341results about How to "Meet welding requirements" patented technology

The water soluble soldering flux specially for lead-free soldering material consists of boric acid and organic acid activator 5.0-10.0 wt%, non-ionic surfactant or cationic surfactant 0.1-1.0 wt%, co-solvent 8.0-20.0 wt%, filming agent 0.1-1.0 wt%, corrosion retardant 0.1-0.5 wt%, except deionized water. The compounding process includes the following steps: mixing co-solvent and partial deionized water, adding filming agent under stirring, adding the rest deionized water, activator and surfactant after dissolving, adding corrosion retardant while stirring to dissolve, stilling, and filtering to obtain the filtrate as the soldering flux. The water soluble soldering flux has excellent soldering assisting performance on lead-free soldering material, environment friendship and other advantages.

The present invention relates to a flexible reconfigurable automobile welding clamp comprising a base desk, a clamping mechanism and an independent main positioning mechanism. The present invention is characterized in that the clamping mechanism comprises an upright post, an inner sleeve, an outer sleeve, a L-shaped upright post, a flat plate connecting piece, a compacting block and a compacting connecting bar; the inner sleeve is fixed on the upright post; the outer sleeve is sheathed outside of the inner sleeve and the inner sleeve and the outer sleeve is adjustably connected with each other; the L-shaped upright post is fixed on the outer sleeve and is fixedly connected with the flat plate connecting piece on the side surface; the front end of the flat plate connecting piece is fixedly connected with the compacting block by the compacting connecting bar; the independent main positioning mechanism comprises a positioning piece, a middle transition piece, a L-shaped block, a flat plate provided with holes, a L-shaped connecting block and a flat plate; the flat plate provided with holes is fixedly connected on the flat plate by the L-shaped connecting block; the L-shaped block is connected with the flat plate provided with holes and is connected with the middle transition piece. The clamp of the present invention has a high flexibility, is adapted to a plurality of different workpieces, can be reconfigured rapidly, thereby the cost is reduced and the production efficiency is improved.

A welding and positioning tool for an air conditioner air return net frame comprises a rack, two clamping devices arranged on the rack and a first drive device driving one clamping device to be far away from or get close to the other clamping device, wherein each clamping device comprises a base, two corner clamping mechanisms arranged on the base and a second drive device driving one corner clamping mechanism to be far away from or get close to the other corner clamping mechanism; each corner clamping mechanism comprises a mounting plate, a side edge positioning mechanism fixed on the mounting plate and a top pressing mechanism fixed on the mounting plate; four corner clamping mechanisms can be reasonably distributed at four corners of the frame through horizontal movement of the clamping devices and longitudinal movement of the corner clamping mechanisms, the side edge positioning mechanisms and the top pressing mechanisms tightly press two side bars at the corners, and the 45-degree notches in the end parts of the side bars can be accurately matched and meet the welding requirement.

The invention discloses a reconfigurable automatic flexible welding production platform and an operation method thereof. The reconfigurable automatic flexible welding production platform comprises a production line main body, an accompanying platform, an accompanying fixture, a lifting mechanism, welding robots, a welding robot control center, a fixture transfer trolley, a fixture base and a production platform control center, wherein the accompanying platform can move on a line body; the accompanying clamp is positioned on the accompanying platform; the lifting mechanism is positioned on two sections of the line body; the welding robots are positioned at the two sides of a line body welding station; the welding robot control center controls movement of the welding robots and welding action of a fixed welding gun; the transfer trolley is responsible for replacing a fixture; the fixture base stores fixtures for producing different kinds of assemblies; the production platform control center controls movement of the whole production platform, wherein the movement comprises operation of a welding production line main body and operation of the lifting mechanism, so that high-flexibility requirements of automatic welding production for various small assembly components are reached, and production capacity is re-designed for realizing coordination of production tasks and production capacity.

