1118 results about "Nitriding" patented technology

The invention discloses a high-strength and high-toughness aluminum nitride ceramic and a preparation method thereof, and relates to the technical field of ceramics, a sol-gel method is adopted to coat the surface of aluminum nitride with a stable shell layer to form a core-shell structure, meanwhile, the low lattice mismatch rate of a core-shell interface is utilized to reduce thermal resistance, and toughness and thermal conductivity are both considered; according to the external magnetic field tape casting method, the magnetic dipole moment orientation principle is utilized, an external magnetic field is applied in the tape casting stage, the in-plane mechanical property is improved, and the fracture toughness is improved through the magnetism of aluminum nitride whiskers; a reinforcement is introduced to improve the mechanical property and corrosion resistance of the aluminum nitride ceramic material, multi-granularity powder is compounded, large-particle aluminum nitride powder is used as a sintering and heat-conducting framework material, and high activity provided by submicron particles is utilized to promote sintering, so that the sintering temperature of aluminum nitride can be remarkably reduced, and the performance is greatly improved; and the aluminum nitride substrate expands more application fields on a future packaging circuit.

The invention belongs to the field of metal materials, and provides a hard alloy wear-resistant steel ball suitable for mine ore grinding and a preparation method thereof.The hard alloy wear-resistant steel ball is prepared from waste steel pig iron as a basic raw material and chemical components including 2.1%-2.2% of C, 9.8%-10.0% of Cr, 0.10%-0.20% of V and 0.03%-0.06% of Ti; a core-shell precipitated phase microstructure design with MN / MCN as a hard core and chromium carbonitride as a gradient self-passivation shell layer is formed through medium-frequency induction furnace smelting, controlled nitrogen introduction establishment of a V-Ti-C-N microalloy system, bottom pouring solidification and austenitizing quenching and tempering heat treatment processes, and the performance indexes that the surface hardness is HRC60-63 and the core hardness is HRC54-58 are achieved; the average particle size of a core-shell precipitated phase is in dispersed distribution of 20-200nm, the shell thickness is 5-50nm, and the alloy steel ball has excellent wear resistance and corrosion resistance under the high-impact and high-wear working conditions of wet ore grinding, solves the problem of insufficient wear resistance and corrosion resistance of a traditional alloy steel ball, and has wide mine ore grinding application value.

The invention relates to the technical field of stainless steel pneumatic cylinder barrels, and particularly discloses a wear-resistant stainless steel pipe for a pneumatic cylinder barrel and a preparation process thereof.The wear-resistant stainless steel pipe for the pneumatic cylinder barrel comprises the steps that firstly, a powder metallurgy method is adopted, tungsten carbide, cerium oxide, chromium nitride and other components are added into stainless steel powder, and the performance of a steel pipe base body is enhanced; the corrosion-resistant alloy layer is deposited on the surface of the steel pipe, so that the corrosion resistance, wear resistance and other properties of the steel pipe are enhanced, finally, a silicon nitride wear-resistant ceramic layer is sintered on the surface of the corrosion-resistant coating, and two lubricants of graphite and molybdenum sulfide are synthesized in gaps and holes of the wear-resistant ceramic layer. The defects on the ceramic surface are blocked; and the ceramic coating is endowed with a self-lubricating function.

The invention relates to the field of nitriding furnaces, in particular to an ammonia gas circulating system of a nitriding furnace, which comprises a furnace body, a furnace cover and a gas inlet mechanism, the furnace body is provided with a containing cavity, the furnace cover is connected to the furnace body and covers a cavity opening of the containing cavity, and the gas inlet mechanism comprises a gas inlet main pipe, an annular pipeline, an electromagnetic valve and a detection assembly, one end of the gas inlet main pipe is connected to the outer wall of the annular pipeline, the other end of the gas inlet main pipe is used for being connected with an external ammonia gas storage mechanism, the electromagnetic valves are connected to the annular pipeline, the other ends of the electromagnetic valves extend into the furnace body, the electromagnetic valves are circumferentially distributed around the axis of the annular pipeline at intervals, and the detection assembly is embedded in the containing cavity to control the electromagnetic valves to be opened and closed. External ammonia gas is conveyed to the annular pipeline through the gas inlet main pipe, then the ammonia gas is input into the furnace body through the multiple electromagnetic valves distributed around the axis of the annular pipeline in the circumferential direction at intervals, meanwhile, the detection assembly controls the electromagnetic valves to be opened and closed through the pressure intensity in the containing cavity, the ammonia gas introduced into the nitriding furnace is evenly distributed to all positions in the nitriding furnace, and the uniform nitriding effect is improved.

