111 results about "Austempering" patented technology

The invention discloses a wear-resistant alloy casting part for electric machinery and a production process thereof, and relates to the technical field of electric casting part optimizing.The production process comprises the steps that raw materials are smelted to 1550-1620 DEG C under the protection of argon, and heat preservation is conducted for 30-60 minutes; composite modification treatment; performing low-pressure sand mold casting or die-casting molding; after a casting is austenitized for 1.5-3 hours at the temperature of 980-1050 DEG C, two-stage isothermal quenching is conducted in a salt bath, specifically, in the first stage, heat preservation is conducted for 15-25 minutes at the temperature of 280-320 DEG C, and in the second stage, heat preservation is conducted for 45-60 minutes at the temperature of 180-220 DEG C; and surface laser cladding is conducted, specifically, homogeneous alloy powder is adopted for conducting laser cladding with the lap joint rate being 35-50% on the working face of the casting part. The method has the beneficial effects that through the design principle of multi-scale cooperative strengthening and the cross-dimension coupling effect of material components, the process path and the microstructure, breakthrough improvement of the performance of the wear-resistant alloy casting is achieved.

The invention relates to the technical field of quenching treatment, in particular to a nodular cast iron isothermal quenching cooling method and an isothermal quenching cooling device.The method comprises the steps that when nodular cast iron of the current batch is subjected to cooling treatment in a cooling stage before isothermal quenching in a salt bath furnace, a thermal image of the surface of the salt bath furnace is collected in real time; acquiring a first characteristic value of each nodular cast iron; obtaining a furnace wall area and a non-furnace wall area in each thermal image; obtaining an average temperature value of each non-furnace-wall area; acquiring a local high-temperature area in each thermal image; acquiring a high-temperature characteristic value of each thermal image; acquiring a second characteristic value of each nodular cast iron; and the optimal rotating speed of the stirring device is obtained when the next nodular cast iron of the nodular cast iron of the current batch is subjected to cooling treatment in the cooling stage before isothermal quenching. The invention aims to improve the isothermal quenching cooling quality of the nodular cast iron by adjusting the rotating speed of the stirring device during the isothermal quenching cooling of the nodular cast iron.

The invention provides a production process of a high-low tooth screw, relates to the technical field of screw production, and solves the problems of poor skid resistance, low fastening efficiency, unbalanced mechanical properties, insufficient corrosion resistance and the like of a traditional screw through innovative design and process optimization. SCM435 alloy steel is selected, spaced anti-skid teeth are pressed within the range of 270 degrees in the circumferential direction of the head of the screw through a four-station cold header, high-low alternating tooth forms are twisted on the rod portion, the gradient hardness of the surface and the core portion is achieved through isothermal quenching, surface treatment is combined with zinc-nickel alloy electroplating and a polytetrafluoroethylene coating, and the corrosion resistance and the assembly smoothness are improved; full-process intelligent detection is realized through machine vision, three-coordinate measurement and torsion test. The local layout of the anti-skid teeth reduces material consumption and improves meshing efficiency, the high-low tooth form reduces assembly torque and stabilizes pre-tightening force, gradient heat treatment enhances fatigue resistance, the composite coating improves corrosion resistance, and intelligent detection guarantees product consistency.

The invention provides a gradient martensite-bainite complex-phase structure construction forming manufacturing method for a high-carbon steel bearing under an extreme working condition, and relates to the technical field of bearing manufacturing. The method comprises the steps that the target carbonitriding temperature is determined according to the first target carbon potential of a workpiece to be machined, the target carbonitriding time is determined according to the target carbonitriding layer depth, and carbonitriding is conducted on the rolled workpiece to be machined according to the target carbonitriding temperature and the target carbonitriding time; the target austenitizing temperature is determined according to the second target carbon potential of the carbonitriding furnace, the to-be-machined workpiece subjected to carbonitriding treatment is put into a high-temperature box-type furnace, and austenitizing is conducted on the to-be-machined workpiece subjected to carbonitriding treatment according to the target austenitizing temperature; and the target isothermal quenching temperature is determined according to the second target carbon potential in the carbonitriding furnace, and the austenitized to-be-machined workpiece is immersed into a low-temperature salt bath furnace according to the target isothermal quenching temperature for isothermal quenching. The wear resistance, strength and toughness of the bearing can be improved.

