210 results about "Carburizing" patented technology

The invention provides a Q890qE and Q420qE bridge steel flat butt joint combined welding method which comprises the following steps: step 1, grinding and derusting grooves of upper and lower asymmetric double-sided V-shaped joints to expose metallic luster; 2, preheating is conducted in an electric heating mode; 3, a solid welding wire CO2 gas shielded welding is adopted for backing welding of one weld joint on the upper V-shaped deep groove side; 4, welding seams are filled in the side of the V-shaped deep groove through submerged arc automatic welding, and the filling thickness is about 1 / 2 of the groove depth; 5, back gouging is conducted on the back face through carbon arc air gouging, and a carburized layer is polished and cleaned till metallic luster is exposed; 6, the V-shaped shallow groove is welded and filled; seventhly, the submerged arc automatic welding continues to weld the remaining weld joints of the V-shaped deep groove till the remaining weld joints are filled; and 8, postweld heat treatment is conducted. According to the method, a combined welding method of solid welding wire CO2 gas shielded welding bottoming, submerged arc automatic welding filling and capping is adopted, the problems of welding cold cracking and early joint breakage of the dissimilar bridge steel are solved by combining joint design, and the mechanical properties of a welding seam and a fusion area meet the standard requirements.

The invention provides a heat treatment method for a wind power gear forge piece. The heat treatment method comprises the following steps that 1, after-forging waste heat temperature equalization is carried out; 2, segmented forced controlled cooling is carried out till the forge piece reaches a furnace entering window, and forced cooling is carried out on the forge piece; at least three temperature measuring points are arranged on the forge piece; 3, isothermal normalizing for the first time, wherein the forge piece is placed in an isothermal furnace; 4, low-temperature reaustenitizing is conducted, specifically, the forge piece subjected to the first isothermal normalizing is heated to 860-910 DEG C, heat preservation is conducted, and the forge piece is reaustenitized; 5, secondary isothermal normalizing is conducted, specifically, the forged piece obtained after austenitizing is cooled to 645-670 DEG C in a controlled cooling mode, and isothermal heat preservation is conducted; the forge piece is heated to 380-450 DEG C, heat preservation is conducted, then the forge piece is cooled to 200 DEG C or below along with a furnace, and the forge piece is taken out of the furnace for air cooling. According to the method, a uniform and refined ferrite and pearlite structure is obtained in the core of the large-section forge piece, the hardness is stabilized within the range of 165-185 HBW, and the subsequent carburizing and quenching distortion sensitivity is reduced.

The invention relates to a high-speed rail gear steel bar produced through a continuous casting and rolling process and a manufacturing method of the high-speed rail gear steel bar, and belongs to the technical field of metallurgy. The steel comprises the following chemical components in percentage by mass: 0.15 to 0.20 percent of C, less than or equal to 0.40 percent of Si, 0.50 to 0.90 percent of Mn, 1.50 to 1.80 percent of Cr, less than or equal to 0.025 percent of P, less than or equal to 0.025 percent of S, less than or equal to 0.30 percent of Cu, less than or equal to 0.005 percent of Ti, 0.02 to 0.05 percent of Al, 1.40 to 1.70 percent of Ni, 0.25 to 0.35 percent of Mo, 0.015 to 0.035 percent of Nb, less than or equal to 0.0030 percent of Ca, 0.0090 to 0.0150 percent of N, less than or equal to 0.0012 percent of [O], less than or equal to 0.0001 percent of [H] and the balance of Fe and inevitable impurity elements. A narrow hardenability bandwidth control technology is realized by establishing a hardenability prediction model, accurately controlling smelting components and uniformly controlling solidification components, and the hardenability bandwidth of the material is less than or equal to 4 HRC; the gear steel is subjected to high-temperature carburization at 980 DEG C for 4 h, and the grain size reaches the level 5 or above.