The invention discloses halogen-free cleaning-free soldering flux for lead-free solder, which comprises the compositions in percentage by weight: 1.5 to 4.5 percent of organic acid activator, 0.5 to 8.5 percent of high-quality abietic resin, 0.3 to 1.5 percent of activated reinforcer, 0.2 to 0.8 percent of surfactant, 3.0 to 15.0 percent of wet strengthening agent, and the balance being solvent isopropanol, absolute ethyl alcohol or deionized water. The soldering flux fully meets various regulation requirements for limiting halogen. The soldering flux developed by using a novel material which does not contain the halogen can scientifically reduce the surface tension of the lead-free solder, strengthen the wetting power of the lead-free solder, improve the solderability, can be compatible with a plurality of welding materials, and has no corrosion effect on lead-free solder alloy; composing materials are volatilized by stages during the welding process, so after the welding, the surface of a PCB board has less residue, even spread, less ion residue, and reliable electrical insulating property, and does not need to be washed; and the soldering flux is a novel environment-friendly halogen-free cleaning-free soldering flux for the lead-free solder.

The invention provides a stainless steel tube for a brake system of a rail vehicle and a method for producing the same. The stainless steel tube comprises the following components in weight percentage: less than 0.030 percent of C, more than 0 percent or less than 1.00 percent of Si, more than 0 percent or less than 1.50 percent of Mn, less than 0.40 percent of P, less than 0.015 percent of S, 10.5 to 12.50 percent of Cr, 0.30 to 1.00 percent of Ni, less than 0.030 percent of N, more than 0 percent or less than 0.10 percent of Cu, 6*(C+N) to 0.75 percent of Ti and Nb, and the balance of Fe and inevitable impurities. The method for producing the stainless steel tube comprises the following steps of: smelting, continuous casting, hot rolling, punching or extruding, and deep processing of the steel tube; the method is characterized in that molten iron is made into molten steel according to the components of the stainless steel tube; at the hot rolling step, the start-rolling temperature is between 1,080 and 1,150 DEG C, and the end-rolling temperature is between 850 and 900 DEG C; and the punching or extruding deformation temperature is controlled to be between 850 and 1,100 DEG C. The stainless steel tube produced by the method has the advantages of good corrosion resistance, good welding, mechanical and cold processing properties, and low price.

The invention discloses an electron beam welding method for ultra supercritical partition plates, and relates to a welding method for ultra supercritical partition plates for solving the problems of difficulty in welded seam formation, high welding deformation, difficulty in clearing seams, difficulty in ensuring the welding quality and the like in a manual welding or gas protection welding process during welding the ultra supercritical partition plates. The method comprises the following steps of: ruling, assembling, checking, spot welding, vacuumizing, welding seams, turnover welding, checking, and performing thermal treatment. In the seam welding step, the accelerating voltage is 55 to 60kV, the welding speed is 200 to 800mm / min, the electron beam current is 50 to 350mA, the focusing current is 1,500 to 2,000mA, the scanning oscillation amplitude of electron beams in the X direction is 0 to 5.4, the scanning oscillation amplitude of the electron beams in the Y direction is 0 to 6.0, the gun distance is 220 to 320 millimeters, and the scanning waveform is circular. The method is used for electron beam welding of the ultra supercritical partition plates of a steam turbine.

The invention discloses a submerged arc welding wire of a high tensile pipeline steel. The welding wire material comprises the following chemical components in percentage by weight: not more than 0.10 of C, not more than 0.6 of Si, 1.3-1.8 of Mn, 1.4-2.5 of Ni, 0.25-0.55 of Mo, not more than 0.12 of Ti, not more than 0.05 of V, not more than 0.35 of Cr, 0.0005-0.005 of B, not more than 0.015 of S, not more than 0.015 of P, and the balance of Fe and other inevitable impurities. The submerged arc welding wire of the high tensile pipeline steel provided by the invention has the yield strength of deposited metals of more than 690MPa and the tensile strength of more than 785Mpa, has attractive welding formation, high intensity, high flexibility and high crack resistance without defects of cracking, undercut and the like, and has favorable matching effect with X100 level pipeline steel plates, and meets the requirement on the welding of oil-gas transmission pipelines under the condition of higher pressure.

