Composite cutter tooth for dredger and preparation method of composite cutter tooth

Abstract

The invention discloses a composite cutter tooth for a dredger and a preparation method of the composite cutter tooth, and belongs to the technical field of dredging equipment. The technical problems that an existing cutter tooth for the dredger is poor in abrasion resistance and short in service life are solved. The composite cutter tooth for the dredger comprises a cutter tooth base body and a cutter tooth tip. The cutter tooth tip is arranged on the cutter tooth base body; the cutter tooth base body comprises, by mass, 0.15%-0.25% of C, 0.1%-0.3% of Si, 1.0%-2.0% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.010% of S, 0.01%-0.05% of V, 0.03%-0.1% of Ni, 1%-2% of Cr, 0.01%-0.2% of Al and the balance Fe and inevitable impurities. The composite cutter tooth for the dredger has good obdurability matching and excellent wear resistance, and the service condition of the cutter tooth of the dredger can be met.

Description

Technical Field

[0001] The invention relates to the technical field of dredging equipment, and in particular to a composite cutter tooth for a dredging vessel and a preparation method thereof. Background Art

[0002] Large offshore dredging equipment is the core equipment of marine construction, and is the "national heavy equipment" for marine resource development, island and reef construction, and port construction. Dredging equipment (dredgers) are mainly divided into cutter suction dredgers and trailing suction dredgers. Cutter suction dredgers use rotating cutters to loosen the soil on the riverbed or seabed, mix it with cement into mud, suck it into the pump body through the mud suction pipe, and send it to the mud discharge area through the mud discharge pipe. During the construction of the cutter suction dredger, dredging, mud transportation and mud unloading are all integrated and completed by themselves, with high production efficiency. It is suitable for dredging in inland lakes and coastal ports with small wind and waves and low flow rate, and is more suitable for excavating sand, sandy loam, silt and other soils. Trailing suction dredger is a large self-propelled, bunker-type dredger equipped with a rake head excavator and a hydraulic mud suction device. When dredging, the rake suction pipe is lowered to the river bottom, and the vacuum effect of the mud pump is used to absorb mud from the river bottom through the rake head and the mud suction pipe into the mud bin of the dredger. When the mud bin is full, the rake is lifted and sailed to the mud dumping area to open the mud door to unload the mud, or the excavated mud is directly discharged from the ship. It is suitable for the excavation and maintenance of unprotected, narrow and long coastal access channels, and is most efficient when excavating silt. The failure mode of the auger teeth is mainly mechanical wear or broken teeth. The rake teeth have similar functions to the auger teeth. Their function is to loosen the soil, chop the soil, and form a mud-water mixture of appropriate concentration in their cavity, which is sucked by the mud pump. The failure mode is mechanical and corrosive wear or broken teeth. Therefore, as a consumable steel used in large quantities, the steel used for the teeth of large offshore dredging equipment is generally made of low-alloy cast steel, and it is required to have excellent wear resistance, good comprehensive mechanical properties (strength and toughness) and processability (casting).

[0003] The domestic main products used are rake teeth and reamer teeth produced by internationally renowned dredging companies in domestic OEM factories. The material composition and process are from abroad. The main material of the teeth in the domestic market is medium-carbon alloy steel. The hardness of this type of reamer teeth after heat treatment is usually around 48HRC, and the impact toughness is good. Although it can meet the use requirements of reamer teeth, the working time is not long and the wear is very serious. The service life is generally less than 50 hours. The product performance is difficult to reach the level of imported teeth. The teeth and tooth seat materials widely used internationally are a type of boron-containing alloy steel with martensite, bainite, etc. as the matrix, and some containing boride as the wear-resistant hard phase. The tooth tip and tooth seat achieve the difference in mechanical properties through fine-tuning of alloy elements and heat treatment processes, making them more suitable for use conditions.

