123results about How to "Avoid air holes" patented technology

The invention discloses a forging method of a coupler knuckle for railway vehicles. The coupler knuckle for railway vehicles is formed by forging, and coupler knuckle products for railway vehicles with qualified performance and size are forged by the working procedures of material preparation, heating and blank forming, die forging and forming, trimming, heat treatment, preliminary processing, heat treatment, shot blasting, fault detecting and machining. The forging method of the coupler knuckle for railway vehicles, in which the coupler knuckle for railway vehicles has compact texture, high toughness and good fatigue performance, solves the defects of air pore, shrinkage porosity, inclusion, crack, short service life and the like of the coupler knuckle of the existing cast steel vehicle coupler.

The invention provides silicon carbide particle reinforced aluminum matrix composite which comprises, based on the total volume of the composite, 60-70vol% of silicon carbide and 25-40vol% of aluminum alloy. The aluminum alloy comprises, based on the total weight of the aluminum alloy, 74-90.9wt% of aluminum, 8.0-15.0wt% of silicone, 1.0-10.0wt% of magnesium, and 0.1-2wt% of rare earth. The invention further provides a preparation method of the silicon carbide particle reinforced aluminum matrix composite. The silicon carbide particle reinforced aluminum matrix composite is small in crystalline grain size, low in amount of shrinkage hole, air holes and impurities, and fine in mechanical properties and thermal conductivity.

The invention discloses a steel stud and thick aluminum plate frictional stud welding method, which is characterized in that the welding end part of a steel stud is subjected to certain structural design, the steel stud is rotated, is applied with frictional acting force, and is contacted and rubbed with an aluminum plate, and the steel stud is slowly embedded into the thick aluminum plate. Double characteristics of frictional stud welding and threaded connection are realized, so that a welded joint with good performance is manufactured. By the method, steel studs with middle and small diameters are welded with thick aluminum plates. According to the method, the welding strength of the stud welding can be obviously improved, the influence of defects in common welding on the joint quality is reduced, and the service life is greatly prolonged.

The invention discloses an electric arc fused deposition laser shock forging additive manufacturing method. The electric arc fused deposition laser shock forging additive manufacturing method comprises the following steps that (1) an electric arc welding device is controlled to move and conduct metal fusing position, so that a weld layer is formed; (2) the temperature of an electric arc fused deposition metal area of the weld layer is collected through a temperature sensor, the collected data are sent to the controller, and the controller controls a laser generator to conduct synchronous shock forging on the electric arc fused deposition metal area at the easy plasticity deformation temperature; (3) the step (2) and the step (3) are repeatedly executed, the weld layers are stacked layer by layer, and then a workpiece is formed. The invention further provides an electric arc fused deposition laser shock forging additive manufacturing device. By the adoption of the electric arc fused deposition laser shock forging additive manufacturing method and device, in the manufacturing process of the part, metal grains are refined, the microstructure is optimized, the possible internal defects of pores, fusion failure, shrinkage porosity and the like of an ordinary electric arc additive manufacturing formed metal part are avoided, and meanwhile the comprehensive mechanical performance of the metal part is also improved.

The present invention discloses an austenite gray cast-iron material with a weight percentage of chemical composition as follows: C 1.5-2.9 percent, Si 1.5-3.0 percent, Mn 5.0-7.5 percent, Ni 5.0-8.0 percent, Cu 3.0-6.0 percent, Al more than 0 and less than or equal to 0.3 percent, the total amount of impurity less than or equal to 0.25 percent and the remainder is Fe. The metallurgical structure of the austenite gray cast-iron material is that A-type graphite and fine carbides with a quantity of less than or equal to 4 percent are distributed on the austenite matrix. The preparing method is that an IF (intermediate frequency) induction furnace is used to melt the charge. When the temperature reaches 1500 degrees Celsius system, a casting ladle is poured in and an inoculation in the ladle is conducted by using shivers of silicoferrite 75 and ZL109. When the temperature reaches around 1450 degrees Celsius system, the pouring is conducted. The material can be used for the inlaid ring of a piston, the cost is lower than the austenite gray cast-iron of L-NiCuCr1562 and the performance is approximate or equal to the austenite gray cast-iron of L-NiCuCr1562.

