12results about How to "Improve flexural toughness" patented technology

The invention provides 1700MPa-grade hot-formed steel with high cold bending performance and a preparation method and application thereof. The surface layer of the hot-formed steel has a soft-phase ferrite structure, the secondary surface layer of the hot-formed steel has a mixed structure of soft-phase ferrite and martensite, and the core layer of the hot-formed steel has a carbon-poor martensite structure. The preparation method comprises any one or a combination of at least two of the following conditions: (A) the coiling temperature after hot rolling is 650-700 DEG C; (B) the pickling speed is less than or equal to 150m / min; (C) the continuous annealing temperature is 780-830 DEG C; (D) the atmosphere in the furnace is mixed gas of nitrogen and hydrogen; and (E) the dew point temperature is-35 DEG C to-17 DEG C. Through fine component design and process integration, the contradiction between the strength and the toughness of the material is successfully solved, double guarantee of high strength and high toughness is achieved, meanwhile, the requirement for light weight is met, and the competitiveness of an existing product is improved.

The application provides a 1700MPa-grade hot forming steel with high cold bending performance and a preparation method and application thereof. A surface layer of the hot forming steel has soft ferrite structure, a subsurface layer has mixed structure of soft ferrite and martensite, and a core layer has carbon-poor martensite structure. The preparation method comprises any one or a combination of at least two of the following conditions: (A) the coiling temperature after hot rolling is 650-700 DEG C; (B) the pickling speed is less than or equal to 150 m / min; (C) the temperature of continuous annealing is 780-830 DEG C; (D) the atmosphere in the furnace is a mixture of nitrogen and hydrogen; (E) the dew point temperature is-35 DEG C to-17 DEG C. Through fine component design and process integration, the application successfully solves the contradiction between material strength and toughness, realizes double guarantee of high strength and high toughness, simultaneously meets the light weight requirement, and improves the competitiveness of existing products.

The invention provides 1000 MPa grade hydrogen induced delayed cracking resistant plating-free hot forming steel which comprises the following components in percentage by mass: 0.06%-0.08% of C, 0.5%-1.0% of Mn, 0.3%-1.5% of Si, 0.08%-0.25% of Al, 0.012%-0.028% of Ti, 0.03%-0.25% of (Nb + V + Mo), 1.5%-3.0% of Cr, 0.005%-0.05% of (La + Ce), 0.0035%-0.0081% of N and the balance of Fe. The invention further provides a preparation method of the hot forming steel. According to the hot forming steel provided by the invention, through element selection and content control, the hot forming steel has good high-temperature oxidation resistance, relatively high bending toughness and relatively good hydrogen-induced delayed cracking resistance; and the preparation process of the hot-formed steel is short in flow, efficient and green.

The present application relates to the technical field of fiber reinforced geopolymer, and particularly discloses a fiber reinforced geopolymer and a drainage pipeline prepared from the same. The fiber reinforced geopolymer comprises mineral powder, fly ash, quartz sand, alkali activator, fiber, latex powder and rubber powder. The mineral powder and the fly ash are sequentially added, stirred at low speed, and mixed uniformly. While stirring, the fiber is slowly added and dry-stirred, then the quartz sand and the rubber powder are added, and water is added to stir uniformly. The latex powder is dissolved in water after being added, forms a coating layer to wrap the surface of the fiber or the geopolymer raw material, changes the interface characteristics of the fiber and the geopolymer matrix, slows down the occurrence of the polymerization reaction, makes the mechanical properties of the EGC material decrease, improves the interface bonding between the fiber and the geopolymer matrix, forms a structure of the synergistic effect of the fiber-latex powder-geopolymer matrix, increases the fracture energy of the fiber reinforced geopolymer, and improves the bending toughness of the fiber reinforced geopolymer.