The invention discloses a method and equipment for calculating the carbon concentration in the vacuum low-pressure carburization process, and relates to the field of vacuum low-pressure carburization. The first strong carburizing process serves as a target strong carburizing process, the first strong carburizing concentration analytical formula serves as a target strong carburizing concentration analytical formula, and strong carburizing process calculation operation is executed, specifically, based on the carburizing state parameters, the carbon concentration of the target strong carburizing process is calculated through the target strong carburizing concentration analytical formula; after the strong carburizing process calculation operation is executed, the diffusion process after the target strong carburizing process serves as a target diffusion process, and diffusion process calculation operation is executed: based on the carburizing state parameters, the carbon concentration of the target diffusion process is calculated through a diffusion carbon concentration analytical formula; after the diffusion process calculation operation is executed, whether the target diffusion process is the last diffusion process is detected, and if yes, the calculation process is ended; the carbon concentration calculation accuracy and calculation efficiency can be improved.

The utility model provides a novel lifting appliance disc welding part for heat treatment of a composite drill rod. The novel lifting appliance disc welding part comprises a large lifting disc and a fan-shaped disc, the mounting groove is formed in the surface of the large hanging scaffold, and the fan-shaped disc is arranged in the mounting groove. According to the novel lifting appliance disc welding piece for heat treatment of the composite drill rod, the welding rod penetrates through the mounting hole in the surface of the fan-shaped disc, the external thread end is matched with the T38 clamping sleeve to limit the welding rod on the surface of a large lifting disc, and the composite drill rod lifting appliance disc and the composite drill rod are connected and assembled; after the matched clamping sleeve between the threads and the external thread end are stabilized, the composite drill rod is hoisted, so that the problem that the composite drill rod cannot be subjected to heat treatment in a carburizing furnace is solved, and while the problem is solved, the composite drill rod is convenient to use and good in hoisting stability, and the service life of the composite drill rod is prolonged. And the hoisting problem of the composite drill rod carburizing furnace in production is well solved.

The invention relates to a method for producing liquid steel in an electric arc furnace (2) comprising successively: - defining a targeted nitrogen content wt. %Ntarg of the produced liquid steel, - introducing a metal load in the electric arc furnace (2) and - melting it for generating a steel bath (10) and a slag (12); - carburizing the steel bath (10) by adding a carbon amount equal to or greater than a minimum denitrogenation carbon amount CdeN said amount CdeN being defined as a function of the nitrogen content in excess to wt. %Ntarg at the beginning of the step (E4), - injecting a flow of oxygen to reach a nitrogen content wt. %N such that wt. %N ≤ wt. %Ntarg, - tapping the steel bath (10) to obtain the produced liquid steel.

The application relates to the field of a test method for the uniformity of a carburizing and quenching system, in particular to a method for evaluating the uniformity of a shaft furnace carburizing and quenching system, and discloses a method for evaluating the uniformity of a shaft furnace carburizing and quenching system, which comprises the following steps: selecting different steel materials according to different functional parts of the shaft furnace carburizing and quenching system; arranging detection points in the functional parts, a plurality of detection points are arranged in each layer, and the positions of the detection points in each layer are different; placing the steel materials on the detection points; processing the steel materials through the functional parts, and detecting the steel materials after the processing is completed; comparing the average value obtained by counting the detected values with a standard value, if the average value meets the standard value, the uniformity of the functional part is better, otherwise, the uniformity is poorer. The method solves the problem that the effective hardening layer depth uniformity of the entire production system of the shaft furnace carburizing and quenching system cannot be evaluated when a workpiece passes through the shaft furnace carburizing and quenching system, and achieves the effect of performing uniformity detection on the entire production system of the shaft furnace carburizing and quenching system.

The application provides a corrosion agent and method for displaying G20CrNi4 granular bainite structure, the corrosion agent is prepared by 2%-4% nitric acid alcohol solution, hydrochloric acid and ferric chloride in the proportion of 100ml:0.3-0.7ml:0.4g-0.6g; the method for displaying granular bainite structure comprises sample preparation, corrosion agent preparation, granular bainite structure corrosion and metallographic microscope observation. The corrosion agent provided by the application is simple to prepare, the method for displaying granular bainite structure is stable and reliable, simple to operate, and can realize corrosion and clear display of granular bainite structure of carburizing bearing steel.