The invention relates to a preparation method of an aluminum-titanium-boron wire grain refiner. The preparation method is implemented by continuous cast rolling after smelting and specifically comprises the following steps: (1) melting: adding a pure aluminum ingot into a crucible furnace, melting into liquid aluminum, and heating; (2) alloying: sequentially adding potassium chloride, potassium fluotitanate and potassium fluotitanate into the liquid aluminum in the liquid aluminum heating process in the step (1), and heating while stirring until the reaction is complete, thereby obtaining liquid alloy aluminum; (3) stirring, degassing and deslagging: transferring the liquid alloy aluminum prepared in the step (2) into an industrial-frequency core-free holding furnace, and stirring and degassing; and (4) continuous cast rolling: transferring the deslagged liquid aluminum into a mold, carrying out rubber filtration, crystallizing the wheel die cavity, carrying out continuous rolling by a continuous rolling machine, and taking up to obtain the aluminum-titanium-boron wire. The preparation method avoids the phenomenon of blistering or loosening since the liquid aluminum is oxidized or absorbs gas, and enhances the elongation percentage of the aluminum-titanium-boron wire.

The invention discloses a non-preheating electric arc melting welding method of thick-wall red copper and austenitic stainless steel, which includes the following processing steps: 1. the method adopts tungsten electrode helium arc welding added with nickel-copper alloy welding wires of Phi 2 to 4mm for welding; the welding current is 180 to 400A; protective gas is pure helium, the flow volume of which is 10 to 15L per minute; the diameter of the tungsten electrode is Phi 4 to 5mm; the length for positioned welded joints is 10 to 15mm and the distance between the two welded joints is 100 to 150mm; 2. the method adopts the tungsten electrode helium arc welding added with the nickel-copper alloy welding wires of Phi 2 to 4mm for welding under the non-preheating condition; the welding current is 180 to 400A; the protective gas is helium, the flow volume of which is 10 to 15L/min; 3. after the backing welding, the non-preheating welding is used for filling the welded joint. The method solves the problems of the non-preheating welding of the thick-wall red copper and austenitic stainless steel and the hot cracking trend, which improves the solidification temperature, strength and plasticity of the welded joint and prevents the hot cracking and stomata by adding the nickel-copper alloy welding wire by hand.

The invention discloses a large ship propeller casting technology. The technology includes the first step of sand mold manufacturing, the second step of riser and chilling block arrangement, the third step of melting and pouring, the fourth step of cast drying and cooling and the fifth step of cleaning and riser gas cutting. In the step of riser and chilling block arrangement, two round open risers are arranged at the upper end of a sand mold, and an outer chilling block is placed on the portion, close to the thick and large part of a propeller hub, at the lower end of the sand mold. In the step of melting and pouring, a large double-furnace-body medium-frequency electric furnace is adopted so that a cast alloy ingot can be melted into cast alloy melt, then the cast alloy melt is poured in a bottom injection type pouring mode, and a large ship propeller casting is manufactured after pouring is completed. In the step of cast drying and cooling, after pouring is completed, the large ship propeller casting is dried through an electric hot air furnace, and then heat preservation, cooling and demolding are carried out. In the way, the technology is simple and easy to control, the blade outline precision and the surface quality of a propeller can be improved, the defect that pores, wrinkles and the like occur in the surface of the propeller is avoided, and accordingly the finished product yield of the large ship propeller is effectively increased.

