30results about How to "Reduced propensity to form" patented technology

The invention relates to a sand mould of precoated sand for casting single piston ring and a manufacturing method of the sand mould. The sand mould comprises a circular tray body, a pouring system arranged on the circular tray body, a retainer ring and air outlet holes, wherein the pouring system comprises a downsprue, a flow gate, a cross gate and a dead head, the downsprue penetrates through the middle part of the circular tray body, the flow gate arranged on the facade of the circular tray body is communicated with the downsprue through the cross gate, the flow gate is communicated with a ring body groove, the dead head is arranged to be opposite to the flow gate, and the dead head is communicated with the ring body groove through more than two inclined pouring gates; and the retainer ring higher than the surface of the sand mould is arranged on the periphery of the facade of the circular tray body, and more than four air outlet holes passing through the circular tray body are symmetrically arranged on the inner side of the ring body groove between the cross gate and the dead head along the axial line of the cross gate. The piston ring processed by the invention is stable in quality and high in yield, the piston ring casting has the advantages of clear outline, high dimension precision and good surface quality, and the piston ring casting is liable to clean, thereby reducing the processing allowance, reducing the successive processing cost and improving the production efficiency.

The invention relates to a method for connecting a nickel-based superalloy with a Ti2AlNb alloy or a Ti3Al-based alloy, in particular to a diffusion welding connecting method adopting Cu foil and Ti foil as a composite interlayer. The diffusion welding connecting method comprises the steps that the nickel-based superalloy and the Ti2AlNb alloy or the Ti3Al-based alloy are processed into the neededsizes, ground and polished; the Cu foil and the Ti foil are subjected to oxidation film removing, and are placed into acetone with a welded base material to be subjected to ultrasonic cleaning; and the Cu foil makes contact with the nickel-based superalloy, the Ti foil makes contact with the Ti2AlNb alloy or the Ti3Al-based alloy, and thus a welded test piece with the structure of the Ti2AlNb alloy or the Ti3Al-based alloy/the Ti foil/ the Cu foil/ the nickel-based superalloy is obtained, a welded workpiece is placed into a vacuum heating furnace, the pressure is applied, and welding is completed after heating, heat preservation and cooling heat circulating. The welding temperature can be lowered, forming of a brittle phase of a joint is controlled, and the property of the joint is improved; and the obtained shearing strength of the joint at the room temperature reaches 240-310 MPa.

The invention discloses a preparation method of ferronickel-based alloy spherical powder for 3D printing. The preparation method comprises the following steps that 1) burdening is conducted by using the following chemical composition proportion of, in percentage by mass, 44.77%-51.5% of Ni, 18%-20% of Fe, 21.0%-22.5% of Cr, 1.0%-2.0% of Co, 8.0%-9.5% of Mo, 0.5%-1.0% of W, 0%-0.02% of C, 0%-0.01%of Mn and 0%-0.2% of Si; 2) the ingredients in the step 1) are prepared into an alloy ingot by adopting a vacuum induction melting horizontal continuous casting process, a shrinkage cavity defect at the head of the alloy ingot is removed, and then the alloy ingot is machined into an electrode bar; 3) the electrode bar in the step 2) is placed in a plasma rotating electrode powder making machine toform metal spherical powder; and 4) the prepared metal spherical powder is screened by adopting an ultrasonic vibrating screen under the protection of high-purity argon to obtain the ferronickel-based alloy spherical powder for the 3D printing.

The invention discloses antioxidant nickel-based high-temperature alloy powder and a preparation method thereof. Ni, Cr, W and other alloy elements are taken in proportion, the alloys are firstly putinto a vacuum induction furnace for melting and then put into in a vacuum self-consuming furnace for remelting to obtain a mother alloy ingot, and the mother alloy ingot is made into an electrode bar;the electrode bar is put into a plasma rotating electrode powder making machine, and the end of the electrode bar is melted by using a plasma gun to obtain spherical powder; screening is conducted onthe spherical powder through an ultrasonic vibrating sieve; and electrostatic separation is conducted on the spherical powder to remove non-metallic impurities from the spherical powder to obtain pure alloy powder. By means of the preparation method of the antioxidant nickel-based high-temperature alloy powder, by adopting Nb element to replace a part of W element, the content of W element is reduced, the forming tendency of carbon oxide of W is weakened, and the content of the carbon oxide of W in the alloy is significantly reduced.

