11results about How to "Avoid heat cracks" patented technology

The application belongs to the technical field of laser additive manufacturing, and particularly relates to an array type laser additive manufacturing method and device, which comprises the following steps: S1, digital model import and layering slicing; S2, scanning path planning and filling setting; S3, array type laser synchronous output control; S4, powder flow and powder feeding path control; S5, according to the width of the additive, the width of single track cladding is adjusted in real time; S6, according to the slice layer material of the additive, the matching material is delivered; S7, S1-S6 are repeated, and layer-by-layer accumulation is performed until the part manufacturing is completed. The application can accurately control the grain size, improve the material microstructure, and improve the mechanical properties; the generation of defects such as thermal cracks and pores is reduced, the stability of the deposition process is ensured; the interlayer bonding is optimized, the quality of multi-layer deposition is ensured; the residual stress is reduced, the size precision, shape stability and fatigue performance of the part are improved; the post-processing requirement is reduced, and the processing cost is reduced.

The invention discloses a release agent for casting a refractory material and a preparation method of the release agent. The formula of the release agent comprises 55-65% of high-purity silicon carbide, 35-46% of a polyvinyl alcohol solution, 0.4-0.9% of sodium benzoate, 0.01-0.05% of octanol and 0.5-2.0% of xanthan gum. Wherein the mass percentage SiC content of the high-purity silicon carbide is greater than or equal to 97%, and the particle size is 1-2mm; the mass percent concentration of the polyvinyl alcohol solution is 4-14%. The preparation method comprises the steps of weighing, burdening, stirring and mixing, dispersing by a colloid mill and the like. The release agent can obviously prevent sand burning of a sand mold to the fused-cast refractory product, reduces the demolding resistance of the product after annealing, and improves the casting quality of the fused-cast refractory product.

The application discloses a multi-furnace body series connection step-by-step continuous heating furnace, and relates to the technical field of heating furnaces.The heating furnace comprises a furnace loading base, a preheating base is fixedly installed at the rear bottom end of the furnace loading base through bolts, a heating base is fixedly installed at the rear side of the preheating base through bolts, and a furnace loading structure is arranged.The furnace loading structure comprises two fixed support rails which are fixedly installed at the top end of the furnace loading base through bolts.The application is provided with a plurality of furnace bodies, the preheating furnace body is separated from the heating furnace body, the high-temperature flue gas of the heating furnace body is used as the heat source of the preheating furnace body to preheat the steel billet, the flue gas temperature discharged from the preheating furnace body is the final flue gas temperature of the heating furnace body, a small amount of burners can be arranged in the preheating furnace body as auxiliary heating and adjusting burners, the flue gas temperature of the heating furnace can be accurately controlled, the flue gas temperature can be controlled at the lower limit of the anti-dew-point corrosion temperature, the energy consumption is reduced, and the chimney is not corroded.

The invention discloses chemical pressure vessel processing equipment which comprises a processing table, two preprocessing assemblies, two cooling assemblies and two polishing assemblies, two baffles are fixedly connected to the processing table, mounting seats are slidably connected to the two baffles respectively, first sliding grooves are formed in the two mounting seats respectively, and the two first sliding grooves are communicated with the processing table. And a plurality of first rotating rollers are rotationally connected to the two mounting bases correspondingly, a notch is formed in the machining table, and a plurality of second rotating rollers are rotationally connected into the notch. The rack drives the first gear to rotate through the electric telescopic rod, so that the first grinding wheel on the mounting block is attached to the welding contact surface of the container storage tank to grind and polish the container storage tank, and adverse effects of burrs, rust and other impurities on the welding contact surface on the subsequent welding quality are avoided.

The present invention relates to the technical field of manufacturing a Tokamak device for controlled nuclear fusion, and in particular to a welding method for a low-magnetic stainless steel structure of a Tokamak device. A welding method for a low-magnetic stainless steel structure of a Tokamak device comprises the following steps: Step 1, grinding and cleaning the groove surface to be welded and the parent material within 20 mm of the groove surface to be welded before welding; Step 2, adopting multi-layer and multi-pass welding technology for welding; Step 3, after welding, adopting an aging treatment method to release internal stress. The beneficial effects of the present invention are: it can effectively prevent thermal cracks, reduce stress and avoid cracking; the metal arc gas shielded welding and tungsten arc argon welding use special shielding gas plus conventional welding materials to achieve the control of the relative magnetic permeability of the weld, which has high economic benefits. The relative magnetic permeability of the weld can be controlled without post-weld heat treatment, which solves the problem that large components or on-site components cannot be heat treated.

The application discloses a kind of vacuum electron beam welding methods of beryllium aluminum alloy, belong to metal material welding technical field, comprising the following steps: A, beryllium aluminum alloy plate is polished and cleaned and is handled;B, beryllium aluminum alloy plate is clamped with welding fixture, and the position to be welded is placed in the welding work area of electron beam welding system workstation;C, electron beam welding system is pumped to welding work vacuum degree, sets welding process parameter;D, preheating treatment is carried out to workpiece before welding, starts electron beam welding system, and beryllium aluminum alloy plate is welded;E, after welding, carries out postwelding slow cooling treatment.The application is designed by electron beam welding process and tooling fixture, optimizes electron beam welding heat input, controls cooling rate and the like mode, improves the uniformity of weld molten metal composition and organization, and the beryllium aluminum alloy weld obtained is not only free from crack, pore and other welding defects, simultaneously, but also makes the mechanical property of welded joint better than base material.

