76 results about "Austempering" patented technology

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.

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 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.

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 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 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.

The invention relates to the technical field of horizontal continuous casting temperature control, in particular to a continuous casting control method for isothermal quenching ductile iron production, which comprises the following steps: acquiring the temperature of each preset position in a heating furnace in real time, and acquiring the heating power of the heating furnace and the temperature of a casting in real time; for the Smith predictor used for temperature control in the heat preservation stage in the austenitizing process and the isothermal quenching process, the time constant of a reference model in the Smith predictor is adjusted, and the temperature is controlled based on the adjusted Smith predictor; the process of adjusting the time constant comprises the following steps of: obtaining a temperature distribution factor, thermal response lag time and a power influence factor at each acquisition moment; and further obtaining a heat transfer compensation coefficient at each acquisition moment, and adjusting a time constant of a reference model in the Smith predictor. The invention aims to improve the accuracy of temperature control and avoid temperature fluctuation in the heat preservation stage.

The invention discloses a heat treatment process for improving hydrogen embrittlement resistance of advanced high-strength steel for an automobile, and particularly relates to the field of heat treatment. Comprising the following steps: homogenizing a steel ingot to obtain a steel billet; freely forging the steel blank to obtain a casting blank; performing hot rolling on the casting blank to obtain a hot-rolled steel plate; carrying out austenitizing treatment on the hot-rolled steel plate to obtain an austenitized steel plate, and carrying out isothermal quenching on the austenitized steel plate in a salt bath furnace; wherein in the austenitizing process, the temperature ranges from 900 DEG C to 1000 DEG C, and the heat preservation time ranges from 25 min to 35 min; in the isothermal quenching process, the temperature is lower than the Ms point, and the time is 6300-8700 s; and cooling the isothermal quenching steel plate to obtain the steel plate subjected to heat treatment. According to the method, variant distribution characteristics are regulated and controlled, hydrogen traps are increased, the local gathering degree of hydrogen is effectively reduced, and the hydrogen embrittlement resistance of the metal material can be fundamentally improved.

The invention belongs to the technical field of isothermal quenching cooling, and particularly relates to spheroidal graphite cast iron isothermal quenching cooling equipment and a using method thereof.The spheroidal graphite cast iron isothermal quenching cooling equipment comprises an isothermal box, bases, a guide rail frame, an oil sealing type cooling mechanism, a pressure storage type gas filtering mechanism and an inching type oil supplementing mechanism; the guide rail frames are symmetrically arranged on the inner walls of the two ends of the isothermal box in pairs, and the oil sealing type cooling mechanism comprises an oil supply mechanism, an isothermal mechanism, a material carrying mechanism and a box sealing mechanism. According to the spheroidal graphite cast iron isothermal quenching cooling equipment and the using method thereof, quenching oil consumed in the oil quenching process can be automatically supplemented according to the content of steam and organic waste gas released when the quenching oil makes contact with a high-temperature workpiece, and waste gas generated in the oil quenching process can be pressurized and adsorbed.

The application relates to the field of aluminum alloy materials, and provides a manufacturing method of a high-strength thin-wall aluminum alloy extrusion casting part, and aims to solve the problems of insufficient strength and large heat treatment deformation of the existing aluminum alloy extrusion casting part. The method adopts an Al-Si-Mg-Cu-Zn series casting alloy with a specific component proportion, and through steps of an optimized extrusion casting process, solid solution treatment, precooling treatment and isothermal quenching, an organizational structure containing 1.0-3.5 vol% Al5Mg8Si6Cu2 strengthening phase is formed, the strengthening phase forms a semi-coherent interface with a matrix during precipitation, and the mechanical properties of the casting are effectively improved. The casting prepared by the application has a tensile strength of greater than or equal to 368 MPa, a yield strength of greater than or equal to 316 MPa, and a flatness deviation of 0.1-0.25 mm / 100 mm, is suitable for manufacturing thin-wall structural parts with high requirements for high strength and high dimensional accuracy, and has a wide engineering application prospect.

The application discloses a kind of multilayer gradient heat treatment processes of hydraulic shears blade, belong to metal heat treatment technical field.The present heavy blade toughness mutual repulsion and subsurface easy peeling problem, the application includes the following steps: the whole preheating blade after pretreatment is heated to 900~920 DEG C;Through time sequence interlock logic control high frequency power supply, and combine dynamic coupling algorithm accurate control high-frequency pulse time, make blade cross section form from inside to outside austenite solid solubility level difference;Subsequently, high-pressure pure nitrogen pulse precooling is used, and is put into double-groove ladder nitrate bath with air transfer to carry out isothermal quenching, realize spatial staggered peak change;Finally, cryogenic and multiple gradient tempering are carried out.The application successfully builds triple microstructure gradient of high toughness self-tempering martensite in the heart, high alloy lower bainite in transition zone and surface ultrafine martensite in the blade, completely eliminates the structure stress mutation, greatly improves the service life and fatigue peeling resistance of the blade.

