46results about How to "Guaranteed fatigue performance" patented technology

The invention discloses a heat treatment method for improving the high-temperature endurance property of a GH2132 bolt. The bolt is subjected to head forming and heading first and then subjected to solid solution treatment process; and afterwards, the processed bolt is subjected to two aging processes and finally processed to a finished product. The high-temperature endurance property of the bolt is improved sharply, and the fatigue life of the bolt can be guaranteed. According to the heat treatment method, the solid solution process and the two aging processes are adopted, so that the high-temperature endurance property of the GH2132 bolt is improved by a large margin, and the fatigue property and application security are ensured. The technical problem that grain size and high-temperature endurance cannot be guaranteed at the same time in conventional heat treatment production is accordingly solved successfully and therefore the heat treatment method can be popularized in the field of aero-engine GH2132 bolts.

The invention relates to an optimum design method of an entire grid beam. By use of the electron beam fuse deposition molding technology, the method specifically comprises the following steps: step one, optimizing a structure size of a component according to a grid beam structure design allowable value given by design input to obtain an optimized size parameter; step two, determining force directions of different sections according to the size parameter, and designing that a fiber placement path of each section of the component is consistent with the force direction in combination with the mechanics optimum of a fiber placement direction; step three, lowering stress concentration of a stress region higher than the design allowable value according to the design allowable value; step four, if the entire grid beam is the component with high length ratio and stiffness mutation, first dividing the entire grid beam into a plurality of sections to be synchronously molded, and then performing the centralized molding connection. By use of the optimum design method of the entire grid beam disclosed by the invention, the process feasibility of the entire grid beam based on the electron beam fuse deposition molding technology can be guaranteed, and the strength, rigidity, the life and other design requirements can be satisfied at the same time.

The invention discloses a method for preparing a rubber asphalt mixture. The method comprises the following steps: adding tyre rubber powder into the road petroleum asphalt, and carrying out the stirring and reaction for 45 to 120 minutes to prepare the rubber asphalt; and adding N,N'-ethidence dioleamide into the heated stone material in the mineral aggregate, stirring the mineral aggregate evenly, then adding the rubber asphalt into the mineral aggregate, and stirring the mixture evenly to obtain the composite modified rubber asphalt mixture finished product. The obtained rubber asphalt mixture can simultaneously improve the high temperature performance and bonding performance of the rubber asphalt mixture.

The invention discloses fine crystal non-quenched and tempered steel for a connecting rod and belongs to the technical field of special alloy steel. The fine crystal non-quenched and tempered steel is characterized by being prepared from the following elements in percentage by weight: 0.10-0.20% of (Ti+Nb), 0.35-0.45% of C, 0.60-0.70% of Si, 0.75-0.9% of Mn, 0.08-0.10% of P, 0.05-0.07% of S, 0.10-0.20% of Cr, 0.05-0.25% of V, 0.0005-0.001% of B and the balance of Fe. The metallographic structure of the alloy steel is upper bainite. On the premise that the expansion fatigue property of the connecting rod is ensured, the alloy steel is good in cutting processing property and expansion property.

The invention discloses a process for controlling an extreme upper-limit Mn content R350HT steel rail flash welding joint structure, and belongs to the technical field of steel rail flash welding. According to the process for controlling the extreme upper-limit Mn content R350HT steel rail flash welding joint structure, the technical problem that a martensitic structure is prone to being caused inan R350HT steel rail flash welding joint in the prior art is solved. The process comprises a welding process and post-welding treatment; in the welding process, the welding heat input is controlled to be 8.5-9.5 MJ pulsation or preheating flash welding, wherein the welding upsetting amount is 15.5-16.0 mm; and in the post-welding treatment, the joint is naturally cooled to 575-585 DEG C, then heat preservation is carried out and the joint is cooled to be less than or equal to 250 DEG C, and finally, the joint is naturally cooled to the room temperature. By comprehensively controlling the chemical components, a hot rolling process, the welding process and the post-welding cooling of a steel rail, abnormal structures, such as the martensitic structure, cannot exist in the steel rail flash welding joint, and the mechanical property of the joint is ensured at the same time.

