156results about How to "Avoid heat cracks" patented technology

The CO2 gas protected single-sided welding and double-sided forming process includes the following steps: cutting bevels in the pieces to be butt welded; spot welding to fix the bevels; adhering ceramic lining to the opposite side of the bevels; filling smashed metal wires in the thickness capable of forming welding seam over 7 mm between the bevels; bottoming welding under the protection of CO2 gas at the welding current of 420-540 A; and 6. the subsequent welding. The present invention has the advantages of double-sided forming via single-sided welding, capacity of preventing heat crack in large current condition, and no weld penetration.

The invention relates to a method for welding a large liquified natural gas storage tank. The method uses alternating rectangular wave current for welding with a welding parameter of between 8.156 and 24.32 KJ/cm and the interlayer temperature of energy input of between 18.9 and 24.32 KJ/cm of 300 DEG C, and selects low carbon type nickel-based welding wire. The method overcomes the problem of arc blow in welding, not only can avoid impact on 9 percent Ni steel during carbon gouging, but also can save welding materials and manpower so as to accelerate construction process and improve welding efficiency. Welding with the process can improve the cold temperature flexibility of a macrograin area of a welding zone, avoid generation of brittle tissue of a fusion area, avoid generation of cold and heat crack in welding, has excellent quality of weld joint, and effectively ensure the cold temperature flexibility of 9 percent Ni steel welding joints. The method well control the quality of the weld joint, and ensures the overall quality of the natural gas storage tank.

The invention provides a grinder of a bullet train tread cleaner, wherein the grinder is made of a composite material; the composite materials comprises modified phenolic resin 6818, iron powder, copper fibres, steel fibres, sepiolite, potassium feldspar, graphite, cryolite and aluminium oxide; the invention further provides a production method of the grinder.

The invention relates to a high-friction coefficient composition brake shoe. The high-friction coefficient composition brake shoe comprises a steel backing and a friction material, the friction material comprises the following raw materials including, by weight, 1-5 parts of aramid fiber, 8-12 parts of butadiene-acrylonitrile rubber, 0.5-1 part of stearic acid, 0.3-1 part of an accelerant, 0.6-1 part of sulphur, 0.5-1 part of zinc oxide, 4-7 parts of phenolic resin, 10-20 parts of inorganic composite fiber, 8-15 parts of iron powder, 10-20 parts of barium sulfate, 7-15 parts of kibdelophane powder, 5-10 parts of steel wool fiber, 1-3 parts of bauxite, 8-15 parts of potassium feldspar powder, 2-5 parts of mica, 2-5 parts of flake graphite, 5-10 parts of sepiolite fiber and 2-5 parts of molybdenum disulfide. By means of the high-friction coefficient composition brake shoe, the change of the speed of the wear rate of the high-friction coefficient composition brake shoe can be basically identical to the change of the adhesion coefficient of a wheel track, the abrasion loss when a vehicle is braked is less, failure can not occur in braking, and the traffic safety is guaranteed. The invention provides a production method of the high-friction coefficient composition brake shoe at the same time.

A WC—Co material or polycrystalline diamond-Co material that has a gradient in the grain size of the particles. Specifically, the material may have a top layer that has coarse grains that is designed to dissipate the heat caused by friction (and thus prevent thermal cracking). The material will then have a bulk substrate that is made up of finer grains and provide adequate hardness for the material. The top layer is positioned on top of the bulk substrate.

The invention provides a synthetic brake shoe which comprises the following raw materials in parts by weight: 3-5 parts of phenol formaldehyde resin, 1.5-3.5 parts of nitrile-butadiene rubber, 1.5-3.5 parts of graphite, 3.5-5.5 parts of reduced iron powder, 4.5-6.5 parts of steel fiber, 1.5-3.5 parts of wollastonite, 2.5-4.5 parts of meerschaum, 3.5-5.5 parts of potash feldspar, 0.05-0.20 part ofaluminum oxide, 0.15-0.40 part of sulfur and 0.05-0.20 part of accelerator. The invention selects preferable raw materials and formula to develop the synthetic brake shoe which has the advantages of long service life, low abrasion mating plate and high friction factor. The car loading examination proves that the synthetic brake shoe satisfies the design requirements, does not generate harmful damascene, and does not generate thermal damage on the wheels; the service life is apparently longer than the currently universal synthetic brake shoe with high friction factor, reaching 0.2-0.24 millionkilometers per year; and the application and maintenance cost is lowered, the operation time for replacing the brake shoe is shortened, and the conveying efficiency is enhanced.