A method for solder welding aluminum electromagnetic wire and brass comprises aluminum electromagnetic wire and brass connector. The invention comprises that first plating nickel on the surface of brass connector to improve the connecting strength between the solder and the brass connector and the corrosion resistance of aluminum copper connector, while said nickel layer can insulate aluminum atom and copper atom to avoid them to form rigid metal compound layer which will reduce the strength of connector, then using drug Al-Si rigid solder as non-corrosion aluminium fluoride potassium, using flame welding to weld the aluminum electromagnetic wire and the nickel layer of brass connector, the brass connector is treated with neutral oil removing, ultrasonic oil removing, water washing, acid washing, water washing, activating, waster washing, nickel plating, and drying. The inventive aluminum electromagnetic wire and brass connector have same anti-drawing strength, while the resistance of aluminum copper connector is less than the aluminum electromagnetic wire.

The present invention relates to a flux cored wire for the gas shielded welding of weathering steel. The wire consists of a steel strip and a core. The steel strip is a carbon steel strip. The core comprises components of the following percentages by weight: 34 to 38% of TiO2, 2.0% of NaF2, 3 to 5% of SiO2, 11 to 12% of Mn, 3 to 5% of Ti-Fe, 5 to 6% of Si-Fe, 3 to 5% of Mg, 2 to 3% of Ni, 3.0 to 4.0% of Cr, 2.0 to 2.5% of Cu, 0.1 to 0.3% of Zr and the balance of ferrous powder. The flux cored wire has excellent welding technical performance, mechanical properties and anti-corrosion properties. The chemical compositions, the mechanical properties and the anti-corrosion properties of deposited metal all meet the welding requirements of weathering steel Q450NQR1. The present invention provides a flux cored wire suitable for weathering steel Q450NQR1.

The invention discloses a vacuum brazing method of a gas burner of a combustion chamber of a gas turbine, which relates to a welding method of a gas burner, in particular to a vacuum brazing method of a gas burner of a combustion chamber of a gas turbine, and solves the problems that the welding quality is poor, the welding deformation is big, and the production period and the quality of the gas turbine are affected when the prior art is adopted for welding the gas burner. The method comprises the following main steps: firstly, cleaning all surfaces, operating platforms and jig surfaces of parts of a nozzle to be welded, secondly, performing primary welding, thirdly, performing primary brazing filler metal coating, fourthly, performing primary brazing, fifthly, performing secondary welding, sixthly, performing secondary brazing filler metal coating, and seventhly, performing secondary brazing. The method is used for welding the gas burner of the combustion chamber of the gas turbine.

The invention relates to an inner circular seam welding machine system and an inner circular seam welding method. The inner circular seam welding machine system comprises a welding gun for welding a welded joint between a pipe fitting and a welding part, a pipe fitting placing platform with a pipe fitting placing plane which is horizontally located, and a pipe fitting external diameter location device arranged on the tube placing platform, wherein the pipe fitting placing platform is used for placing a pipe fitting to be welded; and the pipe fitting external diameter location device is used for locating the pipe fitting with the external diameter of the pipe fitting on the pipe fitting placing platform.

The present invention discloses a backing material for a double metal composite saw blade, and a preparation method thereof. The backing material is manufactured from waste iron and steel, chrome, nickel, copper, molybdenum, niobium, vanadium, tungsten and other raw materials by carrying out smelting, forging, hot rolling, acid washing, spheroidization annealing, cold rolling and other steps. The backing material can meet welding requirements of the double metal saw blade, wherein the double metal saw blade produced from the backing material has characteristics of good quality and long service life.