Disclosed in the present invention is a clean heat treatment control method for achieving high hardness and minimal deformation of a cold-work die, comprising: double-stage isothermal high-pressure gas quenching: introducing a high-pressure gas quenching gas into a vacuum furnace and stopping introduction of the high-pressure gas quenching gas once the surface temperature of a cold-work die has been cooled to a metastable austenite zone; enabling the temperature of a core portion of the cold-work die to be reduced to 50ºC above the metastable austenite zone by means of gas circulation, and then continuing to introduce the high-pressure gas quenching gas until the surface temperature of the cold-work die is reduced to a martensite point or below; then continuing to heat the cold-work die to a lower bainite zone, maintaining the temperature to enable the core portion to undergo lower bainite transformation, and then cooling the cold-work die to room temperature; and then carrying out high-temperature tempering two or three times. According to the present invention, two-stage vacuum high-pressure gas quenching isothermal treatment, i.e., vacuum high-pressure gas quenching and isothermal quenching in the metastable austenite zone and the lower bainite zone, is performed, and thermal stress and structural stress are controlled by means of the two-stage isothermal treatment so as to control the deformation of the die, thereby achieving accurate control of the structure and stress, controlling the deformation of the die to be within 0.05%.

The invention relates to a preparation technology and a use method of a wear-resistant steel ball for a large semi-autogenous mill, which are characterized in that a scrapped car shell, a scrapped cold roll and waste silicon carbide are used as main furnace charges to smelt molten steel in an electric furnace, and a small amount of aluminum-silicon-calcium alloy, rare earth magnesium-silicon-iron alloy and nano TiC are added to improve the quality of the molten steel. Molten steel is directly poured into a square billet on a square billet continuous casting machine, after the continuous casting square billet is rolled and forged, forging waste heat water cooling short-time quenching and isothermal quenching composite heat treatment is adopted, the wear-resistant steel ball with excellent obdurability and wear resistance is obtained, the phenomena of cracking, stripping and out-of-round do not occur when the wear-resistant steel ball is used on a large semi-autogenous mill, wear is low, and the service life of the wear-resistant steel ball is prolonged. And the production efficiency of the large semi-autogenous mill can be remarkably improved, the ore grinding cost is reduced, and remarkable economic and social benefits are achieved in application and popularization.

The invention discloses high-toughness low-carbon bainite steel and a preparation method and application thereof, and belongs to the technical field of metal heat treatment, and the high-toughness low-carbon bainite steel comprises the following chemical components: 0.2-0.3% of C, 1.50-1.70% of Si, 0.3-0.6% of Al, 0.1-0.3% of Mo, 1.80-2.1% of Mn, 0.75-0.95% of Cr, 0.01-0.03% of Ni and inevitable impurities. The preparation method comprises the following steps that steel is subjected to heat preservation heat treatment and then sequentially subjected to two-stage isothermal quenching heat treatment, two times of subzero treatment and tempering treatment, and the high-toughness low-carbon bainite steel is obtained. According to the preparation method disclosed by the invention, the low-carbon bainite steel is ensured to have good comprehensive mechanical properties on the basis of a preparation process combined with structure regulation and optimization. And in addition, a complex process is avoided, the production efficiency is improved, and rapid and large-batch production of the low-carbon bainite steel is facilitated.

