135 results about "Non-metallic inclusions" patented technology

The invention belongs to the technical field of bar production, and particularly relates to a production method of a steel bar for a heavy-load automobile half axle, and the steel bar comprises the following chemical components in percentage by mass: 0.39-0.42% of C, 0.25-0.35% of Si, 1.45-1.70% of Mn, less than or equal to 0.013% of P, less than or equal to 0.006% of S, less than or equal to 0.25% of Cr, less than or equal to 0.25% of Ni, 0.15-0.20% of Mo, 0.06-0.10% of V, less than or equal to 0.15% of Cu and the balance of Fe and inevitable impurities. The method has the advantages that high-performance, high-purity and low-cost production of the steel bar for the heavy-duty automobile half shaft is realized through green short-process production of'ecological electric furnace + LF + RH + continuous casting 'in combination with low-carbon component design and a controlled rolling and controlled cooling process. And macrostructures and non-metallic inclusions of the finished steel meet the requirements of high-end products.

The invention provides an electrolyte composition, an electrochemical in-situ etching method of non-metallic inclusions for heavy rail steel and application of the electrochemical in-situ etching method. The electrolyte composition comprises the following components in parts by weight: 1.6 to 2.3 parts of lithium chloride, 10 to 13.5 parts of acetylacetone, 45 to 84 parts of methanol and 2 to 43 parts of a reagent A, the reagent A is a mixed aqueous solution of ethylenediamine tetraacetic acid and sodium citrate. The lithium chloride, the acetylacetone, the methanol and the reagent A in specific parts are matched for use, the obtained electrolyte composition is used for in-situ electrochemical etching of the heavy rail steel, and three-dimensional in-situ etching of the non-metallic inclusions in the heavy rail steel can be successfully achieved. The in-situ information of the non-metallic inclusions in the hypereutectoid heavy rail steel is reserved, and the three-dimensional morphology of the non-metallic inclusions can be presented more comprehensively.

The invention discloses a method for evaluating the machinability of sulfur-containing free-cutting steel. The method comprises the following steps: (1) testing the hardness of a section; (2) assigning hardness test data; (3) grade evaluation of sulfide inclusions; and (4) comprehensive assignment calculation is conducted, specifically, the product of the hardness absolute value grade assignment, the hardness standard deviation grade assignment and the sulfide inclusion grade assignment serves as the comprehensive assignment, the turning performance of the materials is sequenced according to the comprehensive assignment, and the smaller the comprehensive assignment is, the easier machining is. According to the evaluation method disclosed by the invention, before the sulfur-containing free-cutting cold-drawing bar is cut, the machinability of the bar is visually evaluated by detecting the hardness, the uniformity of the hardness and the distribution pattern of non-metallic inclusions and through assignment calculation, so that bar processing enterprises can be helped to estimate the processing efficiency and calculate the cost, and the processing efficiency of the bars is improved. And a guiding effect is achieved on enterprise production and operation.

This invention provides a high-end vacuum argon-oxygen refining apparatus (VODC furnace) for special metal materials and its refining method, belonging to the technical field of metallurgical refining equipment. It solves the problems of complex structure and high manufacturing and production costs associated with existing VOD furnace vacuum systems. This invention separates the vacuum system from the blowing system through modular design, employs a movable vacuum sealing structure and optimized furnace design, achieving a significant reduction in equipment and production costs. The refining method, by controlling the vacuum degree, oxygen blowing parameters, and stirring intensity, reduces non-metallic inclusions in the steel, achieving a hydrogen content of less than 1.5 × 10⁻⁶. ‑6 Oxygen content less than 2.0 × 10 ‑5 The chromium recovery rate in stainless steel reaches 98%-99%, and the refined steel possesses superior properties. Production efficiency is significantly improved while ensuring product quality. Compared with traditional equipment, this invention reduces equipment investment costs by more than 30%, shortens the refining cycle by 25%, and reduces energy consumption by 20%, making it particularly suitable for small-batch, multi-variety production of high-end specialty metal materials.