The invention discloses a coherent nanophase reinforced medium-entropy alloy with excellent thermal stability and a preparation method, the coherent nanophase reinforced medium-entropy alloy comprises 30 at.%-33 at.% of Ni, 30 at.%-33 at.% of Co, 30 at.%-33 at.% of Cr, 5 at.%-7 at.% of Al and 1.0 at.%-3.0 at.% of Ta, gamma'phase is added into the NiCoCr medium-entropy alloy with excellent mechanical properties to form elements Al and Ta, and then a nanophase is introduced into a NiCoCr alloy matrix through an aging process, so that the thermal stability of the alloy is improved. A gamma + gamma'structure similar to a high-temperature alloy is constructed, and meanwhile, the strength of the NiCoCr alloy is also greatly improved through the nano precipitation strengthening effect; the alloy not only has the characteristic of high toughness, but also has excellent structure thermal stability, so that the alloy has great competitive advantages in alloys with similar structures, has great engineering application prospects in the high-temperature field, and is expected to become a next-generation high-temperature structural material.

The invention discloses a directional solidification method capable of reducing the number of freckles in a variable-section casting. By adding a radiation baffle on the top of a formwork of the variable-section casting, cooling rate or solidification rate is increased, so that freckles are removed. By means of the radiation baffle, radiant heat of a heating body on the upper portion is blocked, heat absorbed by liquid phase is reduced, so that casting cooling rate is increased, dendritic structure can be refined, thermosolutal convection flow resistance is increased, solidification rate is increased, and the possibility that dendritic growth rate is larger than interdendritic flow rate is increased. By the adoption of the method, cooling rate and solidification rate can be increased during casting solidification, and the possibility of freckle formation is reduced. Specific implementation is easy, material sources are wide, consumption is low, and the original formwork does not need to be changed.

The invention belongs to the field of welding materials, and particularly relates to a matched flux-cored wire for medical gas and vacuum seamless copper pipe fusion welding. The matched flux-cored wire comprises a TU1 semi-hard copper alloy sheath and a flux core; the flux core comprises 2.1%-3.2% of CuSi16 powder, 2.2%-3.0% of CuMn30 powder, 1.5%-2.2% of CuP12 powder, 3.0%-3.8% of AlSr40 powder,2.8%-3.6% of nanometer F3Ti powder, 3.2%-4.5% of nanometer NdF3 powder, and the balance FTD1 electrolytic copper powder; and the filling rate of the flux core is 32%-38%. Chemical components of deposited metal are uniform, inclusion, cracks and air hole defects are avoided, the air tightness is good, the minimum value of the tensile strength of the deposited metal is 306 MPa, the minimum value ofthe percentage elongation after fracture is 31.6%, and a component formed by fusion welding the seamless copper pipe completely meets the medical gas and vacuum requirements.

The invention belongs to the field of casting of complex hollow single crystal blades, and particularly relates to a wax mold assembly structure of a cover plate integral casting and cantilever structure single crystal blade. Due to the fact that the blade cover plate is integrally cast and the cast hole diameter on the cover plate is small, a blade ceramic core (forming a blade tip cast hole part) is extremely prone to breakage. In addition, the blade is of a cantilever structure and cannot be positioned, so that the defects of core shift, core exposure, mixed crystals, striped crystals and the like of the blade are extremely prone to occurrence in the directional solidification process. However, the combination mode of the wax molds is a main factor influencing the defects. According to the wax mold assembly structure, the ceramic core boss is reasonably designed at the allowance of the blade tip of the blade to solve the problem of core shift of the blade; the freedom degree and the fixed end of the mold core are reasonably designed based on the expansion difference value of the mold core and the mold shell, and mold core breakage is avoided; and the runner position is adjusted to reduce the blade defect forming tendency. The percent of pass of the single crystal blades formed through the mold assembling method is high.

The invention belongs to the technical field of welding materials, and particularly relates to a low-hydrogen easy-to-weld alkaline flux-cored wire prepared from steel slag and used for structural steel. The flux-cored wire is formed in a manner that a low-carbon cold-rolled steel strip is wrapped with flux core powder, and the flux core powder comprises 22%-28% of steel slag, 7.5%-9.0% of Mo40V40Al20 powder, 5.6%-8.2% of FeMn60Si34C 0.02 powder, 4.1%-5.0% of FeTi80-A powder, 7.8%-9.6% of CaF2 powder plated with Ni on the surface, 4.2%-6.0% of nano TiO2, 3.1%-3.8% of 200-mesh nitrocellulose powder, 2.1%-3.0% of feldspar and the balance FHT100.25 iron powder reduced. During welding, the flux-cored wire is stable in electric arc, small in splashing, good in post-welding forming, easy to deslag, suitable for all-position welding, low in residual hydrogen content in deposited metal, uniform in chemical component and high in mechanical property, and is an innovation in the aspect of alkaline flux-cored wires.