86results about How to "Avoid fatigue cracking" patented technology

A multiplex fluid pump assembled from a plurality of pump bodies connected side by side between opposing end plates with a plurality of fasteners tightened to compress the pump bodies between the end plates. Raised surfaces on opposite exterior side surfaces of each pump body are engaged with an adjacent end plate or an adjacent pump body to apply a pre-compressive force at the raised surfaces and thereby inhibit the initiation of fatigue cracks.

The invention provides a method of cooling a rail weld zone. The method includes a first rail web portion cooling process of cooling a rail web portion cooling region of the rail weld zone in a part of a temperature range until the completion of transformation from austenite to pearlite, a second rail web portion cooling process of cooling the rail web portion cooling region after the entire rail web portion of the rail weld zone is transformed to pearlite, a foot portion cooling process of cooling a foot portion of the rail weld zone, and a head portion cooling process of cooling a head portion of the rail weld zone. When cooling time of the first and second rail web portion cooling processes is t minute, a k value satisfies an expression represented as −0.1t+0.63≦k≦−0.1t+2.33.

The invention provides a two-sided welding method for a U-shaped ribbed slab unit welding seam. The two-sided welding method comprises the following steps: cleaning the welding surface of a piece to be welded; placing a U-shaped rib on the surface of the piece to be welded, wherein an assembly groove is formed between the end part of a U-shaped ribbed web plate and the surface of the piece to be welded, and the groove angle is 50-60 degrees; carrying out positioning welding on the U-shaped rib and the piece to be welded in the horizontal position to obtain a U-shaped ribbed slab unit; welding a fillet welding seam at the jointing position of the inner side of the U-shaped ribbed web plate and the piece to be welded; and placing the U-shaped ribbed slab unit welded with the fillet welding seam on an anti-deformation slanting tension bed to carry out welding of an outer side welding seam, wherein a process of twin-wire submerged arc welding with single power supply is adopted. According to the two-sided welding method, a jointing welding seam between the U-shaped rib and the piece to be welded is changed into a two-sided fillet welding seam form from a single-sided fillet welding seam form in the prior art, so that stress amplitudes at a weld root and a weld toe are greatly lowered, the problem of initiation of fatigue cracks of the welding seam at the weld root is solved, and the fatigue performance at the weld toe is also improved.

A threaded pipe connector, including: a pipe body including an external thread on one end; and a coupling including an internal thread on a corresponding end. Both the external thread and the internal thread are buttress threads capable of matching with each other. A ratio of thread height to pitch is 0.25-0.35, bearing surface angle is −15-3°, and guide surface angle is 10-50°. A clearance is provided between a thread crest and a thread root after engagement of the external and internal threads. A sealing area between the pipe body and the coupling includes in sequence a first cylindrical transitional area, a cylindrical sealing area, a secondary cylindrical transitional area, a conical sealing area, and a conical transitional area. Tapers of both sides of the conical sealing area are the same. One end of the conical transitional area is connected with a torque shoulder.

The invention discloses a molten Al—Si alloy corrosion resistant composite coating and a preparation method and application thereof. The composite coating layer comprises an aluminized layer and a TiO₂ thin film layer from the surface of a basal body to the external in sequence. The preparation method of the coating layer comprises the following steps: (S1) the surface of a Fe-based alloy is treated; and then, a solid powder permeating agent is adopted to permeate aluminum; (S2) sand-blasting the aluminized Fe-based alloy; (S3) the Fe-based alloy is washed and dried after sand blasting; and (S4) a TiO₂ thin film layer is deposited on the surface of the dried aluminized Fe-based alloy by adopting an atomic layer vapor deposition method.

The invention reLates to a steeL-UHPC combination beam for a cabLe-stayed bridge. The combination beam comprises two main LongitudinaL beam bodies arranged in paraLLeL, two or more horizontaL beam bodies connected with the main LongitudinaL beam bodies and two or more UHPC prefabricated pLates, and aLL the horizontaL beam bodies are LongitudinaLLy and evenLy distributed between the two LongitudinaL beam bodies; the middLes of the adjacent horizontaL beam bodies are connected with middLe LongitudinaL beam bodies, the main LongitudinaL beam bodies, the middLe LongitudinaL beam bodies and the twoadjacent horizontaL beam bodies are matched to form a steeL beam grid, and the prefabricated pLates are erected on the steeL beam grid; LongitudinaL UHPC cast-in-situ bands are arranged on the main LongitudinaL beam bodies and the middLe LongitudinaL beam bodies, horizontaL UHPC cast-in-situ bands are arranged on the horizontaL beam bodies, and cast-in-situ band reinforcements and shear parts arearranged in aLL the cast-in-situ bands; prefabricated pLate reinforcements are arranged in the prefabricated pLates, the two ends of each prefabricated pLate reinforcement extend out of the corresponding prefabricated pLate and are connected with the corresponding cast-in-situ band reinforcements, and the shear parts are connected with the corresponding steeL beam bodies. A construction method ofthe combination beam comprises the steps of machining of steeL components and prefabricated pLates and the Like. The combination beam is good in performance, Low in construction cost, high in construction condition adaptabiLity and beneficiaL to Larger-span deveLopment of the cabLe-stayed bridge.