The invention relates to a method for purifying molten iron in a furnace based on a decomposable foaming sand core, and belongs to the technical field of foundry metallurgy. According to the method, an alkaline phenolic resin sand core internally provided with sodium bicarbonate is adopted, and the alkaline phenolic resin sand core extends into the position, 100-200 mm away from the bottom, in the furnace through a special clamp in the molten iron standing stage. Sodium bicarbonate in the sand core is slowly decomposed at high temperature to release a large number of microbubbles, and non-metallic inclusions in molten iron are effectively captured and brought out in the floating process. Deep and uniform purification of the molten iron is achieved through a slow-release foaming mechanism, the purity of the molten iron and the casting quality are remarkably improved, and the method has the advantages of being easy and convenient to operate, low in cost and free of additional equipment and is particularly suitable for the production process of cast iron smelting in an intermediate frequency furnace.

The invention discloses a production process of high-efficiency low-inclusion large-specification steel for a wind power main shaft bearing ring, and belongs to the technical field of steel for wind power bearings. According to the process, a CaO-SiO-AlO-MgO quaternary refining slag system is adopted, so that the inclusion adsorption efficiency and the slag system stability are improved; a crystallizer, a secondary cooling zone and tail end three-stage electromagnetic stirring are adopted, and the casting blank with the ultra-large specification of phi 800-1200 mm is adapted; eAF-CONARC short-process smelting is integrated, and energy consumption and residual element fluctuation are reduced; and a segmented slow cooling process is adopted, and hydrogen diffusion and stress release are enhanced. The casting blank produced through the method is compact in macrostructure (the center porosity is smaller than or equal to 1.0 grade), the non-metallic inclusion grade is smaller than or equal to 0.5 grade, the molten steel O is smaller than or equal to 0.0007%, the H is smaller than or equal to 0.00005%, the smelting period is shortened by 16.7%, the energy consumption per ton of steel is reduced by 13.3%, and the mechanical property and the hardening layer depth after hardening and tempering meet the requirements of the ultra-large-specification wind power main shaft bearing ring.

The present invention belongs to the technical field of alloy steel, and relates to a large-size medium-carbon bainite non-quenched and tempered steel for direct cutting processing and a production process thereof. The composition is: C 0.35-0.45%, Si 0.3-1.0%, Mn 1.5-2.0%, P≤0.012%, S≤0.006%, Cr 0.6-1.2%, V 0.04-0.2%, Nb 0.01-0.03%, Mo 0.15-0.2%, B 0.0005-0.00015%, Al 0.02-0.04%, Ti 0.015-0.025%, Ni 0.1-0.2%, O≤15ppm, N 110-180ppm, with the balance being Fe and unavoidable impurities. By combining optimized composition and process, the present invention achieves good control of non-metallic inclusions and macrostructure, with yield strength all above 750 MPa, demonstrating broad application prospects.

[Problem] To provide a method for manufacturing a compression-processed product in which the size of gaps formed between non-metal inclusions and a matrix included in a steel material is appropriately controlled in consideration of a deformation phenomenon occurring in the non-metal inclusions and the matrix in compression processing. [Solution] A method for manufacturing a compression-processed product in which a steel material containing non-metal inclusions is subjected to multiple iterations of compression processing, wherein the rolling reduction rate for the steel material in each of the multiple iterations of the compression processing is set to within a range not greater than an upper limit rolling reduction rate, the upper-limit rolling reduction rate corresponding to a target gap area ratio in relationship information derived in advance from the relationship between the rolling reduction rate in a compression process performed on a target steel containing non-metal inclusions and the gap area ratio of gaps formed between the non-metal inclusions and a matrix by the compression process, the target gap area ratio being the target value of the gap area ratio after completion of the plurality of compression processes performed on the steel.