The invention belongs to the technical field of cutting pick preparation processes, and particularly relates to a preparation method of a high-wear-resistance cutting pick, which is characterized in that steel for a cutting pick body comprises the following chemical components in percentage by mass: 0.55 to 0.75 percent of C, 0.9 to 1.2 percent of Cr, 0.15 to 0.30 percent of Mo, 0.5 to 1.0 percent of V, 0.17 to 0.37 percent of Si, 0.5 to 0.8 percent of Mn, trace elements and the balance of Fe; the trace elements comprise 0.05 to 0.1 percent of Ni, 0.002 to 0.005 percent of B, 0.005 to 0.01 percent of Nb, 0.005 to 0.01 percent of Ti, less than 0.035 percent of S and less than 0.035 percent of P; the preparation method comprises the following steps: 1) preparing the cutting pick body; (2) preparing the cutting pick; and 3) carrying out isothermal quenching heat treatment on the cutting pick. The method has the beneficial effects that steel is optimized in microstructure and performance by optimizing steel components for the cutting pick body and parameters such as temperature, time and cooling rate of each heat treatment link, the wear resistance of the cutting pick is excellent, the urgent requirement for high performance of the cutting pick in modern industrial production is met, and the service life of the cutting pick is prolonged.

The invention relates to the technical field of metal casting, in particular to an isothermal quenching nodular cast iron ADI continuous casting method which comprises the steps that the temperature of a crystallizer used in the ADI continuous casting process is collected in real time; calculating a heat exchange coefficient in the crystallizer in real time; friction force generated when the casting blank is pulled out of the crystallizer is collected in real time; presetting each period, and obtaining period steady-state indexes of the heat exchange coefficient, the temperature and the friction force in each period; respectively acquiring abrupt change points of friction force and temperature in each period on a time sequence, and screening friction force change points and temperature change points from the abrupt change points; the lag time length of each friction force change point is obtained; the continuous casting stability index and the suspension confidence coefficient of each period are obtained; and evaluating the abnormal condition of the continuous casting process in each period through the stopping confidence coefficient of each period. According to the method and the device, the unplanned shutdown caused by misjudgment is reduced by timely finding the abnormal phenomenon in the continuous casting process, and the continuous casting production efficiency of ADI is improved.

The invention relates to the technical field of isothermal quenching, and provides an austempered ductile iron isothermal quenching method for prolonging the service life of an ADI casting, which comprises the following steps: collecting and measuring the thickness and surface area of the casting to be subjected to isothermal quenching, and carrying out preheating treatment, first heat preservation treatment, heating to austenitizing temperature treatment and second heat preservation treatment on the casting, the heat flow and the casting temperature are collected in the isothermal quenching process of the casting; marking a target acquisition moment and a prediction basis moment, determining a quenching heat release influence coefficient and a prediction weight of the target acquisition moment, and obtaining a casting temperature prediction value of a next adjacent acquisition moment of the target acquisition moment in combination with the casting temperature; and performing temperature compensation on isothermal quenching of the casting according to the temperature predicted value of the casting, and performing air cooling operation and cleaning on the casting subjected to isothermal quenching to finish isothermal quenching of the austempered ductile iron. According to the invention, the temperature compensation process of isothermal quenching can be ensured to be carried out stably.

The invention provides a preparation method of a low-cost, high-strength and high-toughness ADI casting, and mainly relates to the field of casting materials and heat treatment. The invention discloses a preparation method of a low-cost high-strength high-toughness ADI casting. The preparation method comprises the following steps: smelting; 60% of low-manganese steel scrap with the manganese content smaller than or equal to 0.5% and 40% of scrap iron are taken and added into a smelting furnace to be smelted, low-temperature smelting is conducted at the temperature of 1460-1480 DEG C, and then high-temperature standing is conducted for 5-10 min within the range of 1490-1510 DEG C; spheroidizing and inoculating; the spheroidizing bag containing the molten iron is hoisted to a wire feeding spheroidizing machine to be subjected to spheroidizing treatment; casting is conducted; the molten iron obtained after spheroidizing inoculation is subjected to casting molding in a mold; heat treatment is conducted, specifically, the cooled casting is heated to 840 + / -10 DEG C, and then isothermal quenching is conducted under the temperature condition of 370 + / -10 DEG C; the method has the beneficial effects that cost can be reduced, efficiency can be improved, and casting products with higher quality can be prepared with lower cost.