The invention discloses a titanium alloy thin-wall structure precision milling surface state robustness process control method. The titanium alloy thin-wall structure precision milling surface state robustness process control method comprises the following steps of carrying out a titanium alloy milling test based on a primary milling process parameter range of a titanium alloy thin-wall structural member; measuring residual stress parameters, obtained by the milling test, of the titanium alloy thin-wall structural member; establishing a first relation model according to milling parameters and the residual stress parameters of the titanium alloy thin-wall structural member; maximizing the residual stress distribution envelope area in the first relation model as a target function and solving to obtain a milling robustness process parameter domain of the titanium alloy thin-wall structural member; and machining the titanium alloy thin-wall structural member based on the milling robustness process parameter domain. According to the method, the sudden change of the surface state of the structural member due to the action of uncontrollable factors in machining is compensated by adjusting the controllable process parameters, it is guaranteed that the fatigue performance of the structural member reaches the expected effect, and the size and form and position precision of the titanium alloy thin-wall structural member is improved.

The invention discloses a tough combined bridge deck composed of cold-bent Z-shaped steel. The tough combined bridge deck comprises cold-bent curled Z-shaped steel, transverse reinforcing steel bars and ultrahigh-toughness concrete. And the cold-bent Z-shaped steel is transversely and continuously placed along the bridge deck and forms bridge deck steel framework through fillet weld welding. The lower side flange of the cold-bent Z-shaped steel is long and plays a role in reinforcing the outer side of the plate surface; the upper side flange is short and is provided with a row of circular holes, and the transverse reinforcing steel bars penetrate through the cold-bent Z-shaped steel flanges through the circular holes. And the ultrahigh-toughness concrete is poured on the bridge deck steelskeleton to play a role in protecting the bridge deck steel skeleton. In the combined bridge deck slab system provided by the invention, the ultra-high toughness concrete can ensure that tiny cracks of below 100 microns are not generated or only generated, and the toughness and durability of the structure are improved; the construction mode of combining the cold-bent Z-shaped steel and the transverse reinforcing steel bars replaces the anti-shearing and anti-pulling effects of studs, meanwhile, the out-of-plane stability of the bridge deck slab is improved, the material cost and the construction complexity are remarkably reduced, and the fatigue performance is excellent.

The invention relates to a multi-station forming technology for a driven pulley piston of a CVT (Continuously Variable Transmission). The multi-station forming technology comprises the steps of S1, shearing a plate, S2, falling, S3, drawing, S4, upsetting and S5, shaping; in the step S1, a high-strength steel plate with a thickness of 5.5-6.5 mm is used as a raw material and subjected to spheroidizing annealing treatment; in the step S3, the drawing coefficient is 0.65-0.85; the step S3 comprises the following steps of S31, inner hole drawing, S32, outer circle drawing, and S33, step drawing;in the S31, a falling blank is subjected to inner hole drawing for many times to form a cap-shaped blank with a center hole; in the S32, the cap-shaped blank with the center hole is subjected to the outer circle drawing to obtain a first-stage stepped inverted cup-shaped blank; and in the S33, the outer circle of the top of a large-end barrel of the first-stage stepped inverted cup-shaped blank isdrawn to form a transition step to obtain a second-stage stepped inverted cup-shaped blank. The multi-station forming technology is suitable for the forming of the driven pulley piston of the CVT, has the characteristics of low material loss, simplicity in machining, reliable quality and light weight, and is easy to popularize and use.

The invention discloses a process for flash welding a medium control limit Mn content R350 HT steel rail with a joint structure, and belongs to the technical field of steel rail flash welding. By means of the process, the technical problem that a process in the prior art easily results in a martensite structure on an R350HT steel rail flash welding joint is solved. The process comprises a weldingprocess and post-welding treatment; in the welding process, the welding heat input is controlled to be 6.5-8.0 MJ pulsation or preheating flash welding, and the welding upset forging amount is 14.0-15.0 mm; and in the process of post-welding treatment, the joint is naturally cooled to 515-545 DEG C, is subjected to heat preservation, then cooled to less than or equal to 250 DEG C, and finally naturally cooled to room temperature. By comprehensively controlling the chemical components, the hot rolling process, the welding process and the post-welding cooling of the steel rail, no abnormal structures such as the martensite structures in the steel rail flash welding joint are guaranteed, and the mechanical property of the joint is ensured at the same time.