The invention discloses a high-chromium-steel supporting roller and a preparing method thereof. The method includes: a first step of material preparation, namely a step of preparing outer layer high-chromium molten steel of the supporting roller and center globular graphite molten iron of the supporting roller; a step of centrifugal pressure casting, namely a step of performing centrifugal pressure casting by adoption of a centrifugal roller mold, with the inner diameter of the centrifugal roller mold being 560-900 mm, maintaining the temperature (for a period of time), and unpacking to obtain a supporting roller workblank; and a step of subjecting the supporting roller workblank to thermal processing. By addition of V and Nb which are alloy elements to the outer layer casting molten steel, surface hardness of the supporting roller is uniform (not more than 1.0/1.5 degree), and can reach 50-65 HSD according to demands of users. By adding a BaCa nucleating agent improving the balling degree into the center globular graphite molten iron, the tensile strength of a roller neck is not less than 550 MPa. Accordingly, the high-chromium-steel supporting roller is extremely high in abrasion resistance and high in toughness and thermal fatigue resistance, and the accidents of fatigue cracks, peeling and falling on both sides of the roller body during operation of the supporting roller are almost avoided.

The invention discloses a railway vehicle chassis with a large-section draft, bolster and buffer structure. The railway vehicle chassis comprises a draft bolster buffer, a front end beam, a left side beam, a right side beam and a floor, the draft bolster buffer comprises a small draft sill, a buffer beam, a large draft sill and a bolster, the floor comprises an in-pillow floor, an out-pillow left floor, an out-pillow right floor, an end floor, a middle cover plate and a floor transition sectional material, the front end beam is connected with the left side beam, the right side beam and the small draft sill, the end floor is erected on the left side beam and the right side beam, the middle cover plate is erected on the large draft sill, the out-pillow left floor is erected on the large draft sill and the left side beam, the out-pillow right floor is erected on the large draft sill and the right side beam, the floor transition sectional material is erected on the bolster, the in-pillow floor is connected to the floor transition sectional material in an inserted mode, the in-pillow floor is erected on the left side beam and the right side beam, and the upper surfaces of the buffer beam, the large draft sill and the bolster are flush with the upper surface of the floor. The structural strength is improved.

The invention discloses a wheel of a motor vehicle. The wheel comprises a wheel spoke and a wheel rim which is arranged around the wheel spoke and fixedly connected with the wheel spoke, wherein a plurality of first reinforcing bodies are bulged on a fixed part of the wheel spoke and formed by bulging towards the outer side of the wheel spoke; heat dissipation holes are formed in the first reinforcing bodies; screw cap bases are bulged on the fixed part of the wheel spoke; a plurality of second reinforcing bodies are bulged on the fixed part of the wheel spoke and connected with the screw cap bases; the screw cap bases and the second reinforcing bodies are formed by bulging towards the outer side of the wheel spoke; the first reinforcing bodies and the second reinforcing bodies extend in the radial direction of the wheel spoke; and the plurality of the first reinforcing bodies and the plurality of the second reinforcing bodies are distributed at intervals in the circumferential direction of the wheel spoke. The wheel of the motor vehicle is good in work stability and long in service life.

The invention discloses a wave-preventing device of railway liquid tank car, which has a pair of longitudinal wave-preventing boards which are symmetrically arranged on the inside top of a tank body so as to longitudinally divide the inside top of the tank body into three portions; two sides of the pair of longitudinal wave-preventing boards are symmetrically provided with a plurality of transverse wave-preventing boards and a plurality of transverse middle-dividing boards are arranged between the pair of the longitudinal wave-preventing boards so as to longitudinally and transversely divide the inside top of the tank body into a plurality of chambers; and the longitudinal wave-preventing boards and the transverse wave-preventing boards are integrated with the inside top of the tank body via corresponding supplementary boards. The wave-preventing device can effectively improve dynamics performance of the car, ensure traveling safety, prolong the service life of the car and facilitate the maintenance and the washing for the tank body, and is suitable for the tank car carrying various liquid media.

