60results about How to "Increase the residual compressive stress" patented technology

The invention provides a laser compound strengthening technology, which comprises the following steps of (1) carrying out femtosecond laser micro machining on a blade area of a hard alloy cutter, so as to obtain pits arranged in certain sequence; (2) carrying out laser shock peening in the blade area of the hard alloy cutter; (3) coating on the surface of the cutter after laser shock peening; and (4) carrying out laser shock wave microtexture forming process on the blade area of the coated hard alloy cutter, so as to obtain a laser compound strengthening model. The laser compound strengthening technology comprises four steps, namely, laser micro machining, laser chock peening, surface coating, and the laser shock wave microtexture. According to the laser compound strengthening technology, residual compressive stress, infiltration characteristic, heat transmission, cooling and lubricating conditions of the blade area can be obviously improved, built-up edges and burrs are reduced, and nickel base material is prevented from being attached to the surface of the cutter, so that the service life of the cutter is prolonged, and the stability of the manufacture quality is improved.

The invention provides a device and method for cavitation jet flow reinforcement of shaft parts. The device comprises a workpiece processing system, a high-pressure water supply system, a low-pressure water supply system, a reservoir and a nozzle device. The nozzle device is of a T-shaped structure, a through hole is formed in the central axis of the nozzle device, annular flow channels which communicate with high-pressure water holes are formed in the outer side of the through hole, a plurality of contraction flow channel layers uniformly distributed are arranged on the inner wall of the nozzle device, the contraction flow channel layers are provided with contraction flow channels uniformly distributed along the circumference, and the contraction flow channels communicate with the through hole and the annular flow channels. According to the device and the method, high-pressure water and low-pressure water are supplied to the annular flow channels and the through hole respectively, the contraction flow channels are made to generate cavitation bubbles, the surfaces of the shaft parts are reinforced by local ultrahigh pressure and high-strength shock waves generated when the cavitation bubble are collapsed, and external energy is prevented from being introduced so as to achieve the cavitation effect compared with laser cavitation reinforcement. The whole device system is simple in structure and beneficial to rapid reinforcement of long shaft parts.

The invention relates to a method to produce nitridation metal ceramics that belongs to ceramics material producing field. It adopts optimizing material ingredients, improving nitridation process technology, forming grads structure to improve hardness of the surface and inner tenacity. The ingredients of the metal ceramics is 29<=Tic<=45, 8<=Tin<=12, 28<=Ni<=32, 11<=Mo<=15, 7<=WC<=10, 0.5<=C<=1, 0.5<=NbC<=1. The process to produce is as following steps: first, mixing Tic powder and TiN powder to produce compound including millimicron grade of Ti(C, N) solid solution compound by mechanism alloying. Making the compound mixed with WC, NbC, Mo, Ni, C powder according to the previous ingredients, adding molding dosage for molding; degreasing, sintering and nitridation processing under high temperature and high pressure. The material has high hardness, high bending strength, HV>=2000 and DELTAbb>=1800Mpa. It can be used for cutting tools, drawing die and compression die.

The invention relates to a preparation method of a high-residual internal stress Ni-Mn-Ga magnetically-driven memory alloy film. The preparation method comprises the steps of: 1, preparing an Ni-Mn-Ga alloy target material: respectively taking 47 parts of Ni, 32 parts of Mn and 21 parts of Ga according to the mol part ratio for preparing materials, and preparing the target material by using a non-self-consumption vacuum arc furnace under the argon protection atmosphere; 2, cleaning a substrate; and 3, preparing an Ni-Mn-Ga film by using a high-vacuum magnetic control sputtering instrument: placing the target material prepared in the step 1 on the monocrystalline silicon substrate cleaned in the step 2, applying bias voltage on the substrate by using the high-vacuum magnetic control sputtering instrument to generate magnetic control sputtering, and preparing the Ni-Mn-Ga film. The Ni-Mn-Ga alloy film prepared by optimizing bias process parameters of the magnetic control sputtering substrate has high residual stress which can assist an external magnetic field to drive a martensite twin-plane boundary to move, thus the threshold value of the magnetic filed can be effectively reduced.