This invention discloses a dual-frequency composite induction strengthening process for medium carbon steel, gradient hardened layer parts, and a production system. The process includes: selecting SAE 1045 medium carbon steel and performing quenching and tempering pretreatment; precision machining to form outer circular channels and inner ball channels; performing dual-frequency composite induction hardening on the outer circular channels and inner ball channels respectively, i.e., preheating to 680-750℃ with medium-frequency current, then rapidly heating to 880-920℃ with high-frequency current followed by spray cooling, and using thermal balance control to form a gentle transition zone with a width of 2-5mm between the two hardened zones, where the hardness gradient along the axial line connecting the two hardened zones does not exceed ΔHRC10 / mm; finally, low-temperature tempering. This invention also discloses wear-resistant parts with a dual-layer composite hardened layer structure and a gradient transition zone prepared using this process, as well as an online composite strengthening production system. This invention replaces low-carbon alloy steel with medium-carbon steel and replaces overall carburizing with local dual-frequency induction hardening, which can reduce raw material costs and energy consumption, reduce deformation, and obtain a hardened layer that meets the depth requirements, thus realizing online continuous production of heat treatment and machining.

The invention belongs to the field of ferrous metallurgy, and particularly relates to high-temperature-resistant carburizing aluminum-free 20CrMnTi gear steel and a preparation method thereof, and the gear steel comprises the following chemical components in percentage by weight: 0.18%-0.23% of C, 0.17%-0.23% of Si, 0.95%-1.15% of Mn, 1%-1.35% of Cr, 0.04%-0.06% of Ti, less than or equal to 0.0008% of B, less than or equal to 0.020% of P, less than or equal to 0.015% of S, less than or equal to 0.010% of Alt, less than or equal to 0.005% of N and the balance of Fe and other inevitable impurities. The aluminum-free 20CrMnTi gear steel has the advantages that the three-in-one design thought of component design, precipitated phase regulation and control and process optimization is adopted, the aluminum-free 20CrMnTi gear steel is obtained, and the aluminum-free 20CrMnTi gear steel is refined in grain under high-temperature carburization, high in hardenability, low in cost and suitable for high-end transmission parts.

The present application belongs to the field of metal materials, and particularly relates to a high-temperature carburizing process method of gear steel quenched by different media. The present application develops the carburizing process of gear alloy carburizing steel by finite element simulation mode, and proposes a double-medium quenching process to improve the phase organization of the core of the sample, reduce the martensite content of the core, increase the bainite content, thereby reduce the hardness of the core, and further improve the toughness of the core of the sample, on the basis of ensuring the control of production cost, without increasing the process flow and improving the use performance. The carburized surface is still martensite organization, and the high hardness of the surface layer is maintained.

The present invention belongs to the field of metal surface treatment and relates to a composite boronizing agent and a solid boronizing method for oil pipes. The composite boronizing agent comprises a boronizing agent and graphite. Calculated on the basis of mass percentage, the graphite is 10-14% of the mass of the boronizing agent. The boronizing agent comprises the following raw materials in mass percentages: boron source: 10-15%, catalyst: 12-20%, activator: 8-10%, dispersant: 4-6%, filler: 50-55%, and flow aid: 8-12%, and the dispersant is triethanolamine borate. In the composite boronizing agent of the present invention, the triethanolamine borate can remove impurities from an inner surface of an oil pipe, improve the boronizing effect and boronized layer quality, and form a protective film to prevent carburization, promote boronizing, and enhance boronized layer bonding strength. In addition, through the combined action of triethanolamine borate and graphite, the boronizing agent can be prevented from agglomerating or adhering to the inner surface of the oil pipe after boronizing treatment, and the uniformity of boronizing can further be improved.

To provide a bearing component with high durability, a method for manufacturing the same, and a rolling bearing equipped with the bearing component. [Solution] The present invention provides a method for manufacturing bearing components, comprising: (1) a carburizing and nitriding treatment step performed in a temperature range of A1 transformation point to 900°C; (2) a quenching and hardening treatment step of cooling to a temperature below the A1 transformation point; (3) a low-temperature tempering treatment step performed in a temperature range of 90 to 170°C; (4) a sub-zero treatment step performed in a temperature range of 0°C or lower; and (5) a tempering treatment step performed in a temperature range of 160 to 240°C.