In a process and an apparatus for austempering, metal workpieces and optional tempering bodies are quenched in a quenching volume V of a quenching apparatus, in which the quenching volume V is flowed through by a cooling fluid, and the workpieces are tempered by thermal radiation of the tempering bodies, by thermal radiation of one or more heating elements arranged in the quenching apparatus, or by a thermal fluid in such a way that an average temperature T(t) of the workpieces follows a progression over time according to the relationshipT⁡(t)=T0+T1[1+tanh⁡(-tτ)]where t is the time in seconds, 150° C.≤T0≤250° C., 600° C.≤T1≤820° C., 12 s≤τ≤24 s, 0 s≤t≤Γ and 180 s≤Γ≤240 s.

The invention provides an efficient and accurate Marbainite complex-phase heat treatment method for a high-carbon steel bearing, and relates to the technical field of bearing manufacturing. The method comprises the following steps: controlling an austenitizing process by adopting target austenitizing process parameters to obtain target austenite; the method comprises the following steps: controlling the process of transforming a target austenite phase into a target bainite by adopting a graded isothermal quenching process, and determining primary isothermal quenching process parameters according to target bainite nucleation parameters in the primary isothermal quenching process; in the secondary isothermal quenching process, secondary isothermal quenching process parameters are determined according to the target bainite growth parameters; and in the third-stage isothermal quenching process, third-stage isothermal quenching process parameters are determined according to the target bainite volume fraction parameters. By means of the method, refined control over the phase proportion and morphology of the complex-phase structure can be achieved while the bainite of the rolled bearing steel is rapidly formed.

A method for manufacturing a wave gear device comprises: a hot forming step of hot forming an alloy steel composed of nickel, copper, molybdenum, and silicon into a first molded product having a silk hat-type housing shape at a first temperature of 950 to 1300°C; a normalizing step of isolating the first molded product at the first temperature for a predetermined time and, after the isolating time has elapsed, slowly cooling the first molded product to a second temperature of 750 to 900°C; an austempering step of isolating the first molded product at the second temperature and then cooling it to a third temperature of 250 to 400°C to form residual austenite in the first molded product; a heat treatment step of isolating the first molded product that has undergone the austempering step at the third temperature and then cooling it at room temperature to stabilize the microstructure of the first molded product; and a gear forming step of turning and toothing the first molded product that has undergone the heat treatment step to form a second molded product having a soluble external gear shape. The method comprises a step and a trip step of applying impact to the surface of the second molded product to induce a processing-induced transformation in some of the austenite remaining in the second molded product, thereby transforming the surface of the second molded product into martensite.

The invention provides a steel wire rod for a 2300MPa-grade steel-cored aluminum strand and a production method of the steel wire rod. The method sequentially comprises the following steps of molten iron pre-desulfurization, converter smelting, external refining, continuous casting, casting blank heating, high-speed wire rolling and online isothermal quenching and tempering, and the steel wire rod is obtained. On the basis of adjustment of chemical components of the wire rod and control over production processes such as continuous casting, rolling and online quenching-tempering treatment, the homogeneity of steel is improved, the metallographic structure of the wire rod prepared through the production method is mainly sorbite, the sorbite rate is larger than or equal to 97%, and the sorbite lamellar spacing is 45-65 nm; the tensile strength is 1620 to 1700 MPa, and the percentage reduction of area is 35 to 44 percent; the steel wire rod is drawn, galvanized and twisted into a galvanized steel strand which can be used for a steel core of a steel-cored aluminum strand.