[0004] At present, the relevant patents of large dredgers are mainly concentrated in the structure, with the focus on higher efficiency, larger capacity, etc., and rarely involve the steel materials used for the teeth. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a composite cutter tooth for a dredger and a preparation method thereof, so as to solve the technical problems of poor wear resistance and short service life of existing cutter teeth for dredgers.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions:

[0007] On the one hand, the present invention provides a composite cutter for a dredger, comprising a cutter base and a cutter tip; the cutter tip is arranged on the cutter base;

[0008] The components of the tooth matrix include, by mass percentage, C: 0.15-0.25%, Si: 0.1-0.3%, Mn: 1.0-2.0%, P: ≤0.010%, S: ≤0.010%, V: 0.01%-0.05%, Ni: 0.03-0.1%, Cr: 1%-2%, Al: 0.01-0.2%, and the remainder is Fe and unavoidable impurities.

[0009] In one possible design, the components of the tooth matrix include, by mass percentage: C: 0.18-0.25%, Si: 0.11-0.3%, Mn: 1.3-2.0%, P: ≤0.008%, S: ≤0.009%, V: 0.03%-0.05%, Ni: 0.04-0.1%, Cr: 1.3%-2%, Al: 0.1-0.2%, and the remainder is Fe and unavoidable impurities.

[0010] In one possible design, the components of the tooth matrix include, by mass percentage: C: 0.20-0.25%, Si: 0.15-0.3%, Mn: 1.6-2.0%, P: ≤0.007%, S: ≤0.007%, V: 0.03%-0.05%, Ni: 0.06-0.1%, Cr: 1.4%-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

[0011] In one possible design, the components of the tooth matrix include, by mass percentage: C: 0.2-0.24%, Si: 0.24-0.28%, Mn: 1.6-2.0%, P: ≤0.006%, S: ≤0.006%, V: 0.03%-0.04%, Ni: 0.07-0.1%, Cr: 1.5%-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

[0012] In one possible design, the components of the tooth matrix include, by mass percentage: C: 0.15%, Si: 0.11%, Mn: 1.0%, P: 0.008%, S: 0.007%, V: 0.01%, Ni: 0.03%, Cr: 1.30%, Al: 0.01%, and the remainder is Fe and unavoidable impurities.

[0013] In one possible design, the tooth tip is made of WC-15Co cemented carbide.

[0014] On the other hand, the present invention also provides a method for preparing a composite cutter tooth for a dredger, which is used to prepare the composite cutter tooth for a dredger; the preparation method comprises the following steps:

[0015] Step 1, smelting and casting the cutter tooth matrix according to the component design requirements of the cutter tooth matrix to obtain a casting blank or ingot of the cutter tooth matrix;

[0016] Step 2, sequentially performing high temperature homogenization treatment and heat treatment on the cast blank or ingot of the cutter tooth matrix;

[0017] Step 3, machining the front end of the heat-treated tooth matrix to open a cemented carbide inlay groove;

[0018] Step 4: Induction heating welding is performed on the cutter tooth base body with the carbide inlay groove and the cutter tooth tip.

[0019] Furthermore, in step 2, the billet or ingot of the tooth matrix is ​​heated to 1000-1200° C. in a heating furnace for high temperature homogenization treatment.

[0020] Furthermore, in step 2, the temperature is kept at 1000-1200° C. for 0.5-2 h.

[0021] Furthermore, in step 3, after the high-temperature homogenization treatment, the billet or ingot is heat treated, specifically including first quenching treatment and keeping it warm for a certain time; then tempering treatment and keeping it warm for a certain time.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] (1) The steel for dredger blades provided by the present invention ensures that the steel obtains tempered martensite + residual austenite (volume fraction ≥ 1%) + carbide by precisely controlling the mass percentages of elements such as C, Si, Mn, Cr, V, and Ni in the steel, and combines the quenching + low-temperature tempering process, thereby ensuring that the steel for dredger blades has a good match of strength and toughness and excellent wear resistance, and ensuring that the steel of the present invention can meet the service conditions of dredger blades.

