117results about How to "Lower the preheat temperature" patented technology

The invention provides a novel high-strength or ultrahigh-strength steel laser-arc composite heat source welding method, which belongs to the technical field of the welding of high-strength or ultrahigh-strength steel. The method aims to solve the technical problem that the higher temperature needs to be adopted for preheating in order to prevent cold cracks during the welding of the high-strength or ultrahigh-strength steel. The welding method mainly comprises the following steps: the laser power is higher than 800 watts, a composite form that laser (2) is ahead and electric arc (3) follows is adopted along the welding direction, the filament spacing h is controlled to between 3 and 7 millimeters, and an included angle theta between an electric arc welding gun (4) and the horizontal plane is between 45 and 60 DEG. When the method is used to weld, a composite heat source welding pool is elongated and the oscillation of the pool is sharpened, so that the solidification rate of pool metal is reduced and grains are refined, thereby reducing the cold crack sensitivity during the welding process of the high-strength or ultrahigh-strength steel. The welding method can reduce the preheating temperature of the welding of the high-strength or ultrahigh-strength steel, and even can realize high-strength non-preheating welding.

The invention relates to the technical field of high molecular materials and particularly relates to preparation and application methods of a selective laser sintering polypropylene powdery material. The method comprises the following steps: obtaining polypropylene powder by a freeze grinding method; grading and collecting by an airflow screening machine, selecting polypropylene powder with the granularity in a range of 200-800 meshes and returning coarse materials which do not meet the fineness requirement to a stock bin and continuously smashing; and adding 100 parts of polypropylene powder, 0.1-1 part of graphite powder, 0.01-0.5 part of antioxidant and 0.5-6 parts of metallic soap salt and uniformly mixing in a high speed mixer, wherein the granularity of the graphite powder is 1000-5000 meshes and the antioxidant is a compound antioxidant consisting of phenols and phosphonate or thioester in a weight ratio of 1:1. The polypropylene powder prepared by the invention has excellent sintering performance and the SLS (Selective Laser Sintering) formed piece prepared by the polypropylene powder has high mechanical property and dimensional precision.

The invention provides a method for preparing a diesel oil component or jet fuel component by using animal and plant oil. The method comprises the following steps of: (1) dividing the animal and plant oil into at least two parts, introducing the at least two parts of animal and plant oil to a plurality of catalyst beds of a first hydrogenation reactor, and enabling the at least two parts of animal and plant oil and a hydrodeoxygenation catalyst to contact and react to obtain n-alkanes with the carbon number of 8-24; (2) filling an isomerization catalyst in a second hydrogenation reactor, introducing a reaction product obtained in the step (1) to the second hydrogenation reactor, and reducing a condensation point after isomerization reaction to obtain a diesel oil component; or, (3) filling a selective cracking catalyst in the second hydrogenation reactor, introducing the reaction product obtained in the step (1) to the second hydrogenation reactor, and then, carrying out selective hydrocracking and isomerization to obtain a jet fuel blending component. The method provided by the invention is high in jet fuel yield; and the prepared jet fuel blending component is good in quality and can be mixed with the traditional petroleum-based jet fuel according to any proportion so as to be an excellent blending component.

The invention discloses a method for manufacturing an aluminum alloy hub. The method comprises the following steps: first, manufacturing an aluminum alloy hot rolled plate into a round-sheet-shaped blank; second, stretching the round-sheet-shaped blank into a disc-shaped blank through a spinning machine or punch press; third, extruding the spoke central part of the disc-shaped blank; fourth, punching and trimming the extruded blank; fifth, arranging the punched and trimmed blank into the spinning machine and spinning the blank into a hollow rotating body hub blank with high strength; sixth, conducting stabilizing treatment or solid solution aging hot treatment on the hollow rotating body hub blank formed in a spinning mode; seventh, conducting machining and surface treatment. According to the method for manufacturing the aluminum alloy hub, a material and manufacturing process used by the aluminum alloy hub are improved, Al-Mg-Si aluminum alloy bars in a cast state are adopted as a raw material so that the aim of simplifying the process can be achieved, and the process of upsetting, forging and prefabricating the disc-shaped blank and the like are not needed before spinning forming.