The invention relates to a vacuum gravity casting method of an aircraft engine block. The method comprises the following steps: graphite paint is dipped on the surface of a mesoporous sand core of a die used for gravity casting, chilling coating is coated at the part of the die used for gravity casting close to an air passage, a sealing cabin provided with the die is vacuumized before casting through a snake-shaped casting opening, and the mesoporous sand core and the sealing cabin are filled with compressed air after casting. Due to the adoption of the closed vacuum casting, the casting is performed through the snake-shaped casting opening, and as the graphite paint and the chilling coating are adopted, the compressed air is blown in the mesopore to carry the heat away, the shrinkage cavities in the casting part are greatly reduced, the qualification rate of the finished products of the casting part is improved to about 90 percent from 20 percent and the production cost is greatly reduced.

The invention provides a forming method of a flange ring for an automobile tail gas recycling device. By combining necking in spindown with reducing spinning, a tube billet can be directly formed to obtain the flange ring for the automobile tail gas recycling device, so the surface quality and integral mechanical property of the flange ring are improved; meanwhile, the productivity and the utilization rate of materials are improved.

The invention provides a centrifugal aluminum casting method of a cage type rotor of a motor. The centrifugal aluminum casting method comprises the following steps of: 1, preheating a rotor iron core; 2, preheating an aluminum casting die; 3, melting aluminum; 4, centrifugally casting: clamping the rotor iron core and the aluminum casting die which reach preheating requirement onto a centrifugal machine, starting the centrifugal machine to stably rotate according to a set initial rotating speed, rapidly injecting aluminum liquid from an upper die sprue of the aluminum casting die at the time, starting a centrifugal machine accelerating button when a die cavity is filled with the aluminum liquid, so that the centrifugal machine rotates according to the set full speed; and 5, dismantling the die after the centrifugal machine naturally stops and the aluminum liquid is solidified. The centrifugal aluminum casting method disclosed by the invention gives different centrifugal machine rotating speeds according to rotors of different diameter sections and effectively avoids castings from generating object quality defects, such as air pores, shrinkage cavities, tissue loosening and the like.

The invention discloses a plastic microinjection structure additionally with longitudinal-torsional ultrasonic vibration. The plastic microinjection structure comprises a housing and an injection sleeve connected with the housing, wherein an injection nozzle is formed in one end part of the injection sleeve; a piezoelectric ceramic piece for energy conversion is arranged in the housing; an injection screw rod is arranged in the injection sleeve and is fixedly connected with the piezoelectric ceramic piece in the housing; the piezoelectric ceramic piece is electrified to enable the injection screw rod to generate the high-frequency longitudinal-torsional ultrasonic vibration. According to the plastic microinjection structure provided by the invention, an axial reciprocating vibration part is decomposed into circumferential high-frequency torsion by virtue of a injection screw rod structure, so that a plastic raw material is further sheared and thinned, the injection operation is smoothly and uniformly performed under the conditions of relatively low pressure and temperature, and the influence of pores and warpage of a plastic product on the precision of the product and the working efficiency of a machine is avoided.

The invention discloses a preparation method for a molybdenum alloy electrode, the method comprises the steps that firstly, molybdenum powder and ZrH2 powder are mixed evenly to obtain alloy powder; secondly, an alloy bar is obtained by compressing the alloy powder through isostatic cool pressing; thirdly, the alloy bar is placed into a medium-frequency induction sintering furnance, heat preservation is conducted after heating up, and a sintered alloy bar is obtained; fourthly, the sintered alloy bar is placed into a muffle furnace for heating and heat preservation, repeated firing forging is conducted on the sintered alloy bar subjected to heat preservation, and a forged alloy bar is obtained; fifthly, the forged alloy bar is machined, and a semi-finished product of the molybdenum alloy electrode is obtained; sixthly, stress relief annealing is conducted on the semi-finished product of the molybdenum alloy electrode, and a finished product of the molybdenum alloy electrode is obtained. The molybdenum alloy electrode prepared by the preparation method has the advantages that the recrystallization temperature is high, the high temperature mechanical properties are good, the recrystallization temperature can be greater than 1250 DEG C, the glass erosion resistance property is good, the service life is prolonged by more than 25% compared with a pure molybdenum electrode, and a glass solution cannot be polluted and colored.

