54 results about "Carburizing" patented technology

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.

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 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.

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.

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 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.

This utility model discloses a vacuum furnace carburizing and quenching heat treatment fixture, relating to the field of heat treatment process technology. It includes a support plate with multiple first screw holes and multiple vents at its top. A vertical column is located at the top of each first screw hole, and a pad is fixedly connected to the bottom of the vertical column. An externally threaded rod is fixedly connected to the bottom of the pad. A second screw hole is located at the top of the vertical column, and a sleeve is fitted onto the outer side of the vertical column. A horizontal plate is fixedly connected to the side wall of the sleeve, and multiple notches are located at the top of the horizontal plate. A crossbar is placed inside each notch. This utility model, through a series of structural features, allows the number of support rods to be flexibly increased or decreased according to the number of metal parts, thereby facilitating the fixture to meet different support requirements for metal parts and accelerating the flow of hot air between adjacent metal parts, thus improving the carburizing and quenching effect of the metal parts.

A method for predicting the austenite grain size of cold-extruded gear steel after carburizing belongs to the field of metal material testing technology. The method mainly includes the following steps: taking samples from hot-rolled round steel and processing them into specimens of specified dimensions; normalizing the specimens; then performing spheroidizing annealing; cold-heading the spheroidized annealed specimens; then performing pseudo-carburizing treatment; finally, preparing the specimens into metallographic samples, etching them with picric acid aqueous solution, and observing the grain size under a metallographic microscope. This invention, through a coupled process of heat treatment and cold heading deformation, can effectively detect the austenite grain size of cold-extruded gear steel after carburizing, directly characterizing the material's resistance to grain coarsening during the carburizing process after cold extrusion.

The application discloses a vacuum low-pressure carburizing heat treatment method for improving the structure and performance of 1Cr13 steel. The method comprises the following steps in sequence: vacuum pre-activation, pulse low-pressure carburizing, three-stage diffusion homogenization, high-temperature short-time austenitizing, multi-stage step quenching and three-time stabilization tempering. The vacuum pre-activation removes the surface oxide film and improves the carburizing activity; the pulse low-pressure carburizing in combination with the three-stage diffusion makes the carburized layer form a continuous and gentle carbon gradient and dispersed carbide; the multi-stage step quenching and the three-time tempering refine the martensite, reduce the stress peak value and stabilize the residual austenite. After the treatment, the hardness of the carburized layer is HRC 54-59, the depth is 0.75-1.05 mm, the wear resistance is increased by 2-3 times, and there is no pitting in the salt spray test for 720-960 hours. The application is suitable for the strengthening treatment of 1Cr13 steel valve core, rotating shaft, die mandrel and other wear-resistant and corrosion-resistant parts.

The application provides a large-diameter sodium valve driving device, relates to the technical field of nuclear reactor control equipment, and specifically comprises a casing, a driving motor, a transmission worm, a transmission worm wheel and an output shaft. The transmission worm has a driving part and a transmission part, the driving part is in transmission connection with a driving shaft, and the transmission part is arranged at intervals with the driving part in the axial direction of the transmission worm. The transmission worm wheel has an outer edge and an inner edge, the outer edge is in meshing transmission connection with the transmission part. The output shaft is inserted into the worm wheel and in transmission connection with the inner edge, and is used for connecting the sodium valve. The driving shaft and the driving part are made of low-alloy carburizing steel containing chromium, manganese and titanium, the outer edge is made of high-tin nickel bronze, and the transmission part is made of medium-carbon alloy structural steel containing chromium. The application forms a stable transmission structure through the combination of multiple materials, can maintain stability under sodium fire high temperature, avoids transmission failure caused by thermal deformation or material degradation, and meets the emergency action requirements in the sodium leakage accident of a nuclear power plant.

This utility model relates to the field of carburizing and quenching technology, and discloses a multi-purpose air-cooled circulation device for the front chamber of a carburizing and quenching furnace; it includes a quenching furnace front chamber, and further includes: a first connecting pipe connected to the right side of the quenching furnace front chamber, the other end of the first connecting pipe being connected to a filter box; and a filter structure disposed inside the filter box; after the workpiece is quenched, the air in the quenching furnace front chamber is adsorbed by a fan, which allows the hot air to adsorb oil, odors and harmful gases in the hot air when passing through the filter structure. At the same time, when the hot air is transported again, the heat of the hot air can be transferred through the cooling structure inside the cooling box, so that the temperature of the hot air is reduced, and then transported back to the quenching furnace front chamber through the second connecting pipe, which can quickly reduce the temperature of the quenching furnace front chamber, accelerate the cooling rate of the workpiece, and prevent the workpiece from being oxidized and discolored due to prolonged high temperature.