The invention belongs to the technical field of precision casting, and particularly relates to a multiple-connection-blade precision casting method. The position of an edge plate of a multiple-connection-blade shell is coated with a cooling agent, a pouring system is improved, a flow gate and a cross gate at the air inlet edge are removed, and the preheating temperature and the pouring temperature of the shell are further optimized. According to the technical scheme, the problems of cracks and looseness during precision casting multiple-connection-blade production are effectively solved, the qualified rate of a guide blade of a low-pressure turbine is improved to more than 60% from 20%, the production efficiency is improved, and the economic benefit is obvious.

The invention relates to a boiling-resistant epoxy adhesive as well as a preparation method and application thereof. The boiling-resistant epoxy adhesive consists of a component A and a component B; epoxy resin, toughener and coupling agent are mixed, and are stirred and heated, activated inorganic filler and activated inorganic flame retardant are added, polyhydric alcohol or polyhydric phenol is then added, and thereby the component A is prepared; anhydride and catalyst are mixed and heated, activated inorganic filler and activated inorganic flame retardant are then added, and after depressurization for defoaming, the component B is prepared; when in use, the component A and the component B are uniformly mixed according to the proportion by weight of 1 to 3:1, and thereby the boiling-resistant epoxy adhesive is prepared. Compared with the prior art, the boiling-resistant epoxy adhesive has high adhesive force for electronic elements, is convenient to use, and has excellent high-temperature-resistant property, high strength and good weather fastness and impregnating property, the surface properties of solidified product is excellent, and the post-solidification phenomenon caused by cracking is prevented.

A multi metal base hardfacing alloy is provided. The atom percent of each element in the alloy is smaller than 35%. When the alloy is used as a welding material, it has advantages such as low operating temperature, better physical strength hardiness, acid resistance, basic resistance, anti-oxidation, and interface obturation.

The invention discloses a direct reduction process for sponge iron production implemented by using the non-catalytic conversion of CH4, and the direct reduction process comprises the following steps: feeding a feed gas rich in CH4 and subjected to purification and pressure regulation and a stock gas output by a shaft furnace and subjected to cooling, dust removal, pressurization and decarburization into a tube furnace together and preheating; feeding the preheated coal gas into a non-catalytic pure oxygen reforming furnace, performing combustion reaction and heating on the preheated coal gas and oxygen in the non-catalytic pure oxygen reforming furnace, and performing non-catalytic conversion on the CH4 so as to generate CO+H2; after the high-temperature coal gas discharged from the non-catalytic pure oxygen reforming furnace and the stock gas discharged at the front end and subjected to cooling, dust removal, pressurization and decarburization are mixed and cooled, feeding the mixed gas into the shaft furnace and reducing iron ores, thereby producing sponge irons; and after the stock gas discharged from the shaft furnace is subjected to cooling, dust removal, pressurization and decarburization, feeding part of the stock gas and the supplementary feed gas rich in CH4 into the tube furnace and the non-catalytic pure oxygen reforming furnace together, wherein the other part of the stock gas is used as the cold-doped coal gas of the high-temperature coal gas discharged from the non-catalytic pure oxygen reforming furnace. Because the preheating temperature is low, no carbon precipitation occurs, and no strict limitation on the H2S content of the feed gas rich in CH4 exits, so that the bonding of the sponge irons can be prevented.

The invention discloses a manufacturing technology and device for an improved forged steel roller neck high nickel chrome molybdenum alloy cast composite roller. The roller comprises, by mass percent, 3.0%-3.6% of C, 0.60%-1.20% of Si, 0.30%-1.20% of Mn, 3.0%-5.0% of Ni, 1.0%-2.0% of Cr, 0.40%-1.2% of Mo, 0.1%-2% of W, 0.5%-1.0% of Cu, not larger than 0.05% of P, not larger than 0.03% of S, 0.04%-0.06% of Mg, 0.1%-0.3% of Nb, 0.1%-0.30% of Ti, 0.2%-0.6% of V, 0.05%-0.2% of B, 1.5%-2.5% of Ba, 1%-2% of Ca, 1%-3% of Sb, 0.02%-0.18% of N, 1.0%-2.0% of Y / RE and the balance Fe and inevitable micro elements. Yttrium base rare-earth nodulizing and Ba, Ca, and silicon iron composite inoculation are adopted, Nb, Ti, V, B and Sb are added for modification, and the mechanical performance of the roller is improved; by the adoption of the forged steel roller neck, the strength of the roller is improved, an induction heater is adopted to carry out in-mold whole heating casting on a core stick, a water cooled crystallizer is molded, a composite layer interface can be dynamically controlled, the technology is simple, the efficiency is high, power consumption is small, the cost is low, no composition segregation exists, and the service life of the roller is long.