The invention discloses a heat treatment process of an M62 material for an X-ray tube bearing. The heat treatment process comprises the following steps: S1, preparing the M62 material; s2, the M62 material is subjected to high-temperature annealing process machining, and the M62 material subjected to high-temperature annealing process machining is subjected to turning treatment to obtain a bearing turning part; s3, the bearing turning part is subjected to third-time preheating machining, and the bearing turning part subjected to third-time preheating machining is subjected to quenching heat preservation treatment; s4, on the basis of the step S3, isothermal quenching machining is conducted on the bearing turning part subjected to quenching and heat preservation treatment; and S5, based on the step S4, low-temperature tempering machining is conducted on the bearing turning part subjected to isothermal quenching machining, and high-temperature tempering machining is conducted on the bearing turning part subjected to low-temperature tempering machining twice. The method solves the problems of low cutting efficiency caused by high annealing hardness after heat treatment of the traditional M62 material, high material performance dispersity and shortened service life caused by non-uniform heating of the internal structure of the alloy, and overhigh hardness and insufficient toughness after heat treatment.

The invention relates to the field of aluminum alloy materials, provides a manufacturing method of a high-strength thin-wall aluminum alloy extrusion casting part, and aims at solving the problems that an existing aluminum alloy extrusion casting part is insufficient in strength and large in heat treatment deformation. According to the method, an Al-Si-Mg-Cu-Zn series casting alloy with a specific component proportion is adopted, an organization structure containing 1.0-3.5 vol% of Al5Mg8Si6Cu2 strengthening phase is formed through the steps of an optimized extrusion casting process, solution treatment, pre-cooling treatment, isothermal quenching and the like, the strengthening phase forms a semi-coherent interface with a matrix in the precipitation process, and the mechanical property of a casting is effectively improved. According to the casting manufactured through the method, the tensile strength is larger than or equal to 368 MPa, the yield strength is larger than or equal to 316 MPa, the flatness deviation is 0.1-0.25 mm / 100 mm, and the method is suitable for manufacturing thin-wall structural parts with the high requirements for high strength and high dimensional precision and has wide engineering application prospects.

The invention relates to the technical field of metal heat treatment, and discloses a multi-section isothermal quenching furnace which comprises a main body assembly and a quenching furnace body, a sealing door is arranged on one side of the quenching furnace body, a conveying belt is arranged at the bottom of the quenching furnace body, a base is fixed to the bottom of the conveying belt, and a conveying assembly is arranged on the quenching furnace body and used for conveying the quenching furnace body. Comprising a conveying part, the conveying part comprises a conveying pipe, the conveying pipe is connected to one side of the quenching furnace body in an inserted mode, and a closing plate is arranged on one side of the conveying pipe. The device has the beneficial effects that when the pressure in the furnace is too high, the valve can be automatically opened to release the pressure without manual opening, so that the pressure in the furnace can be kept balanced, the pressure change can be monitored in real time and quickly responded, the time difference of manual operation does not exist, and the working efficiency is improved. The valve can be opened in time to release pressure when the pressure just exceeds a safety range, and irreversible damage to a furnace body caused by rapid rising of the pressure is avoided.

The invention belongs to the technical field of bearing steel preparation, and particularly relates to a superfine structure 8CrMo4V bearing steel preparation method which comprises the following steps that 1, 8Cr4Mo4V steel is subjected to forging treatment; (2) the forged 8Cr4Mo4V steel is subjected to temperature control rolling; 3, the 8Cr4Mo4V steel is subjected to isothermal quenching ultrafine treatment; and 4, the 8Cr4Mo4V steel is subjected to deep cooling and tempering treatment. Results show that the method can obviously refine original austenite grains and martensite substructures.

The application belongs to the technical field of laser additive manufacturing, and particularly relates to a laser additive manufacturing CrNiMo steel and a preparation method and application thereof. The application is prepared through secondary isothermal quenching treatment, specifically, under the temperature of 320 DEG C to 380 DEG C, heat preservation for 20 min to 45 min, so that the undercooled austenite occurs lower bainite phase transformation, and the first isothermal quenching treatment is completed; the sample after the first isothermal quenching treatment is preserved at 240 DEG C to 300 DEG C for 10 min to 20 min, fine lath-shaped martensite is obtained, and the second isothermal quenching is completed; and during the two isothermal quenching processes, nano-scale precipitates are dispersedly precipitated at the lath interface, significant strengthening is generated, the optimal organizational morphology of lower bainite + martensite + a small amount of dispersed carbide + residual austenite is realized, and the balance of high strength and high toughness is achieved. Compared with the prior art, the tensile strength of the CrNiMo steel prepared by the application is increased by more than 60%, and the impact toughness is increased by more than 100%.