The utility model discloses a widening structure for new and old bridges with large height difference, which relates to the field of widening transformation of old bridges and comprises a first bridge body and a second bridge body. The first bridge body embedded steel bars and the second bridge body embedded steel bars are embedded in the tops of the first bridge body and the second bridge body respectively; the first bridge floor cast-in-place layer and the second bridge floor cast-in-place layer are both poured at the top ends of the first bridge body and the second bridge body; the anchoring steel bars are embedded in the top of the second bridge body and located at the bottoms of the second bridge body embedded steel bars, the lightweight concrete precast blocks are arranged at the top end of the second bridge body, and the outer sides of the lightweight concrete precast blocks are matched with the second bridge body embedded steel bars and the anchoring steel bars correspondingly. The lightweight concrete leveling layer is reasonable and reliable in structure, the lightweight concrete precast blocks are adopted to replace a traditional concrete leveling layer, the weight is reduced by 30%-50%, the dead load of the newly-added leveling layer is controlled within 15% of the live load of an original bridge, and the influence on the original bridge structure is remarkably reduced.

The invention discloses a self-crosslinking type soft low-smoke halogen-free flame-retardant polyolefin cable material as well as a preparation method and application thereof. The cable material comprises the following raw materials in parts by weight: 30-40 parts of modified polyethylene; 30 to 40 parts of modified polypropylene; 25 to 35 parts of an ethylene-tetrafluoroethylene copolymer; 30-40 parts of a fuming inhibitor; 40 to 50 parts of a halogen-free flame retardant; 2-3 parts of a lubricant; 2-3 parts of a compatibilizer; and 7-11 parts of a thermoplastic elastomer. The flame-retardant and smoke-suppression effects are achieved through aluminum hydroxide at the initial stage of combustion, the thermal decomposition temperature of PE and PP materials can be remarkably reduced through magnesium hydroxide, meanwhile, the excellent carbonization and flame-retardant effects on polymers are achieved, an isolation belt for isolating fire can be formed through the heating expansion characteristic of pentaerythritol phosphate melamine salt, and the flame-retardant and smoke-suppression effects are achieved. And the phosphorylated linseed oil is used as a bio-based flame retardant, so that harmless treatment of harmful substances can be realized during combustion, and the fireproof performance of the cable is further improved.

The present invention relates to the technical field of electronic products, and discloses a plastic shell structure of an electronic product, including a plastic shell, wherein the number of the plastic shells is two and they are arranged left and right, a card slot is provided on the front of the plastic shell, a heat dissipation hole is provided on the front of the plastic shell and is located on the opposite side of the card slot, and a connecting transverse groove is provided on the opposite side of the two plastic shells. The plastic shell structure of the electronic product and the process improvement method are provided with an annular groove and an installation transverse groove. When protecting the electronic product, the two plastic shells are spliced ​​by using a connecting shaft column and an installation sleeve. During the splicing process, the connecting block on the connecting shaft column enters the interior of the installation sleeve along the installation transverse groove, and then the connecting shaft column is rotated to make the connecting block rotate into the annular groove at different positions for card connection, thereby changing the connection distance between the two plastic shells, facilitating the protection of electronic products of different sizes, and having higher applicability.

This invention discloses a high-toughness crack-resistant concrete and its preparation method, relating to the field of building materials technology. The high-toughness crack-resistant concrete includes cementitious materials, aggregates, water, admixtures, and reinforcing components. The reinforcing components include a multi-scale hybrid fiber system and a time-compensated shrinkage system. The multi-scale hybrid fiber system includes micro-scale high-modulus fibers and macro-scale crack-resistant fibers. The micro-scale high-modulus fibers are used to inhibit the initiation of cracks in the concrete matrix and induce crack refinement. In this invention, by setting up a multi-scale hybrid fiber system and utilizing the synergistic effect of micro-scale high-modulus fibers and macro-scale crack-resistant fibers, the entire process of concrete cracking is controlled. Due to their small diameter and large specific surface area, the micro-scale high-modulus fibers can be uniformly distributed in the concrete matrix, effectively inhibiting crack initiation and inducing crack refinement after crack formation.