The invention provides a quartz glass crucible used for silicon single crystal pulling, in particular to a quartz glass crucible which inhibits the area of crystalline silica obtained by crystallizing amorphous silica to be less than 10% of the area of the crucible and inhibits the density of the dent generated by open bubbles on the inner surface of the crucible to be 0.01-0.2count/mm<2> and to a method which uses the quartz crucible and inhibits the melting loss speed of the inner surface of the crucible to be less than 20mu m/hr for silicon single crystal pulling, thus preventing air holes.

The invention relates to a high-activity cathode and a preparation method thereof. The method comprises the steps of: providing a Ni net used as a cathode base body; preparing transition layer coating liquid, wherein the content of Rh(NO3)3 is 1g/L to 3g/L; coating the transition layer coating liquid on the Ni net and carrying out drying and thermal decomposition treatment to obtain a transition layer on the Ni net; preparing active layer coating liquid, wherein the contents of H2PtCl6 6H2O, RuCl3 3H2O and Ce(NO3)3 6H2O are respectively 3 to 6 g/L, 15 to 25 g/L and 1 to 2 g/L; and coating the active layer coating liquid on the Ni net with the transition layer and carrying out drying and thermal decomposition treatment to obtain an active layer on the transition layer. The composition of the high-activity cathode prepared by the method is Ni/Rh2O3/RuO2-Pt-CeO2, the transition layer and the active layer of the base body surface are realized through separated coating, the loading quantity of the rhodium element in the coating layer is only 0.08 to 0.2 g/m<2>, the coating layer manufacture processes comprise pre-drying and thermal decomposition, the air hole generation is avoided, the bonding force of the transition layer with the Ni base body is greatly enhanced, the integral stability of the electrode is good, and the reverse current impact resistance capability and the poisoning resistance capability are greatly enhanced.

The invention belongs to the technical field of material science, and particularly relates to a repairing composite layer of an amorphous/nanocrystalline cooling roller and a preparation method of the repairing composite layer. The composite layer consists of two layers, namely a copper-based alloy layer connected with base materials and a nickel-based alloy layer, wherein the copper-based alloy layer comprises the following components by weight percent: 7-9% of Ni, 8-12% of Sn, 5-15% of Co, 0.8-2% of Si and the balance being Cu; the nickel-based alloy layer comprises one of Ni-Co alloy, Ni-P alloy, Ni-Fe alloy and Ni-Cr alloy, and the weight content of Ni in alloy is 60-75%. The preparation method comprises the following steps of pretreating the surface of the cooling roller, electroplating the copper-based alloy layer and performing wide-strip cladding on the nickel-based alloy layer by a high-power laser. The prepared composite coating is uniform and compact, and excellent in wear resistance and heat resistance, and has the characteristics of high cladding efficiency and high energy absorptivity of the cooling roller to the laser beam.

The invention discloses a piece of combined insulator hardware and a production method thereof. A standard joint of the combined insulator hardware and a connection bar adopt a split type structure and are fixed together by friction welding. The connection bar and a seal-adhesive seat of the insulator adopt an integrated structure or a split type structure; the connection bar and the seal-adhesive seat are fixed together by friction welding if the connection bar and the seal-adhesive seat adopt a split type structure. The standard joint is a Y-shaped double-ear or a ball head or a ball socket or a U-shaped double-ear or a straight line shaped single ear or a hanging ring-shaped single ear. The production method is that: according to the application characteristics of the specific parts of the hardware, a piece of hardware is divided into two or three parts and respectively produced to satisfy different strength and hardness requirements; then all the parts are fixedly welded together by friction welding technique. By adopting the invention, industrialization of the production of the insulator hardware can be easily realized, product quality and qualified rate in production are enhanced, the working efficiency is improved, the management difficulty in production is reduced and good social and economical benefits can be achieved.