The invention discloses a high-frequency pulse current assisted surface shot blasting reinforcement machining device. The device is characterized by consisting of a surface shot blasting reinforcement device and a pulse power supply device; the surface shot blasting reinforcement device comprises a shot blasting chamber, a shot blasting mechanism mounted on the shot blasting chamber and used for blasting shots into the shot blasting chamber, and a workpiece clamping mechanism arranged in the shot blasting chamber and used for fixing workpieces; and the pulse power supply device is connected to the workpieces during shot blasting to apply pulse current on the workpieces. The invention further discloses a high-frequency pulse current assisted surface shot blasting reinforcement machining method; the method uses an electroplastic effect of high-frequency pulse current to improve the surface plasticity of such aviation parts as titanium alloys and aluminum alloys, to reduce the hardness, to improve the surface shot blasting reinforcement effect of the parts and to improve the wear resistance and the fatigue intensity of the aviation parts.

The invention relates to a novel spring pre-strengthening finishing composite shot blasting method. The method includes that a spring is subjected to pre-strengthening finishing composite shot blasting by a shot blasting machine, the pre-strengthening finishing composite shot blasting includes three processes, the shot blasting strength is 0.23Amm in the first process, the shot blasting strength is 0.45Amm in the second process, the shot blasting strength is 0.15Amm in the third process, and shot blasting mediums of three-time shot blasting are same to obtain a processed spring product. Compared with shot blasting methods in prior art, the novel spring pre-strengthening finishing composite shot blasting method has the advantages that the beneficial effect of residual compressive stress is increased, and negative influences caused by surface roughness of a part can be avoided to greatest degree.

The invention discloses a post-carburization surface strengthening method for a low-carbon steel part; the method strengthens the surface of the low-carbon steel part that is carburized by means of existing ultrahigh-pressure digital control water jet, i.e. mixed abrasive is charged into a mixing pipe through self-gravity and negative pressure that is produced by a high-speed water flow to mix with water, and the mixed abrasive accelerated by the water flow, in conjunction with the water flow, is sprayed from a nozzle to the surface of the part at a high speed; during spraying, steel pellets of high hardness provide high impact on the surface of a workpiece, whereas glass pellets of low hardness will partly break during spraying and mix with the water flow to produce liquid grinding action on the surface of the workpiece; therefore, after being strengthened by mixed abrasive jet blasting, the workpiece surface has higher residual pressure stress than that from traditional blasting and also has small surface roughness.

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

A fatigue resistant turbine through bolt formed from a base material covered by a first surface modification and a second surface modification is disclosed. The first surface modification may be in contact with the base material and, in at least one embodiment, may be a low plasticity burnished layer that increases the residual compressive stresses on an outer surface of the turbine through bolt. The second surface modification may cover the first surface modification and, in at least one embodiment, may be a spinel oxide layer on the low plasticity burnished layer. The second surface modification may be positioned on the first surface modification or on the bare turbine through bolt contact surface without low plastiocity burnishing on the shaft of the turbine through bolt. The first and second surface modifications reduce the likelihood of fretting fatigue failures.

The invention belongs to the technical field of ceramic materials, and particularly relates to preparation of pressureless sintering high-thermal-conductivity and high-strength aluminum nitride ceramic. The aluminum nitride ceramic is prepared by carrying out oxidation treatment on an aluminum nitride sintered body obtained by pressureless sintering, a compact oxide layer with a proper thickness can be formed on the surface of the aluminum nitride sintered body through proper oxidation treatment, the residual compressive stress in an aluminum nitride matrix can be increased through the formation of the oxide layer, and the change of the residual compressive stress is beneficial to preventing expansion of cracks in the aluminum nitride ceramic and reducing the contact thermal resistance ofan aluminum nitride grain boundary. According to the aluminum nitride ceramic provided by the invention, after oxidation treatment, the thermal conductivity can be improved to 185-210 W/(m.K), the bending strength is improved to 390-460 MPa, the dielectric constant is 9-10, the dielectric loss is 0.8*10<-3> to 2.4*10<-3>, and the application requirements of industries such as semiconductor devicesand integrated circuits can be met.