The invention discloses an electroslag smelting method of low-Si low-Al B-containing heat-resistant stainless steel. According to the electroslag smelting method, the qualification rate of head and tail components of a steel ingot of an electric furnace casting rod after electroslag remelting reaches 100% through a quaternary slag system, and the sum of a fine system and a coarse system of non-metallic inclusions meets the requirement of not higher than grade 3; the thermal stress and phase change stress cracking of the steel ingot is prevented through stress relief annealing of the steel ingot, the tensile stress generated due to thermal expansion and cold contraction in the cooling process of the steel ingot and the phase change stress generated due to structural transformation are eliminated through the low-temperature annealing process, the steel ingot is prevented from cracking during long-time storage or saw cutting, many defects in the prior art are overcome, and the quality of the steel ingot is improved. The method has a remarkable industrial application prospect.

The present invention relates to an Fe-Ni alloy consisting of C: 0.001 to 0.2 mass%, Si: 0.001 to 0.2 mass%, Mn: 0.005 to 0.7 mass%, Ni: 30.0 to 45.0 mass%, Cr: 0.3 mass% or less, Al: 0.001 to 0.1 mass%, Ti: 0.001 to 0.020 mass%, O: 0.007 mass% or less, Mg: 0.0030 mass% or less, N: 0.010 mass% or less, Ca: 0.0015 mass% or less, Na: 0.00005 to 0.001 mass%, the balance being Fe and unavoidable impurities, wherein non-metallic inclusions containing CaO-SiO2-Al2O3-MgO-MnO-Na2O-based complex oxides as essential components, and further containing one or more non-metallic inclusions of CaO, MgO, MgO·Al2O3, MnO·SiO2, and Na2O as optional components, wherein the number ratio of CaO-SiO2-Al2O3-MgO-MnO-Na2O inclusions is 40% or more in all non-metallic inclusions, thereby producing an Fe-Ni alloy having excellent surface properties.

This invention discloses a medium carbon steel for steering screws in new energy vehicles and its production method. The chemical composition of the medium carbon steel, by mass percentage, is as follows: C: 0.45%~0.70%, Si: 0.25%~0.55%, Mn: 0.45%~1.05%, Cr: ≤0.40%, Mo≤0.40%, Ni≤0.40%, P≤0.035%, S: 0.015%~0.035%, O≤0.0012%, with the balance being Fe and unavoidable impurities. The production method includes a complete process: molten iron pretreatment – ​​converter smelting – LF refining – RH furnace vacuum degassing – continuous casting – rolling – quenching and tempering – finishing – sub-critical quenching – low-temperature tempering. By controlling the composition to reduce the addition of expensive alloying elements, and through a composite heat treatment of "quenching and tempering + sub-critical quenching + low-temperature tempering," a hardness gradient of ≥60HRC on the surface and 22~28HRC in the core is achieved, with no decarburized layer on the surface. Simultaneously, strict control of non-metallic inclusions enhances the purity of the steel. This invention's product is compatible with cyclone milling processes, exhibits minimal quenching deformation, and can be straightened, meeting the high precision and long service life requirements of steering screws in new energy vehicles.

To provide a method for evaluating inclusions to enlarge an observation surface in a test piece, thereby enabling accurate measurement of the size and the type of nonmetallic inclusions that cause fatigue fracture in a desired steel material in a short time and at low cost.SOLUTION: A method for evaluating an inclusion evaluation includes: performing a tensile test on a test piece obtained by introducing hydrogen into a precursor metal piece having an internal hardness of more than 400 HV and a surface hardness of 250-400 HV, to cause fracture originating from a nonmetallic inclusion affected by the introduced hydrogen, and measuring the size and / or identifying the type of the nonmetallic inclusion acting as the fracture origin.SELECTED DRAWING: Figure 1

The utility model discloses an anti-blocking rod for continuous casting, which comprises a stopper rod body (1) and a stopper rod head (2), and is characterized in that a variable-diameter transition area (3) of which the diameter is suddenly reduced is arranged between the stopper rod body (1) and the stopper rod head (2), and the maximum diameter of the stopper rod head (2) can be reduced to 88%-92% of the diameter of the stopper rod body (1) by the variable-diameter transition area (3). According to the stopper rod, the obvious reducing transition area of which the diameter is suddenly reduced is arranged between the stopper rod body and the stopper rod head, so that the inflow angle of molten steel can be locally changed, and non-metallic inclusions in the molten steel can be effectively prevented from being deposited on the stopper rod head, so that the anti-blocking effect is achieved, the continuous casting flow control is improved, and the service life of the stopper rod is prolonged. Irregular oscillation or rod punching caused by inclusion deposition of the stopper rod is reduced, and finally the quality of a continuous casting steel billet is improved.