The invention discloses a vacuum air-pressure infiltration forming method of a fiber reinforced aluminum base composite material, and belongs to the technical field of advanced composite materials; and the method is to deposit thin-layer metal elements on the surfaces of woven fiber prefabricated bodies in a physical vapor deposition mode and to finally perform hot isostatic pressing on the fiberreinforced aluminum base composite material to realize vacuum air-pressure complete infiltration of the fiber reinforced aluminum base composite material. The difficulty of incapability of realizing complete infiltration in the vacuum air-pressure infiltration forming process of the fiber prefabricated bodies is solved under the condition of the preheating temperature of the fiber prefabricated bodies lower than 450 DEG C; such defects as micro holes and looseness in the composite material are eliminated; the infiltration formation of the high-performance fiber reinforced aluminum base composite material is realized; the industrial batch production can be realized; and the broad application prospect is achieved in such fields as aerospace and national defense and military.

The invention discloses a method for preparing a hard particle coating on a hard substrate through laser-assisted cold spraying. The method comprises the following steps: subjecting the hard substrate to sand blasting, wherein the hardness of the hard substrate is 300 HV; preheating a spherical hard particle with a diameter in a range of 30 to 50 mu m, wherein preheating temperature is 300 to 600 DEG C, and the hard particle is one or more selected from the group consisting of 2Cr13, 17-4PH, Ni45, Ni60 and Inconel718; carrying out spraying on the surface of the hard substrate by using compressed air having a pressure of 1.5 to 3.0 MPa and carrying the preheated hard particle; and starting laser to synchronously heat a spraying area so as to form the hard particle coating on the surface of the hard substrate, wherein laser power density is 3*10<5> to 5*10<5> W / cm<2>, and wavelength is 850 to 1060 nm. The method provided by the invention can substantially improve plastic deformation generated during collision between the hard particle and the substrate, so the binding force of the coating is improved; thus, the coating with higher stability is obtained.

A method for preparing oxidated pellets from pure hematite concentrate includes the following steps: after the hematite concentrate is preprocessed until the specific surface area is larger than or equal to 1300cm2.g-1, compound additive which accounts for 0.5 to 1.6 percent by weight of the total amount of hematite concentrate is added, damp milling is then carried out, pelletizing, drying, preheating and roasting are sequentially carried out after damp milling, and thereby the finished oxidated pellet product is obtained. The compound additive is the mixture of humic acid, calcium peroxide and paigeite, the mixture is ground to the grain size of negative 0.074mm after mixing, and the percentage by weight is not lower than 95 percent. The method solves the problems in the preparation of oxidated pellets from the hard-to-pelletize, hard-to-roast hematite concentrate, such as poor pellet quality, high preheating and roasting temperatures, long time, low finished pellet product strength. The method is simple, the quality of the prepared hematite concentrate pellets is high, the preheating and roasting temperatures are low, the time is short, and the method is suitable for the preparation of the oxidated pellets from the hematite concentrate, particularly the preparation of the oxidated pellets from hard-to-pelletize, hard-to-roast spiegeleisen concentrate. The method can realizeindustrialized production.

The invention discloses a modified manufacturing process for a high-chromium cast iron composite roll through a forged steel roll neck and equipment. The material comprises, by mass, 3.0%-3.6% of C, 0.60%-1.20% of Si, 0.30%-1.20% of Mn, 3.0%-5.0% of Ni, 1.0%-2.0% of Cr, 0.40%-1.2% of Mo, 0.1%-2% of W, 0.5%-1.0% of Cu, 0%-0.05% of P, 0%-0.03% of S, 0.04%-0.06% of Mg, 0.1%-0.3% of Nb, 0.1%-0.30% of Ti, 0.2%-0.6% of V, 0.05%-0.2% of B, 1.5%-2.5% of Ba, 1%-2% of Ca, 1%-3% of Sb, 0.02%-0.18% of N, 1.0%-2.0% of Y / RE and the balance Fe and inevitable microelements. Yttrium-based rare earth nodulizing and compound inoculating of Ba, Ca and silicon iron are adopted, and modification treatment is conducted by adding Nb, Ti, V, B, and Sb, so that the mechanical property of the roll is improved. The strength of the roll is improved through the forged steel roll neck. Overall in-mold heating and fusion casting are conducted on a core rod through an induction heater. Forming is conducted through a water cooled crystallizer. A composite layer interface can be dynamically controlled. The process is simple, the efficiency is high, power consumption is small, the cost is low, composition segregation is avoided, and the service life of the roll is long.