The invention discloses an electric engine assembly integral forming process based on precision integral casting, which comprises the following steps: designing a split type precision mold through computer aided design software, and carrying out nitriding treatment to improve the performance; selecting a specific aluminum alloy raw material, performing vacuum induction melting and refining, and injecting the aluminum alloy raw material into a preheated and sprayed mold cavity in a low-pressure casting manner; and demolding after air cooling and water cooling are combined, then after-treatment procedures such as deburring and heat treatment are conducted, and finally detection and assembly are conducted. A conformal cooling water channel design and an ultrasonic-assisted smelting technology are adopted in the process innovation, and the casting process is monitored in real time. According to the process, manufacturing procedures are reduced, compared with a traditional mode, the production efficiency is improved by 30%-50%, the cost is reduced by 20%-30%, the assembling problem is effectively avoided, the sealing performance and reliability of the electric engine are improved, the service life of the electric engine is prolonged, high integration is achieved, and the modern industrial requirement is met.

The present invention provides a steel sheet having high strength and high ductility, and a method for manufacturing the same.　The steel sheet has a specific component composition and a structure mainly composed of ferrite. The amount of N present as AlN and the total amount of N satisfy relational expression (1), and the amount of Nb present as Nb precipitates and the total amount of Nb satisfy relational expression (2). The yield strength is 500 MPa or greater, the HR30T hardness is 66 or greater, and the total elongation is 7.0% or more. (1): (Amount of N present as AlN) / (total amount of N) ≤ 0.40 The total amount of N is the amount of all N included in the steel sheet. (2): 0.10 ≤ (amount of Nb present as Nb precipitates) / (total amount of Nb) ≤ 0.80 The total amount of Nb is the amount of all Nb included in the steel sheet.

The invention provides a ceramic heating plate and a processing method of the ceramic heating plate. The machining method of the ceramic heating plate comprises the steps that the ceramic heating plate formed through normal-temperature isostatic pressing is prepared, the upper surface of the ceramic heating plate is made of aluminum nitride, at least an electrostatic adsorption metal wire mesh electrode is embedded in the ceramic heating plate, the process temperature of normal-temperature isostatic pressing forming is lower than 25 DEG C, and the process air pressure of normal-temperature isostatic pressing forming is lower than 200 Mpa; the process temperature of the high-temperature and high-pressure sintering is higher than 1500 DEG C, the process air pressure of the high-temperature and high-pressure sintering is higher than 100 Mpa, and the high-temperature and high-pressure sintering is used for avoiding the use of a binder or a ceramic layer spraying process, so that the heating temperature is increased, the sparking phenomenon of an equipment corrosive agent under high electrostatic adsorption voltage is avoided, and the service life of the equipment corrosive agent is prolonged. The service life of equipment is prolonged; and the safety performance of the process is improved.

The invention discloses a preparation method of angular aluminum nitride large-particle powder, which comprises the following steps: weighing raw material aluminum powder, aluminum nitride powder and a sintering aid according to a ratio, uniformly mixing, carrying out compression molding, carrying out combustion synthesis on a raw material blank in a high-pressure nitrogen atmosphere to obtain aluminum nitride ceramic, and crushing and screening to obtain the angular aluminum nitride large-particle powder of 20-200 mu m. According to the invention, one-step synthesis and sintering of aluminum nitride are realized by utilizing combustion reaction heat release of aluminum powder and nitrogen, the method has the characteristics of simple process and low preparation cost, and the prepared angular aluminum nitride large-particle powder can be used as a high-thermal-conductivity filler for electronic packaging.

The invention provides an ultra-low carbon duplex stainless steel all-position welding flux-cored wire and a welding method thereof.The outer skin of the flux-cored wire is a stainless steel strip, the flux-cored wire is filled with powder, and the powder comprises, by mass, 18-25% of natural rutile, 20-30% of stainless steel powder, 20-30% of stainless steel powder, 20-30% of stainless steel powder and the balance stainless steel powder. 3-5% of sodium titanate; 5-10% of quartz sand; 0.5 to 4 percent of zircon sand; 1-3% of sodium fluoride; 15 to 25 percent of ferromolybdenum; 3-6% of nitrided ferrochrome; 2-4% of electrolytic manganese; 5-8% of nickel powder; 27 to 32 percent of metal chromium; 0.5-2% of magnesium powder; 0.5 to 1.5 percent of bismuth oxide; and 1-4% of silicon iron. The flux-cored wire is used for all-position welding of third-generation duplex stainless steel, welding spatter is small, and weld joint forming is good; the carbon content of a weld joint is extremely low, and through component and welding process control, weld joint metal has strength, plasticity, toughness and corrosion resistance equivalent to those of base metal. And the double requirements of high strength and toughness and high corrosion resistance in the manufacturing fields of submarine pipeline laying, shipbuilding, marine gas field exploitation and the like are ensured.