The invention relates to the technical field of alloy steel processing, in particular to high-bearing-capacity high-precision surface strengthened steel and a micro-deformation heat treatment process thereof, and the high-bearing-capacity high-precision surface strengthened steel comprises carbon, chromium, silicon, manganese, nitrogen, boron, oxygen, sulfur, phosphorus, nickel, molybdenum and other metal elements. According to the method, a semi-finished product is subjected to surface severe deformation microalloying treatment, surface carbonitriding treatment, isothermal quenching (including waste heat austenitizing, water isothermal quenching and deep cooling), acid pickling and blackening treatment, and the final product is obtained. By adopting the design of reducing the carbon content component, the core part of the bearing has higher toughness, and the surface has high strength and high hardness after surface carburization, so that a part product with good core part toughness and high surface strength is finally obtained. According to the technology, the deformation of a final product is extremely low, the precision is improved, and the subsequent machining procedure can be removed. The amount of retained austenite in the surface structure of the final product is less than 3%, the surface hardness is not less than 63 HRC, and the lowest hardness of the core part is not greater than 45 HRC.

This invention discloses a multi-layer gradient heat treatment process for hydraulic scissor blades, belonging to the field of metal heat treatment technology. Addressing the problems of strong-toughness mutual repulsion and easy subsurface spalling in existing heavy-duty blades, this invention includes the following steps: preheating the pretreated blade to 900-920℃; controlling the medium and high-frequency power supply through timing interlock logic and precisely controlling the high-frequency pulse time using a dynamic coupling algorithm, creating a gradient of austenite solid solubility from the inside to the outside of the blade cross-section; subsequently, precooling with high-pressure pure nitrogen pulses and isothermal quenching in a double-groove stepped nitrate bath with air transfer to achieve spatially staggered phase transformation; finally, deep cryogenic treatment and multiple gradient tempering. This invention successfully constructs a triple microstructure gradient within the blade: high-toughness self-tempered martensite in the core, high-alloy lower bainite in the transition zone, and ultrafine martensite on the surface, completely eliminating abrupt changes in microstructure stress and significantly improving the blade's service life and resistance to fatigue spalling.

This invention belongs to the field of metal heat treatment technology and discloses a heat treatment process for end-tooth gauges. First, 9CrWMn material is quenched and heated to a high temperature of 800–880°C. The quenching and holding time is determined based on the effective wall thickness of the end-tooth gauge and the heating equipment. Then, the quenched and held 9CrWMn material is rapidly transferred to isothermal quenching oil for isothermal quenching at a temperature of 190–230°C. After isothermal quenching, the 9CrWMn material is transferred to a cold environment for cooling for more than 2 hours. After cooling, the 9CrWMn material is returned to the isothermal quenching oil for tempering. The tempering oil temperature is the same as the isothermal quenching oil temperature in step two, and the tempering time is determined based on the effective wall thickness of the end-tooth gauge. Through the above process, 9CrWMn end tooth gauges with an effective wall thickness ≤40mm can be thoroughly quenched, with both the surface and core hardness ≥HRC62. At the same time, the parts do not crack during quenching. This invention can make the hardness of 9CrWMn after quenching reach up to HRC65~67, which can significantly improve the wear resistance and dimensional stability of the parts.

The invention discloses a casting process of a high-strength and high-toughness nodular cast iron crankshaft. The casting process comprises the following steps: step 1, optimizing components; step 2, smelting and pretreatment; step 3, spheroidizing and inoculation treatment; fourthly, a pouring system is designed; step 5, solidification control; step 6, isothermal quenching; step 7, surface strengthening; step 8, finishing and detecting; the hardenability is improved through the nickel element, upper bainite is formed through isothermal quenching, graphite is refined through three-time inoculation, and balance of strength and toughness is achieved. Shrinkage cavities are effectively eliminated through the stepped pouring system and the chilling block layout, and the process yield is increased to 75%. Ionic nitriding and laser shock are superposed, so that the surface hardness, the wear resistance and the fatigue strength are remarkably improved, and the requirements of high-load working conditions are met. And compared with a forged steel crankshaft, the weight is reduced by 12%, the cost is saved by 35%, and the green manufacturing requirement is met.

The invention discloses a heat treatment method for reducing decarburized layers and improving hardness of a 30CrMnSiNi2A alloy steel material, and the heat treatment method comprises the following steps: S1, placing a to-be-treated alloy steel material in a controllable atmosphere furnace, and carrying out purging treatment by adopting inert gas; s2, the controllable atmosphere furnace is started, isothermal quenching treatment is conducted on the alloy steel material, and inert gas is introduced in the heating stage and the heat preservation stage of isothermal quenching treatment correspondingly; s3, the quenched alloy steel material obtained after isothermal quenching treatment is transferred into a nitrate tank to be subjected to decarburization treatment; and S4, the decarburized alloy steel material obtained after decarburization treatment is placed in a tempering furnace to be subjected to tempering treatment. Compared with a traditional isothermal quenching process method, the heat treatment method disclosed by the invention not only reduces the thickness of an incompletely decarburized layer, but also remarkably improves the hardness value of the surface layer of the material and greatly improves the use performance of the 30CrMnSiNi2A alloy steel material under the condition of conforming to HB6735, so that the mechanical property requirement is met.