75results about How to "No crack defect" patented technology

The invention discloses a preparation method of a fiber-toughened SiC ceramic-based composite material three-dimensional member. The method comprises the following steps: adding fiber to liquid-state high char yield resin, pouring to a photo-curing mold, performing polymerization and curing on the resin, then manufacturing a controllable porous carbon preform through a thermolysis method, then performing high-temperature siliconizing, and preparing a SiC ceramic matrix by in-situ reaction of silicon on a carbon support to realize the manufacturing of the SiC ceramic-based composite material three-dimensional member. The method has the characteristics of near net shape formed variable cross-section complex structure, no crack defects, short production period, low cost and the like, and can be applied to development and manufacturing of blades of engines and other aerospace high-temperature-resistant complex structure parts.

The invention discloses a pulsed switch-on preheating flash butt welding process for steel rims of heavy trucks, which belongs to the technical field of welding, and comprises the steps of blanking, reeling, flattening, welding condition setting, fitting, pulsed flash preheating, continuous flash, charged upsetting, pressure maintaining, clamp loosening, deburring, and the like. The process is characterized by comprising the controlled process parameters as follows: the overhanging length is 20-50mm; the flash allowance is 5-12mm; the upset allowance is 5-10mm; the upset force is (2-3)*105 N; the clamp force is (3-6)*105 N; the pulsed switch-on preheating process is (4-10) times*(0.5-1.2) s, (0.1- 0.2) s per pulse; the preheating and welding voltage is 10.8-14.6 V; the flash time is14-30s; and the upset charged time: 0.3-2s. The process disclosed by the invention has the advantages that the degree of automation is high; the process is suitable for welding steel rims (thickness: 3-8mm, width: 300-400mm) of heavy trucks, and after the welded steel rims are sequentially subjected to trimming, flaring, roll shaping and expanding, the welded joints have no crack defect.

The invention provides a process technique of using continuous casting process to produce sulfur-containing easy-to-cut steel SUM43, during melting, contolling sulfur content in the steel according to the medium-top limit required by steel composition, and contolling the Mn content to the top limit; necessarily firing molten steel in tunish to above 1000 deg.C; as electric melting, adding high-sulfur iron in 30%-50%; adding sulfur in refining furnace by sulfur iron block and sulfur-feeding iron wire process; the continous casting stage adopts a course-control mthod and the controlling cooling strength of secondary-cooling system: adopting a secondary-cooling system, the front stage adopts all-water spray cooling and the back stage adopts steam-water spray cooling, and automatically regulating the spray water rate of the secondary cooling. The surface finish of cast blanks reaches grade 6 above; over 90% of cast blanks have no crackes on the surfaces. The sulfur iron and sulfur-feeding iron wire process can accurately control sulfur content.

The invention provides a method for preventing a selective laser melting nickel-based superalloy from cracking, and belongs to the field of additive manufacturing. According to the method, a workpiecewhich is high in density, free of crack defects and excellent in mechanical property is prepared by reducing low-melting-point phase forming elements Zr and B in the nickel-based superalloy and adjusting the total content of Al and Ti in the alloy to be smaller than or equal to 4.5wt% in combination with special selective laser melting (SLM) process parameter control. Through the method, component design is reasonable, the preparation process is simple, and the obtained workpiece has excellent properties and is convenient to apply on a large scale.

Provided is a process for preparing a cladding layer of ceramic-metallic composite material, belonging to the technical field of superficial treatment. The technique includes that the surface of a metallic member is cleaned, unoiled and sprayed sand, enabling the surface of the metallic member to be roughened, then the method of electric arc spraying or plasma spraying is employed to prepare the coating layer of ceramic-metallic composite material on the surface of the metallic member, the scanning remelting of the coating layer is carried out by utilizing a plasma arc gun with micro beam and the like. The parameters of the invention include that a compression nozzle of the plasma arc gun with the diameter of 0.6 to 1.3 millimeters is chosen, the ionized gas flow is 0.08 to 0.2 liter every minute, the protective gas flow is two to three liters every minute, the plasma arc current is 10 to 30A when the thickness of the coating layer is less than 600 micrometers, the plasma arc current is 25 to 60A when the thickness of the coating layer is 600 to 1500 micrometers, the distance between the head portion of the plasma arc gun with micro beam and the surface of the coating layer is two to five millimeters, and the relative move speed of the plasma arc gun with micro beam to the member is two to eight millimeters every second. The invention has the advantages of simple technique, stable quality, low cost and high manufacture efficiency.

The invention relates to a technical method for repairing a block falling defect of a flap sliding rail chromium-plated surface through laser cladding, and belongs to the technical field of laser processing. The method is mainly used for repairing abrasion defects of an airplane flap sliding rail. According to the method, ultra-high-strength steel powder good in weldability and good in abrasion resistance is selected to serve as a cladding material for a 30CrMnSiNi2A ultra-high-strength steel workpiece, and reasonable laser cladding process parameters are adopted to repair the sliding workingsurface of the flap sliding rail. A chromium-plated layer of the non-repair surface in the repair process does not fall off; no crack defect exists on the repair portion; and the abrasion resistance of a repair structure is equivalent to that of an original matrix material, so that the service life of the workpiece is prolonged. A certain type of airplane flap sliding rail repaired through the method has been installed and applied.

