49results about How to "Improve contact fatigue life" patented technology

The invention discloses a carburizing bearing steel, which comprises the following chemical elements in percentage by mass: 0.10-0.16% of carbon, 0.40-0.90% of manganese, 0.15-0.40% of silicon, 1.30-1.80% of chromium, 3.10-3.80% of nickel, 0.02-0.09% of molybdenum, 0.015-0.040% of aluminum and 0.0040-0.0070% of nitrogen, less than or equal to 0.0010% of oxygen, less than or equal to 0.020% of phosphorus, 0.005-0.020% of sulfur, less than or equal to 0.0020% of titanium, less than or equal to 0.15% of copper, less than or equal to 0.025% of tin, less than or equal to 0.015% of antimony, less than or equal to 0.030% of arsenic, and the balance of Fe and inevitable impurities, wherein the ratio of aluminum/nitrogen is more than or equal to 3. The carburizing bearing steel disclosed by the invention is easy for carburizing surface treatment, and has excellent strength and toughness.

The invention relates to a forging forming method for an inner ring and an outer ring of a motor train unit bearing with reasonable streamline distribution. According to the forging forming method, the structure size of a die used in a forging forming process is optimized and designed by using deform software, the metal streamline distribution is simulated, and the more reasonable die structure size and matching clearance are obtained; carburized steel with low purity is subjected to streamline distribution simulation manufacturing instead of novel carburized steel which has high purity and streamline distribution difficult to observe, the reasonably distributed metal streamline is obtained, the mechanical property of a product is improved, and the contact fatigue life of the product is prolonged. By the adoption of the method for the development, the quality of an actual product formed by forging and forming during mass production of the inner ring and the outer ring of the motor train unit bearing is ensured, and mass production of ferrule forgings for motor train unit bearings is realized.

The invention provides a method for heat treatment of ultrahigh-carbon bearing steel. The method comprises the following steps of austenitizing a bearing steel part, keeping a certain amount of residual carbides, performing constant temperature treatment in a lower bainite area to form a certain amount of super bainites, and performing oil quenching or water cooling to obtain part of martensite. The structure of the ultrahigh-carbon bearing steel after the heat treatment comprises super bainites, martensite, the remaining carbides and the residual austenites, and the method ensures that the ultrahigh carbon bearing steel has a longer contact fatigue life and higher impact toughness.

The invention relates to a manufacturing method of high wearproof gear steel. The manufacturing method comprises the following steps: 1, smelting, wherein molten steel comprises the following components: 0.15-0.60% of C, 0.50-1.3% of Si, 0.50-1.2% of Mn, 0.60-1.5% of Cr, equal to or less than 0.030% of P, equal to or less than 0.035% of S, 0.010-0.050% of Al, 0.008-0.025% of N and the balance of Fe; 2, pouring: pouring molten steel into steel billets; 3, rolling: after heating the steel billets, rolling the steel billets in a single-phase region at the initial rolling temperature of 980-1100 DEG C, sequentially carrying out intermediate rolling, pre finish rolling and finish rolling, during the rolling process, controlling cooling, after intermediate rolling, carrying out spraying coolingon the steel billets, after pre finish rolling, carrying out spraying cooling on the steel billets once more, then, carrying out KOCKS finish rolling, and controlling the finishing temperature to be 780-900 DEG C to obtain an unstable austenite; and 4, cooling: carrying out blast cooling the steel billets on a cooling bed, controlling the average cooling rate to be 40-80 DEG C/min and the final cooling temperature to be 300-480 DEG C, after final cooling, carrying out air cooling on the material to the room temperature, and in the cooling process, converting the austenite into ferrite and pearlite. After carburizing, quenching and tempering, the rolled steel has excellent wear resistance.