The invention discloses a cyaniding-composite isothermal quenching synergistic strengthening and high strengthening and toughening method for 18Cr2Ni4WA steel, and relates to the technical field of heat treatment of high-strength alloy steel. The method can effectively reduce the core hardness on the premise of ensuring the surface hardness and wear resistance, and comprises the following steps: 1, quenching and tempering; 2, carbonitriding treatment is carried out; 3, composite isothermal quenching; and 4, carrying out ice-cooling treatment and low-temperature tempering treatment. According to the 18Cr2Ni4WA steel cyaniding-composite isothermal quenching synergistic strengthening and high strengthening and toughening method, the surface hardness of the strengthened and high strengthening and toughening 18Cr2Ni4WA steel prepared through the 18Cr2Ni4WA steel cyaniding-composite isothermal quenching synergistic strengthening and high strengthening and toughening method is 750 HV0.2 or above, meanwhile, the core hardness is lower than 420 HV0.2, the tensile strength is higher than 1600 MPa, the surface hardness and the core hardness are both considered, and meanwhile the mechanical property is enhanced. According to the method, the strengthened 18Cr2Ni4WA steel with high toughness can be obtained.

The invention relates to the technical field of manufacturing of metal composite materials, and discloses a corrosion-resistant and wear-resistant bimetal composite cylinder liner which is prepared through the following steps that the inner wall of an outer-layer matrix steel pipe is pretreated and coated with an interface activation flux; raw materials containing waste steel, ferrochrome and the like are molten, ferrotitanium and ferroboron are sequentially added for alloying, then ferric oxide powder and metal yttrium are added for modification treatment, and inner-layer alloy liquid is obtained; the preheated outer-layer matrix steel pipe is placed in a rotating state, and the inner-layer alloy liquid is poured; and after the to-be-solidified pipe fitting is cooled to the room temperature, the pipe fitting is heated to the austenitizing temperature, heat preservation is conducted, and then isothermal quenching treatment is conducted. According to the method, interface oxides are effectively removed and firm metallurgical bonding is promoted by utilizing the interface activation flux; a core is formed through in-situ reaction of metal yttrium and ferric oxide so as to refine grains; and a lower bainite and retained austenite mixed structure is obtained through isothermal quenching, the comprehensive mechanical property of the cylinder sleeve is improved, and the service life of the cylinder sleeve is prolonged.

The invention relates to the field of trolley drill rod quenching, in particular to a high-strength trolley drill rod quenching process and an isothermal quenching furnace thereof.The high-strength trolley drill rod quenching process comprises the steps that a trolley drill rod is subjected to carburizing treatment and then cooled to the preset temperature, the preset time is maintained, and the trolley drill rod is cooled to the set temperature within the set time through flowing inert gas; and the trolley drill rod is controlled to move in the flowing inert gas. According to the isothermal quenching process of the trolley drill rod, a uniform granular bainite structure can be obtained on a trolley drill rod base body, first-grade retained austenite martensite and carbide structures are obtained on the carburized surface, the toughness and strength of the trolley drill rod are enhanced, the fatigue performance is improved, and the rock drilling service life can be prolonged by 30%-60%. The hardness uniformity of the trolley drill rod is improved, an automatic straightening machine does not need to be adopted for straightening the trolley drill rod, equipment investment is reduced, and cost is reduced. Heat energy in cooling water can be extracted through the heat energy pump, heat energy recovery in the trolley drill rod isothermal quenching process is fully utilized, and the purpose of saving energy is achieved.