The invention relates to the technical field of aircraft fuel system mechanical part accessory repairing, in particular to a method for repairing aircraft fuel system aluminum silicon alloy shell casting defects. The method includes the following steps of S1, decomposition cleaning; S2, defect positioning and removal; S3, dye penetration; S4, cleaning; S5, protection; S6, surface pretreatment; S7,preheating before spraying; S8, cold spraying; S9, coating processing; S10, stress relief treatment; S11, dye penetrant inspection; and S12, anti-corrosion treatment. According to the method for repairing the aircraft fuel system aluminum silicon alloy shell casting defects, the problems of a heat crack of a shell and base material annealing softening caused by large heat input of a traditional surfacing process are effectively avoided, the repairing problem of the aircraft fuel system aluminum silicon alloy shell casting defects is solved, at the same time, casting defect repairing of the shell can be realized under the operation temperature of less than 120 DEG C, the problem of scrapping of a whole part of accessories due to shell damage or secondary damage caused by repairing is avoided, and economic benefits are significant.

The invention relates to the technical field of casting of ingots, and provides a round ingot die. The round ingot die comprises a die body, a lug and an insulation board; an inner cavity is formed in the die body; the cross section of the outer side surface of the die body is polygonal wave shaped. According to the round ingot die, the radiating area of the side surface of the ingot is increased; hot melt at the outermost layer can be quickly cooled to form a chilling layer; the thickness increase of the chilling layer is sped up; therefore, static pressure in pouring of hot melt can be borne; crack can be prevented; the difficulty at pouring of the round ingot can be greatly reduced; meanwhile, the size precision of the outer side surface of the round ingot die cannot influence the size precision of the round ingot, so that the requirement on the processing precision of the outer side surface of the round ingot die is reduced, the process and working houses are decreased, and the cost can be saved. The invention further provides a round ingot manufacturing method. The method is that the degree of superheat of hot melt is 40 to 55 DEG C; the linear speed of pouring of an ingot body is 80 to 220mm/min; the linear speed of filling and pouring of a dead head of the insulation board is 35 to 90mm/min. The method can properly reduce the casting temperature and speed; the round ingot can be quickly radiated; therefore, the surface cracks can be decreased.

The invention relates to a 7-series high-strength aluminum alloy variable polarity plasma arc welding method. The method aims at solving the problem that in the prior art, the welding quality is poor. The vertical welding process is adopted, 7-series high-strength aluminum alloy workpieces are fixed through clamps after being vertically placed, a variable polarity plasma welding gun provided with an automatic wire feed device is horizontally placed on one side of the workpieces, the gun head of the welding gun right faces a welding seam between the two workpieces to conduct variable polarity plasma arc welding, the current selection range of the positive polarity and the negative polarity of the variable polarity plasma arc welding is between 190 A and 260 A, and the current selection range of the negative polarity is between 240 A and 300 A. A variable polarity plasma arc welding power supply serves as a power supply of the plasma welding gun. The 7-series high-strength aluminum alloy variable polarity plasma arc welding method has the advantages that 7-series high-strength aluminum alloy with a thickness ranging from 6 mm to 12 mm can be welded, it can be ensured that the reasonable temperature gradient section is formed between a liquid molten pool and solid metal in the welding process, the stable hole punching effect can be obtained, hole punching molten pool force and the heat balance can be ensured, the defects of welding hot cracks, pores and the like can be overcome, the appearance of the welding seam is uniform and neat, the welding deformation is small, and the welding efficiency is high.