[0024] (2) The present invention obtains WC cemented carbide reinforced composite teeth by controlling the process, and the tooth matrix is ​​tempered martensite + residual austenite (volume fraction ≥ 1%) + carbide, especially the content of residual austenite is greater than or equal to 1%, so it has good toughness. However, as the actual working conditions become more and more severe, the requirements for the abrasive performance of the teeth are getting higher and higher. WC cemented carbide is embedded in the tip of the teeth to enhance the wear resistance and corrosion resistance of the tooth wear surface, thereby improving the service life of the teeth in actual working conditions and greatly increasing the tooth replacement cycle.

[0025] (3) The steel for dredger teeth prepared by the composition and method of the present invention has good comprehensive mechanical properties, with a yield strength of ≥1050MPa, a tensile strength of ≥1300MPa, a hardness of ≥55HRC, and an impact energy of ≥25J at room temperature. The comprehensive mechanical properties far exceed the level of domestic steel for teeth.

[0026] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0028] Figure 1 The microstructure diagram of the steel for the base body of the cutter tooth provided in Example 1 of the present invention;

[0029] Figure 2 The microstructure diagram of the steel for the base body of the blade provided in Example 2 of the present invention;

[0030] Figure 3 The microstructure diagram of the steel for the base body of the cutter tooth provided in Example 3 of the present invention;

[0031] Figure 4 The microstructure diagram of the base steel of the blade teeth provided in Example 4 of the present invention;

[0032] Figure 5 The structure of the blade base of the present invention is shown in FIG. Figure 1 ;

[0033] Figure 6 The structure of the blade base of the present invention is shown in FIG. Figure 2 .

[0034] Reference numerals:

[0035] 1-tooth base; 2-carbide inlay groove. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0037] The invention provides a composite cutter for a dredger, comprising a cutter tooth matrix 1; the components of the cutter tooth matrix 1 include, by mass percentage: C: 0.15-0.25%, Si: 0.1-0.3%, Mn: 1.0-2.0%, P: ≤0.010%, S: ≤0.010%, V: 0.01%-0.05%, Ni: 0.03-0.1%, Cr: 1%-2%, Al: 0.01-0.2%, and the remainder is Fe and unavoidable impurities.

[0038] C: Carbon is a typical interstitial solid solution strengthening element. Increasing the carbon content in the alloy is an effective way to improve the strength of the alloy. However, too high a C content will reduce the plasticity and welding properties of the steel. Therefore, the C content is controlled between 0.15 and 0.25%.

[0039] Si: Si is a deoxidizer in steelmaking, but excessive silicon is detrimental to the steel's resistance to hydrogen sulfide corrosion. Therefore, the content of Si in the present invention is controlled at 0.1-0.3%.

[0040] Mn: Mn can increase the content of retained austenite and improve toughness. In the present invention, the Mn content is controlled to be 1.0-2.0%.

[0041] P: P is an impurity in steel and is not conducive to toughness. In the present invention, the P content is controlled to be ≤0.010%.

[0042] S: S seriously deteriorates the corrosion resistance and toughness of steel. In the present invention, its content is controlled to be ≤0.010%.

[0043] Cr: Cr is also an element that improves the hardenability of bucket steel, ensuring that the bucket steel obtains martensite structure when quenched. At the same time, Cr is also a corrosion-resistant element, which can significantly improve the corrosion resistance. The Cr content is controlled to 1-2%.

[0044] V: can form fine dispersed VC particles, refine the grains by pinning the grain boundaries, and form carbides during the heat treatment and tempering process to achieve precipitation strengthening. However, when the V content in the steel is too high, large VC particles are formed in the molten state, which significantly reduces the toughness of the material. Therefore, the V content in the present invention is controlled to be 0.01% to 0.05%.

[0045] Ni: can improve hardenability, reduce critical transition temperature, reduce diffusion rate of elements in steel, and improve hardenability. Since nickel is a scarce resource, its usage should be minimized in practical applications. Therefore, the content of Ni in the present invention is controlled to be 0.03-0.1%.