The invention relates to a welding clamp. The welding clamp comprises a first supporting plate and a second supporting plate, wherein the first supporting plate and the second supporting plate are connected in a pivoted mode, an arc-shaped angle positioning plate is arranged between the first supporting plate and the second supporting plate, one end of the angle positioning plate is fixed to the first supporting plate, the other end of the angle positioning plate penetrates through the second supporting plate, the radian of the angle positioning plate is 180 degrees, and the first supporting plate and the second supporting plate are respectively connected with a clamping device for locking a workpiece to be welded in a sliding mode. According to the welding clamp, the included angle between two workpieces is adjusted through the first supporting plate capable of rotating relatively or the second supporting plate capable of rotating relatively, angle positioning is carried out through the angle positioning plate, and the included angle between the two workpieces is made to meet the welding requirement; the distance between welding edges of the two workpieces are adjusted through the sliding clamping devices to meet the requirements for the welding angle and the welding joint height; the welding clamp is simple in structure, is easy and convenient to operate and largely reduces production and machining cost.

The invention relates to a high-strength high-toughness fluoride-basic type sintered flux. The high-strength high-toughness fluoride-basic type sintered flux consists of the following compositions in percentage by weight: 22 to 26 percent of MgO, 25 to 27 percent of CaF2, 21 to 23 percent of Al2O3, 14 to 16 percent of SiO2, 4 to 7 percent of CaO, 3 to 5 percent of MnO, 0.3 to 0.6 percent of Na2, less than or equal to 3 percent of FeO, less than or equal to 0.03 percent of S and less than or equal to 0.04 percent of P. Through controlling a basicity (BI1W) scope of the sintered flux, the oxygen content and the impurity content in the sintered flux are reduced, thereby ensuring the purity of weld metal and improving low-temperature impact toughness of the weld metal. The high-strength high-toughness fluoride-basic type sintered flux is matched with a YS-H08D welding wire to weld a high-strength Q420q bridge structure steel; the weld metal has high low-temperature impact toughness, yield strength and tensile strength; a Charpy impact absorption work Akv(40 DEG C below zero) is between 169 and 202J; and the impact absorption power has small dispersion degree. The high-strength high-toughness fluoride-basic type sintered flux can be matched with a plurality of welding wires and can be used for welding a plurality of low alloy steels such as a spiral seam hidden arc welding steel tube of an X80 steel grade, which also has high low-temperature impact toughness.

The invention relates to a brazing method of an aluminum electromagnetic wire and brass. The method comprises the following steps: an aluminum electromagnetic wire and a brass connector are included; firstly nickel electroplating treatment or chemical nickel plating treatment is performed on the surface of the brass connector to enhance the connection strength of a solder and a brass connecting piece and the corrosion resistance of a copper aluminum connector; the nickel plating layer can isolate aluminum atoms from copper atoms to prevent the mutual diffusion and to form a compound layer between friable metals, thus reducing the strength of the copper aluminum connector; and then flux-cored Al-Si hard solders are adopted, the solders adopt non-corrosive potassium fluoroaluminate soldering flux, and the nickel plating surfaces of the aluminum electromagnetic wire and the brass connecting piece are partially lapped and brazed through gas brazing. During the braze welding, the mass percents of the main components of the flux-cored Al-Si hard solders are 9.0 to 13.0 percent of Si, less than 4.70 percent of Cu, and less than 0.20 percent of Zn in sequence. In the aluminum electromagnetic wire and the connector of the brass connecting piece which are welded by adopting the method, the tensile strength of the connector is approximately equal to that of the aluminum electromagnetic wire.