A method for preparing and using a high-carbon high-alloy steel isothermal quenching structure etchant, which belongs to the field of analysis and testing. It solves the problem that the existing Lepera etchant raw material picric acid is prohibited, and the conventional nitric acid alcohol etchant is difficult to efficiently and accurately etch and display the metallographic structure of high-carbon high-alloy steel after isothermal quenching. Preparation: A nitric acid alcohol solution with a volume fraction of 4% to 10% is mixed with a sodium metabisulfite solution with a mass fraction of 0.5% to 1%. Use: 1. Wire cutting sample preparation; 2. Grinding and polishing sample preparation; 3. Sample corrosion; 4. Metallographic structure observation. The present invention has low cost, convenient and safe operation, and no pollution; under the premise of ensuring safety, the etchant is used to achieve efficient and accurate observation, analysis and evaluation of the isothermal quenching structure of high-carbon high-alloy steel, so as to further evaluate the effectiveness of the isothermal quenching process; when used, it only takes 25 seconds to obtain an ideal tissue morphology. The present invention is suitable for metallographic etching of the isothermal quenching structure of high-carbon high-alloy steel.

The invention relates to the field of ferrous metallurgy, in particular to high-purity, high-homogeneity and fully-quenched GCr20MnMoRE rare earth bearing steel for a large cylindrical roller and a preparation method of the high-purity, high-homogeneity and fully-quenched GCr20MnMoRE rare earth bearing steel. The alloy comprises the following components in percentage by weight: 0.90 to 1.20 percent of C, 0.10 to 0.60 percent of Si, 0.60 to 1.20 percent of Mn, 1.60 to 2.20 percent of Cr, 0.40 to 1.0 percent of Mo, 0.10 to 0.50 percent of Ni, 0.005 to 0.020 percent of RE and the balance of Fe and inevitable impurities. According to the rare earth alloy steel for the large cylindrical roller, through RE + Mo co-alloying, molten steel purification and inclusion modification, liquation is avoided, and the hardenability is improved, so that network carbide, structure consistency and hardness uniformity are controlled. Moreover, the high-purity, high-homogeneity and full-through-quenching large cylindrical roller is obtained through the process technologies of purification smelting, rare earth deep deoxidation, airtight protection pouring, low-oxygen secondary remelting, high-temperature homogenization, uniform large deformation, forging rolling rapid cooling, efficient spheroidizing annealing, isothermal salt bath isothermal quenching, multiple gradient tempering and the like.

The application discloses a heat treatment method for improving the content of residual austenite of high-strength steel and improving low-temperature impact toughness, the quenching temperature is 830-870 DEG C, and the holding time is 10-30 min; the quenching furnace is set as follows: the steel plate heat transmittance of the heating section is 1.4-1.8 min / mm, the heating time is 1.4*h min, wherein h is the thickness of the steel plate, the target temperature of each section is lower than the quenching temperature by 70 DEG C, 50 DEG C, 20 DEG C and 0 DEG C; the quenching cooling process is as follows: after the austenitized steel plate is taken out from the quenching furnace, the steel plate is sent into a quenching machine to perform isothermal quenching, the quenching medium temperature is a constant temperature between 20 DEG C and 200 DEG C, the water amount ratio of each region of the quenching machine is set according to the following table parameters, the quenching machine roller speed is controlled to be 15-25 m / min, and the quenching end temperature is controlled to be 400-500 DEG C; and after quenching, the steel plate is transported to a cooling bed to be air-cooled to room temperature. The application solves the problems of high manufacturing cost and long delivery cycle of high-strength steel plates.

The application discloses a high-strength and high-toughness nodular cast iron crankshaft casting process, which comprises the following steps: step one, component optimization; step two, smelting and pretreatment; step three, spheroidizing and inoculation treatment; step four, pouring system design; step five, solidification control; step six, isothermal quenching; step seven, surface strengthening; step eight, finishing and detection; the application improves the hardenability by nickel element, forms upper bainite through isothermal quenching, combines three times of inoculation to refine graphite, and realizes the balance between strength and toughness. The stepped pouring system and the cold iron layout effectively eliminate shrinkage holes, and the process yield is increased to 75%. The ion nitriding and laser shock superposition significantly improve the surface hardness, wear resistance and fatigue strength, and meet the demand of high-load working conditions. Compared with forged steel crankshafts, the weight is reduced by 12%, the cost is saved by 35%, and the green manufacturing requirement is met.