Provided is a multilayer electronic component which has: a ceramic element body (1) wherein an internal electrode (2) having Ni as the main component is embedded; and external electrodes (3a, 3b) which are formed on the both end portions of the ceramic element body (1) and are electrically connected with the internal electrode (2). The external electrodes (3a, 3b) respectively have double layer structures composed of first metal layers (4a, 4b), which are brought into contact with the ceramic element body (1), and second metal layers (5a, 5b) formed on the surfaces of the first metal layers (4a, 4b), and the external electrodes are formed by sintering after the ceramic element body (1) is formed. The first metal layers (4a, 4b) contain at least Ni, and second metal layers (5a, 5b) are formed of Cu. The first metal layers (4a, 4b) are formed of either Ni or a Ni-Cu alloy, and contain 80 atm% or less (including 0 atm%) of Cu, preferably 10-50 atm% of Cu. Thus, in the multilayer electronic component, protrusion of the internal electrode to the sides of the external electrodes is suppressed and the external electrodes having a high density are provided.

The invention provides a manufacturing method of a coupler knuckle, which comprises the following steps of blanking, heating for the first time, free forging, heating for the second time, die forging for the first time, trimming for the first time, heating for the third time, die forging for the second time, trimming for the second time, processing, heat treatment and flaw detection, wherein in the step of processing, the pattern draft of a blank making piece is processed; in the step of heat treatment, the quenching and tempering treatment is performed on the blank making piece; in the step of flaw detection, the flaw detection is performed on the surface of the blank making piece; if the qualification is obtained after the flaw detection, the product manufacturing is completed; and if the qualification is not obtained after the flaw detection, the product is moved to a waste area. According to the manufacturing method of the coupler knuckle, the coupler knuckle forging process is determined to be the free forging blank making, two-time die forging and two-time trimming production processes in accordance with the structural features of a forging coupler knuckle. After the coupler knuckle which is produced by adopting the forging process is used, casting defects such as air holes, slag inclusion, shrinkage porosity and the like of the casting coupler knuckle can be completely avoided, the internal quality of the coupler knuckle is guaranteed, and the service life of the coupler knuckle is prolonged.

The invention discloses a bonding process of a solar condenser lens assembly. The bonding process comprises the following steps of enabling one ends of pressure-sensitive adhesive films to align with one ends of lenses, and bonding the painting surfaces of the lenses to the lower surfaces of the pressure-sensitive adhesive films; rotating a pressure-sensitive adhesive tape roller, utilizing an elastic push roller to push the pressure-sensitive adhesive films to the other ends of the lenses, and enabling a release paper recycling roller to drive release paper on the lower surfaces of the pressure-sensitive adhesive films to rotate; cutting and separating the pressure-sensitive adhesive films matched with the lenses according to the dimensions of cut lenses; respectively enabling a plurality of glass surfaces of the cut lenses to be adsorbed and flatly attached onto an adsorption surface of a convex die; removing the release paper on the upper surfaces of the pressure-sensitive adhesive films, and attaching the convex die adsorbing the plurality of cut lenses onto a back plate, wherein two ends of the convex die align with two ends of the back plate; and taking off the convex die, and utilizing the elastic push roller to gradually push the glass surfaces of the lenses to enable the upper surfaces of the pressure-sensitive adhesive films to completely contact with the bonding surface of the back plate. By means of the bonding process of the solar condenser lens assembly, the bonding effect is good, and the bonding performance is stable. Furthermore, the bonding process can be widely applied to the field of production of the solar condenser lens assembly.