The invention provides heat-shrinkable fiber web reinforced large-span box arch C80 high-toughness concrete and a preparation method thereof. Multi-scale toughening of the concrete for the large-span reinforced concrete box arch is achieved by designing the material composition and the structure, the proportion of C-A-S-H gel in gelling slurry is increased by optimally designing the raw material composition and the hydration process of a high-aluminum-phase gelling material, and toughening of a C80 concrete material on the nanoscale molecular scale is achieved; by utilizing the characteristic that heat-shrinkable fibers in a fiber reinforced material are reconstructed by hydration heat release molecules of a cementing material and generate shrinkage, by doping the heat-shrinkable fibers, applying uniform pre-compressive stress to the interior of the cementing slurry and doping CaCO3 whiskers, the toughening of the C80 concrete material on a micron scale is realized; by doping the copper-plated straight steel fibers and the multi-anchor-point steel fibers, the toughening of the C80 concrete material on the macroscopic scale is realized.

The present application discloses an impermeable concrete and a preparation process thereof, and relates to the field of concrete. The raw materials of an impermeable concrete include: 380-460 parts of cement, 120-200 parts of fly ash, 650-800 parts of sand, 1000-1200 parts of stone, 10-20 parts of water reducer, 50-70 parts of expansion agent, 50-65 parts of modified nano-silicon dioxide, 12-20 parts of composite fiber, and 140-200 parts of water; the modified nano-silicon dioxide raw materials include: 58-70 parts of nano-silicon dioxide, 12-18 parts of silane coupling agent, 2-5 parts of sodium silicate, and 180-240 parts of deionized water; the The composite fiber consists of modified polyvinyl alcohol fiber, glass fiber and steel fiber, wherein the modified polyvinyl alcohol fiber raw materials include 36-48 parts of polyvinyl alcohol fiber, 1.7-3.5 parts of dioctyl adipate, 3-5 parts of silane coupling agent, 45-68 parts of ethanol, 1-3 parts of sodium persulfate, 12-18 parts of alkyl acid polyoxyethylene ether, 35-49 parts of deionized water and 7-13 parts of polyethylene glycol; by modifying the nano-silica and polyvinyl alcohol fiber, the impermeability, crack resistance and freeze-thaw resistance of the concrete are further improved.

The invention belongs to the technical field of magnetic metal material preparation, and particularly relates to an iron-based amorphous alloy with low coercive force, high ductility and toughness and strong forming ability and a preparation method. The iron-based amorphous alloy has a general formula of Fe B C < c > S < d > P < e > M < f >, wherein M is V; 0 < = f < = 0.8; d > e; 0.13 < = b / a < = 0.17; d + e < = c; or 4.0 < = c + d + e < = 5.0. The saturation flux density of the iron-based amorphous alloy is larger than or equal to 1.66 T or the magnetic induction intensity B800 under the condition of 800 A / m is larger than or equal to 1.65 T, the coercive force after annealing is smaller than or equal to 1.0 A / m, and the iron-based amorphous alloy has high amorphous forming ability and bending toughness. The iron-based amorphous alloy provided by the invention has high saturation flux density, low coercive force and low iron loss. The iron-based amorphous alloy does not contain precious metal elements, easy-to-oxidize elements and high-melting-point elements, is low in cost, has low requirements on industrial equipment and is beneficial to industrial production.

The present application relates to the technical field of building materials, and in particular to a concrete material based on modified coral microcrystalline composite fiber and a preparation method thereof. The concrete material based on modified coral microcrystalline composite fiber comprises cementitious materials, coarse aggregate, fine aggregate, modified coral microcrystalline composite fiber, water reducing agent and mixing water. The modified coral microcrystalline composite fiber is prepared by wet spinning with modified coral microcrystalline and polyvinyl alcohol as raw materials. The modified coral microcrystalline is aragonite type calcium carbonate microcrystalline modified by a silane coupling agent. By adding the modified coral microcrystalline composite fiber to the concrete base material, the industry pain point of traditional fibers that are not toughened and not enhanced in compressive resistance is solved. The 28d splitting tensile strength, bending toughness and compressive strength of the prepared concrete material are simultaneously improved, and a comprehensive breakthrough in the mechanical properties of concrete is achieved.