[0046] Al: Al can improve the corrosion resistance of the material. Too high Al content will significantly reduce the toughness. Therefore, in the present invention, the Al content is controlled to be 0.01-0.2%.

[0047] In steel alloys, the above elements not only have their own unique functions, but also interact with each other in complex ways, jointly affecting the properties of the alloy.

[0048] It should be noted that regarding the combination of C and alloying elements: C and strong carbide-forming elements Cr and V can form stable carbide particles. For example, Cr carbides help improve corrosion resistance and hardness, while V carbides help refine grains and precipitation strengthen. However, since too high a C content will damage the plasticity and weldability of the steel, the C content needs to be precisely controlled.

[0049] Regarding the synergistic effect of Si and Mn: Si, as a deoxidizer, can reduce the oxygen content in steel, thereby improving the purity of steel. Mn can increase the residual austenite content of steel and increase toughness. The combination of the two can ensure the purity of steel while improving the toughness of steel; but care must be taken to control the content of Si to avoid adverse effects on resistance to hydrogen sulfide corrosion.

[0050] Strict control of P and S: P and S, as impurity elements, have an adverse effect on the toughness of steel. By strictly controlling their content (≤0.010%), the purity and comprehensive mechanical properties of steel can be significantly improved. This control usually requires the use of advanced smelting and refining technology.

[0051] Regarding the improvement of corrosion resistance of Cr and Ni: Cr and Ni are both important elements for improving the corrosion resistance of steel. Cr can form a dense oxide film on the surface of steel to prevent further corrosion; Ni can reduce the critical transition temperature of steel and improve hardenability, thereby indirectly enhancing corrosion resistance; the combination of the two can significantly improve the corrosion resistance of steel, and is suitable for parts that need to work in harsh environments for a long time.

[0052] Regarding the precipitation strengthening of V, Cr and Ni: V plays a role in grain refinement and precipitation strengthening by forming fine dispersed VC particles. When V is used in combination with Cr and Ni elements, these fine VC particles can coexist with Cr and Ni carbides to form a more complex strengthening phase, further improving the strength and toughness of the steel. However, the V content must be precisely controlled to avoid the formation of large particles of VC and reduce toughness.

[0053] Regarding the balance between Al’s corrosion resistance and toughness: the addition of Al can improve the corrosion resistance of steel, but too high Al content will damage toughness. Therefore, while controlling the Al content, it is necessary to comprehensively consider its dual effects on corrosion resistance and toughness to find the best balance.

[0054] In the composite cutter of the above-mentioned dredger, the microstructure of the cutter matrix 1 is tempered martensite with a small amount of retained austenite and a small amount of VC precipitation; wherein the volume fraction of retained austenite is greater than 1%, and the retained austenite can not only improve the corrosion resistance and toughness of the cutter tooth, but also improve its processing performance; the volume fraction of tempered martensite accounts for the vast majority, which can play a role in improving the strength and stiffness of the matrix; carbides pin the grain boundaries to refine the grains and play a precipitation strengthening effect.

[0055] Based on the actual service environment, the present invention develops a steel-based composite material with good wear resistance and high strength as a cutter tooth material for dredging equipment (dredger), and the effect is significantly better than the existing medium-carbon alloy steel cutter teeth.

[0056] In one embodiment of the present invention, the components of the tooth matrix 1 of the present invention include, by mass percentage: C: 0.18-0.25%, Si: 0.11-0.3%, Mn: 1.3-2.0%, P: ≤0.008%, S: ≤0.009%, V: 0.03%-0.05%, Ni: 0.04-0.1%, Cr: 1.3-2%, Al: 0.1-0.2%, and the remainder is Fe and unavoidable impurities.

