34results about How to "Fine grain size" patented technology

The invention relates to the technical field of permanent magnetic material preparation and in particular to a preparation method for a high performance as cast condition neodymium iron boron magnet. By means of the composite process combining technology of casting and large strain plastic deformation and the technology of double orientation, grain size is effectively refined, and grain boundary and grain orientation are controlled, so that the high performance neodymium iron boron magnet which is fine in grains, even in grain boundary phase distribution and complete in grain orientation is prepared, and good matching of high coercivity and high magnetic energy product is obtained.

The invention relates to a processing method for grain refinement of a CrNiMoV high pressure steel forging. The processing method is capable of improving comprehensive mechanical properties of the forging and comprises the following steps: step S01, using steel scrap of grade 2 or above grade 2, nickel remnants, steel cuttings, nickel-containing pig iron and spongy iron as electroslag ingots and controlling the content of each element; step S02, carrying out pre-forging heating on the materials selected in the step S01 to a temperature of 1180 to 1210 DEG C and maintaining the temperature for 15 h; step S03, carrying out wide-anvil compaction and temperature-controlled forging on the electroslag ingots heated in the step S02; step S04, carrying out preheat treatment on a forging obtained after forging in the step S03; and step S05, carrying out quenching on the forging having undergone preheat treatment and then carrying out tempering at a temperature of 600 + / - 10 DEG C. According to the processing method provided by the invention, production efficiency is improved and production cost is reduced through control of chemical composition of raw materials and changing of production technology.

The present invention belongs to an activated sintering method of a high-density aplitic non-magnetic Tungsten-Cu alloy. Tungsten-Cu composite powders are adopted as raw materials with an average particle size of less than 500nms, and the average size of the tungsten particles is less than 300nms. The base bodies of needed shapes and sizes are prepared adopting conventional moulding method and directly sent into a welding furnace to be sintered in a mixed atmosphere of protection and reducibility or in an atmosphere of reducibility. The sintering temperature is 1100-1340 degrees Celsius system, the heat holding time is 40-60 minutes and the present invention adulterates no activating agents. The prepared aplitic Tungsten-Cu alloy adopting the present invention is characterized in that the grain granularity is fine, the average grain size of tungsten is less than or equal to 800nms, the organizational structure is evenly distributed and the relative density of the alloy is more than 99 percent. The high density Tungsten-Cu alloy prepared using the invention has an excellent mechanical property and thermal conductivity, guards against the aliquation of copper efficiently, and is fine in granularity and high in intensity, plasticity and thermal conductivity. The invention is simple in technics, easy to control, pollution-free, low in investment cost, low in energy consumption and applicable to a mass industrial production.

There is provided a novel bearing steel composition and a method of forming a bearing. The bearing steel composition comprises: Carbon 0.4 to 0.8 wt %; Nitrogen 0.1 to 0.2 wt %; Chromium 12 to 18 wt %; Molybdenum 0.7 to 1.3 wt %; Silicon 0.3 to 1 wt %; Manganese 0.2 to 0.8 wt %; and Iron 78 to 86.3 wt %.

The invention discloses a method for controlling the heat crack and residual stress of a Fe-based fusion-repair layer via an ultrasonic impact, which belongs to the field of process technology. The method comprises the following steps of: step 1, controlling installation for an ultrasonic impact gun for heat crack; step 2, controlling installation for an ultrasonic impact gun for residual stress; and step 3, performing impact treatment on the Fe-based self-fluxing alloy powder fusion-repair layer having a thickness of 0.5-3 mm during a welding process. The method disclosed by the invention has the following advantages that (1) the heat crack tendency of the Fe-based self-fluxing alloy powder fusion-repair layer caused by the difference of material parameters with matrix metal can be suppressed; (2) the surface residual tensile stress of the fusion-repair layer can be reduced, and the working life of a workpiece can be prolonged simultaneously; and (3) the crystalline grain diameter of the fusion-repair layer can be reduced, and the ductility and toughness of the fusion-repair layer can be improved based on improvement for the wear resistance of the fusion-repair layer.

The invention discloses a technology for manufacturing a low-temperature mold pressing tee through an X80 steel plate. According to the technology, a tee pipe fitting is prepared through the X80 steelplate by combining a welding technology with a pressing forming technology, the grain size and strength loss allowances caused by multiple times of heating and long heating time in the machining process are increased, and the tee pipe fitting can be normally used for a long time in the -45 DEG C extremely cold weather. The tee pipe fitting prepared through the technology has the small grain size,high strength and low welding crack sensitivity coefficient, the homogeneity degree of all parts of the product is greatly improved, and the tee pipe fitting can be suitable for the -45 DEG C operating environment.

The invention relates to a manufacturing method of a nanocomposite aluminum-based bearing material, which uses high-purity, particle-sized Al, Pb, and Cu powders according to a certain weight percentage of Al+Pb+Cu under argon protection, and uses a ball mill to perform high-energy ball milling. , After ball milling in a ball mill at a certain speed for a certain period of time, the powder prepared by ball milling is rolled and compounded on a thermal sprayed aluminum steel back by continuous powder pressing, and then sintered at different temperatures under the protection of argon, and then cooled. The invention has the advantages of simple process, low manufacturing cost, and easy realization of large-scale industrial production. The invention can obtain a nanocrystalline Al-based solid solution as a matrix on which Pb and Cu are evenly distributed. 9 al 4 、CuAl 2 The nano-phase composite structure of the second phase, the wear resistance of the manufactured Al-Pb-Cu bearing material has been greatly improved.