The invention relates to the technical field of polishing, and particularly discloses a gallium nitride polishing method. The gallium nitride polishing method provided by the invention comprises the following steps: sequentially carrying out first-time polishing treatment and second-time polishing treatment on gallium nitride by using a first polishing solution, a first polishing pad, a second polishing solution and a second polishing pad to obtain polished gallium nitride. According to the method, the GaN surface is polished twice, the grinding material of the polishing solution and the type hardness trend of the polishing pad during the first polishing and the second polishing are limited, on the premise that the polishing rate is increased and the roughness of the GaN surface is reduced, the problem that micro cracks and internal cracks appear on the GaN surface after the GaN surface is treated through an existing polishing process is solved, and the quality of the GaN surface is improved. And the surface quality and the product percent of pass of GaN are greatly improved.

The invention provides a high-wear-resistance and low-dilution gas shielded welding wire and a preparation method thereof, and belongs to the technical field of welding wire manufacturing. The welding wire consists of the following raw materials in parts by weight: 45-52 parts of iron; 18-22 parts by weight of an electrolytic nickel plate; 6-8 parts by weight of high-purity molybdenum powder; 4-6 parts by weight of nano tungsten powder; 3-4.5 parts by weight of a vanadium nitride alloy; 1.2 to 1.8 parts by weight of a niobium-iron alloy; 0.8-1.5 parts by weight of aluminum magnesium alloy powder; 0.3 to 0.6 part by weight of lanthanum cerium mixed rare earth; 0.15 to 0.25 part by weight of ferroboron alloy; 0.5 to 0.8 part by weight of metal silicon powder; 0.2 to 0.4 part by weight of a magnesium-calcium alloy; and 0.1-0.3 part by weight of titanium hydride powder. The hard framework is formed through gradient distribution of carbides such as molybdenum, tungsten and vanadium, the wear-resisting life is remarkably prolonged, melting mixing of base metal is reduced through the nickel-based alloy, the consistency of deposited metal components is ensured, free hydrogen is fixed through hydrogen trap phases such as titanium and niobium, and a moisture absorption path is blocked in combination with a surface passivation film.

The invention discloses a high-strength stainless steel seamless steel pipe and a machining process thereof, and relates to the technical field of alloy treatment. The processing technology of the high-strength stainless steel seamless steel tube comprises the following steps: step 1, pretreating the stainless steel seamless steel tube to obtain a pretreated stainless steel seamless steel tube; 2, an ion nitriding process is adopted for conducting synchronous nitriding treatment on the inner pipe and the outer pipe of the pretreated stainless steel seamless steel pipe, and the nitrided stainless steel seamless steel pipe is obtained; and 3, the plasma spraying technology is adopted, the surfaces of the inner pipe and the outer pipe of the nitrided stainless steel seamless steel pipe are each coated with a compression-resistant protective layer, and the high-strength stainless steel seamless steel pipe is obtained through microwave treatment. Pretreatment, plasma nitriding treatment and plasma spraying treatment are sequentially conducted on the inner pipe and the outer pipe of the stainless steel seamless steel pipe with the specific component proportion, the compressive strength, the fatigue resistance and other performance of the inner pipe and the outer pipe of the stainless steel seamless steel pipe are synergistically enhanced, and the quality of the stainless steel seamless steel pipe is improved.