The application discloses a production method of high-strength and high-toughness gear steel without normalizing treatment. The gear steel adopts a Cr-Mn based hardenability system and is micro-alloyed by V, Nb and Al. The production process comprises smelting, continuous casting, controlled rolling and controlled cooling, and a key heat treatment process of directly slow cooling to quenching temperature after high-temperature carburizing. The V, Nb and Al carbonitrides pin the grain boundaries at high temperature, and inhibit the growth of austenite grains during the carburizing process. The application enables the gear steel to be directly quenched without normalizing treatment after high-temperature carburizing, and fine crystal structure and high comprehensive performance are obtained, so that the production process is greatly simplified, and the cost and energy consumption are reduced.

The following (in mass percent): 35.0-38% nickel, 26.0-30.0% chromium, >0.7-1.50% silicon, 0.40-1.30% aluminum, 0.00-1.0% manganese, 0.0001-0.05% magnesium and / or calcium, 0.015-0.12% carbon, 0.001-0.150% nitrogen, 0.001-0.030% phosphorus, 0.0001-0.020% oxygen, maximum 0.010% sulfur, less than 1.0% molybdenum, and less than 1.0% iron. 1. Use of a nickel-iron-chromium alloy having outstanding high temperature corrosion resistance, containing 0.01% cobalt, less than 0.5% copper, less than 1.0% tungsten, the balance iron and normal process impurities, as a semi-finished product in a carburizing, sulfiding and simultaneously chlorinating environment, in which the following relationship must be satisfied: Fc=-1.2+0.29×Ni-4.6×Si-4.4×Al<2.5(1a), where Ni, Si and Al are the concentrations of the respective elements in mass%.

The utility model discloses a kind of carburizing bearing steel production and processing device related to carburizing furnace technical field, rotation drive connection is provided with the supporting rod of carburizing furnace coaxial arrangement in carburizing furnace, supporting rod is detachably installed with the material rack for placing workpiece, and can be synchronous with supporting rod Rotating, material rack includes the outer frame of "n" type structure, outer frame upper portion is equipped with lifting ring, a plurality of matrix arrangement is equipped on the outer frame both sides side wall, and one-to-one corresponding through opening, and tray is detachably installed between the corresponding through opening of outer frame both sides side wall;The utility model not only can rotate carburizing operation to bearing steel workpiece, effectively eliminate furnace temperature / atmosphere dead angle, and also greatly improve the contact area of carburizing gas and workpiece, effectively guarantee the uniformity of workpiece carburizing.

This invention belongs to the field of vanadium-titanium slag comprehensive utilization technology, specifically disclosing a method for recycling and recovering vanadium from vanadium-containing secondary resources. The method includes the following steps: mixing vanadium-containing secondary resources with flux, smelting and forming slag in a smelting pool to obtain molten vanadium-containing slag; adding high-carbon molten iron to the molten vanadium-containing slag and mixing, then injecting reducing gas or argon into the smelting pool; after injection, allowing the mixture to settle and smelt for collection, separating the slag and iron to obtain vanadium-containing molten iron and low-vanadium slag; using a converter vanadium extraction process to obtain high-vanadium slag and molten iron, with the high-vanadium slag used for vanadium extraction. This invention also utilizes a molten iron carburizing and recycling vanadium collection process to further collect vanadium from the incompletely collected low-vanadium slag, significantly improving vanadium recovery efficiency and reducing resource waste. This invention features a short process, high recovery rate, low production cost, and low pollution. The obtained high-vanadium slag can be used for vanadium extraction using existing mature processes, thereby achieving efficient extraction and utilization of vanadium from vanadium-containing secondary resources.