The invention discloses a contractible composite core for metal casting, which is characterized in that a plurality of movable core blocks form an annular core, and end gaps and end gap liquid blocking devices are arranged among the movable cores to prevent casting liquid from flowing out of the end gaps; the bottom of each core block is a plane and is placed on the plane of the lower die or is respectively arranged on different rolling or static pressure guide rails, a gap between each core block and the bottom of the lower die is smaller than an overflow edge value or is filled with a refractory material, and each core block can freely move inwards along with the shrinkage of a casting in a solidification shrinkage stage after casting liquid is poured; and hot cracks caused by the obstruction of the mold core can be prevented.

The utility model discloses a heat crack resistant casting reinforcing rib structure of an automobile brake disc, which is arranged on an inner side friction plate close to a wheel and positioned in a space between an outer side friction plate and the inner side friction plate, and comprises a plurality of radial reinforcing ribs, an outer ring reinforcing rib and an inner ring reinforcing rib, each radial reinforcing rib is arranged in an S shape, the outer ring reinforcing ribs are annularly arranged on the outer ring of the inner side friction plate in the circumferential direction of the inner side friction plate, and the inner ring reinforcing ribs are annularly arranged on the inner ring of the inner side friction plate in the circumferential direction of the inner side friction plate. According to the brake disc, the radial reinforcing ribs, the outer ring reinforcing ribs and the inner ring reinforcing ribs are matched with one another to form a complete reinforcing structure system and act together in different directions, so that the brake disc can bear complex stress conditions, the overall mechanical property is improved, and the brake disc better meets the requirements under various brake conditions; and safe and reliable operation of an automobile brake system is ensured.

This invention relates to the field of casting technology and discloses a casting process for marine engine blades, comprising: preparing three types of molding sand with different compositions: surface molding sand, intermediate molding sand, and back molding sand; sequentially filling the surface of the pattern with surface molding sand, intermediate molding sand, and back molding sand using a layered compact molding method to form a gradient structure mold; introducing CO2 gas to harden the mold; applying a silica sol coating to the surface of the mold cavity; drying the surface to form a siliceous glassy film from the silica sol; pouring molten metal into the mold after closing the mold, and pouring at high temperature to decompose the organic pore-forming agent in the back molding sand to create pores in situ; and demolding after solidification and cooling to obtain the casting. This invention, through its gradient layered structure and surface sealing treatment, reduces the mold expansion rate while establishing a permeability gradient from the surface to the back layer, preventing molten metal penetration and promoting gas expulsion, effectively solving the problems of hot cracking, porosity defects, and surface sand adhesion in the casting of marine engine blades.

The invention discloses a heating method for improving high-temperature oxidation resistance and crack resistance of a 9Ni steel billet, which comprises the following steps of: controlling the temperature of a preheating section and the O2 content in mixed gas, and adjusting the O2 content, the heating rate and the heat preservation temperature in the mixed gas of a first soaking section, a second soaking section and a third soaking section, so as to promote the rapid generation of compact Fe3O4 on the surface of the 9Ni steel billet in the preheating process, thereby improving the high-temperature oxidation resistance and crack resistance of the 9Ni steel billet. The formation of holes and hot cracks in an outer oxide layer is effectively controlled, so that the diffusion effect of oxygen from the surface of the 9Ni steel billet to the interior of the 9Ni steel billet in the preheating and high-temperature soaking processes is obviously inhibited, and the stable control of weak oxidation and shallow crystal cracks on the surface of the 9Ni steel billet in the high-temperature heating process is realized; by means of the method, the problem that the production cost is high due to the fact that the metal yield is low under the high-nickel condition in the 9Ni steel billet hot rolling process can be effectively solved, the surface quality of a rolled plate can be fully guaranteed, and meanwhile environment-friendly and cost-reducing production of 9Ni steel billet non-oxidation coating heating is achieved.

The invention relates to the technical field of high-speed train railway vehicles, and discloses a resistance reduction and heat dissipation compatible high-speed train head vehicle bogie full-coating structure which comprises a coating main body, a heat dissipation plate, a limiting pin, a first deep groove ball bearing, a second deep groove ball bearing, a third deep groove ball bearing, a pull rod, a bearing seat and a pneumatic guide rod. The heat dissipation plates are externally tangent, the heat dissipation plates and the wrapping body are internally tangent, and the heat dissipation plates are connected with the limiting pins through rectangular splines. Compatibility of pneumatic resistance reduction and heat dissipation is achieved by dynamically adjusting the heat dissipation plate, the pneumatic resistance in the train operation process is remarkably reduced, meanwhile, the heat dissipation performance of a bogie area is enhanced in the braking state, and the braking device is prevented from being overheated and losing efficacy. A precise connection structure is adopted, operation stability and durability are guaranteed, interference of components is avoided through optimization design, the train suspension system adapts to the requirements of multiple working conditions, the train operation safety and efficiency are improved, and the train suspension system has important application value.