The present invention discloses a preparation method of a graphite-like carbon nitride-yttrium-stabilized zirconium oxide composite hydrogen barrier coating. First, a low-carbon steel substrate is pretreated to obtain a pretreated substrate; then zirconium n-propyl alcohol, n-propyl alcohol, acetylacetone and yttrium nitrate are mixed and reacted, aged to obtain a yttrium-stabilized zirconium oxide sol; the sol is coated on the pretreated substrate and dried, and the coating, drying and repeated treatments are followed by pre-sintering, followed by repeated coating, drying, and finally heat treatment to obtain a yttrium-stabilized zirconium oxide coating YSZ; melamine and thiourea are mixed, calcined and ground to obtain powdered graphite-like carbon nitride g-C3N4; finally, g-C3N4 powder and a coating coated with YSZ are sintered to obtain a graphite-like carbon nitride-yttrium-stabilized zirconium oxide g-C3N4 / YSZ composite coating. The hydrogen barrier coating prepared by the present invention can solve the problem that hydrogen embrittlement is prone to occur when current steel equipment is used in a hydrogen environment, and improve the safety of steel equipment during hydrogen energy utilization.

To provide an Fe-Ni-Cr alloy that can suppress intergranular cracking (nitriding resistance) and also inhibit the formation of red scale (oxidation resistance) even in a gas atmosphere containing nitrogen and water vapor, such as ammonia combustion gas, at a medium-high temperature range of 500 to 700°C.SOLUTION: The present invention relates to an Fe-Ni-Cr alloy that has a predetermined component composition, a nitriding resistance index of 81 or higher, and 3.0 or more of fine crystalline grains with a grain size of 0.5 μm or less present in the plate thickness direction in the alloy surface layer. The Fe-Ni-Cr alloy is obtained by introducing strain (transformation) on the surface of the alloy material by polishing or the like, then performing heat treatment, and generating fine crystalline grains using the introduced strain (transformation) as a driving force. Nitriding resistance index: Cr+3Ni-10Mo≥81.SELECTED DRAWING: None

The invention discloses high-toughness and high-thermal-conductivity aluminum nitride ceramic and a production process, and relates to the related field of aluminum nitride ceramic. Hexagonal boron nitride and Ti3SiC2 composite particles with the surfaces coated with titanium nitride are introduced into aluminum nitride ceramic, a cerium oxide sintering aid and a reasonable organic adding system are supplemented, synergistic improvement of thermal conductivity and toughness is achieved, Ti3SiC2 is subjected to TiN nanometer coating, interface stability and oxidation resistance are enhanced, combination of Ti3SiC2 and a matrix is improved, and the thermal conductivity and toughness of the aluminum nitride ceramic are improved. The fracture toughness and the mechanical strength of the ceramic are obviously improved; meanwhile, aluminum nitride and hexagonal boron nitride construct an efficient thermal conductivity network, so that the material keeps excellent thermal conductivity, the overall scheme is reasonable in structural design and scientific in component matching, and the obtained ceramic is high in density, high in thermal conductivity, excellent in mechanical property and high in thermal shock resistance.

The invention discloses a smelting process of a nickel-chromium-iron-based alloy, which comprises the following steps of: smelting and pouring a cast ingot by adopting an EAF (Electric Arc Furnace)-LF (Ladle Furnace)-VOD (Vacuum Oxygen Decarburization) furnace-LF (Ladle Furnace)-die casting process route, carrying out VOD vacuum oxygen decarburization by utilizing coarse smelting molten steel obtained by full scrap steel smelting in the electric arc furnace, and using nitrogen in the LF furnace to replace nitrided chromium iron to increase nitrogen. The desulfurization and deoxidation control parameters of each furnace are optimized, and finally the yield of Cr is controlled to be 99% or above and the yield of C is controlled to be 0.025% or below through a VOD oxygen blowing decarburization model; according to an LF furnace nitrogen increasing model, the nitrogen content of molten steel is accurately controlled, meanwhile, oxygen in the molten steel is controlled to be 0.003% or below, other chemical components meet the standard requirements, and the problem that the nickel-chromium-iron-based alloy is smelted through an electric arc furnace, and key elements cannot be accurately controlled is solved.

An aluminum nitride ceramic welding assembly comprises a first aluminum nitride ceramic piece, a second aluminum nitride ceramic piece and a third aluminum nitride ceramic piece, a second pin hole corresponding to the first pin hole is formed in the welding surface of the second aluminum nitride ceramic piece; two ends of the aluminum nitride ceramic positioning pin are respectively inserted into the first pin hole and the second pin hole; and the slurry layer containing rare earth oxide is arranged on the welding surface of the first aluminum nitride ceramic piece, and the distribution density of the rare earth oxide is gradually reduced from the position close to the first aluminum nitride ceramic piece to the position far away from the first aluminum nitride ceramic piece. High-temperature displacement errors are eliminated by means of cooperative positioning of pin holes in the first aluminum nitride ceramic piece and the second aluminum nitride ceramic piece and aluminum nitride ceramic positioning pins; and meanwhile, generation of brittle phases is inhibited by utilizing a form that the distribution density of rare earth oxides in the slurry layer is gradually reduced from near to far, so that the effects of a high-precision welding interface and joint strength enhancement are obtained, and the reliability and the service life of the aluminum nitride ceramic component are improved.