A vacuum carburizing treatment method, includes: supplying an inert gas into a heating chamber in which a carburizing treatment is performed on a workpiece, making the pressure in the heating chamber become a pressure equal to or higher than an atmospheric pressure, and then opening a charging port for the workpiece provided at a bottom portion of the heating chamber; charging the workpiece from the charging port; increasing the temperature inside the heating chamber to a temperature at which a vacuum carburizing treatment is performed; and supplying a carburizing gas into the heating chamber that has been vacuum-evacuated and performing a vacuum carburizing treatment on the workpiece.

This invention provides a high-temperature carburizing bearing steel and its preparation method, relating to the field of aerospace bearing steel preparation technology. The method includes the following steps: preparing a steel ingot with a composition meeting set requirements; subjecting the ingot to anisotropic pre-straining and solution treatment to eliminate high-temperature ferrite and coarse carbide enrichment zones, thus obtaining a billet; and finally subjecting the billet to hot forming double-refining treatment to obtain the carburized bearing steel. This invention, by reducing the content of ferrite-forming elements and increasing the content of austenite-forming elements, helps promote the transformation of high-temperature ferrite into austenite during solidification, reducing solute segregation bands and brittle-inducing phases in the as-cast microstructure. The anisotropic pre-straining and solution treatment causes carbides to precipitate, consuming alloying elements in the high-temperature ferrite, and introduces high-density crystal structure defects and increases recrystallization grain boundary area, promoting the dissolution and transformation of high-temperature ferrite, further improving compositional uniformity, thereby avoiding brittle fracture problems caused by element segregation.

To provide a self-aligning roller bearing that improves wear resistance and suppresses grease degradation. [Solution] When the shortest radial distance of the cage between the rolling surface of each spherical roller and the circumferential side surface of each column is H1, and the shortest radial distance of the cage between the opposing surface and the end face when each spherical roller is furthest from the surface on the inner surface of each pocket that faces the end face of each spherical roller, H2 satisfies H1 ≥ H2. At least one of the outer ring, inner ring, and spherical roller is made of alloy steel for rolling parts with a carbon content C of 0.4 to 0.7 by weight, carburized and quenched to an additional carbon content of 0.35 to 1.0 by weight on the surface and a solid solution carbon content of 0.75 to 1.1 by weight on the surface, with a core hardness of HRC 40 to 64. A DLC coating is provided on the rolling surface of the spherical roller 30, and the DLC coating is mainly made of tungsten carbide or silicon carbide and carbon, with a film thickness of 1 to 2 μm.

This utility model relates to the field of heat treatment technology for thin-walled gears, and discloses a fixture for carburizing and quenching thin-walled gears. The fixture includes a base, a mounting groove on the top edge of the base, an inner wall of the mounting groove that is slidably connected to the surface of a column, a surface of the column that is slidably connected to the inner wall of a lifting block, a lifting hook fixedly connected to the side of the base, a fixing mechanism on the surface of the column, a clamping mechanism in the middle of the fixing mechanism, and a thin-walled gear mounted on the base. This utility model uses threaded rods penetrating both ends to clamp the clamping plate and gear between the two fixing plates using nuts, preventing deformation of the gear during quenching. The opening of the connecting groove and the vortex groove allows the carbon-containing gas flow to fully contact the gear surface, preventing insufficient carburizing and resulting in insufficient gear hardness. The locking protrusion restricts the movement of the gear.

This invention discloses a novel high-wear-resistant oil seal chain manufacturing process, belonging to the field of chain manufacturing technology. The process includes the following steps: Pre-treated chain parts are placed in a carburizing furnace at 530-540℃ with an ammonia flow rate of 2.0 L / min and a mixed liquid flow rate of 0.2 L / min for 9 hours to obtain carburized parts; quenching and tempering: the carburized parts are quenched in a heat treatment device at 880-930℃ for 15-30 minutes, followed by tempering at 220-300℃ for 45-60 minutes to obtain intermediate product 1; blackening: intermediate product 1 is held at 300℃ for 1 hour, then immersed in a blackening solution for 15-30 seconds, and removed to obtain intermediate product 2; shot peening followed by assembly yields the novel high-wear-resistant oil seal chain. This oil seal chain not only has good wear resistance but also excellent corrosion resistance.