[0057] In one embodiment of the present invention, the components of the tooth matrix 1 of the present invention include, by mass percentage: C: 0.20-0.25%, Si: 0.15-0.3%, Mn: 1.6-2.0%, P: ≤0.007%, S: ≤0.007%, V: 0.03%-0.05%, Ni: 0.06-0.1%, Cr: 1.4-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

[0058] In one embodiment of the present invention, the components of the tooth matrix 1 of the present invention include, by mass percentage: C: 0.2-0.24%, Si: 0.24-0.28%, Mn: 1.6-2.0%, P: ≤0.006%, S: ≤0.006%, V: 0.03%-0.04%, Ni: 0.07-0.1%, Cr: 1.5-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

[0059] In one embodiment of the present invention, the present invention provides a composite cutter for a dredger, wherein the components of the cutter matrix 1 include, by mass percentage: C: 0.15%, Si: 0.11%, Mn: 1.0%, P: 0.008%, S: 0.007%, V: 0.01%, Ni: 0.03%, Cr: 1.30%, Al: 0.01%, and the remainder is Fe and unavoidable impurities.

[0060] In one embodiment of the present invention, the present invention provides a composite cutter for a dredger, wherein the components of the cutter matrix 1 include, by mass percentage: C: 0.18%, Si: 0.24%, Mn: 1.6%, P: 0.007%, S: 0.004%, V: 0.03%, Ni: 0.033%, Cr: 1.40%, Al: 0.10%, and the remainder is Fe and unavoidable impurities.

[0061] In one embodiment of the present invention, the present invention provides a composite cutter for a dredger, wherein the components of the cutter matrix 1 include, by mass percentage: C: 0.20%, Si: 0.15%, Mn: 1.3%, P: 0.009%, S: 0.006%, V: 0.03%, Ni: 0.06%, Cr: 1.50%, Al: 0.15%, and the remainder is Fe and unavoidable impurities.

[0062] In one embodiment of the present invention, the present invention provides a composite tooth for a dredger, wherein the components of the tooth matrix 1 include, by mass percentage: C: 0.24%, Si: 0.28%, Mn: 2.0%, P: 0.006%, S: 0.009%, V: 0.05%, Ni: 0.05%, Cr: 1.30%, Al: 0.20%, and the remainder is Fe and unavoidable impurities.

[0063] The composite cutter for dredgers further comprises a cutter tooth tip; the cutter tooth tip is WC-15Co cemented carbide, and the WC-15Co cemented carbide is used as a reinforcing phase of the composite cutter tooth combined with the cutter tooth matrix 1.

[0064] On the other hand, the present invention also provides a method for preparing a composite cutter tooth for a dredger, which is used to prepare the composite cutter tooth for a dredger; the preparation method comprises the following steps:

[0065] Step 1, smelting and casting the cutter tooth matrix 1 according to the component design requirements of the cutter tooth matrix 1 to obtain a casting blank or ingot of the cutter tooth matrix 1;

[0066] In the above step 1, the components of the tooth matrix 1 include, by mass percentage: C: 0.15-0.25%, Si: 0.1-0.3%, Mn: 1.0-2.0%, P: ≤0.010%, S: ≤0.010%, V: 0.01%-0.05%, Ni: 0.03-0.1%, Cr: 1.0-2.0%, Al: 0.01-0.2%, and the remainder is Fe and unavoidable impurities.

[0067] Step 2, performing high temperature homogenization treatment and heat treatment on the cast billet or ingot of the cutter tooth base 1;

[0068] In the above step 2, the billet or ingot of the blade tooth base 1 is heated to 1000-1200° C. in a heating furnace and kept at 1000-1200° C. for 0.5-2 hours to perform high temperature homogenization treatment, followed by heat treatment.

[0069] Compared with the prior art, the present invention can ensure that all alloy elements are dissolved and exist in the matrix in the form of solid solution by subjecting the cast billet or ingot of the blade tooth matrix 1 to high temperature homogenization. When the holding temperature is greater than 1200°C or the holding time is greater than 2h, the austenite grains will grow excessively or even overheat, affecting the final toughness and strength of the material; when the holding temperature is lower than 1000°C or the holding time is less than 0.5h, the alloy elements will not be completely dissolved, the steel composition will be uneven, and the final performance of the material will be affected.