The application belongs to the technical field of liquid metal purification, and provides a CaO-ZrO2 porous ceramic filter and a preparation method and application thereof. The application obtains a preform by impregnating a reticular porous template in slurry A and drying; sprays slurry B on the preform to obtain an embryo, and obtains the CaO-ZrO2 porous ceramic filter after calcination. The application adopts a template replication method-air spraying-in-situ sintering technology, and has the advantages of simple preparation process and low cost. The slurry B is attached to the surface of the zirconia hole rib through the air spraying process on the preform, defects are filled, and the CaO-ZrO2 composite hole rib is constructed. The composite hole rib improves the mechanical properties, thermal shock resistance and non-metallic inclusion adsorption efficiency in the molten metal liquid. The application can be used in the molten metal filtering environment of 1600 DEG C to 1800 DEG C.

The invention discloses a composite material ceramic filter screen for casting and a photocuring 3D printing preparation method. Ansys Fluent fluid dynamics software is used, modeling analysis is conducted on the flowing state of molten metal liquid flowing through the filter screen in the pouring process, and the optimal filter screen design is obtained. The photocuring 3D printing silicon oxide ceramic filter screen comprises the following components in percentage by mass: 65-80% of silicon oxide powder, 10% of magnesium oxide powder, 2-8% of a dispersing agent, 1-3% of a photoinitiator, 9-15% of photosensitive resin and 1% of an anti-settling agent. According to the method, a porous polyurethane plastic carrier is not needed, the filter screen ceramic biscuit is directly obtained by using the silicon oxide slurry and the silicon oxide and magnesium oxide composite slurry in a photocuring 3D printing mode, and then the finished silicon oxide ceramic filter screen is obtained through degreasing and high-temperature sintering. According to the method, it is guaranteed that the product has meshes which are completely consistent in size and shape, the structural strength is high, and the product is not prone to being damaged, large-size inclusions in molten metal are physically screened through the meshes, non-metallic inclusions (such as AlO, SiO and sulfide) are actively captured through the reaction of magnesium oxide and the inclusions, and through the double means of physical interception and chemical capture, the content of impurities in the molten metal is greatly improved. The filtering performance is effectively ensured. In the production process of the product, ceramic chips without structural support are not generated, so that the production process link is simplified, and meanwhile, the emission of toxic and harmful waste materials is reduced.

The application discloses a power-on weir plate of a tundish and a method for removing inclusions, and belongs to the field of tundish technology. The power-on weir plate comprises a power-on weir plate body, a power supply and a conductive structure. The conductive structure is arranged on the power-on weir plate body. The power supply is connected with the conductive structure through a cable. The power-on weir plate body is arranged between a long nozzle and a submerged nozzle of the tundish. The cross-sectional shape of the power-on weir plate body is matched with the cross-sectional shape of the tundish. The bottom of the power-on weir plate body is provided with a steel passing hole. The application can effectively remove non-metallic inclusions in the molten steel of the tundish, prevents the inclusions from entering the crystallizer along with the molten steel, and influences the final quality of the cast slab.

The application discloses a high-nitrogen plastic mold steel, which comprises the following components: C with a mass percentage of 0.28-0.33%, Si with a mass percentage of 0.25-0.38%, Mn with a mass percentage of 0.4-0.8%, Cr with a mass percentage of 14.5-15.5%, Mo with a mass percentage of 0.9-1%, N with a mass percentage of 0.095-0.115%, P with a mass percentage of less than or equal to 0.02%, S with a mass percentage of less than or equal to 0.003%, and O with a mass percentage of less than or equal to 0.0025%. The method for protecting atmosphere electroslag remelting the high-nitrogen plastic mold steel can ensure the nitrogen content of the plastic mold steel and improve the comprehensive characteristics of the plastic mold steel, for example, the setting parameters of the slag system and the filling ratio can ensure that the crystallized steel ingot is dense, the material is uniform, and non-metallic inclusions can be removed well; the N charging flow rate in the remelting process can keep the balance between the furnace atmosphere and the N content in the molten steel, and can ensure that the N content deviation of the whole steel ingot is small and consistent with the parent material before remelting.