The invention relates to environment-friendly and low-temperature residue-free solder paste and a preparing method thereof. According to the technical scheme, the environment-friendly and low-temperature residue-free solder paste is characterized in that the solder paste comprises, by weight, 41.0%-60.0% of Sn, 26.6%-37.7% of Bi, 2.1%-4.4% of a third element alloy and 9.0%-19.0% of scaling powder; and the scaling powder comprises, by weight, 67.0%-75.0% of a carrier, 14.8%-18.8% of an activating agent, 4.6%-8.72% of a thixotropic agent, 0.32%-3.2% of a surface active agent and 1.48%-3.5% of corrosion inhibitor. The environment-friendly and low-temperature residue-free solder paste is provided, halogen-free components are adopted in a formula, volatile components are avoided in the tin paste, and smells are avoided during using. After welding, residues are colorless and transparent, and the effect of replacing Pb containing tin paste or halogen-containing tin paste is achieved. Under the low-temperature welding condition, nano aluminum powder is added, a high-temperature solid solution is formed during welding to serve as an auxiliary part for supplementary welding, poor welding of a Sn-Bi alloy is effectively improved, and the welding requirement for aluminum components on the surface of an electronic component can be met; and meanwhile, the storage period of the tin paste is prolonged, and better wettability is brought.

The invention relates to a welding jig, in particular to a circular seam laser welding jig for thin-walled aluminum alloy end socket flange plates. The circular seam laser welding jig aims to solve the problems that as no special circular seam laser welding jig for the thin-walled aluminum alloy end socket flange plates exists in the prior art, welding deformation is serious, and the welding accuracy cannot meet the welding requirement. An inner platen is located at the upper end face of an inner platen base, a first circular center groove corresponds to a second circular center groove in an up-and-down mode, a first annular groove is machined in the upper end face of the outer edge of the inner platen base in the circumferential direction, a second annular groove is formed in the lower end face of the inner ring of an outer platen in the circumferential direction, the second annular groove of the outer platen is combined with the first annular groove in a pressed mode, an annular interval is reserved between the outer platen and the inner platen, a plurality of hinge bases are evenly distributed and fixedly installed at the outer edge of a lower disc in the circumferential direction, the lower end of each screw rod is hinged to the corresponding hinge base, and the upper end of each screw rod penetrates through the outer edge of the outer platen and is in threaded connection with a second nut. The circular seam laser welding jig is used for welding the thin-walled aluminum alloy end socket flange plates.

A 9Ni steel low hydrogen type nickel-based welding electrode for welding an LNG ship comprises a pure nickel core wire and a coating covered on the surface of the core wire. Ingredients and contents (wt %) of the core wire are as follows: no more that 0.02% of C, no more than 0.01% of S, no more than 0.01% of P, no less than 99.0% of Ni, the rest element content no more than 0.50%, and all the ingredients total 100%. Powder ingredients of the coating comprise, by weight, marble 25-35%, fluorite 10-21%, chromium metal 12-28%, manganese metal 4-10%, ferromolybdenum 8-16%, ferrotungsten 1-6%, ferrocolumbium 7-15%, organic matter 0-2%, sodium carbonate 0-2%, and all the ingredients total 100%. According to the proportion, all the ingredients of the powder are evenly mixed with sodium silicate which accounts for 25-35% of the total mass, and then are sent into a press coater and covered on the core wire, and finished after a low temperature baking and a high temperature baking. The 9Ni steel low hydrogen type nickel-based welding electrode for welding the LNG ship has a good welding manufacturability and can be welded from all the positions, the deposited metals have the advantages of high yield strength, high tensile strength and good low temperature impact toughness, and even have a high low temperature impact value in -196oC.