A composite additive for preparing hematite concentrate pellets comprises the following components: humic acid, calcium peroxide, and paigeite. During application, the composite additive is added which has a mass percent of 0.5%-1.6% of the total mass of the hematite concentrates, and the finished product pellets are obtained by pelletization, preheating, and roasting. Compared with pellets prepared by traditional technology, the hematite pellets prepared by the composite additive of the invention have improved falling strength of the green pellets, and compression strength of the finished product pellets; the preheating temperature and roasting temperature suitable for the pellets are reduced; both the preheating time and roasting time are shortened; the TFe grade is increased by 0.8%-1.2%. The composite additive of the invention has reasonable component ratios, is easy to process and manufacture, has a low using amount and a low residual amount, can significantly improve the pelletability of hematite concentrates which are difficult to be palletized, can improve the green pellet quality, has good heat stability, and can effectively reduce the preheating and roasting temperatures and shorten the preheating and roasting time of hematite concentrates. The composite additive of the invention is applicable to the production of oxidized pellets by hematites, and is especially applicable to the production of oxidized pellets by specularites. The composite additive of the invention is applicable to large-scale industrial production.

The invention relates to a preparation method of a high-reducibility pellet. In the method, hematite concentrate, dehydrated molten iron-smelting sludge, a magnesium-containing additive and a binding agent are mixed according to a mass percentage of 88-95%:1-8%:2.5-5.5%:0.7-1.5%. When the raw materials are uniformly mixed, moisture of the mixed raw materials is controlled to be 4-9%. A wet-grinding process is carried out for 2-9 min, and then a finished product of the high-reducibility pellet is obtained successively through a pelletizing process, a drying process, a pre-heating process and a roasting process after the wet-grinding process finished. The high-reducibility pellet is not less than 60% in TFe, is 1.0-3.0% in MgO content and is 0.8-1.4 in a ratio of CaO to SiO2. By means of the method, not only are problems, such as high temperature during pre-heating and roasting process, a long time and a low strength of the finished product of the high-reducibility pellet and the like, during preparation of an oxidizing pellet by the hematite concentrate are solved effectively, but also the pellet is significantly enhanced in reducing performance, thereby achieving energy conservation and emission reduction during iron smelting.

The invention provides a rare earth treated 690MPa-grade high strength steel plate with a low preheating temperature, and a preparation method of the steel plate. The steel plate is prepared from thefollowing chemical components by mass percent: 0.09-0.15% of C, 0.30-0.45% of Si, 1.58-1.75% of Mn, less than or equal to 0.02% of P, less than or equal to 0.010% of S, 0.04-0.08% of Nb, 0.05-0.08% ofV, 0.010-0.020% of Ti, 0.20-0.40% of Cr, less than or equal to 0.030% of La, 0.020-0.050% of Alt, less than or equal to 0.005% of N and less than or equal to 0.004% of O. The 690MPa-grade high strength steel plate is prepared by adding rare but without Ni and Mo, and has the low preheating temperature, so that the cost is lowered; furthermore, by adopting rare earth treatment, the comprehensive mechanical properties are improved, the service life is prolonged, and the obtained steel plate has good economic benefit.

The invention discloses a manufacturing technique and equipment for a high-performance composite roller shaft. The manufacturing technique comprises the steps that a mandril installed in a combined water-cooling crystallizer is integrally heated to 840-1100 DEG C through an induction heater; molten liquid of a working layer of the roller shaft is poured into the mandril, and then the mandril is continued to be heated for 10-50 minutes; a lifting device is stared so as to lift the heater at a certain speed for 5-15 minutes, and the heater is stopped in the position of a heat-insulating ring; and heating is continued for 10-50 minutes, feeding is conducted on a dead head, and after heating is stopped, cooling is conducted for 30 minutes to 24 hours through water. When the composite roller shaft is manufactured through the manufacturing technique, the number of controllable technological parameters is small, the interface of a composite layer is easy to control, the technique is simple, the efficiency is high, the power consumption is low, the cost is low, the composite layer is free of composition segregation, and the service life of the roller shaft is long; the defect of a centrifugation method that structure segregation is prone to occurring is overcome, and the problems of a CPC method and an ESR method that the production technique is complex, and the cost is high are solved.