The invention belongs to the technical field of metallurgy, and relates to a production method of a high-strength and high-toughness spring steel bar. Comprising the procedures of combined blown converter smelting, ladle furnace refining, RH vacuum degassing treatment, rectangular blank continuous casting production, cogging rolling, steel blank coping, round steel rolling and slow cooling after rolling. In the ladle furnace refining procedure, an alkaline slag former is added in the early stage of refining according to the weight of molten steel, an acid slag former is added in the middle stage of refining, and the alkalinity in the steel is maintained to be 0.8-1.0; in the rectangular blank continuous casting production procedure, the solidification tail end of a casting blank is subjected to a light and heavy pressing process, and 2-9 frames are totally pressed by 26 mm; in the round steel rolling procedure, the heating temperature of a soaking section is 1040-1070 DEG C, and the reduction rate of the first pass and the reduction rate of the second pass are larger than 60%; the final rolling temperature ranges from 650 DEG C to 700 DEG C, and the accumulated reduction rate is larger than 80%. The produced product is low in non-metallic inclusion content, the grain size can reach 9.5 level, and carbon component segregation is within 1.05.

To provide an inclusion evaluation method capable of making a grip part hard to break in a breaking test even when there is almost no change in diameter between the grip part and an effective part.SOLUTION: Provided is an inclusion evaluation method in which hydrogen is charged to a test piece 1 made of a metallic material that gripping portions 3 at both ends and an effective portion 5 provided in an intermediate portion 2 between the gripping portions 3, a destructive test is performed on the hydrogen-charged test piece 1, and the dimensions of a non-metallic inclusion 6 that is the origin of the fracture are measured. The test piece 1 is cut out from a wire and has an outer surface 7 that is formed by an outer surface of the wire, and in the intermediate portion 2, a surface layer 8 is removed from the outer surface 7, and masking 11 is applied to at least the outer surface 7 at the gripping portions 3 to suppress hydrogen penetration, and at least a part of the intermediate portion 2 from which the surface layer 8 has been removed is made into the effective portion 5 without performing the masking 11.SELECTED DRAWING: Figure 1

The invention provides an electric furnace smelting method for high-thermal-conductivity die steel, which comprises the following steps: in the LF smelting process of a ladle furnace, electromagnetic stirring is carried out on a die steel raw material, the frequency is 6-10Hz, the current is 500-800A, electromagnetic stirring is loaded from 60 minutes of smelting in the LF furnace, and electromagnetic stirring is stopped when the LF furnace is finished. The method has the advantages that the high-thermal-conductivity die steel is smelted through the composite steelmaking technology of electromagnetic stirring and slag alkalinity regulation and control, extremely pure molten steel is obtained, secondary oxidation of the molten steel in the casting process is avoided through argon protection casting, the grade of non-metallic inclusions in the cast die casting steel ingot does not exceed 0.5 grade, and the casting quality is improved. And the heat conductivity is improved by 10-20%. The method is stable in technological process, high in operability and suitable for industrial large-scale production, and a reliable technical path is provided for performance improvement of high-end plastic die steel.