The invention provides a flux-cored wire used for low-alloy chrome molybdenum heat-resistant steel. The flux-cored wire comprises a low-carbon steel sheath and a flux core which is stuffed in the low-carbon steel sheath. The flux core comprises the following components in percentage by mass: 30-35% of natural rutile, 2-5% of magnesium oxide, 1.5-3% of barium carbonate, 2-3% of elpasolite, 2-5% of potassium titanate, 15-20% of a silicomanganese alloy, 8-10% of chromium, 3.5-5% of ferromolybdenum, 1-2% of ferro-aluminum, 0.5-2.5% of roasted aluminum oxide, 0.5-1% of nickel powder, 0.5-1.5% of magnetite and the balance of iron powder and inevitable impurities. The flux-cored wire has the advantages that deposited metal composition completely accords with stipulation of related national standards, and the all-position welding requirement of the 1-1.25%Cr-0.5%Mo heat-resistant steel can be met; meanwhile, the mechanical performance indexes of deposited metal completely accord with stipulation of related national standards; impact property of the deposited metal is excellent, and specially, low-temperature impact toughness (minus 30 DEG C) is stabilized at more than 50J; and an impact value is stable.

The invention discloses an electric welding rod with a novel slag system for welding 9Ni steel for storage tanks of LNG (liquefied natural gas) ships. The electric welding rod comprises a core wire and a coating. The coating is coated on the surface of the core wire, the core wire comprises, (in wt%), lower than or equal to 0.02% of C, lower than or equal to 0.01% of S, lower than or equal to 0.01% of P, higher than or equal to 99.0% of Ni and lower than or equal to 0.50% of other elements, and the total quantity of various compositions of the core wire is 100%; the coating comprises, by weight, 10-20% of marble, 15-25% of rutile, 4-10% of fluorite, 1-5% of titanium dioxide powder, 1-5% of potassium cryolite powder, 10-25% of chromium metal, 3-10% of manganese metal, 8-15% of ferro-molybdenum, 1-5% of ferrotungsten, 1-5% of ferrotitanium, 5-10% of ferroniobium, 0-3% of organic matters and 0-3% of soda ash, and the total quantity of various powder compositions of the coating is 100%; the various powder compositions are proportionally uniformly mixed with water glass to obtain a mixture, the mass of the water glass accounts for 22%-30% of the total mass of the coating, the mixture is fed into an extrusion press and is coated on the core wire, and the mixture and the core wire are baked at a low temperature and then are baked at a high temperature to obtain the electric welding rod. The electric welding rod has the advantages that electric arcs are stable during welding, the electric welding rod is low in splashing and good in slag removing property, formed weld joints are attractive, and an all-position welding effect can be realized.

The invention relates to an acidic flux cored wire for ultralow-hydrogen low-temperature steel, consisting of a welding wire steel sheet skin and a flux core, wherein the traditional Chinese powder of the flux core comprises rutile, electrolytic manganese, reduced iron powder, magnesium powder, ferroboron, lithium fluoride, metallic nickel powder, ferrotitanium, titanate, rare-soil silicon, cryolite and feldspar. A steel belt used for the surface of the welding wire comprises the following components by weight percent: less than or equal to 0.05% of C, less than or equal to 0.04% of Si, less than or equal to 3.5% and more than or equal to 1.5% of Mn, less than or equal to 0.015% of P, less than or equal to 0.015% of S and the balance of Fe. The acidic flux cored wire has the advantages that the low-temperature impact toughness is good and the hydrogen content is low; and the acidic flux cored wire is applicable to welding of a large spherical tank of liquefied petroleum gas, an ocean platform and a drilling ship.

The invention discloses a special welding rod for sulfuric acid dew point corrosion-resistant steel. The welding rod comprises a steel core and a coating. The coating comprises, by weight, 33-45% of CaCO3, 18-29% of CaF2, 8-13% of TiO2, 5-9% of SiO2, 4-6% of Si-Fe, 2-4% of Mn, 2-3.5 % of Cr, 0.8-1.5% of Cu, 0.1-0.3% of Sb, 1-1.5% of Na2CO3, 2-4% of rare earth oxide, and the balance iron powder. The welding bar is little in welding splashing, attractive in shape, easy to deslag, high in deposition rate and good in welding performance, and corrosion resistance, deposited metal chemical components and deposited metal mechanical property of the welding bar can meet the welding requirements of the sulfuric acid dew point corrosion-resistant steel. Materials are convenient to purchase, production cost is low, the application range is wide, and use is convenient.