The invention discloses a common rail traffic bainite steel wheel used under the cold and rigor service environment and a manufacturing method of the common rail traffic bainite steel wheel. The common rail traffic bainite steel wheel comprises chemical components including 0.05%-0.30% of C, 0.50%-1.50% of Ni, 0.01%-1.20% of Cr, 0.70%-2.10% of Mn, 0.20%-1.00% of Si, 0.01%-1.00% of W, 0.05%-0.60% of Mo, 0.01%-0.80% of Cu, 0.01%-0.20% of V, 0.001%-0.20% of Nb, 0.0001%-0.0350% of B, 0.001%-0.040% of RE, not larger than 0.020% of P, not larger than 0.020% of S and the balance Fe and inevitable residual elements, wherein the sum of Mn and Cr is larger than or equal to 2.0% and smaller than or equal to 3.0%. By adopting a new alloy design system and alloying principle of C-Ni-Mn-Cr-Mo, after thewheel is molded, a rim obtained after advanced heat treatment obtains a carbide-free bainite organization structure, and the wheel has the excellent comprehensive mechanical property, decay resistance and service performance, in particular has the high low-temperature toughness and low-temperature breaking toughness, meets performance and service safety requirement under the low-temperature environment and is suitable for the cold zone under rigor conditions.

The present invention belongs to the field of alloy steel and its making process, and is especially controlled cooling process and water cooler for high carbon and chromium bearing steel pipe blank after hot rolling. The cooling process includes the following steps: installing 4 water coolers in some interval on the cooling line and water cooling and air cooling the hot rolled pipe alternately in the V-shaped roll way; controlling the finishing temperature of rolled pipe blank to obtain single austenite structure before entering to the water coolers; ensuring the temperature of the hot rolled pipe blank before the first water cooler in 850-910 deg.c and the temperature leaving the fourth water cooler in 560+/-20 deg.c; air cooling the pipe blank with surface temperature recovered to 650+/-30 deg.c in the cooling bed; and fast spheroidizing annealing of the pipe blank. The present invention is superior to available technology.

The invention discloses an intrinsic non-net secondary cementite steel and an application method thereof; the steel comprises the following components by weight percent: 0.8-1.8% of C, 0-3.0% of Al, 0-2.5% of Cr, 0.2-0.8% of Mn, 0-2.0% of Si, 0-0.8% of Mo, 0-0.1% of Nb, 0-0.1% of V, 0-0.1% of Ti, 0-0.05% of Re and the balance Fe. The steel does not have net-shaped secondary cementite in common casting state, annealed state and normalized state, secondary cementite is precipitated in pearlite in a dispersive form and the form of organization is pearlite and dispersive spinodal decomposition organization. The organization is easy for nodulizing which can be realized by heating the organization at 800 DEG C for 1-2h after the routine forging technology. The steel can be widely applied in the fields such as tools, abrasive tools, bearings, rail steels and the like and the steel can improve the carbon content, hardness and wear resistance and service life of traditional materials.

The invention relates to a compound reinforcement method for a gear surface. The compound reinforcement method comprises the following steps: firstly, the gear surface is subjected to shot blasting with steel shots with particle size being 0.6-1 mm; then molybdenum disulfide is mixed with particles with particle size being 0.05-0.1 mm, the mixture is used for performing shot blasting continuously on a gear, and the gear with compound reinforced surface is obtained. By means of the coupled effect of two processes including powerful shot blasting and molybdenum disulfide and particle mixed shot blasting, amplitude of tooth surface compressive stress deeper than the stress in single surface treatment process is obtained, and tooth surface hardness is improved substantially. Meanwhile, the lubricity of the gear surface is improved, the friction coefficient of the tooth surface is reduced, the lubricating capacity and the surface smoothness are improved, and gear meshing vibration noise is reduced. The effect of prolonging both the flexible life and contact fatigue life of the gear simultaneously is realized. The method adopts simple process and flexible conditions, can realize batch production and has good application prospect.

The invention discloses a bainite steel wheel for a rail traffic D-series high-speed train and a manufacturing method thereof. Chemical components of the bainite steel wheel comprise 0.05-0.30% of C,0.10-1.50% of Ni, 0.01-1.20% of Cr, 0.70-2.10% of Mn, 0.20-1.00% of Si, 0.01-1.00% of W, 0.05-0.60% of Mo, 0.01-0.80% of Cu, 0.01-0.20% of V, 0.001-0.20% of Nb, 0.0001-0.0350% of B, 0.001-0.040% of RE, smaller than or equal to 0.020% of P, smaller than or equal to 0.020% of S and the balance Fe and inevitable residual elements, and the sum of Mn and Cr is larger than or equal to 2.0% and smaller than or equal to 3.0%. According to the bainite steel wheel, the novel C-Ni-Mn-Cr-Mo alloy design system and the alloying principle are adopted, after the wheel is formed and subjected to advanced heattreatment, a rim obtains a no-carbide bainite structure, and the wheel has excellent comprehensive mechanical performance, anticorrosion performance and service performance, and especially has the beneficial effects of being high in strength, high in hardness, high in toughness, high in low-temperature toughness, high in wheeltrack rolling contact fatigue resisting performance (RCF), high in heatcrack resisting performance and the like.