A carburizing method using carburizing gas, wherein the supply and cessation of the aforementioned carburizing gas are repeatedly performed, and the supply is started and stopped at a time based on the carbon penetration rate of carbon penetrating into the workpiece through the aforementioned carburizing gas.

The utility model discloses an anti-corrosion and wear-resistant bearing, and relates to the technical field of bearings. The bearing comprises an outer ring, an inner ring assembly is arranged in an inner cavity of the outer ring, a retainer is arranged between the inner ring assembly and the outer ring, and a rolling body is arranged in an inner cavity of the retainer; the inner ring assembly comprises a first connecting sleeve, and a second connecting sleeve is clamped in an inner cavity of the first connecting sleeve. According to the sealing design of the inner ring assembly, through the first connecting sleeve, the second connecting sleeve, the sealing ring and the sealing plate which are connected in a clamped mode, external impurities are effectively prevented from invading, a good working environment is built for the interior of the bearing, and a strength foundation is laid for base-layer high-carbon-chromium bearing steel; the carburized bearing steel and martensitic stainless steel of the reinforcing layer are combined to improve the strength and hardness, the chemical nickel-plated phosphorus alloy and the diamond-like carbon coating of the functional layer endow the bearing with excellent corrosion resistance and wear resistance respectively, and the adaptive capacity of the bearing under complex and severe working conditions is comprehensively improved.

The invention relates to the technical field of carburizing furnaces, in particular to medium carbon steel gear heat treatment equipment capable of improving abrasion resistance, which comprises a furnace body, a heating resistor, sealing equipment and an air outlet pipe, the sealing equipment comprises a telescopic rod, a rotating plate and a sealing cover, and the medium carbon steel gear heat treatment equipment further comprises a fan assembly, a cooling assembly and a feeding assembly. By arranging the outer spiral groove, the inner spiral groove and the sealing pipe, kerosene flows between the sealing pipe and the rotating shaft, heat of the rotating shaft is absorbed through the kerosene, heat transmitted upwards by the rotating shaft is reduced, a sealing oil film is formed between the rotating shaft and the sealing pipe, and the sealing effect is further improved; kerosene can flow around the outer wall of the rotating shaft through the outer spiral groove and the inner spiral groove, the contact area between the kerosene and the rotating shaft is increased, the contact time between the kerosene and the rotating shaft is prolonged, the cooling effect of the kerosene on the rotating shaft is improved, the sealing pipe is made of ceramic and has good abrasion resistance, and abrasion between the bearing and the sealing pipe can be reduced.

The application provides a high-efficiency carburizing method for carburized medium manganese steel and belongs to the technical field of metal materials. The present research takes solid carburizing technology as the core and aims to explore the influence of different carburizing processes on the thickness and quality of the carburized layer. From the perspective of process design, by analyzing the medium manganese steel samples under different carburizing time and temperature conditions, it is found that under certain carburizing time and temperature conditions, ideal carburized layer thickness and carbon content can be obtained. The carburized layer thickness obtained by double-temperature carburizing is 615-952 mu m, and the hardness is as high as 276.7 HV. By controlling the final carburizing temperature and holding time, the control of different carburized layer thickness is realized. Through the present research, important clues for optimizing process parameters and controlling the thickness of the carburized layer are provided, and beneficial references for further optimization of medium manganese steel materials in terms of high strength, wear resistance and the like are provided.

By carburizing nitriding treatment with steel, can provide high surface fatigue strength and high temperature tempering hardness is sufficient high carburizing nitriding treatment with steel and carburizing nitriding steel made of carburizing nitriding treatment, the carburizing nitriding treatment with steel contains C, Si, Mn, P, S, Cu, Ni, Cr, Mo, Al, N, the balance is made of Fe and inevitable impurities, by implementing carburizing nitriding, thereby obtaining carburizing nitriding steel, the carburizing nitriding steel satisfies surface C concentration (mass %) + 12 / 14 x surface N concentration (mass %) = 0.6-1.4, and satisfies 129.7805 x [Cr (mass %)]-76.9797 x [Cr (mass %)] 2 + 339.3375 x [surface N concentration (mass %)]-539.345 x [surface N concentration (mass %)] 2 + 181.4983 x [Cr (mass %)] x [surface N concentration (mass %)]+437.6799>560, and in the case of implementing tempering treatment at 500 DEG C after the carburizing nitriding, the hardness of the part of 0.05 mm depth from the surface is 560 HV or more.