The invention relates to a pass-type straight seam welding machine comprising a welding gun unit, a frame, an automatic centering unit, a to-be-treated material hanging unit, an automatic pushing and bracket lifting unit, a welding mandrel suspension and cylinder inner diameter positioning unit, a cylinder outer ring holding unit, a cylinder end face lifting and positioning unit, a mandrel door opening and closing unit, and an automatic cylinder incoming and outgoing unit. The whole set of machine realizes automatic feeding, positioning, welding and discharging, achieves the purpose that one person operates multiple machines, can meet welding requirements for weldments of different thickness and length, and can serve as the foundation for realizing further unmanned welding.

The invention belongs to the field of a welding wire material, and particularly relates to a welding wire for submerged-arc welding of high-efficiency X100 pipeline steel and the application of the welding wire. The welding wire material comprises the chemical components in percentage by weight: 0.01-0.05 wt% of C, 1.4-2.1 wt% of Mn, 0.1-0.3 wt% of Si, 0.2-0.4 wt% of Mo, 0.05-0.1 wt% of Ti, 0.003-0.005 wt% of B, 0.1-0.4 wt% of Cr, 0.2-0.3 wt% of Cu, 0.3-0.6 wt% of Ni, 0.03-0.08 wt% of Nb, less than or equal to 0.005 wt% of S, less than or equal to 0.005 wt% of P, and the balance of Fe. The welding wire for the submerged-arc welding, disclosed by the invention is matched with an SJ101-100 welding flux deposited metal and has an excellent comprehensive mechanical property, the yield strength is greater than 690 MPa, the tensile strength is greater than 780MPa, and the impact work is greater than 108J in -20 DEG C; after welding, the forming of a welding seam is attractive, the defects of cracking, undercutting and the like do not exist, the strength is high, the toughness is good, the crack resistance is good, the welding seam has a good matching effect with the X100 pipeline steel, and the welding wire has a decisive function on performance of a weld metal as the welding wire is used as a main filling metal; according to the welding wire disclosed by the invention, the welding requirements of an oil and gas transmission pipeline under a situation of higher pressure are met.

The invention discloses a diffusion welding process for a heat exchanger core. The diffusion welding process comprises the following steps: (1) pre-welding pre-treatment: feeding the well assembled heat exchanger core into a diffusion welding furnace, and vacuumizing the interior of the furnace to be below 0.01 Pa; (2) diffusion welding: raising the temperature to 800-850 DEG C at the speed of 15-20 DEG C / min, keeping the temperature for 30 min, after that, raising the temperature to 1,100-1,150 DEG C at the speed of 10-15 DEG C / min, keeping the temperature for 3 h, and performing vacuum cooling to the room temperature, wherein the pressure (8-9.5 MPa) exerted before is kept in the first 2 h and reduced to 4-6 MPa in the last 1 h; and (3) postweld heat treatment: raising the temperature of the heat exchanger core to 1,150-2,000 DEG C, keeping the temperature for at least 20 h, and after that, reducing the temperature in a water quenching manner. According to the diffusion welding process, such parameters as welding temperature, diffusion time and pressure are controlled, the step of heat treatment after diffusion welding is added, so that brittle phases easily generated during diffusion welding are reduced, and the quality of a welded joint of the heat exchanger core is improved.