[0070] In the above step 2, after the high-temperature homogenization treatment, the billet or ingot is heat treated, specifically including first quenching treatment and keeping it warm for a certain time; then tempering treatment and keeping it warm for a certain time.

[0071] In the above step 2, the billet or ingot of the blade base 1 is heated to a quenching temperature of 750-900°C, which is higher than the complete austenitization temperature of the billet or ingot, and the heat preservation time is 0.5-1h, and then water quenched to room temperature.

[0072] In the above step 2, after the quenching treatment, the blade tooth base 1 is heated from room temperature to 200-300° C. for tempering treatment. The holding time of the tempering treatment is 2-5 hours, and then air-cooled to room temperature.

[0073] Compared with the prior art, the present invention controls the low-temperature tempering temperature at 200-300°C and the holding time at 2-5h to ensure that the quenched martensite structure is transformed into tempered martensite, thereby significantly improving the comprehensive mechanical properties and SSCC resistance of the tooth matrix 1.

[0074] Step 3: Perform front-end machining on the heat-treated tooth base 1 to form a cemented carbide inlay groove 2.

[0075] In the above step 3, 2-3 carbide inlay grooves 2 with a width of 5-10 mm and a depth of 5-10 mm are opened parallel to the wear direction at the tip of the tooth base body 1. The carbide inlay grooves 2 are wedge-shaped grooves, such as Figure 5 and Figure 6 As shown, the cemented carbide inlay groove 2 is made into a wedge shape for the purpose of enhancing the bonding performance between the WC-15Co cemented carbide and the tooth matrix 1 and preventing the WC-15Co cemented carbide from directly detaching under actual working conditions.

[0076] Step 4: Induction heating welding is performed between the cutter tooth base 1 with the WC-15Co cemented carbide inlay groove 2 and the cemented carbide.

[0077] In the above step 4, the temperature of induction heating welding is 800-1000°C, and the welding time is 3-7 minutes; during welding, the sufficient fluidity of the solder is ensured so that the space between the WC-15Co cemented carbide and the tooth substrate 1 is completely filled with solder without any gap, thereby obtaining a dredger composite tooth with good bonding performance.

[0078] Specifically, in the above step 4, the mechanical properties of the composite cutter teeth of the dredger obtained are as follows: its yield strength ≥1050MPa, tensile strength ≥1300MPa, hardness ≥55HRC, room temperature impact energy ≥25J, and the base of the tip of the cutter teeth is affected by welding heat, and the yield strength is ≥900MPa, the tensile strength is ≥1200MPa, and the hardness is ≥45HRC.

[0079] It should be noted that the steel for dredger teeth provided by the present invention ensures that the steel obtains tempered martensite + residual austenite (volume fraction ≥ 1%) + carbide by accurately controlling the mass percentage of C, Si, Mn, Cr, V, and Ni elements in the steel, and combines the quenching + low-temperature tempering process, thereby ensuring that the steel for dredger teeth has a good strength-toughness match and excellent wear resistance, and ensuring that the steel of the present invention can meet the service conditions of dredger teeth.

[0080] The present invention obtains WC carbide reinforced composite cutter teeth by strictly controlling the preparation process and process conditions of the composite cutter teeth. The cutter tooth matrix 1 is tempered martensite + residual austenite (volume fraction is 1%) + carbide, and has good strength and toughness.

[0081] As the actual working conditions become increasingly harsh, the requirements for the abrasive performance of the cutter teeth are becoming higher and higher. A WC carbide inlay is set at the tip position of the cutter tooth base 1 to enhance the wear resistance and corrosion resistance of the cutter tooth wear surface, thereby improving the service life of the composite cutter teeth in actual working conditions and greatly increasing the tooth replacement cycle.