This utility model discloses a high-strength, damage-resistant bearing, relating to the field of bearing technology. The utility model includes an outer ring, with a sealing assembly on the inner wall of the outer ring. A cage is fitted onto the surface of the sealing assembly, and balls are slidably connected inside the cage. The sealing assembly includes two inner rings, each extending into the interior of the outer ring on one opposite side. This utility model utilizes the outer ring and a surface wear-resistant and pressure-resistant layer to directly resist the crushing and contact stress of external hard particles, preventing indentations or pits in the raceway. The hardened layer inhibits the propagation of plastic deformation to deeper layers, and the pressure-resistant load-bearing layer releases local stress through reversible elastic deformation, assisting the raceway in quickly restoring its shape after unloading. The surface carburized steel layer forms a tough base to absorb impact energy, preventing the ceramic layer from cracking downwards. The matrix reinforcement layer blocks fatigue cracks caused by internal defects, and the bearing matrix layer provides a stable load-bearing foundation, collectively improving damage resistance and service life.

The present application relates to the technical field of machining, and discloses a planet wheel inner hole carburizing and quenching process, which comprises the following steps: inner hole processing, i.e. processing a stepped inner hole in a planet wheel blank, wherein the inner hole comprises two bearing tracks and a middle hole connected between the two bearing tracks, the inner diameter of the two bearing tracks gradually increases from the end close to the middle hole to the opening end, and the inner diameter of the middle hole is smaller than the minimum inner diameter of the two bearing tracks; and performing overall carburizing and quenching on the inner wall surface of the inner hole. The planet wheel inner hole carburizing and quenching process effectively compensates for the local abnormal expansion caused by the difference in quenching stress between the two ends and the middle part of the inner hole in the tooth width direction. Meanwhile, the overall carburizing and quenching of the inner wall surface of the inner hole suppresses the local abnormal expansion phenomenon caused by the stress mutation in the high-carbon area at the two ends and the low-carbon area in the middle part of the inner hole due to the difference in chemical composition during the quenching process. The present application also discloses a planet wheel, which also has the above technical effects.

The utility model relates to the technical field of rivet manufacturing, and discloses a driving wheel rivet for a shock absorber and a manufacturing die of the driving wheel rivet, the driving wheel rivet for the shock absorber comprises a driving wheel rivet head and a driving wheel rivet rod, the driving wheel rivet rod is fixedly connected to the bottom of the driving wheel rivet head, and the driving wheel rivet head is fixedly connected with the driving wheel rivet rod. A plurality of evenly-distributed cutting blocks are fixedly connected to the bottom of the driving wheel rivet head, an inner hole is formed in the bottom of the driving wheel rivet rod, and the driving wheel rivet head is made of high-strength carburizing steel. According to the utility model, the cutting block at the head of the transmission wheel rivet can be cut into the surface of a workpiece during installation, so that the friction force between the cutting block and the workpiece is increased, and rivet looseness caused by vibration is effectively prevented; and the head part of the driving wheel rivet is made of high-strength carburizing steel, and the rod part of the driving wheel rivet is made of titanium alloy, so that the rivet has the characteristics of high strength and light weight.

The utility model relates to the field of pit-type carburizing furnaces, in particular to a fixing base for a pit-type carburizing furnace, which comprises a mounting main frame body, a furnace body mounted on the mounting main frame body, a limiting bump arranged in the middle of the upper surface of the mounting main frame body and used for placing the furnace body, and mounting columns vertically arranged at four corners of the upper surface of the mounting main frame body, the limiting protruding block in the middle of the installation main frame body is embedded into the bottom of the furnace body, displacement of the furnace body is effectively prevented, the installation top plate is connected with the positioning columns in an inserted mode through the positioning holes, and the installation precision of the top platform is ensured; the supporting plate is divided into the first plate body and the second plate body, the first mounting groove and the second mounting groove which are symmetrically formed in the mounting top plate can be quickly disassembled and assembled through the handle, a customized working table top is formed, a worker can stand conveniently to complete machining of the top of the pit type carburizing furnace, and the operation space for mounting the furnace body on the fixed base is larger.

