349results about How to "Improve high temperature mechanical properties" patented technology

The invention relates to a secondary cooling method for reducing transverse cracks of corners of a microalloy sheet billet, which is characterized in that the cooling temperature of a casting blank is facilitated to reach a temperature for starting the transformation from gamma to alpha by controlling the secondary cooling speed at an earlier stage when the casting blank passes through a vertical section after being delivered out of a crystallizer; at the later stage, the cooling water quantity of the casting blank is reduced, potential heat produced by the solidification of the casting piece is used for reheating the casting piece, and the reheating temperature is controlled to make the casting blank reach more than an austenite phase changing temperature when the casting piece is delivered out of the vertical section; the entire process is under the transformation of gamma to alpha to gamma, so that crystal grains of a final transformation product are smaller; and after the casting blank leaves the vertical section, the casting blank enters the subsequent secondary cooling area in a slowly cooling mode. By optimizing the continuous-casting billet cooling mode, the crystal grains are refined, and second-phase particles in the steel are controlled, so that the high-temperature mechanical property of the casting blank can be improved, simpleness in operation is realized, and the transverse cranks on the surface of the casting blank can be effectively reduced.

The invention relates to a high-performance tungsten / steel composite material based on high-temperature application and a preparation method thereof and belongs to the technical field of preparation of composite materials. By adoption of the high-performance tungsten / steel composite material, the problems of large residual joint stress, low strength, poor heat resistance and high connection temperature in an existing tungsten / steel connector are solved. The high-performance tungsten / steel composite material is prepared from a tungsten-based layer, a titanium layer, a niobium layer, a nickle layer and a steel-based layer which are arranged in sequence and prepared by adopting a welding method. The high-performance tungsten / steel composite material is obtained by superposing the tungsten-based layer, the titanium layer, the niobium layer, the nickle layer and the steel-based layer in sequence according to the superposition mode of the tungsten-based layer, the titanium layer, the niobium layer, the nickle layer and the steel-based layer and carrying out vacuum diffusion bonding. The high-performance tungsten / steel composite material has the advantages that the room-temperature tensile strength is larger than or equal to 352MPa, and the tensile strength at the temperature of 650DEG C is larger than or equal to 338MPa; the structure design is reasonable, the process is simple, the large-scale application is convenient, and simultaneously, the high-performance tungsten / steel composite material can be widely applied in diffusion bonding of refractory metal and other dissimilar metal materials.

The invention discloses ZrB2-SiC composite powder and a preparation method thereof. According to the invention, zircon sand, a boron raw material and a carbon raw material are adopted as main materials. The main materials are mixed, grinded, and are heated under a temperature of 1350 to 1480 DEG C, such that the powder is obtained. The powder comprises components of, by weight: 37 to 63% of ZrSiO4, 16 to 32% of B2O3, and 20 to 28% of C, wherein the boron raw material is calculated according to the amount of B2O3, and the carbon raw material is calculated according to the amount of C element. According to the invention, natural zircon sand with a relatively low price is used as a raw material for producing high-grade ZrB2-SiC. The advantages of ZrB2 and SiC are combined. Mutual complement of advantages can be realized when ZrB2 and SiC are used in the field of high-temperature materials. ZrB2-SiC provides relatively high thermal conductivity, excellent thermal shock resistance and corrosion resistance. When ZrB2-SiC is introduced into the composite powder, high-temperature mechanical properties, oxidative stabilities and corrosion resistances of ultra-high temperature ceramics and refractory materials can be improved.

The invention discloses austenite stainless steel comprising, by weight: C <=0.08%, Si 0.20%-0.70%, Mn 0.50%-1.50%, Ni 19.00%-22.00%, Cr 23.00%-25.00%, Mo 2.65%-2.88%, P <0.005%, S <0.005% and Co < 0.01%. The rest is Fe and impurities. The invention also discloses a manufacturing technology of the above-mentioned austenite stainless steel. The stainless steel of this invention has good creeping performance, oxidation performance, corrosion performance and so on. The stainless steel has good neutron economic performance and cost economic performance. The stainless steel has good anti-neutron void swelling performance, can meet the application needs of SCWR fuel canning or reactor internals, and can provide candidate materials for SCWR. In addition, the stainless steel can also meet the needs of constantly enhanced nuclear reactor temperature, safety and economy.

The invention relates to a light-weight corundum-magnesia alumina spinel refractory material and a preparation method of same, wherein porous corundum-magnesia alumina spinel ceramic material granules are used as an aggregate, wherein ceramic material being 3-5 mm in granular size accounts for 10-18 wt%, ceramic material being 1-2.8 mm in granular size accounts for 25-30 wt%, and ceramic material being 0.1-0.8 mm in granular size accounts for 15-20 wt%; a substrate includes 12-18 wt% of porous corundum-magnesia alumina spinel ceramic material fine powder with nano-scale pore diameter, 12-20 wt% of corundum fine powder, 2-5 wt% of magnesite fine powder and 3-8 wt% of alpha-Al2O3 micropowder. The preparation method includes the steps of: 1) placing the aggregate in a vacuum stirrer, vacuumizing the stirrer, and adding a magnesium chloride solution which accounts for 3-8 wt% of the total weight of the aggregate and the substrate, stirring the mixture, and turning off the vacuumizing system; 2) adding the substrate, stirring the materials, shaping and drying the materials, and performing temperature maintenance at 1450-1650 DEG C, cooling the material to produce the refractory material. In the refractory material, diameters of pores are nano-scale, so that the refractory material is low in heat conductivity and high in strength, has high anti-medium erosion performance and excellent thermal shock resistance.