The invention provides a strain strengthening method for a high-temperature surface of magnesium alloy. The strain strengthening method comprises the following steps: (1) heating a material storage tank until a shot blasting medium reaches a required temperature; (2) after pressurizing air to be required pressure intensity by virtue of an air compressor, supplying air into a high-pressure air heating device through a conveying pipeline to obtain high-temperature and high-pressure gas; (3) heating a magnesium alloy sample to the required temperature; (4) blowing the shot blasting medium by virtue of high-temperature and high-pressure gas to hit the surface of the magnesium alloy sample. According to the strain strengthening method, the shot blasting is carried out by virtue of high-temperature and high-pressure gas, and the heating temperature of the magnesium alloy sample is between magnesium alloy aging temperature and a temperature which is 50 DEG C higher than the aging temperature, so that a starting non-basal slip system of the magnesium alloy sample is met, the plasticity of the magnesium alloy can be improved, the deformability can be improved, a relative high residual compressive stress is achieved, the stability of the residual stress can be improved, and the fatigue performance of the magnesium alloy can be improved; furthermore, a proper shot blasting window can be broadened, and the experimental operation is easily achieved.

A power transmission shaft having an improved strength and ensuring a stable torsion fatigue strength. The power transmission shaft has coupling members respectively provided on the opposite ends of an pipe part made of a steel material. The steel material includes 0.30-0.45% by weight of C, 0.05-0.35% by weight of Si, 1.0-2.0% by weight of Mn, 0.05% by weight or less of Al, 0.01% by weight or less of S, and the remainder (iron Fe and unavoidable impurities). The pipe part has an electro-unite portion that extends in the axial direction. The electro-unite portion and neighborhood thereof are hardened so as to have a Rockwell hardness HRC of 45 or more. Also, another power transmission shaft has coupling members integrally formed on opposite ends thereof. In addition, the shaft is formed from a steel element tube by a plastic working. The shaft has an inner diametrical surface which is subjected to a high-frequency induction hardening and tempering treatment to make the surface portion hardness of the inner diametrical surface to have a Rockwell hardness HRC of 35 or more.

In a method of making a high-pressure accumulator pipe as composite pipe of steel for pressures of up to 1800 bar and above with high static strength and fatigue strength for fuel injection systems with common rail systems for internal combustion engines, a first inner pipe part is inserted into a second outer pipe part with little clearance, and the inner pipe part is connected to the outer pipe part gap-free and by interference fit through mechanical forming. The mechanical forming includes a rolling-in process, wherein the inner pipe part is subjected to a ductile expansion and the outer pipe part is subjected to an elastic expansion using an oversized rolling tool that is moved within the inner pipe part, and wherein a residual compressive stress adjusted to the operating pressure is applied to the inner pipe part after the forming process via the elastic resilience of the outer pipe part.

The invention provides a composite surface treatment method for gear surface strengthening, and surface strengthening treatment can be conducted on wind power and automobile gears. According to the composite surface treatment method for gear surface strengthening, laser quenching treatment and shot blasting composite treatment are adopted, the problem of temper hardening caused by laser quenchingis avoided, meanwhile the residual compressive stress of a dedendum and the hardness value of a gear tooth surface are increased, and the gear surface performance is improved remarkably through the comprehensive coordinating effect of the residual compressive stress of the dedendum and the hardness values of the gear tooth surface.

The invention provides a self-lubricating-type ultrasonic rolling device with a micro-array structure on a tool head. According to the self-lubricating-type ultrasonic rolling device, the efficient transmission of ultrasonic amplitude and frequency between a rolling head and an amplitude variable rod can be realized, and ultrasonic deep rolling strengthening is carried out on a workpiece under a low friction state of the rolling head and the workpiece. The self-lubricating-type ultrasonic rolling device includes the assemblies such as a piezoelectric ceramic stack, the amplitude variable rod and various models of integrated micro-textured rolling heads. The rear end of the rolling head is processed into a screw thread to cooperate with the amplitude variable rod for integrated design, a micro-array structure is prefabricated at the front end part of the rolling head through laser, a self-lubricating material is embedded for polishing treatment, the sliding friction between the rollinghead and the workpiece during processing can be reduced, and a worn area of the rolling head is adhered to improve the tool service life and processing quality; and multiple models of the rolling heads are equipped, different models of the rolling heads can be selected according to difference of workpiece sizes, materials and processing requirements to achieve the best processing effects.