The invention discloses an exhaust system for a rapidly-molding sand core. The rapidly-molding sand core comprises an upper outer mold, a lower outer mold and an overall sand core body; the exhaust system comprises a plurality of sand core exhaust holes, a plurality of first outer mold exhaust holes and at least one second outer mold exhaust hole, wherein the sand core exhaust holes are longitudinally distributed at the bottom of the overall sand core body at intervals; the first outer mold exhaust holes are longitudinally distributed at the bottom of a groove of the lower outer mold at intervals, the number of the first outer mold exhaust holes is the same as the number of the sand core exhaust holes, the positions of the first outer mold exhaust holes correspond to the positions of the sand core exhaust holes, and a first longitudinal exhaust channel of the exhaust system is formed by the first outer mold exhaust holes and the sand core exhaust holes; and the at least one second outer mold exhaust hole is transversely distributed at the bottom of the lower outer mold, at least one end of the second outer mold exhaust hole is led to the exterior of the rapidly-molding sand core, and the second outer mold exhaust hole is communicated with the multiple first outer mold exhaust holes. By means of the exhaust system, the exhaust effect of the sand core is effectively improved, and air holes caused by in-mold suffocation are avoided.

The invention discloses a coating rubber roller for a high-grade automobile plate production line and a manufacturing method thereof, belonging to the field of rubber rollers and preparation methods thereof. The rubber for the rubber roller comprises the following components in percentage by weight: 50.7-58.1% of ethylene-propylene rubber, 29.1-38.1% of carbon black, 2.5-2.9% of naphthenic oil, 2.5-2.9% of ester oligomer, 2.5-2.9% of tackifier, 1.0-1.2% of flow promoter, 1.9-2.2% of vulcanizing agent DCP, 0.28-0.32% of sulfur, 0.18-0.20% of accelerator BZ and 0.18-0.20% of accelerator DPTT. The method comprises the following steps: compounding the rubber; winding and rubberizing; vulcanizing in a vulcanizer; and carrying out lathe grinding. In the rubber compounding process, the materials can be sufficiently dispersed and fused. the rubberizing grain color difference on the roller surface can be eliminated, the consistency of internal and external hardness of the rubber roller is high, and the material distribution consistency and roller surface roughness consistency are high, thereby satisfies the operational requirements for the coating rubber roller for a high-grade automobile plate production line.

The invention provides a preparation method for a tungsten carbide reinforced nickel-based composite coating and belongs to the technical field of laser cladding metal ceramic composites. According tothe reparation method, during laser cladding, a broad beam rectangular spot is used for laser input, the broad beam is large in beam spot area and even in energy distribution, a large-area cladding layer without an overlapping joint area is easy to achieve, coating thermal stress can be effectively relieved, cracks are reduced, and the large-area laser cladding layer can be prepared and is uniform and compact in structure and free of cracks, pores, inclusions or other defects. According to the preparation method, composite powder is fed into the surface of a substrate through a synchronous powder feeding method, and structure uniformity of the composite coating can be ensured. Process parameters of laser cladding and the adding amount of tungsten carbide in the composite powder (claddingmaterials) are controlled precisely, cracks, pores, non-molten parts and other macroscopic defects can be avoided, the problems that a cladding layer is uneven in structure, the structure of an overlapped area is worsened, and bonding strength is lowered can be solved, and thus the structure and comprehensive performance of the coating are improved.

Disclosed is a semisolid process for manufacturing an engine aluminum alloy cam shaft through a radial forging strain provocation method. Aluminum alloy rod materials are preheated and then forged in the radial direction, a blank is remelted again after radial forging, the aluminum alloy cam shaft is extruded and cast, and finally follow-up treatment is carried out on the aluminum alloy cam shaft in the radial direction. Through the process, the uniform aluminum alloy semisolid blank without micro defects can be manufactured, the aluminum alloy cam shaft which has a few micro structure defects and is good in mechanical performance can be formed, and the process is simple and easy to operate.