The invention discloses steel for a hub bearing. The steel for the hub bearing comprises chemical components, by mass percent, including 0.54%-0.58% of C, 0.20%-0.30% of Si, 0.65%-0.75% of Mn, 0.10%-0.20% of Cr, 0.010%-0.030% of Al, 0.015% or less of P, 0.003% or less of S, 0.0025% or less of Ti, 0.20% or less of Ni, 0.15% or less of Cu, 0.10% or less of Mo, 0.0010% or less of [O] and the balanceFe. From the components of the steel for the hub bearing, alloying is carried out through conventional alloy elements such as the C, the Mn and the Cr, the contact fatigue life of the steel for the hub bearing is longer in performance than G55 in national (Carbon Bearing Steel) (GB/T28417-2012) standard.

A case hardening bearing steel having an excellent rolling contact fatigue life in intermediate temperature, in addition, excellent toughness at room temperature is provided. Specific means for solving the problems are as follows. The composition contains, by mass percent, C of 0.15 to 0.30 mass percent, Si of 0.5 to 2.0 mass percent, Mn of 0.3 to 2.0 mass percent, Cr of 1.3 to 2.5 mass percent, Mo of 0.3 to 1.0 mass percent, and O of not more than 0.0012 mass percent in a range where (Si+Mo)≧1.0 mass percent is satisfied, and contains iron and inevitable impurities as remnant; the maximum size of oxide nonmetallic inclusion is not more than 12.5 μm when examined area is 320 mm²; number of the oxide nonmetallic inclusion having a diameter of equivalent circle of 3 μm or more is not more than 250 when the examined area is 320 mm²; in addition, C density of an outer layer is adjusted to be in a range from 0.7 to 1.2 mass percent by carburization.

The invention relates to a carburized bearing steel, which consists of the following components by weight: iron, silicon, chromium, nickel, carbon, copper, manganese, molybdenum, sulfur, aluminum, nitrogen, titanium, tin, oxygen and phosphorus. The carburized bearing steel has high relative purity and long contact fatigue life, and the content of trace elements has no influence to purity while optimizing the comprehensive performance of carburized bearing steel. The carburized bearing steel has good comprehensive mechanical properties, and has hardness, strength, elongation and shrinkage degree superior to ordinary bearing steel, thus being suitable for extensive application.

The invention discloses a bainite steel wheel for a rail traffic truck and a manufacturing method of the bainite steel wheel. The bainite steel wheel for the rail traffic truck comprises the followingchemical components: 0.10-0.40% of C, 0.10-1.50% of Ni, 0.25-1.50% of Cr, 0.70-2.10% of Mn, 0.20-1.00% of Si, 0.01-1.00% of W, 0.05-0.60% of Mo, 0.01-0.80% of Cu, 0.01-0.20% of V, 0.001-0.20% of Nb,0.0001-0.0350% of B, 0.001-0.040% of RE, less than or equal to 0.020% of P, less than or equal to 0.020% of S and the balance of Fe and inevitable residual elements; and moreover, 2.0%</= Mn+ Cr</= 3.0%. A novel alloy design system of C-Ni-Mn-Cr-Mo and an alloying principle are adopted, after wheels are formed and subjected to advanced heat treatment, a carbide-free bainite organization structureis obtained, and the wheels have excellent integrated mechanical property, corrosion resistance and service performance, and particularly have the characteristics of high strength, hardness and toughness, high wheel track rolling contact fatigue (RCF) resistance, hot crack resistance and the like.