The invention provides a MgO-Al2O3-SiO2 ternary component tundish covering agent and a preparation method and application thereof.The tundish covering agent is composed of a base material and auxiliary materials, the base material is siliceous minerals, and the auxiliary materials comprise expansible minerals and melting point adjusting minerals; the preparation method comprises the following steps that siliceous minerals, expansible minerals and melting point adjusting minerals are crushed and screened, and siliceous mineral particles, expansible mineral particles and melting point adjusting mineral particles are obtained respectively; and the siliceous mineral particles, the expansible mineral particles and the melting point adjusting mineral particles are matched, mixed to be uniform and dried, and the MgO-Al2O3-SiO2 ternary component tundish covering agent is obtained. The tundish covering agent prepared by the invention is good in heat preservation and covering effects, low in cost, simple in preparation process, not easy to crack during slagging-off and high in adhesion to non-metallic inclusions.

The invention provides a method and a system for detecting non-metallic inclusions in steel based on background reconstruction. The method comprises the following steps: acquiring a to-be-detected input image; inputting the input image to a background reconstruction module to generate a reconstructed image after inclusion removal; calculating a difference value between the input image and the reconstructed image to obtain a detection result image containing inclusions; the detection result image is processed through a post-processing module to output an inclusion detection result, and the method is low in data labeling requirement, is not influenced by unbalanced inclusion sample types, is higher in algorithm adaptability and robustness, and is higher in accuracy. The problem that a method for detecting non-metallic inclusions in steel is difficult to meet high-precision and high-efficiency quality inspection requirements is solved.

The invention provides a detection and rating method for non-metallic inclusions, which comprises the following steps: scanning a sample by adopting an X-ray tomography system to obtain three-dimensional gray data, and marking the non-metallic inclusions; obtaining three-dimensional morphological parameters and spatial position information of the non-metallic inclusions; counting the obtained three-dimensional morphological parameters and spatial positions to obtain the volume fraction, size distribution concentration ratio, spatial distribution uniformity and shape distribution data of the inclusions; calculating the data by adopting an evaluation model to obtain an inclusion evaluation index, and rating the nonmetallic inclusions of the steel grade on the basis of the inclusion evaluation index. According to the method, the problems of contour distortion and form misjudgment of a traditional method are solved, the objectivity of inclusion rating is effectively improved, an IEI rating result is directly output, a visual basis can be provided for steel quality control and performance pre-judgment, and industrial application is supported.

The invention belongs to the technical field of metallurgy, and particularly relates to a cleanliness control method for medium-carbon aluminum-containing and sulfur-containing structural steel for an automobile transmission shaft. According to the medium-carbon aluminum-containing sulfur-containing structural steel, the technological process of converter-LF refining furnace-RH vacuum treatment furnace-continuous casting is adopted, the alkalinity of refining slag is controlled by determining the type of deoxidation materials in the converter tapping and LF process, the binary alkalinity of refining final slag is controlled to be 3.5-4.0, and the slag deoxidation and inclusion adsorption capacity is enhanced; in the LF process, through a calcium treatment process, aluminum oxide and other impurities difficult to float upwards are subjected to denaturation treatment, and the situation that a large number of calcium sulfide impurities more difficult to remove are generated due to improper calcium treatment is avoided; in the continuous casting process, nozzle nodulation is controlled through nozzle argon blowing, slow pulling speed and other operations. And finally, the castability of the molten steel is improved, meanwhile, non-metallic inclusions of rolled metal are effectively controlled, the flaw detection qualification rate is increased, and meanwhile the product crack occurrence rate of a user is effectively reduced.

The invention discloses a data labeling method of an intelligent non-metallic inclusion detection model based on a metallographic inspection standard, and relates to the technical field of data processing, and the method comprises the steps: collecting a target metallographic image, and carrying out the preprocessing of the collected target metallographic image; calling a corresponding metallographic inspection standard based on the type of the to-be-detected metal material and the detection requirement; performing preliminary positioning and classification on non-metallic inclusions in the target metallographic image by adopting a non-metallic inclusion preliminary identification model based on an image identification algorithm, and generating an automatic labeling result; and marking personnel carry out secondary marking on the non-metallic inclusions in the target metallographic image according to the corresponding metallographic inspection standard and the automatic marking result. According to the data labeling method and system, functions are complete, a complete labeling process is formed, labeling results support export in multiple formats, the training data requirements of different intelligent metallographic detection models can be met, and high universality and practicability are achieved.

