum quenching: 1030°C*4h, quenching; tempering at 350°C*3h+540°C*5h, and the overall hardness of the three temperings corresponds to HRC59, HRC60, and HRC62 respectively.

[0153] It should be noted that due to the addition of multi-element alloys to the components, the strength is higher. During the ring rolling and opening process, greater pressure needs to be applied. However, if the pressure is too high and the pressure increase speed is too fast, the force difference of the blank will be increased, further causing surface cracking. Therefore, the pressure and rate need to be adjusted in combination with the components and process. The material composition determines the high-temperature dynamic yield strength through solid solution strengthening and carbide precipitation, which directly affects the upper limit of pressure setting. For example, 5.4% Cr element can improve creep resistance, making δ y At 950°C, it is still ≥450MPa, supporting the radial pressure threshold of 15MPa; 2.6% Mo element can inhibit dynamic recrystallization and reduce the strain rate sensitivity of the material; when the axial pressure rate is greater than 0.5MPa / s, component optimization (such as adjusting the Mo content to Mo: 2.6%) is required to avoid cracks caused by local hardening; the added Ni forms a synergistic effect with Cr and Mo, which further ensures the smooth implementation of forging.

[0154] By adjusting the radial and axial pressures during the ring opening process, the structures inside and outside the ring are made uniform, so that the average transverse impact energy of the cutter ring 6 product at room temperature is 8.53J and the average longitudinal impact energy is 21.8J, and the average hardness is 61.2 / HRC, which meets the performance requirements of heavy-duty shield disc cutters.

[0155] The cutter rings obtained by the processes of Examples 1-5 of the present invention were sampled and tested:

[0156] 1. Test method and basis: The impact specimen is a U-notch specimen (notch depth 2mm). According to the standard "GB / T229-2020 Metal Materials Charpy Pendulum Impact Test Method", the impact specimen is subjected to a room temperature impact test. The test temperature is room temperature (10-15°C).

[0157] 2. Test method and basis: Rockwell hardness test is carried out on longitudinal specimens in accordance with the Chinese national standard "T230.1-2018 Metallic materials Rockwell hardness test Part 1 Test method".

[0158] Sample code Hardness / HRC Transverse average impact energy / J Longitudinal average impact energy / J ZJ-9-001 59.3 8.65 22 ZJ-9-002 60.5 8.72 22.75 ZJ-9-003 59.8 8.49 21.625 ZJ-9-004 59.5 8.58 24 ZJ-9-005 61.2 8.53 21.8

[0159] The sampled product of the sword casting No. 9 of the present invention was commissioned to a third party to conduct a synchronous sample heat treatment process and then a mechanical test was performed. A variety of 10*10*55 standard U-shaped pendulum impact energy tests were performed. The results are as follows: Figure 5 、 Figure 6 、 Figure 7 and Figure 8 shown.

[0160] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs a structure and embodiment similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A process for preparing a hob cutter ring, characterized in that: The method comprises the following steps: adjusting the metal composition to prepare molten steel - pouring steel ingots - electromagnetic oscillation ingot extraction and electroslag remelting - multi-directional forging - high-temperature homogenization treatment - upsetting the steel ingots, blanking and upsetting, and die forging - rolling and opening the forged cutter ring blank - ultrafine treatment - cutter ring quenching and tempering heat treatment - vacuum quenching the cutter ring - deep cooling at -120°C and tempering three times, after deep cooling, the cutter ring is placed in an airtight state to room temperature and then tempered three times, including tempering at 540°C for two times for 5 hours and then tempering at 530°C for 5 hours, and after being taken out of the furnace, high-frequency induction inner hole softening is performed to ensure that the hardness of the cutter ring inner hole is not less than HRC40; The hole opening process of the cutter ring blank after forging is as follows: radial pressure is controlled to be greater than axial pressure, the ratio of radial pressure to axial pressure is 1.2-1.5, and the maximum radial pressure does not exceed 15 MPa; The metal components are as follows in percentage by mass: C: 0.5% to 0.55%, Si: 0.27% to 0.32%, Mn: 0.40% to 0.45%, Cr: 5% to 7.5%, W: 0.5% to 0.8%, Mo: 2.0% to 2.8%, V: 0.6% to 0.8%, N: 0.007%, Nb: 0.06%, Ni: 0.2% to 0.35%, Cu: 0.2%, S: 0.003%, P: 0.003%, and the rest is Fe and other unavoidable impurities.

2. The process for preparing a hob cutter ring according to claim 1, characterized in that: The electromagnetic oscillation ingot extraction and electroslag remelting method performs bipolar series electroslag remelting on the steel ingot, spray-cooling the steel ingot and synchronously oscillating the magnetic field during the ingot extraction process.

3. The process for preparing a hob cutter ring according to claim 1, characterized in that: The multi-directional forging has an initial forging temperature of 1130-1150° C., a final forging temperature of 900° C., and a reduction rate that decreases gradually from 40% to 30% to 20% to 10% to 5%.

4. The process for preparing a hob cutter ring according to claim 1, characterized in that: The high-temperature homogenization treatment: the heating and holding temperature is 1265° C., and the holding time is 15 hours.

5. The process for preparing a hob cutter ring according to any one of claims 1 to 4, characterized in that: The upsetting and drawing of the steel ingot, blanking upsetting and die forging process are as follows: the heating temperature is 1200-1250° C., the holding time is 2-3 hours, the initial forging temperature is 1150-1200° C., and the final forging temperature is 900-950° C.

6. The process for preparing a hob cutter ring according to claim 5, characterized in that: The ultrafine treatment is as follows: stepwise heating to 1050°C and heat preservation for 3 hours, followed by water quenching and air cooling, and repeated alternating operations, and cycled in sequence until the air cooling temperature after the last water discharge is 150°C-200°C, and then transferred to a trolley furnace set at 920°C, heated and heat-insulated to ensure that the whole is heated evenly, and then heat-insulated for 5-7 hours, and then cooled to 765°C-720°C with the furnace, and after heat preservation for 6-7 hours, cooled to 350°C with the furnace and discharged from the furnace.

7. The process for preparing a hob cutter ring according to claim 6, characterized in that: The knife ring is subjected to tempering heat treatment: stepwise heating to 1030°C and heat preservation for 40 minutes; the knife ring is subjected to vacuum quenching: 1030°C*(3-5h), quenching; tempering at 350°C*3h+(530~540)°C*5h. After three temperings, the overall hardness range is HRC59-HRC60-HRC62.

8. A hob cutter ring obtained by the preparation process according to any one of claims 1 to 7.

9. A disc cutter having the cutter ring according to claim 8.

10. A TMB shield equipment having the disc cutter according to claim 9.

Images