The invention discloses a nickel-based high-temperature alloy turbine supporting base argon arc welding repairing method. The nickel-based high-temperature alloy turbine supporting base argon arc welding repairing method comprises the following steps that firstly, a nickel-based high-temperature alloy welding wire consistent to a supporting base in material component is selected; secondly, surfacetreatment is conducted before repairing; thirdly, a protection cover is pasted on the supporting base through aluminum foil paper, then, inward argon inflation is constantly conducted through an airpipe, the back face of a welding line is arranged in the closed argon protection environment, and the supporting base to which the aluminum foil is pasted is arranged in a special anti-deformation tool; fourthly, argon arc welding repairing is conducted, the notch position is completely and fully welded, complete full welding is achieved through visual checking, the phenomena of undercuts and pitsare avoided, and repair welding is conducted several times till repair welding is finished; fifthly, postweld heat treatment is conducted; sixthly, grinding machining is conducted; and seventhly, lossless detection is conducted. By means of the nickel-based high-temperature alloy turbine supporting base argon arc welding repairing method, the usage and maintenance cost of the engine turbine supporting base is reduced, and the repaired part is free of crack defects.

The invention discloses a manufacturing method of a special welding material for electron beam welding of YGH-60 hard alloy and 45 steel, and relates to an electron beam welding method of dissimilar materials. The manufacturing method solves the technical problems that the available brazed connection method for the hard alloy and the steel has complicated procedures and a fusion welding connection method causes cracks easily. The manufacturing method comprises the steps that 8.3-8.5% of iron powder, 0.45%-0.55% of niobium powder, 0.75%-0.85% of yttrium powder, 0.45%-0.55% of carbon powder and the balance of nickel powder are weighed according to weight percentages, and added into a powder mixing machine to be mixed, and obtained mixed powder is pressed and then put into a vacuum furnace for sintering, therefore, the special welding material for the electron beam welding of the YGH-60 hard alloy and the 45 steel is obtained. The special welding material can be used to weld the dissimilar materials.

A related heat treatment method is characterized in that heat treatment is performed on a medium/high-carbon steel continuous cast slab and a medium/high-carbon alloy steel continuous cast slab. The medium/high-carbon steel continuous cast slab comprises, in percent by mass, 0.25-1.35% of C, 0.10-0.37% of Si, 0.25-0.80% of Mn, P <=0.035%, and S <=0.030%. The medium/high-carbon alloy steel continuous cast slab comprises, in percent by mass, 0.25-1.50% of C, 0.10-2.10% of Si, 0.30-2.60% of Mn, P <=0.035%, S <=0.035%, Cr <=4.50%, V <=1.20%, Mo <=1.20%, Ni <=4.60%, and B <=0.004%. The heat treatment steps comprise that the temperature of the slab entering a heat treatment furnace is 150 DEG C-850 DEG C, the slab heat-treatment warm-keeping temperature is 300-850 DEG C, the slab heat-treatment warm-keeping time is 3-40 hours, the temperature of the slab exhausted from the furnace after being subjected to heat treatment is 150-550 DEG C, the slab heat-treatment heating speed is 5-250 DEG C/h, and the slab heat-treatment cooling speed is 5-100 DEG C/h. The continuous cast slabs subjected to heat treatment does not have crack defects.

The invention discloses a deformable aluminum alloy metal powder material for additive manufacturing and further discloses a preparation method for the deformable aluminum alloy metal powder for additive manufacturing. The deformable aluminum alloy metal powder material is composed of the following components of, by mass, 0.40-0.65% of Si, 0.1-0.7% of Fe, 0.15-0.4% of Cu, 0.05-0.15% of Mn, 0.8-1.2% of Mg, 0.04-0.35% of Cr, 0.05-0.25% of Zn, 0.01-0.15% of Ti, 0.2-0.5% of Sc and the balance Al, wherein the sum of the mass percentages of all the components is 100%. Through the deformable aluminumalloy metal powder for additive manufacturing, the cracking problem of existing 6061 aluminum alloy powder in the process of additive manufacturing is solved.

The invention discloses large-specification high-carbon silicon manganese steel and a manufacturing method thereof. The high-carbon silicon manganese steel comprises, by mass, 0.60-1.20% of C, 0.38-0.80% of Si, 1.00-1.90% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, 0.02-0.06% of Al, 0.020-0.050% of Nb, 0.01-0.04% of Ti, 0.025-0.065% of V, 0.08-0.31% of Cr, 0.10-0.50% of Mo, and the balance Fe and inevitable impurities. According to the high-carbon silicon manganese steel and the manufacturing method, the technical problem of poor center quality of large-specification high-carbon silicon manganese steel produced in the prior art is solved, the continuous casting production of the large-specification high-carbon silicon manganese steel is realized, internal shrinkage cavities of a continuous casting billet are successfully welded, inner porosity is greatly improved, low-power center porosity, general porosity and pattern segregation of the large-specification high-carbon silicon manganese steel are less than or equal to 1.5 grade, the low-power cross section has no defects of residual shrinkage cavities and cracks, and the qualified rate of flaw detection reaches 95% or more is achieved.