The invention discloses a preparation method of a high-hydrophobicity liquid lead bismuth alloy nitride coating capable of increasing a high-temperature contact angle, which comprises the following steps of: pretreating a substrate, depositing a FeCrAl coating on the surface of the substrate by adopting magnetron sputtering, and nitriding the FeCrAl coating to obtain a nitride coating; the invention further discloses the high-hydrophobicity liquid lead bismuth alloy nitride coating for improving the high-temperature contact angle. According to the preparation method, the FeCrAl coating is nitrided, so that the surface strength and corrosion resistance of the FeCrAl coating are improved, the formed FeCrAl nitride layer with a compact structure has high lyophobicity on the liquid lead bismuth alloy, the material surface is in a non-wetting state all the time, the liquid lead bismuth alloy can be effectively prevented from permeating into an alloy matrix, and the service life of the material is prolonged. The material is suitable for being used as a cladding material of a lead-cooled fast neutron reactor.

A preparation method for high-nitrogen austenitic stainless steel. The high-nitrogen austenitic stainless steel comprises the following chemical components in percentages by weight: carbon: ≤0.02%; silicon: 0.4-0.8%; manganese: 10.2-12.5%; chromium: 24.5-26.5%; nickel: 13.5-16.5%; molybdenum: 3.2-4.8%; nitrogen: 0.75-0.95%; phosphorus: ≤0.03%; sulfur: ≤0.0025%; vanadium: 0.016-0.022%; niobium: 0.026-0.034%; copper: 0.2-0.35%; aluminum: 0.01-0.02%; cerium: 0.015-0.025%; and the balance of iron and inevitable impurities. The preparation method comprises the steps of raw material charging, vacuum melting, refining, nitrogen-added alloying, deoxidation and desulfurization, casting, electroslag remelting, and secondary casting. The preparation is implemented by using the processes of smelting in a pressurized induction furnace and electroslag remelting under a protective atmosphere; and nitrogen is added by using a method in which a nitrogen alloy and pressurized nitrogen permeation are combined.

The resistance furnace comprises a base, a furnace body is fixedly installed on the upper end face of the base, two connecting plates are fixedly installed on the inner wall of the base, a sliding block is slidably installed between the two connecting plates through a sliding mechanism, and a toothed plate is fixedly installed on the bottom wall of the sliding block. A rotating shaft is rotationally installed in the base, a transmission motor connected with the rotating shaft is fixedly installed on the outer wall of the base, and the outer wall of the rotating shaft is connected with the toothed plate through a rotating mechanism. The hydraulic rod, the stirring shaft, the stirring blades and other assemblies are arranged, the hydraulic rod accurately controls the stirring shaft to ascend and descend, and the positions of the stirring blades can be flexibly adjusted according to the heating stage and the material amount. The stirring motor drives the stirring blades to stir, so that the limitation of heat transfer is broken, the uniformity of heat transfer is promoted, local overheating or insufficiency is avoided, the heating uniformity is improved, and the stable product quality is guaranteed.

The present invention discloses a method for the combined treatment of secondary aluminum ash by ball milling, sorting, low-temperature roasting and water washing and leaching, which belongs to the technical field of aluminum ash treatment. This technology uses screening to perform step-by-step screening on the secondary aluminum ash after ball milling to obtain secondary aluminum ash with three particle sizes: coarse, medium and fine. The medium-sized secondary aluminum ash is treated by low-temperature roasting, and the fine-sized secondary aluminum ash is treated by low-temperature roasting with a doped electrolytic aluminum electrolyte. After treatment, the medium-sized and fine-sized secondary aluminum ashes are washed and leached together with the coarse-sized secondary aluminum ashes to obtain harmless secondary aluminum ash and inorganic salts. The present invention fundamentally solves the safety risks brought by active substances such as aluminum nitride, aluminum carbide and inorganic salts in the secondary aluminum ash, and at the same time realizes the resource utilization of the secondary aluminum ash.