Disclosed is a vertical vibration isolation spherical steel support with lever assemblies. A lower support plate and a bottom support plate of the spherical steel support are arranged in the verticaldirection; retaining blocks are separately arranged on two sides of the bottom support plate; the side surfaces of the two retaining blocks are separately in contact with two sides of the lower support plate; the upper surface of a bottom plate of the bottom support plate is provided with lever fulcrum curved surfaces which are symmetric about an axis center line of the spherical steel support; the center of the bottom surface of the lower support plate is provided with two embedded curved surfaces which are symmetric about the axis center line of the spherical steel support; the two sets of lever assemblies are arranged in the space enclosed by the lower support plate and the bottom support plate; the two sets of lever assemblies are symmetrically arranged on two sides of the axis centerline of the spherical steel support; and each of the lever assemblies comprises a rotating block, a lever and an elastic body. By virtue of the lever principle, the levers and the elastic bodies, thevertical stiffness of the support is split into the compression stiffness of the elastic bodies through the levers so as to appropriately reduce the overall vertical stiffness of the support. The vertical fundamental frequency is far from the main frequency of the vibration of an upper structure of the support so as to realize the vertical vibration isolation function.

The invention provides a high-speed rail axle with a long fatigue life and a speed of not less than 400 kilometers per hour, and a laser quenching method of the high-speed rail axle. The method comprises the following steps: a quenching machine tool is vertical, the axle is vertically placed, a laser device is axially vertical to the axle, and the spot size is kept stable in a laser quenching process; a plurality of rows of gas nozzles are formed at different angles to ensure good and uniform cooling at an R-angle transition part of the axle; the depth H of a hardening layer is selected to be1.0-2.0mm, the laser output power P is 2000-8000W, the laser scanning speed is 500-1300mm/min, and the laser overlapping rate is controlled between 30% and 40%. Compared with the prior art, after theaxle is subjected to the heat treatment of normalizing, quenching and high-temperature tempering, laser quenching is carried out on the whole length of the axle, and after the laser quenching, the surface hardness is not less than 630 HV, the surface residual compressive stress exceeds -800 MPa, and the fatigue strength exceeds 690 MPa.

The invention relates to the field of steel rail welding, and discloses a method for regulating and controlling a microscopic structure of a steel rail welding joint. The method comprises the following steps that 1, an accelerated cooling device is used, water mist is adopted as a cooling medium, a to-be-cooled joint rail waist part obtained through flash welding is subjected to first-stage accelerated cooling, and meanwhile, the temperature of the center position of a welding seam of the joint rail waist is measured and monitored; 2, when the temperature is reduced to a first preset temperature, compressed air is adopted as a cooling medium to carry out second-stage accelerated cooling on the joint rail waist part, and meanwhile, the temperature of the center position of the welding seamof the joint rail waist is measured and continuously monitored; and 3, when the temperature is reduced to a second preset temperature, accelerated cooling is stopped, and then the joint is placed in air to be naturally cooled to the room temperature. According to the method, waste heat of the steel rail welding joint is utilized, so that abnormal structures such as intergranular cementite in a pearlite steel rail flash welding joint can be effectively ensured to be normal, and meanwhile, the hardness, the static bending performance and the like of the joint can be ensured to meet the use requirements.

The invention discloses a prefabricated assembly type toughness combined bridge deck slab with cast-in-place wet joints and a manufacturing method. The combined bridge deck slab is composed of profile steel combined prefabricated parts, prefabricated connecting parts, high-strength bolts and cast-in-place ultrahigh toughness concrete. In the section steel combined prefabricated parts, a bolt hole is formed in a flange of wide hot-rolled H-shaped steel, a transverse round steel bar is welded to a flange plate on the wide hot-rolled H-shaped steel, and ultrahigh-toughness concrete is poured after the high-strength bolts and screws are pre-embedded. In the prefabricated connecting parts, a bolt hole is formed in a flange of narrow hot-rolled H-shaped steel, and a transverse round steel bar is welded on a flange plate on the upper side of the narrow hot-rolled H-shaped steel. In the construction process, the section steel combined prefabricated parts and the prefabricated connecting parts are arranged side by side at intervals, the prefabricated parts are connected into a whole through the high-strength bolts, and the ultrahigh-toughness concrete is cast in situ on the upper portions of the prefabricated connecting parts, so that the cast-in-situ wet joints are formed. The system provided by the invention has the advantages of high toughness, high prefabrication degree, no need of arrangement of studs, no need of field welding, low cast-in-place concrete proportion, convenience in construction and remarkable improvement of structural fatigue performance.