The invention belongs to the field of mechanical manufacture cutting cutters, and in particular relates to a SiZrCN gradient composite coating cutter and preparation method thereof. The coating is the SiZrCN gradient composite coating prepared by adopting a composite coating method of unbalanced magnetron sputtering and electric arc plating; the surface of the coating cutter is SiZrCN gradient composite coating with gradually-changed gradient of nitrogen content, a Ti transition layer and a SiZrC transition layer are sequentially arranged between a cutter base body and the coating. By adopting the SiZrCN ultra-hard carbon-nitrogen compound coating, because two metals including Si and Zr are added in the coating at the same time, the nitrogen content of the coating structure component is gradually changed in a gradient manner, so that the cutting machining performance of the cutter can be improved. The coating has high hardness and heat stability, and also has good diffusion prevention and wear prevention performances, good plastic deformation resistance ability and excellent friction and wear resistance property. In the cutting process, the cutter can effectively prevent the occurrence of cracking of cutting edges and hot cracks, guarantee the machining surface quality of the workpieces, and prolong the service life of the cutter by more than 70%.

The invention discloses a stainless steel band electrode electroslag surfacing welding strip and a welding flux. The Mo element is not added into a transition layer welding strip, but the surfacing metal has sufficient Mo; and the welding strip and the welding flux can be matched to be applied to large-scale surfacing on the inner wall or the outer wall of a container and can meet corrosion-resistant and high-temperature-resistant requirements. When the welding strip and the welding flux are matched for surfacing, the dilution rate is ultralow and is 5 to 12 percent and the production efficiency is high; slag is easy to remove, a formed welding bead is attractive and welding defects do not exist; the intergranular corrosion resistance is excellent; and cracks do not exist during surfacingbending.

The invention relates to an aluminum alloy plate strip preparation method based on vacuum centrifugal casting and a vacuum centrifugal casting device. The preparation method comprises the following steps that raw materials are prepared according to components of a target aluminum alloy; a cast pipe blank is cast in a vacuum centrifugal casting manner; the cast pipe blank prepared through vacuum centrifugal casting is split, the split cast pipe blank is leveled, and an aluminum alloy cast plate blank is obtained; and the aluminum alloy casting plate blank is rolled, and an aluminum alloy plate strip is obtained. According to the preparation method, under the action of centrifugal force, the feeding environment in the solidification process of aluminum alloy melt liquid can be obviously improved, and casting defects such as shrinkage porosity and shrinkage cavities can be effectively bridged under the action of the centrifugal force. Due to the fact that vacuum centrifugal casting is completed under the vacuum condition, a melt does not make contact with air, melt oxidation can be effectively avoided, the defect of oxide inclusion in the cast pipe blank is greatly reduced, and the quality of the pipe blank is improved.

The invention relates to a device and a method for a water-cooling hot wire argon tungsten-arc welding of an austenitic stainless steel tube. If the sensitization and tendency of generating hot cracks are controlled only by reducing welding current and welding voltage and reducing welding hot input, the welding efficiency is reduced, and the welding characteristic of high-efficiency mechanical hot wire argon tungsten-arc welding cannot be fully played. In the method for the water-cooling hot wire argon tungsten-arc welding of the austenitic stainless steel tube, the prewelding preparation is performed first, namely the height and position of a welding gun are adjusted, an austenitic stainless steel straight tube is subjected to butt joint, and the water supply position of cooling water is adjusted; the welding gun and wires of welding equipment are protected by the same gas course; and when welding priming coats and the tube rotate to the position of 270 degrees, a cooling water valve is opened, and a welding joint is subjected to spray cooling by a spraying device until all priming coats, filling layers and covering layers are welded completely. The device and the method are used for the argon arc welding of the austenitic stainless steel tube.