The invention discloses a 38CrMoAl material and a vacuum nitriding method, and relates to the field of nitriding processes of special-shaped parts, and the nitriding method comprises the steps that S1, after a 38CrMoAlA steel part is put into a furnace, the furnace is filled with air, heating is conducted, pre-oxidation is conducted, and a pre-oxidation workpiece is obtained; s2, vacuumizing, refilling nitrogen, and raising the temperature to a nitriding temperature; s3, after the temperature is increased to the nitriding temperature, ammonia cracking gas is introduced into the furnace for nitriding treatment; and S4, nitrogen removal. And the problem of furnace temperature uniformity in the vacuum nitriding process can be effectively improved. According to different nitriding stages, the concentration of nitrogen atoms in the furnace can be automatically and accurately controlled, the ammonia gas consumption is reduced, and the nitriding layer depth and the nitriding layer quality are improved.

The invention discloses a manufacturing method of an aluminum nitride copper-clad lining plate. The manufacturing method comprises the steps of laser cutting, protective film printing, by-product cleaning, solder printing, sintering, laminating exposure and development, copper etching, solder etching and plate splitting. By optimizing and integrating the process route, the aluminum nitride substrate with a'cutting seam 'does not need to be customized by a substrate supplier, so that the purchase cost is reduced; secondly, about 11% of solder printing is reduced, meanwhile, consumption of subsequent solder etching liquid medicine is reduced, and the manufacturing cost is reduced; the product area in contact with the alkaline liquid medicine is controlled on the cutting seam and the product surface within 10 microns of the edge of the cutting seam, so that adverse effects on the product are avoided; and the rubber discharging efficiency in the sintering stage is improved to a certain extent.

The invention relates to the technical field of thermal spraying and surface nitriding, in particular to a high-thermal-conductivity wear-resistant hot-corrosion-resistant high-entropy alloy coating with a multi-layer structure and a preparation method thereof, and the high-thermal-conductivity wear-resistant hot-corrosion-resistant high-entropy alloy coating comprises a first NiCr bonding layer, a second AlCoCrNiMo high-entropy alloy transition layer, a third AlCoCrNiMoBSi high-entropy alloy functional layer and a fourth nitriding modification layer. According to the method, the high-entropy alloy powder is prepared through step-by-step mechanical alloying and solid solution-aging treatment, and compared with a traditional method, the preparation process is remarkably simplified. Based on the inherent wear resistance and thermal corrosion resistance of the high-entropy alloy, a coating system with a gradient function is prepared by adopting an oxygen-kerosene supersonic flame spraying technology, and then a nitriding modified layer is formed through nitriding treatment. According to the multi-layer structural design, good transition and bonding strength between layers are achieved, meanwhile, excellent heat conduction performance is achieved, and the abrasion resistance and the heat corrosion resistance of the coating are remarkably improved.

Provided is a Ni-based alloy tube that can obtain sufficient nitridation resistance in a high-temperature ammonia environment. The Ni-based alloy tube according to the present disclosure has the chemical composition described in the specification, and the developed area ratio Sdr on the inner surface of the Ni-based alloy tube satisfies the formula (1). Cr / ((2.0 + 0.8×Fe + 6.0×Ti)×(1.5 + 10.0×Sdr)) ≧ 0.9 (1) Here, for each element symbol in the formula (1), the content in mass% of the corresponding element is substituted. When an element is not contained, "0" is substituted for the corresponding element symbol.

The invention relates to the technical field of bolt heat treatment, in particular to a wind power blade high-strength bolt heat treatment process which comprises the following steps: presetting a bolt heat treatment state, and performing impact treatment on the root of a bolt thread through a bolt heat treatment device to form a nanocrystalline layer; in the atmosphere of ammonia gas containing Ce-La mixed rare earth, three-section pulse type nitriding is carried out; and under the action of a transverse stable magnetic field, water-based atomized quenching liquid containing polyvinyl alcohol and graphene is adopted for gradient cooling. The method has the beneficial effects that through the synergistic effect of the multiple steps of surface mechanical nanocrystallization pretreatment, rare earth element gradient nitriding, magnetic field assisted gradient quenching, pulse current cryogenic composite tempering and the like, the comprehensive performance of the high-strength bolt of the wind power blade is remarkably improved through the technical scheme. And specifically, the surface hardness is greatly improved, meanwhile, good toughness of the core part is kept, the corrosion resistance of the bolt is remarkably improved, the fatigue life of the bolt is remarkably prolonged, and the service life of the bolt in an extreme marine environment is longer.