Belonging to the technical field of metal materials, the invention discloses a molten salt corrosion resistant nickel-based superalloy with excellent performance. In terms of weight percentage, the alloy comprises: less than or equal to 0.08% of C (preferably in the range of 0.03-0.06%), 0.5-5% of Fe, 6.0-8.0% of Cr, 12-18% of Mo, less than or equal to 2% of Ta, less than or equal to 2% of Ti, less than or equal to 2% of Nb, and the balance Ni, wherein the sum of Ti, Nb and Ta is greater than or equal to 1% and less than or equal to 2%. In addition to excellent room temperature plasticity, high temperature structure stability and high mechanical properties under high temperature, the alloy also has good resistance to molten salt corrosion, and can meet the use demands of molten salts and irradiation environments with high use temperature and performance requirements. Thus, the molten salt corrosion resistant nickel-based superalloy is suitable for high-temperature structural materials of molten salt nuclear reactors.

The invention discloses a high-toughness medium entropy high temperature alloy and a preparing method thereof. The alloy comprises chemical components including, by weight percent, 28.5 to 32.5% of Cr, 31.5 to 33.4% of Co, 32 to 35% of Ni, 0.5 to 6% of Al, 0 to 6% of Ti, 0 to 3% of Ta, 0.02 to 0.12% of C, 0.002 to 0.015% of B, 0.005 to 0.12% of Zr, 0.005 to 0.15% of RE, and larger than or equal to2% and smaller than or equal to 6% of Al+Ti+Ta, wherein Re is one of Ce, La and Y. The preparing method of the alloy comprises the steps that the raw materials are burdened and smelted according to the proportion, an electrode bar is forged and subjected to remelting, forging is carried out, an alloy bar is prepared, and the alloy bar is subjected to solid solution and aging heat treatment. The alloy is provided with a reasonable component ratio, a wide heat machining window and a heat processing system, the prepared alloy bar has the higher temperature strength, good heat machining and oxidation resistance properties, and the alloy is a candidate material of aero-engine and industrial gas turbine heat end parts.

The invention discloses a high-temperature high-strength TiAl-Nb monocrystal and a preparation method thereof. Based on the atomic percent, the high-temperature high-strength TiAl-Nb monocrystal comprises the alloy components: Ti-(43-47) Al-(6-10)Nb-(0.1-1)(C, Si), and the balance of Ti. The preparation method comprises the following steps: smelting TiAl-Nb button-shaped master alloy ingot casting by using an electro-magnetic induction suspension method; preparing a cylindrical rod-shaped sample by means of differential pressure suction casting or gravity casting; directionally condensing the cylindrical bar by using an optical float-zone crystal growth system to guarantee that the heating power is between 65% and 70%, the growth velocity is 5-30mm / h, the relative rotation speed is 20-40r / min and the argon flow protection is carried out for 3-5L / min; finally obtaining a TiAl-Nb monocrystal test bar; and performing desegregation heat treatment on the TiAl-Nb monocrystal bar to finally obtain the monocrystal test sample. By adopting the TiAl-Nb monocrystal alloy material prepared by using preparation method disclosed by the invention, the alloy pollution caused by a traditional Bridgman directional condensation method can be effectively avoided, a solid-liquid interface shape during condensation is controlled by regulating the heating power so as to quickly obtain the TiAl-Nb monocrystal, and after the desegregation of the TiAl-Nb monocrystal, the high-strength TiAl-Nb monocrystal alloy of which the yield strength is 637MPa at a temperature of 900 DEG C, the elongation percentage is 8.1% and the ductile-brittle transition temperature is not lower than 900 DEG C can be obtained.

The invention discloses a non-sintering sialon bonded corundum-spinel castable and a method for preparing an RH (Ruhstahl Hausen) insert tube prefabricated member inner core with the same. The castable comprises the following raw materials: 50-72% of fused white corundum, 8-21% of spinel, 2-9% of silicon metal powder, 3-11% of 200-mesh fused white corundum, 2-6% of alpha-alumina and 3-7% of rho-alumina; besides, an additive FS60 with weight accounting for 0.04-0.13% of total weight of various raw materials is added. The castable and the method have the beneficial effects that as the castable adopts sialon bonding, impacts of existence of CaO in existing traditional castable cement on the high temperature property and corrosion resistance of the prefabricated member are overcome, thus greatly improving the high temperature strength and thermal shock resistance of the castable; in combination with the 1700 DEG C service conditions of the product, generation of sialon in the service process is achieved, the production cost is effectively reduced, and the service life of the product is prolonged by 30-50%.

The invention provides high-gamma'-content nickel-based high-temperature alloy powder for additive manufacturing, a using method therefore and a nickel-based high-temperature alloy component, and relates to the technical field of powder-based additive manufacturing. The high-gamma'-content nickel-based high-temperature alloy powder for additive manufacturing comprises the following chemical components in percentage by weight: 12-14% of Cr, 8-9% of Co, 3.8-4.2% of Al, 3.8-4.2% of Ti, 2.4-2.8% of W, 1.9-2.1% of Ta, 1.6-2.0% of Mo, 1.0-1.2% of Nb, 0.1-5% of Fe, 0.1-2.0% of Hf, 0.12% or less of C, 0.1% or less of Si, 0.02% or less of n, less than 0.03% of Zr, 0.01% or less of B, and the balance Ni and impurity elements. By using the high-temperature alloy powder, compact and crack-free complex parts meeting the strength requirement in the ultrahigh-temperature environment can be printed through the selective laser melting technology.