The invention discloses a heat treatment method of ultrahigh-carbon bearing steel. The ultrahigh-carbon bearing steel comprises the following components in percentage by weight: 1.5%-2.5% of C, 0.6%-1.2% of Mn, 0.01%-0.1% of V, 0.1%-1.0% of B, 0.1%-0.24% of Be, 0.2%-1.8% of Ni, 1.2%-1.8% of Si, 0.4%-0.8% of Ti, 0.05%-0.08% of W, 2.5%-4.5% of Cr, 0.12%-0.16% of Al, 0.05%-0.16% of Re and the balance Fe. The heat treatment method comprises the following steps: (S1) annealing, wherein the steel is insulated by 3-7 h at 780-820 DEG C, is cooled to 700-760 DEG C at a speed of 20-40 DEG C/h for insulation by 1-2 h, is cooled to 550-650 DEG C at a speed of 10-30 DEG C/h for insulation by 1-2 h, and is discharged from a furnace for air cooling; and (S2) normalizing, wherein the temperature in the furnace is increased to 900-980 DEG C; and the steel is put in the furnace for insulation by 2-3 h, and is cooled in air through dispersion. The heat treatment method can guarantee the improvement of the toughness of the bearing steel under the condition of not reducing the hardness, and prominently prolongs the contact fatigue life.

The invention discloses a production process method for reducing the carbide mesh grade of a GCr15 bearing steel bar, and relates to the field of metallurgical special steel production and manufacturing. According to the production process method for reducing the carbide mesh grade of the GCr15 bearing steel bar, in the produced bearing steel bar, the content range of C, Cr, Nb and Re meets the following formula: 1.7 < = 7.88 (% C) + 0.75 (% Nb) + 1.48 (% Re)-4.25 (% C) (% Cr) < = 1.8, and secondary cementite is promoted to be separated out to be finer, more dispersed and more uniform through the compounding and coordinating effect of all the elements; through component design, low-temperature rolling and rapid cooling after rolling, precipitation and aggregation growth of secondary carbides on a grain boundary are inhibited, so that the carbide mesh grade of the GCr15 bearing steel bar is controlled to be smaller than or equal to 1.0 grade, and the method is suitable for producing the bearing steel bar with the specification of phi 16-40 mm.

The invention discloses a bainite steel wheel for a rail traffic passenger car and a manufacturing method thereof. The bainite steel wheel comprises the chemical components of 0.08-0.35% of C, 0.10-1.50% of Ni, 0.25-1.50% of Cr, 0.70-2.10% of Mn, 0.20-1.00% of Si, 0.01-1.00% of W, 0.05-0.60% of Mo, 0.01-0.80% of Cu, 0.01-0.20% of V, 0.001-0.20% of Nb, 0.0001-0.0350% of B, 0.001-0.040% of RE, 0-0.020% of P, 0-0.020% of S, and the balance Fe and inevitable residual elements, and in addition, the sum of Mn and Cr is larger than or equal to 2.0% and smaller than or equal to 3.0%. According to thebainite steel wheel for the rail traffic passenger car and the manufacturing method thereof, the novel C-Ni-Mn-Cr-Mo alloy design system and the alloying principle are adopted, after the wheel is formed, advanced heat treatment is conducted, then, the carbide-free bainite structure of a rim is obtained, and the wheel has the characteristics of being excellent in comprehensive mechanical property,corrosion resistance and service performance, high in strength, hardness, toughness, wheel rail rolling contact fatigue (RCF) resistance and hot crack resistance, and the like.

A long-life bearing steel for general purpose use is provided at low cost with no use of specific secondary refining process. Specifically, a bearing material having a component composition in which C: 0.95 to 1.10 mass %, Si: 0.15 to 0.70 mass %, Mn: 1.15 mass % or less, Cr: 0.90 to 1.60 mass %, and P: 0.025 mass % or less are contained, S and O, that are elements forming nonmetallic inclusions, are contained at S: 0.025 mass % or less and O: 0.0012 mass % or less, and the rest is composed of Fe and incidental impurities, wherein the maximum diameter of the oxide-based nonmetallic inclusion is more than 10 mum, but 15 mum or less in an inspection area: 320 mm2, the number of oxide-based nonmetallic inclusions having an equivalent circle diameter of 3 mum or more is 250 or less in the inspection area: 320 mm2, while in the material, AlN is contained at 0.020 mass % or less, and or the number of sulfide-based nonmetallic inclusions having a thickness of 1 mum or more is 1,200 or less in the inspection area: 320 mm2.