The invention discloses an electron beam welding method of a titanium alloy material and CVDNb. The electron beam welding method comprises the following steps: performing oil removal, acid pickling and drying on faces to be welded of a TC4 annular test piece and a CVDNb annular test piece with a graphite matrix; butting the TC4 annular test piece with one face, having the graphite matrix, of the CVDNb annular test piece, and fixing the two abutted test pieces on a fixture; fixing the pieces to be welded by using a three-jaw chuck within a vacuum chamber of an electron-beam welding machine and adjusting the periphery and end faces of a weld joint; preheating one side of the CVDNb annular test piece by means of suppositional focus welding; and welding one side of the TC4 annular test piece by means of substantial focus welding. According to the electron beam welding method, an electron beam is applied to act on a TC4 parent metal and a CVDNb less-melting or not-melting is adopted, and a TC4 liquid metal is brazed with a preheated CVDNb parent metal to realize connection; as a result, such defects as easy splashing, pores, poor formation and the like due to that the electron beam directly acts on loose CVDNb are avoided.

The invention discloses a brazing method of a high-volume-fraction silicon carbide particle reinforced aluminum matrix composite material and an aluminum-silicon alloy. The brazing method includes thefollowing steps that S1, the to-be-welded surfaces of the silicon carbide particle reinforced aluminum matrix composite material and the aluminum-silicon alloy are subjected to surface clearing; S2,ceramic powder is prearranged on the to-be-welded surface of the aluminum-silicon alloy after treatment in the S1; S3, a brazing filler metal is placed between the to-be-welded surfaces of the aluminum-silicon alloy and the silicon carbide particle reinforced aluminum matrix composite material to form a to-be-welded part; and S4, under the protective atmosphere, the to-be-welded part is heated up,kept warm and pressurized to 5-20 MPa, and continuous heat preservation and pressure maintaining are conducted, and then the to-be-welded part is furnace-cooled to the room temperature. According tothe brazing method, oxide films on the surfaces of the silicon carbide particle reinforced aluminum matrix composite material and the aluminum-silicon alloy are broken by using the hard ceramic powderto assist the metal brazing filler metal, the brazing filler metal is fully wetted and spreads on the surfaces of the silicon carbide particle reinforced aluminum matrix composite material and the aluminum-silicon alloy, and metallurgical bonding of the connection surface of the silicon carbide particle reinforced aluminum matrix composite material and the aluminum-silicon alloy is induced.

The invention relates to a gearbox casing die-casting die which comprises a movable die (2), a fixed die frame (4), a movable die frame (3), a fixed die (6), a sprue bush (8), an inclined guide pillar (9), a fixed die core I (10), a fixed die core II (11), a fixed die core III (12), a guide pillar (13), a guide sleeve (8), a first sliding block (20) and a second sliding block (24). The three fixed die cores are fixed with the fixed die (6) together. The gearbox casing die-casting die is characterized in that the first sliding block (20), the second sliding block (24), the fixed die (6), the movable die (2), the fixed die core I (10), the fixed die core II (11), the fixed die core III (12) and a movable die insert (19) form a gearbox casing die cavity (1). According to the invention, a produced gearbox casing casting is high in quality and has no appearance defect; the production efficiency is high; the defects of shrinkage porosity, air pores, size deviation and the like are overcome; the gearbox casing casting which completely meets the requirements can be produced; the casting is high in quality.

A water-base foundry coating comprises quartz powder, and also comprises the components: diatomite for removing crystal water and accounting for 8%-12% by mass of quartz powder, silica sol accounting for 6%-10% by mass of quartz powder, white mud accounting for 0.6%-1%by mass of quartz powder, carboxymethyl cellulose sodium accounting for 6%-10% by mass of quartz powder, bentonite accounting for 6%-10% by mass of quartz powder, and the balance additive. The water-base foundry coating is good in high temperature resistance and combining performance, has capabilities of storing gas and exhausting gas, and helps to avoid disadvantages of pores, pin holes, depression and the like on castings.