[0082] It should be emphasized that only by strictly following the composition design and preparation process conditions of the present invention can the strength and toughness of the steel with the composition of the present invention be matched and fully reach the required range.

[0083] Examples 1-4

[0084] Embodiments 1-4 of the present invention provide a method for preparing steel for dredging ship teeth. The components of the steel in embodiments 1-4 include, by mass percentage: C: 0.25-0.4%, Si: 1-2%, Mn: 0.5-1.5%, P: ≤0.010%, S: ≤0.010%, V: 0.01-0.05%, Ni: 0.03-0.1%, Cr: 1%-2%, Al: 0.01-0.2%, and the remainder is Fe and unavoidable impurities.

[0085] The method for preparing the steel of Examples 1-4 comprises:

[0086] Step 1: smelting and casting the base blade teeth to obtain a casting blank;

[0087] Step 2: heat treating the blade tooth base 1 after high temperature homogenization treatment;

[0088] Step 3: Perform front-end machining on the heat-treated cutter teeth to create a carbide inlay groove 2.

[0089] Step 4: Induction heating welding of the slotting cutter teeth and the cemented carbide.

[0090] The specific preparation methods of the steels of Examples 1-4 are shown in Table 1 below, the corresponding components are shown in Table 2, the microstructures are shown in Table 3, and the mechanical properties are shown in Table 4. The microstructure of Example 1 is shown in Table Figure 1 As shown, the microstructure of Example 2 is as follows Figure 2 As shown, the microstructure of Example 3 is as follows Figure 3 As shown, the microstructure of Example 4 is as follows Figure 4 shown.

[0091] Table 1 Preparation process conditions of Examples 1-4

[0092]

[0093] Table 2 Chemical composition of Examples 1-4

[0094]

[0095] Table 3 Microstructure of the tooth matrix prepared in Examples 1-4

[0096] Serial number Microstructure Example 1 Tempered martensite + 1.19% retained austenite + second phase VC Example 2 Tempered martensite + 1.02% retained austenite + second phase VC Example 3 Tempered martensite + 1.16% retained austenite + second phase VC Example 4 Tempered martensite + 1.18% retained austenite + second phase VC Comparative Example 1 Tempered martensite + 0.30% retained austenite + second phase VC Comparative Example 2 Tempered martensite + 0.43% retained austenite + second phase VC Comparative Example 3 Tempered martensite + 0.31% retained austenite + second phase VC Comparative Example 4 Tempered martensite + 0.26% retained austenite + second phase VC

[0097] It can be seen from Table 3 that the tooth matrix of the present invention is tempered martensite + retained austenite (volume fraction ≥ 1%) + carbide, especially the content of retained austenite is 1.02-1.19%, and the content of retained austenite is greater than or equal to 1%, so it has good strength and toughness. The content of retained austenite in Comparative Examples 1 to 4 is relatively low, and the toughness is low due to the low content of retained austenite.

[0098] Table 4 Mechanical properties of the composite teeth prepared in Examples 1-4

[0099]

[0100] It can be seen from Table 4 that the yield strength of the composite cutter teeth of the present invention is 1169-1192 MPa, the tensile strength is 1446-1477 MPa, the hardness is 57-59 HRC, and the room temperature impact energy is 26-27 J. The yield strength, tensile strength, hardness, and room temperature impact energy of the cutter teeth of Comparative Examples 1 to 4 are all lower than the performance of the composite cutter teeth of the present invention.

[0101] Table 5 Mechanical properties of the composite tooth matrix of Examples 1-4

[0102]

[0103] It can be seen from Table 5 that due to the influence of welding heat, the mechanical properties of the tooth matrix are slightly lower than the overall performance of the composite tooth. The yield strength of the tooth matrix of the present invention is 921-1009 MPa, the tensile strength is 1151-1277 MPa, and the hardness is 47-50 HRC.