The invention discloses a copper-steel dissimilar metal welding method. A copper part and a steel part are welded together to form a copper-steel corner welding workpiece. The copper-steel dissimilar metal welding method comprises the following steps: firstly, a surfacing copper based alloy welding material is heated on one side of the copper part so as to form a copper based alloy transition layer on the welding surface of the copper part, secondly, assembling the steel part on the copper part to perform spot welding after cooling the copper part and trimming weld joints, and finally adopting a copper based welding rod to weld the copper based alloy transition layer and the steel part together, wherein the welding method is gas shield welding in a cold state. The copper-steel dissimilar metal welding method adopts a surfacing copper based alloy transition layer in a hot state so as to enable the copper based alloy welding material to be combined with the copper part well, then the copper-steel corner welding is performed in the cold state which is convenient to operate, and penetration ratio of weld metal can be controlled effectively, thereby preventing weld joint hot crack from being produced and meeting the welding requirements.

The invention relates to a method and device for joining members. According to the method of the invention, at least one of the members (12, 14) is made of fibre reinforced plastics, and a member complex is joined by friction welding of the members (12, 14) using an initially separate friction element (20), wherein the friction element (20) forms a fixed composition part of the member complex during the welding and friction process. The device according to the invention includes a support device (16) for fixing the members (12, 14) and a drive device (18) for rotating and pressing the friction element (20), wherein the force applied to the member (12, 14) by the support device (16) can be adjusted independent of the force applied to the friction element (20) by the drive device (18).

A disk rotor assembly for a vehicle may include an adaptor adapted to be mounted on a hub and to receive torque of a wheel, a disk rotor generating a braking force, a transmitter engaging the adaptor with the disk rotor and adapted to transmit the torque received by the adaptor to the disk rotor or to transmit the braking force generated by the disk rotor to the adaptor, and engaging member for engaging the adaptor, the disk rotor, and the transmitter altogether.

The invention relates particularly to a submerged-arc welding wire for CO2 (Carbon Dioxide) corrosion resistant high-strength pipeline steel. The technical scheme is that the submerged-arc welding wire for the high-strength pipeline steel comprises the following chemical components: 0.02-0.06 wt% of C, 0.20-0.40 wt% of Si, 1.20-2.00wt% of Mn, 3.00-8.00wt% of Cr, and 0.20-0.40wt% of Cu, 0.04-0.10 wt% of (V+Ti+B), not more than 0.001 wt% of S, not more than 0.002 wt% of P, and the remain of Fe and inevitable impurities. The submerged-arc welding wire for the high-strength pipeline steel provided by the invention is matched with an SJ101-G soldering flux for use, requirements of intensity, tenacity and CO2 corrosion resistance of a welding joint formed by the welded submerged-arc welding wire for the CO2 corrosion resistant high-strength pipeline steel can be met by mechanical property and corrosion resistance of formed weld metal; moreover, the property of the welding joint is matched with base metal, so that technical requirements of oil and gas pipelines prepared by welding can be met; and the welding joint is good in CO2 corrosion resistance.

The invention provides a gravity casting process of a lead-free brass tap, which has the advantages that a flowing distance of a product in a casting process is short, the simultaneous solidification is achieved, hot cracks are reduced; a heat balance effect of a mould is good, so that heat balance of the product is facilitated, and the stress micro-cracks during cooling are reduced. The gravity casting process of the lead-free brass tap comprises the following step of casting and forming lead-free brass liquid through a gravity casting device, wherein the gravity casting device comprises an upper half mould, a lower half mould and a sand core, wherein mould cavities matched with a tap body in shape are respectively and correspondingly arranged between the upper half mould and the lower half mould, the sand core is arranged in the mould cavities between the upper half mould and the lower half mould, the shape of the sand core is matched with the shapes of a water inlet part and a water outlet part of the tap and an inner cavity of an installing part of a valve core, a casting cavity is formed between the sand core and the mould cavity, a sprue in which lead-free molten copper is cast is arranged in the lower half mould, the sprue is connected with the casting cavity, the sprue is provided with an internal sprue and an external sprue, and the internal sprue is correspondingly arranged at the casting cavity for forming the water inlet part of the tap body.