This invention relates to the field of wear-resistant steel technology, and more specifically to a wear-resistant steel with both high hardness and excellent impact toughness, and its preparation method. To overcome the defects and shortcomings still existing in the current research and development of high-stress impact wear parts, the preparation method of this application includes repeated temperature control during smelting, casting, normalizing, isothermal quenching, and tempering. The resulting wear-resistant steel has the following chemical composition and mass percentages: C: 0.25-0.42%, Si: 1.0-2.0%, Mn: 0.8-1.5%, Cr: 1.2-1.6%, Ni: 0.5-1.0%, Mo: 0.3-0.5%, Cu: 0.4-0.7%, RE: 0.03-0.08%, P≤0.032%, S≤0.040%, with the balance being Fe and unavoidable impurities; and (Mn+Ni+Cu)≥2.0%. The method optimizes the alloy composition and rationally designs the isothermal quenching process below the Ms point, enabling the martensitic + metastable austenitic steel to maintain high hardness while retaining excellent toughness, overcoming the shortcomings of traditional technologies. Combining high hardness and excellent impact toughness, this martensitic wear-resistant steel exhibits better wear resistance under high stress than traditional water-quenched martensitic steel and isothermally quenched bainitic steel.

The invention discloses 15.8 grade ultrahigh strength delayed fracture resistant steel for fasteners and a manufacturing method of the 15.8 grade ultrahigh strength delayed fracture resistant steel. The 15.8 grade ultrahigh strength delayed fracture resistant steel comprises, by mass, 0.40%-0.50% of C, 0.15%-0.35% of Si, 0.50%-1.00% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.010% of S, 0.90%-1.20% of Cr, 0.10%-0.20% of Ni, 0.70%-0.90% of Mo, 0.20%-0.40% of V, 0.02%-0.08% of Nb, 0.010%-0.020% of Ti, 0.020%-0.040% of Al, 0.0040%-0.0080% of N and the balance Fe and inevitable impurity elements. The manufacturing process comprises the steps of converter smelting, LF refining, RH vacuum degassing, continuous casting, heating and cogging, flaw detection and coping, high-speed wire rolling, follow-up treatment and the like, a lower bainite structure is obtained after a wire rod is subjected to annealing, wire drawing, cold heading and isothermal quenching heat treatment, and the mechanical properties of the lower bainite structure are as follows: the tensile strength is 1500-1670 MPa, the yield strength is larger than or equal to 1200 MPa, the ductility is larger than or equal to 9%, and the percentage reduction of area is larger than or equal to 48%; and the material has excellent delayed fracture resistance, and is suitable for high-end fields such as aerospace, rail transit and the like.

The invention belongs to the technical field of metal material heat treatment, and particularly relates to Cu-containing high-carbon bainite complex-phase steel based on isothermal quenching and a preparation technology. The invention relates to a high-temperature-resistant steel plate, which comprises the following chemical components in percentage by mass: 0.65 to 0.70 percent of C; 1.80% to 1.90% of Si; 1.00% to 1.10% of Cr; 1.05% to 1.10% of Ni; cu: 0.52 to 1.12%; 0.38% to 0.42% of Mo; wherein the balance is Fe and inevitable impurities with the total amount smaller than 0.05%. The microstructure of the Cu-containing high-carbon bainite complex-phase steel comprises a superfine bainite ferrite batten, retained austenite and a dispersed epsilon-Cu precipitated phase, and the width of the bainite ferrite batten is smaller than 200 nm. The material adopts high carbon and high silicon, and the complex-phase bainite steel is prepared by austenitizing a steel billet and then carrying out isothermal quenching heat treatment at the temperature above the martensite transformation starting temperature. The Cu-containing high-carbon bainite complex-phase steel has the advantages of high strength, high hardness, good plasticity and good toughness in the aspect of mechanical properties, the preparation process is simple, and industrial production is easy.