The invention discloses low-heat-treatment-deformation hafnium microalloyed gear steel and a preparation method thereof, and belongs to the technical field of high-temperature carburized gear steel. The gear steel comprises the following components in percentage by mass: 0.17%-0.23% of C, 0.15%-0.35% of Si, 0.80%-1.10% of Mn, 1.00%-1.30% of Cr, 0.01%-0.10% of Ti, 0.02%-0.10% of Hf, less than or equal to 0.020% of P, less than or equal to 0.015% of S and the balance of Fe and impurities, and the ratio of Hf to Ti is controlled to be 0.4-1.5. The preparation method comprises the steps of smelting, continuous casting, rolling, controlled cooling and low-deformation heat treatment. Through Hf microalloying, the high-temperature stability of HfN / C and the thermal expansion property matched with a matrix are utilized, after carburization is conducted at the temperature larger than or equal to 930 DEG C, ASTM 8-grade or above superfine grains can still be kept, the quenching stress is remarkably reduced, the tooth direction deviation of the gear is smaller than or equal to 0.05 mm, unification of high-temperature efficient carburization and extremely low deformation is achieved, and the high-precision gear is suitable for manufacturing of new energy automobiles and other high-precision gears.

The utility model relates to the technical field of zoned temperature control heating, and discloses a low-pressure carburizing vacuum furnace heating chamber with zoned temperature control, which comprises a vacuum furnace which has heat conductivity and is provided with a vacuumizing module, and further comprises a plurality of heating bins which are annularly and uniformly arranged, and the vacuum furnace is arranged in one of the heating bins; the rotary bin changing structure comprises a rotary disc and a C-shaped circular track which are connected through a connecting rod. The turntable is rotationally arranged in the center of all the heating bins, and the C-shaped circular track is rotationally arranged at the tops of all the heating bins; the vacuum furnace is connected with the C-shaped circular track; every two adjacent heating bins are connected through the corresponding automatic partition structure, and after the rotary table rotates, the vacuum furnaces pass through the corresponding automatic partition structures and are transferred into the adjacent heating bins; a nitrogen tank and an acetylene tank; and the two are arranged on the turntable and are respectively connected with the vacuum furnace through gas conveying pipes. Compared with the prior art, the temperature control device has the advantages that the temperature of each heating bin can be independently adjusted and controlled, so that the partitioned temperature control is realized.

The invention discloses a double-tooth sun gear machining method and an inner hole allowance determining method, and relates to the technical field of gear machining. The machining method of the double-tooth sun gear sequentially comprises the steps of blank forging, semi-finish turning, outer circle tooth A hobbing, inner hole and two end face coating of an anti-seepage agent, carburizing, quenching, shot blasting, finish turning, inner hole tooth B rough gear shaping machining, inner hole tooth B fine gear shaping machining, outer circle tooth A grinding machining, burn inspection, magnetic powder inspection, tooth part precision detection and bench work. The inner hole allowance is determined by adopting test bars with the same material and the same process, and accurate reservation is realized through quantitative calculation by detecting the radial hardness distribution rule of the test bars. The core technology is a combination method of differential seepage prevention, test bar allowance quantification and staged machining, the machinability of inner hole and end face seepage prevention is ensured before carburization, the performance is ensured through normal hardening of outer teeth, hardened layer residues and material waste are avoided through precise allowance, and the bearing performance of the inner teeth is ensured.