A carburized steel according to the present invention comprises, by wt%, 0.01 to 0.30% of C, 1.00% or less (excluding 0) of Si, 1.50% or less (excluding 0) of Mn, 2.00% or less (excluding 0) of Cr, 0.030% or less of P, 0.0500% or less of S, 0.3% or less of Ni, 0.30% or less of Mo, 0.30% or less of Cu, 0.500-0.01% of sol. Al, 0.100% or less of Nb, 0.30% or less of V, 0.050% or less of Ti, 0.0050% or less of B, 0.0200% or less of N, and the balance of Fe and inevitable impurities, and satisfies the following equations (1) and (2). Equation (1): [Al] / [C] ≥ 2.0 Equation (2): 0.4 ≤ [C]+(0.054×[Si])+(0.042×[Mn])+(0.015×[Cr])+(0.432×[Al]) ≤ 0.8 (wherein [Al], [C], [Si], [Mn], and [Cr] each represent the content (%) of the corresponding element).

The utility model discloses a star type sleeve with good impact resistance belongs to the coupling workpiece technical field, this star type sleeve with good impact resistance, include: star type sleeve component, star type sleeve component includes upper star type half cover and lower star type half cover, and the upper star type half cover is fixedly connected through bolt between lower star type half cover, and the outside surface of one side of lower star type half cover is provided with four installation locking grooves, four groups of locking components, and locking components include baffle, movable cambered surface block, transmission plate and two reset springs, this star type sleeve with good impact resistance, and the upper star type half cover and lower star type half cover all adopt the material of alloy carburizing steel this high strength, high toughness, high wear resistance and good fatigue performance make, not only have good impact resistance, and according to the actual demand of connecting smooth shaft or spline shaft etc.

This invention relates to the field of petroleum hydrocarbon pyrolysis, and discloses a quench boiler that mitigates coking and carburization, its preparation method, and its application. The method includes: (1) contacting a reducing gas with the tubes of the quench boiler to perform a first reaction, obtaining a pretreated quench boiler; (2) contacting a low-oxygen partial pressure gas with the pretreated quench boiler to perform a second reaction, obtaining a quench boiler with an oxide film on the inner surface of the tubes that mitigates coking and carburization; wherein the oxygen content of the reducing gas is 0 ppm; and the dew point of the low-oxygen partial pressure gas is -20°C to 20°C. The preparation process of this quench boiler is simple, and it can significantly reduce coking and carburization in the quench boiler, extending its operating cycle.

This invention discloses a wide-range gradient controllable residual stress calibration block and its preparation method, belonging to the field of stress calibration technology. The preparation method includes processing a carburized steel substrate into a blank and sequentially performing carburizing and quenching, shot blasting, grinding to remove the surface oxide layer, and shot peening. The shot-peened blocks are divided into at least two groups, and tempered in different temperature ranges to obtain blocks with different residual compressive stress levels. The different temperature ranges are selected from at least two of the following: 50-150℃, 150-250℃, and 350-450℃. At least a portion of the tempered blocks undergoes surface corrosion treatment to remove the deformation layer of a predetermined depth and fine-tune the residual stress value. Finally, the blocks are rust-proofed and stored. This invention solves the problems of existing calibration blocks having single stress values, poor stability, and short shelf life. It achieves the acquisition of stable calibration blocks with different stress gradients within the same material batch.

The application relates to the field of ethylene cracking, and discloses an alloy furnace tube and a treatment method and application thereof. The method comprises the following steps: (1) performing first heat treatment on the alloy furnace tube in the presence of a reducing atmosphere to obtain a pretreated alloy furnace tube; and (2) performing second heat treatment on the pretreated alloy furnace tube in the presence of a low-oxygen partial pressure atmosphere to obtain an alloy furnace tube with an oxidation film on the inner surface; wherein the content of oxygen in the reducing atmosphere is 0 ppm; and the dew point of the low-oxygen partial pressure atmosphere is-40 DEG C to 40 DEG C. By performing heat treatment on the alloy furnace tube in the presence of the reducing atmosphere and the low-oxygen partial pressure atmosphere, a dense and stable oxidation film can be formed on the inner surface of the furnace tube, catalytic coking is inhibited or slowed down, the degree of carburization of the furnace tube is reduced, and the service life of the furnace tube is prolonged. The cracking furnace tube provided by the application for a hydrocarbon cracking device can adapt to various hydrocarbon raw materials, and the operation cycle of the cracking furnace is significantly prolonged compared with the prior art.