The invention discloses a high-performance trapezoidal aluminum alloy material, the composition of which is: silicon Si 7.4-7.5%, iron Fe≤0.12%, copper Cu0.42-0.46, magnesium Mg0.4-0.45%, titanium Ti0. 1-0.15%, the total impurity content is <0.02%, and the balance is aluminum. The production method is as follows: add cold material with the same composition, the ratio is 15-20% of the capacity of the melting furnace, then add the electrolytic aluminum liquid ingredients, through electromagnetic stirring treatment to achieve uniform composition of the aluminum liquid, add alloy materials in turn, through refining, degassing box, The pure aluminum solution is obtained from the filter box, and the horizontal casting is achieved through the balance adjustment. The adjustment amount of the aluminum liquid matches the speed of the casting machine, and the cooling method, cooling water flow and pressure are reasonably distributed, forming a process from liquid to crystallization in the cooling area of ​​the crystallizer. The best condition, to ensure the grain size of the trapezoidal aluminum alloy. The product of the invention has uniform composition, high strength, fine grain size, first-class pinhole degree, low hydrogen content and few impurities, and comprehensively improves the mechanical properties of the alloy product.

The invention discloses an amorphous magnesium-aluminum-base composite hydrogen storage material and a preparation method thereof. The amorphous magnesium-aluminum-base composite hydrogen storage material is prepared from an amorphous Mg17Al12 matrix and a transition metal hydride in a mass ratio of 100:(0.5-10), wherein the transition metal hydride is one or more of TiH2, ZrH2 and ScH2. The preparation method comprises the following steps: a) in an inert atmosphere, uniformly mixing raw materials Mg powder and Al powder according to the proportioning of the Mg17Al12, and preparing amorphous Mg17Al12 matrix powder by low-temperature ball milling; and b) carrying out mechanical ball milling on the prepared amorphous Mg17Al12 matrix powder and transition metal hydride powder under the protection of the inert gas to obtain the amorphous magnesium-aluminum-base composite hydrogen storage material. The composite hydrogen storage material has excellent medium / low-temperature hydrogen absorption / desorption properties.

The invention relates to a method for preparing AlN nanopowder by adopting high-energy ball milling under assistance of plasma and belongs to the technical field of nanometer preparation. According to the method, a bipolar nanosecond-level high-voltage marrow-pulse power supply or an alternating current power supply is taken as driving source under barometric pressure, dielectric barrier discharge plasma is obtained in nitrogen or mixed gas of the nitrogen and argon so as to assist the high-energy ball milling to prepare the AlN nanopowder. The method has the advantages that the operation is simple, the cost is low, the grain size of the AlN nanopowder is smaller than that of aluminum nitride prepared by only adopting ball milling, the malposition defect is large, the internal energy of the grain is high, the required temperature of carbon thermal reduction reaction is low, the conversion rate is high, and the like.

The invention relates to a 5-series aluminum alloy panel, as well as a preparation method and application thereof. The preparation method of the 5-series aluminum alloy panel is characterized by forced cooling a hot-rolled aluminum alloy panel to be below 200 DEG C at the cooling speed being 15 to 25 DEG C / s. By adopting the cooling method provided by the invention, a fine-grain panel with the grain size being smaller than 30mum can be prepared, so that the strength and the extensibility of the 5XXX-series, particularly 5083 aluminum alloy panel material are improved.

The invention belongs to the technical field of ceramic materials, and discloses a high-entropy ceramic composite material with oxidation resistance and its preparation method and application. The ceramic composite material (Hf 0.2 Zr 0.2 Mo 0.2 Cr 0.2 Ti 0.2 )B 2 ‑xvol% SiC is in HfO 2 , ZrO 2 、MoO 3 、Cr 2 o 3 、TiO 2 Adding solvent and ball milling medium to the amorphous boron powder is mixed, and the mixed powder is pressed into a green body, and heat treatment is carried out under vacuum conditions, and the vacuum heat treatment is carried out to obtain (Hf 0.2 Zr 0.2 Mo 0.2 Cr 0.2 Ti 0.2 )B 2 High-entropy solid solution powder obtained after mixing SiC (Hf 0.2 Zr 0.2 Mo 0.2 Cr 0.2 Ti 0.2 )B 2 ‑xvol% SiC high-entropy composite material powder is obtained by filling the high-entropy composite material powder with a protective atmosphere when the temperature is raised to 1000-1400°C by spark plasma sintering, and then calcined at 1800-2200°C, where 0≤x≤30. The relative density of the obtained high-entropy ceramic composite material is 95%-99.9%, the grain size of the high-entropy ceramic composite material is 1-3 μm, and the fracture toughness is 4-12 MPa·m 1 / 2 , after heat treatment at 1600°C-2000°C, the weight change rate is 0.3-2wt%.