The utility model relates to the technical field of heat dissipation towers, in particular to a heat dissipation tower for cooling water of a carburizing furnace, which is large in unit water treatment capacity, increases the flowing length and time of the cooling water, and improves the heat dissipation effect and the heat dissipation quality of the cooling water. Comprising a tower body, a water inlet pipe, a water delivery pump, an annular water distribution pipe, a connecting rod, an air exhaust component, a flow slowing component and a stirring component, the water inlet pipe is installed on the upper portion of the tower body, the water delivery pump is installed on the water inlet pipe, and the annular water distribution pipe is installed on the upper side of the interior of the tower body through the connecting rod; the air exhaust component is mounted at the top of the tower body, the flow slowing component is mounted on the lower side in the tower body, and the stirring component is mounted at the bottom of the tower body.

The invention provides a carburizing and quenching process for reducing deformation of a thin-wall gear. The carburizing and quenching process comprises the steps that S200, the multiple thin-wall gears are stacked on the stacking frame in the axial direction with the positioning end faces of the thin-wall gears as the reference; s300, the thin-wall gear is heated to the carburizing temperature of 920 + / -10 DEG C in a multi-stage stepped mode; s400, the thin-wall gear is subjected to heat preservation for 1320 min and then enters a carburizing procedure; s500, the thin-wall gear treated through the carburizing procedure is subjected to tempering treatment and then cooled; s600, measuring the ellipse deformation of each thin-wall gear subjected to slow cooling in the carburizing process; s700, the thin-wall gears on the stacking frame are rearranged according to the ellipse deformation amount; and S800, the thin-wall gears stacked again are subjected to multi-section stepped heating quenching. The carburizing and quenching stepped heating process relieves thermal stress concentration and reduces the risk of thermal deformation, so that the production quality of the thin-wall gear can be ensured while the production efficiency of the thin-wall gear is ensured.

The invention relates to a method for producing liquid steel in an electric arc furnace (2) comprising successively: - defining a targeted nitrogen content wt. %Ntarg of the produced liquid steel, - introducing a metal load in the electric arc furnace (2) and - melting it for generating a steel bath (10) and a slag (12); - carburizing the steel bath (10) by adding a carbon amount equal to or greater than a minimum denitrogenation carbon amount CdeN, said amount CdeN being defined as a function of the nitrogen content in excess to wt. %Ntarg at the beginning of the step (E4), - injecting a flow of oxygen to reach a nitrogen content wt. %N such that wt. %N ≤ wt. %Ntarg, - tapping the steel bath (10) to obtain the produced liquid steel.

The application belongs to the technical field of metal materials, and particularly relates to a high-life cutter steel and a carburizing method of a cutter. The chemical composition of the steel is as follows: C: 0.18%-0.22%, Si: 0.25%-0.30%, Mn: 0.50%-0.60%, P<=0.010%, S<=0.015%, Cr: 1.9%-2.0%, Ni: 1.80%-2.20%, Cu: 0.20%-0.50%, and the rest is Fe and inevitable impurities. The steel can effectively meet the performance requirements of fatigue resistance and high hardness of the cutter steel through component design and heat treatment methods, and a manufacturing method with significantly improved comprehensive mechanical properties and fatigue resistance is obtained. Through inhibition of carbide precipitation, optimization of carbon distribution and reduction of residual austenite, the surface hardness and fatigue performance are simultaneously improved.

The present application belongs to the technical field of waste gas purification, and discloses a heat treatment waste gas treatment device, which comprises an industrial carburizing furnace and a centrifugal pipe. A convex cap is fixed between the top of the centrifugal pipe. A fixing sleeve is fixed to the inner top surface of the convex cap. The bottom of the fixing sleeve extends downward to the inside of the centrifugal pipe. An air inlet pipe is connected to the side of the centrifugal pipe close to the top edge. When the waste gas is introduced into the centrifugal pipe for separation, the air delivered to the inside of the centrifugal pipe is driven to rotate by a centrifugal driving device. Under the action of centrifugal force, the fine particulate matter suspended in the air is collected to the middle of the bottom of the centrifugal pipe. The fine particles can fall into the neutralizing solution in the inside of the conical disc. As the fine particles are absorbed by the neutralizing solution, the weight of the conical disc as a whole is increased, so that it slides downward to trigger the traction device to drive the switching assembly to switch the flow direction of the air flow through the filter cartridge, so that the filter cartridge can be cleaned.