The invention discloses a preparation method of a high-hardness and high-strength expanding pyramid of a mechanical expanding mill. The preparation steps are as follows: (1) smelting, spheroidizing, inoculating and casting; (2) annealing; (3) plugging holes with refractory clay and asbestos, blocking grooves, sealing center holes so that the preparation works are completed; (4) charging the expanding pyramid of which the large end downwards faces into a tooling of which the bottom is a plane, placing the tooling inside a well-type heating furnace and drying the refractory clay so as to complete the charging operation; (5) by controlling the temperature-raising speed and the temperature-raising temperature, heating; (6) by controlling the temperature-raising speed, the temperature-raising temperature and the temperature-raising time, austenitizing; (7) by controlling the time and temperature, carrying out three-stage quenching; and (8) by controlling the time and temperature, tempering. The high-hardness and high-strength austenitic-bainitic nodular cast iron expanding pyramid subjected to above treatment steps has no defects such as quenching cracks, high quenching depth, good compressive strength, impact toughness and hardness, can meet the needs of machining and cannot be deformed after machining. The expanding pyramid is suitable for preparing steel tubes having steel grade of X60-X80 and wall thickness of 10-18 mm.

The invention discloses a near alpha titanium alloy metal powder material used for additive manufacturing. The powder material comprises, by mass percent, 3.1 to 6.2% of Al, 1.0 to 2.1% of Zr, 0.4 to1.8% of Mo, 0.6 to 2.3% of V, 0.2 of Fe, 0.1% of Sn, 0.1% of C, 0.05% of N, 0.01% of H, 0.13% of O, 0.30% of inevitable impurities and the balance Ti, and the mass percent of the above components is 100%. The invention further discloses a preparing method of the near alpha titanium alloy metal powder material used for additive manufacturing. The method is used for the near alpha titanium alloy metal powder material, and the problem that an existing titanium alloy powder cannot meet the part strength need is solved.

The invention discloses an elastic-rigid coupling regulating and controlling aluminum alloy sheet electron beam welding stress deformation fixture. The problems of crack defect caused by large residual stress caused during rigid constraint and damage to the surface of a test piece caused by point constraint in the welding process are solved. The fixture comprises a fixture shell, three constraintdevices, three constraint baffles and three connecting elements. The three constraint devices are all arranged in the fixture shell, constraint heads arranged on the inner side of an upper end plate on the left side penetrate through left side constraint head mounting holes, constraint heads arranged on the inner side of an upper end plate on the right side penetrate through right side constrainthead mounting holes, and constraint heads arranged on the inner side of a right vertical plate penetrate through lower mounting holes; a constraint baffle is arranged on the outside of each row of constraint heads, the two ends of the constraint baffles are separately arranged in corresponding roughening clamping openings, the constraint baffles are connected with the fixture shell through the connecting elements, and gap of 3mm-8mm are arranged between the constraint baffles and the constraint heads. The elastic-rigid coupling regulating and controlling aluminum alloy sheet electron beam welding stress deformation fixture is used for regulating and controlling the deformation of the plate welding stress.

The invention provides a micro-nano layer-shaped copper/copper alloy composite board and a preparation method thereof. Copper and copper alloy boards with the thickness ranging from 0.5 mm to 2 mm are stacked in a multi-layer manner, then the copper and copper alloy boards are tightly welded together through a thermal diffusion welding treatment means, then the thickness of the boards is reduced to 10 mm or below through a forging treatment process, and finally, the micro-nano layer-shaped copper/copper alloy composite board/foil is obtained through a traditional rolling technology. Compared with the prior art, layers of the board are firmly combined, the number of layers and the thickness of the board are controllable, and the thickness of the composite board can reach the thickness of a foil.

The invention provides a preparation process and a preparation device of a lead bismuth alloy for a nuclear reactor. The preparation process comprises the following steps: 1) preparing raw materials;2) blowing a crucible and materials inside a furnace with nitrogen; 3) with a nitrogen protection device, powering on a medium-frequency sensing furnace to melt an alloy; and 4) casting by using a lead bismuth alloy casting mold. The preparation device comprises the medium-frequency sensing furnace and the lead bismuth alloy casting mold, wherein a water cooling jacket is arranged outside the leadbismuth alloy casting mold; a coil heating device is arranged at a casting hole; and a hydraulic rod is arranged at the casting hole, so that the stability of the crystallization process after casting is ensured, and the lead bismuth alloy is prevented from segregation. Equipment used in the preparation process is simple in structure, and no vacuum smelting or vacuum casting is needed.