The invention provides a steel surface defect online detection method, device and system and a storage medium, and relates to the technical field of defect detection. The method comprises the following steps: acquiring a preset reference spot map; wherein the reference spot map is obtained by establishing a coordinate system for a first aluminum nitride spot image on the surface of a defect-free steel sample under a scanning electron microscope; after the target steel leaves the annealing furnace, generating raised aluminum nitride spots on the surface of the target steel through a pulse nitriding process by utilizing the residual temperature of the target steel; collecting a second aluminum nitride spot image on the surface of the target steel, converting the second aluminum nitride spot image into the coordinate system, and generating an online spot map; and taking the reference spot map as priori knowledge of a pre-trained defect identification model, inputting the online spot map into the defect identification model, and identifying the defect of the target steel. According to the invention, the interference of the steel surface condition and the image quality can be overcome, and the online detection accuracy and efficiency of the steel are improved.

The invention discloses a high-hardness high-thermal-conductivity gradient structure copper material which is composed of a base body and a surface layer combined on the surface of the base body, the base body is oxygen-free copper, and the surface layer is a copper boron nitride alloy composed of two phases of copper grains and a boron nitride film. The surface layer and the base body are metallurgically bonded; the boron nitride thin film in the copper boron nitride alloy is clamped between copper crystal grains to form a gradient distribution structure which is in a net shape to separate and wrap the copper crystal grains, and the boron nitride content of the gradient distribution structure is continuously reduced from the outside to the inside. The invention further discloses a preparation method of the copper material, oxygen-free copper serves as a substrate to form a base body in the copper material, copper-boron alloy with boron components distributed in a gradient mode is prepared on the surface of the oxygen-free copper substrate through laser additive manufacturing, then the copper-boron alloy on the surface of the oxygen-free copper is nitrided into copper-boron nitride alloy through nitriding treatment, and then the surface layer of the copper material is formed. And the composite copper material with high hardness and high thermal conductivity is obtained. The prepared copper material can meet the service requirements of the heat management industry on the wear resistance and the heat dissipation performance of components at the same time.

The invention discloses a high-alloy steel nitriding-laser quenching composite surface strengthening method which comprises the following steps: sequentially polishing the surface of high-alloy steel by using 240-mesh waterproof abrasive paper and 2000-mesh waterproof abrasive paper, then sequentially putting the high-alloy steel into ethanol and acetone for ultrasonic cleaning, and nitriding the pretreated high-alloy steel to form a nitriding layer; and cooling to room temperature along with the furnace under the atmosphere of nitrogen or ammonia gas to obtain the high alloy steel containing the nitriding layer. And blackening treatment is conducted in the atmosphere of argon or nitrogen, then laser quenching treatment is conducted, and high alloy steel surface strengthening treatment is completed. According to the nitriding-laser quenching composite surface strengthening process, the problems that a high alloy steel nitriding layer is shallow (smaller than 0.2 mm), interface brittleness is achieved, and the retained austenite content is high (larger than 20%) are effectively solved, the total treatment time is shorter than or equal to 16 h, the surface hardness of a modified layer is larger than or equal to 600 HV0.1, the thickness of the modified layer is larger than or equal to 1.5 mm, and the nitriding-laser quenching composite surface strengthening process is suitable for preparing key components such as aviation gears and heavy-duty bearings.

The invention discloses non-quenched and tempered steel for an automobile piston and a production process of the non-quenched and tempered steel. The steel comprises the following chemical components in percentage by weight: 0.37%-0.40% of C, 0.60%-0.75% of Si, 1.40%-1.50% of Mn, less than or equal to 0.025% of P, 0.020%-0.040% of S, 0.10%-0.20% of Cr, 0.012%-0.025% of Alt, 0.08%-0.13% of V, 0.015%-0.030% of Ti, less than or equal to 0.05% of Mo, less than or equal to 0.10% of Ni, less than or equal to 0.10% of Cu, 0.015%-0.020% of N and the balance of Fe and inevitable impurities, and the ratio of Alt to N is 0.6-1.0. The RH-LF process is innovatively developed, and stable control over the nitrogen content, zero blockage of a water gap and reduction of bending deformation of steel are achieved in cooperation with the manganese nitride alloy, nitrogen control through bottom blowing of nitrogen, the Ca alloying process and the rolling heat preservation process.