The present application belongs to the technical field of steel metallurgy and powder metallurgy raw material preparation, and discloses a preparation method of tundish high-purity molten steel for powder metallurgy. The tundish is sequentially provided with a pre-agitation zone, a filtration zone and a final purification zone along the direction of molten steel flow. A main electromagnetic stirring coil is installed at the bottom of the pre-agitation zone, an open-pore retaining wall is arranged in the filtration zone, an auxiliary electromagnetic stirring coil and a pouring zone are arranged at the bottom of the final purification zone, and an array-type bottom argon-blowing gas permeable brick is arranged in the pouring zone. The problems of incomplete removal of inclusions and poor molten steel uniformity in the traditional tundish are solved. By using the method, the elimination rate of non-metallic inclusions with a particle size greater than 20 microns is greater than 97%, the molten steel temperature fluctuation is less than or equal to ±2℃, and the composition uniformity error is less than or equal to 0.01%. The method provides stable high-purity molten steel raw material for powder metallurgy atomization powder production, is simple and easy to implement, and is suitable for existing conventional production lines.

The application provides a method for improving the flaw detection qualified rate of head furnace continuous casting billets of wear-resistant steel, and belongs to the technical field of metallurgy; the method adjusts the molten steel composition of the continuous casting billet, controls non-metallic inclusions, hydrogen diffusion in the steel, reduces the segregation of the billet, and improves the two-cooling strength of the continuous casting, so that the flaw detection qualified rate of the head furnace continuous casting billets of the high wear-resistant steel is stably controlled above 99.5%; the method is simple, has strong operability, and is convenient for popularization and application; the method can effectively improve the flaw detection qualified rate of the head furnace continuous casting billets of the wear-resistant steel, and further significantly improves the production qualified rate of the same batch of products.

The invention provides steel for a high-cleanliness track shoe and a preparation method thereof. The steel for the high-cleanliness track shoe comprises the following chemical components in percentage by mass: 0.24%-0.26% of C, 0.22%-0.26% of Si, 1.18%-1.22% of Mn, less than or equal to 0.018% of P, less than or equal to 0.004% of S, 0.35%-0.39% of Cr, 0.0017%-0.0023% of B, 0.022%-0.032% of Ti, less than or equal to 0.30% of Ni, less than or equal to 0.08% of Mo, less than or equal to 0.35% of Cu, 0.018%-0.025% of Al, less than or equal to 0.0015% of H, less than or equal to 0.02% of Pb, less than or equal to 0.03% of Sn, less than or equal to 0.03% According to the method, the gas content and the non-metallic inclusion grade are controlled, the high-cleanliness steel for the track shoe is prepared, and the service life of the track shoe is greatly prolonged.

The invention relates to the technical field of steel for gear steel bars, in particular to CrMn series gear steel with excellent impact performance and a production method of the CrMn series gear steel. The gear steel is prepared from the following chemical components in percentage by mass: 0.23 percent to 0.28 percent of C, 0.11 percent to 0.19 percent of Si, 0.91 percent to 1.09 percent of Mn, 1.01 percent to 1.19 percent of Cr, 0.25 percent to 0.35 percent of Mo, 0.20 percent to 0.30 percent of W, 0.20 percent to 0.30 percent of Ni, 0.03 percent to 0.05 percent of Nb, 0.020 percent to 0.040 percent of Al, less than or equal to 0.0012 percent of [O], less than or equal to 0.006 percent of [N], 0.0010 percent to 0.0030 percent of Ce, 0.0040 percent to 0.0080 percent of Ca and the balance of Fe and inevitable impurities. According to the gear steel, the hardenability J9 is 40-48 HRC, the hardenability J15 is larger than or equal to 28 HRC, and the bandwidth is smaller than or equal to 6 HRC; the room-temperature impact energy AKV is greater than or equal to 80J; in the gear steel, non-metallic inclusions of class A are smaller than or equal to grade 2.0, non-metallic inclusions of class B are smaller than or equal to grade 2.0, and the austenite grain size is 5.5-7.