The invention provides a longitudinal joint automatic welding machine which comprises a machine frame (1). A supporting mechanism and an adsorption device for clamping a workpiece are arranged in the machine frame, the adsorption device comprises an adsorption base (2) fixedly arranged at the upper end of the machine frame (1), a vacuum adsorption tube (3) for adsorbing the workpiece is arranged at the top end of the adsorption base (2) in the length direction, the supporting mechanism comprises a lifting device and a supporting portion which is used for supporting the workpeice and arranged at the upper end of the lifting device, the supporting portion is a V-shaped supporting groove (8) with an upward opening, and the V-shaped supporting groove is located below the adsorption base (2) and is arranged in parallel with the adsorption base (2) on a vertical face. A vacuum adsorption method is adopted for clamping the workpiece, so that working efficiency of welding joint clamping and calibration is improved. The V-shaped supporting groove is adopted to serve as a workpiece supporting frame, so that the problem of poor consistency of the welding quality caused by the adoption of cantilever for supporting the workpiece in ordinary welding is solved.

The invention discloses a coated welding wire for welding low-alloy high-strength steel. The coated welding wire comprises a welding wire substrate and a coating which coats the surface of the welding wire substrate, wherein the welding wire substrate is made from the following components in percentage by weight: 0.029 to 0.041 percent of Ti, 0.01 to 0.015 percent of Al, 0.083 to 0.11 percent of Nb, 0.1 to 0.15 percent of C, 0.2 to 0.3 percent of Cr, 0.3 to 0.5 percent of Si, 0.01 to 0.03 percent of N, 1.4 to 1.7 percent of Ni, 0.1 to 0.6 percent of Mo, less than or equal to 0.002 percent of P, less than or equal to 0.002 percent of S, and the balance of iron and unavoidable impurities, wherein as specified by the following formula, K is between 0.013 and 0.032, K=29[Ti]+52[Al]+27[Nb]-100[N]; [Al], [Ti], [Nb] and [N] represent the weight percentage contents of Al, Ti, Nb and N in the welding wire substrate respectively. The invention further discloses a manufacturing method of the coated welding wire for welding the low-alloy high-strength steel. By adopting the coated welding wire, high strength of welding metal is ensured, the welding performance of the low-alloy high-strength welding wire is improved finitely, the occurrence of cold cracks is controlled, a low splashing rate is achieved, and the welding requirement of the high-strength low-alloy steel is met.

The invention relates to a metallization method of an N-type solar cell, the cell, a module and a system. The metallization method of the N-type solar cell comprises the following steps of forming a groove-shaped structure penetrating through a passivation anti-reflection film on the front surface of an N-type silicon-crystal substrate after processing the N-type silicon-crystal substrate; printing a back-surface electrode on the back surface of the N-type silicon-crystal substrate; printing aluminum paste on the groove-shaped structure to form a front-surface auxiliary grid; printing aluminum-doping silver paste or silver paste to form a front-surface main grid; and sintering the front-surface main grid to obtain the N-type solar cell. The metallization method has the advantages that during the metallization on the front surface of the N-type solar cell, the main grid line uses the silver-containing paste, and thus, the welding requirement can be met better; the auxiliary grid line uses the aluminum paste, thus, the auxiliary grid line and a p+ doping surface can be in excellent ohmic contact, and the production cost brought by the paste also can be greatly reduced.

The invention belongs to the constructional engineering field and relates to a project beam-column joint for a reverse building method. The technical scheme of the project beam-column jpint for the reverse building method is as follows: after a foundation pit is excavated below the bottom elevation of a structural beam, a steel ring plate is welded in an elevation position opposite to the position of the main reinforcement of the structural beam at the outer side of a concrete filled steel tubular column; the width of the steel ring plate meets the welding requirement of the main reinforcement of the structural beam; the thickness of the steel ring plate meets the force transfer requirement of the main reinforcement of the structural beam. The main reinforcement of the structural beam transfers force to the main reinforcement of the structural beam of the adjacent span through the steel ring plate. The joint has the advantages that the connection of the reinforcements of the structural beam and force transfer among the reinforcements of the structural beam in the position of the beam-column joint in a reverse building foundation pit project are realized successfully, and the trouble of different traversing through the reinforcements of the beam-column joint to technicians in a field for a long time is solved.