The invention provides a municipal road reconstruction engineering asphalt pavement lap joint construction method and a lap joint structure. The lap joint construction method comprises the following steps that the edge of an old road surface is milled into a stepped structure, and all layers of milled surfaces are cleaned; all old pavement step layers of the old pavement are sequentially treated according to a first preset mode, and the first preset mode comprises the steps that gravels are laid on one sides of the old pavement step layers to form gravel base layers, after the gravel base layers are rolled, the gravel base layers are maintained, and floating ash and impurities on the surfaces of the gravel base layers are removed; the old asphalt step layers of the current asphalt pavementare sequentially treated according to a second preset mode, and the second preset mode comprises the steps that asphalt concrete is laid on one sides of the old asphalt step layers to form an asphaltconcrete base layer, the asphalt concrete base layer is rolled, and then the surface of the asphalt concrete base layer is cleaned. According to the invention, the new and old asphalt pavement structures are combined and broadened, so that differential settlement and reflection cracks at the joint of the new and old asphalt pavement structures are reduced.

The invention relates to a vehicle tire, especially utility vehicle tire, comprising a tread which has a tread cap (9) and a tread base (8), both produced from a rubber mixture, and a multilayer ply structure (3, 4, 5, 6) with at least one undertread strip (7, 7') covering the ply edges and separating the same from the tread base, said undertread strip being likewise produced from a rubber mixture. The aim of the invention is to reduce temperature and heat build-up in the area of the ply edges. For this purpose, the tread base (8) has a heat conductivity that is by at least 20 % higher than that of the tread cap (9) and a heat conductivity that is by at least 10 % higher than that of the one or more undertread strips (7, 7'), and the tread base (8) contains at least 25 phr of acetylene black.

A fiber reinforced composite, a component for a wind turbine and a method for manufacturing a component for a wind turbine are provided. The fiber reinforced composite includes a plurality of first fibers, the first fibers being arranged in a unidirectional or biax-configuration, a plurality of second fibers, the second fibers being arranged perpendicularly with respect to a lengthwise direction of the first fibers, and a resin impregnating the first and second fibers, wherein a E-modulus of the resin equals an E-modulus of the second fibers. Since the E-modulus of the resin and the E-modulus of the second fibers are equal, an early initiation of fatigue cracks is avoided.

The invention discloses a steel slag semi-flexible composite pavement structure. The pavement structure sequentially comprises an asphalt concrete surface layer, a steel slag semi-flexible layer, a three-dimensional porous material layer, an old cement board layer subjected to fragmentation and a steel slag base layer from top to bottom, wherein the asphalt concrete surface layer is provided witha structure depth; glass beads loaded with nano titanium dioxide are embedded in the structure depth; three-dimensional communication structures are formed among pores of the three-dimensional porousmaterial, wherein the communication porosity is 50-99%, and the pore diameter is 0.1-20 mm; a specific composite structure layer is adopted, therefore, the shrinkage caused by cooling is relatively small, and relatively small temperature stress is generated to avoid temperature cracks; meanwhile, through interaction of different structural layers of all the layers, mutual tensile stress exists among all the layers, and fatigue cracking can be relieved by combining with use of specific functional materials; and the steel slag semi-flexible composite pavement has excellent high-temperature stability, low-temperature crack resistance, fatigue durability and water stability.

The invention belongs to the technical field of forged aluminum alloy, and particularly relates to an anti-fatigue and corrosion-resistant forged Al-Mg-Si-Zr aluminum alloy wheel and a preparation method thereof. The aluminum alloy wheel is composed of Si, Mg, Cu, Fe, Mn, Cr, Ti, Zr and the balance Al. The aluminum alloy material is forged by optimizing alloy components, carrying out graded homogenization treatment on a cast rod and adopting an optimized aluminum rod heating process and a solid solution and aging process after die forging, the fatigue performance can be circulated for about 7 * 107 weeks under the pressure of 200 Mpa, and the stripping corrosion resistance reaches the PA level. In addition, the tumbling process and the surface treatment process are added, the fatigue resistance and the corrosion resistance of the aluminum alloy wheel are further enhanced, the requirement of a wheel biaxial fatigue test is met, and the requirement of an international first-class main engine plant is met.