[0104] Specifically, in the above step 4, the mechanical properties of the composite cutter tooth of the dredger obtained are as follows: its yield strength ≥1050MPa, tensile strength ≥1300MPa, hardness ≥55HRC, room temperature impact energy ≥25J, yield strength ≥900MPa, tensile strength ≥1200MPa, and hardness ≥45HRC.

[0105] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A composite cutter for a dredger, characterized in that: It includes a blade tooth base and a blade tooth tip; The tooth tip of the knife tooth is arranged on the knife tooth base; The components of the tooth matrix include, by mass percentage, C: 0.15-0.25%, Si: 0.1-0.3%, Mn: 1.0-2.0%, P: ≤0.010%, S: ≤0.010%, V: 0.01%-0.05%, Ni: 0.03-0.1%, Cr: 1%-2%, Al: 0.01-0.2%, and the remainder is Fe and unavoidable impurities.

2. The composite cutter for dredger according to claim 1, characterized in that: The components of the tooth matrix include, by mass percentage, C: 0.18-0.25%, Si: 0.11-0.3%, Mn: 1.3-2.0%, P: ≤0.008%, S: ≤0.009%, V: 0.03%-0.05%, Ni: 0.04-0.1%, Cr: 1.3%-2%, Al: 0.1-0.2%, and the remainder is Fe and unavoidable impurities.

3. The composite cutter for dredger according to claim 2, characterized in that: The components of the tooth matrix include, by mass percentage, C: 0.20-0.25%, Si: 0.15-0.3%, Mn: 1.6-2.0%, P: ≤0.007%, S: ≤0.007%, V: 0.03%-0.05%, Ni: 0.06-0.1%, Cr: 1.4%-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

4. The composite cutter for dredger according to claim 3, characterized in that: The components of the tooth matrix include, by mass percentage, C: 0.2-0.24%, Si: 0.24-0.28%, Mn: 1.6-2.0%, P: ≤0.006%, S: ≤0.006%, V: 0.03%-0.04%, Ni: 0.07-0.1%, Cr: 1.5%-2%, Al: 0.15-0.2%, and the remainder is Fe and unavoidable impurities.

5. The composite cutter for dredger according to claim 1, characterized in that: The components of the tooth matrix include, by mass percentage, C: 0.15%, Si: 0.11%, Mn: 1.0%, P: 0.008%, S: 0.007%, V: 0.01%, Ni: 0.03%, Cr: 1.30%, Al: 0.01%, and the balance is Fe and unavoidable impurities.

6. The composite cutter for dredger according to claim 1, characterized in that: The material of the tooth tip of the cutter tooth is WC-15Co hard alloy.

7. A method for preparing a composite cutter tooth for a dredger, characterized in that: Used to prepare the composite blade for dredger according to any one of claims 1 to 6; the preparation method comprises the following steps: Step 1, smelting and casting the cutter tooth matrix according to the component design requirements of the cutter tooth matrix to obtain a casting blank or ingot of the cutter tooth matrix; Step 2, sequentially performing high temperature homogenization treatment and heat treatment on the cast blank or ingot of the cutter tooth matrix; Step 3, machining the front end of the heat-treated tooth matrix to open a cemented carbide inlay groove; Step 4: Induction heating welding is performed on the cutter tooth base body with the carbide inlay groove and the cutter tooth tip.

8. The method for preparing a composite blade for a dredger according to claim 7, characterized in that: In the step 2, the casting blank or ingot of the blade tooth matrix is ​​heated to 1000-1200° C. in a heating furnace for high temperature homogenization treatment.

9. The method for preparing a composite blade for a dredger according to claim 8, characterized in that: In the step 2, the temperature is kept at 1000-1200° C. for 0.5-2 h.

10. The method for preparing a composite blade for a dredger according to claim 7, characterized in that: In step 3, after the high-temperature homogenization treatment, the billet or ingot is heat treated, specifically including first quenching treatment and keeping it warm for a certain time; then tempering treatment and keeping it warm for a certain time.

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