The invention discloses a manufacturing technology and device of a forged steel roller neck alloy nodular cast iron composite roller. The forged steel roller neck alloy nodular cast iron composite roller comprises, by mass percent, 3.2%-3.9% of C, 1.6%-2.1% of Si, 0.4%-0.8% of Mn, not larger than 0.05% of P, not larger than 0.03% of S, 0.2%-0.5% of Cr, 0.3%-0.7% of Mo, 1.4%-2.0% of Ni, 0.04%-0.06% of Mg, 0.06%-0.2% of Nb, 0.1%-0.25% of Ti, 0.2%-0.5% of V, 1.5%-2.5% of Ba, 1%-2% of Ca, 1.0%-2.0% of RE and the balance Fe. Rare-earth nodulizing and Ba, Ca and silicon iron compound inoculation are adopted, and Nb, Ti and V are added for modification, so that the mechanical property of the roller is improved, a forged steel roller neck is adopted to improve the strength of the roller, and an induction heater is adopted to carry out in-mold whole heating casting on a forged steel or cast steel core stick; and a combined type water cooled crystallizer is molded, a lifting device lifts the heater upwards at a certain speed to form area directional solidification, a composite layer interface is dynamically controlled, the technology is simple, the efficiency is high, the electric consumption is small, the cost is low, no composition segregation exists in the composite layer, and the service life of the roller is long.

The invention provides a forming die and method for a magnesium / aluminum alloy bimetal composite pipe, and belongs to the technical field of metal plastic working. The forming die for the magnesium / aluminum alloy bimetal composite pipe comprises a main shaft, an extrusion gasket, an extrusion core pin, an extrusion cylinder lining, an extrusion cylinder, an extrusion die, a die-filling extrusion shaft, a cylindrical roller bearing, a thrust bearing, a gear A, a gear B, a sleeve, a gearbox, an end cap A, an end cap B and a shearing device. The extrusion cylinder, the extrusion cylinder lining,the main shaft and the extrusion core pin simultaneously move to the right to realize the extrusion forming process, furthermore, repeated rotation of the die-filling extrusion shaft in the extrusionprocess is realized through transmission of the gear A and the gear B, and after the extrusion is completed, extrusion remnant materials are cut off by the shearing device. Advantages of high pressuretorsion and extrusion forming are combined, blank is simultaneously subjected to extrusion and torsion actions, so that the metal flow resistance, the preheating temperature of the blank and the diecan be reduced, and the interface quality and dimensional accuracy of the composite pipe is improved.

The invention discloses a manufacturing method of commercial high-magnesium aluminum alloy wheel hubs. The manufacturing method includes the following steps that 1 raw materials of high-magnesium aluminum alloy hot rolled plates are made into annular blank; 2 a spinning machine or a punching machine is used for drawing the annular blank into the shape of a disc, and disc-shaped blank is obtained; 3 the disc-shaped blank which is cooled to the temperature below the re-crystallization temperature is placed into a forging and pressing mould, a forging and pressing machine is used for forging and pressing spoke portions, and forged and pressed aluminum alloy wheel hub blank is obtained; 4 on the spinning machine, the forged and pressed aluminum alloy wheel hub blank is spun into hollow rotating body wheel hub blank; 5 the hollow rotating body wheel hub blank formed through spinning is placed in the environment at the temperature of 100 DEG C-250 DEG C for 0.5-6 hours, and low-temperature stabilizing treatment is achieved; 6 machining and surface treatment are conducted. According to the manufacturing method, the problems that an existing technology is complicated, low in production efficiency and high in energy consumption are solved, and the purposes that energy consumption is reduced, the production efficiency is increased and products have good mechanical properties are achieved.

The invention discloses a method for preparing a synthetic natural gas low-ruthenium methanation catalyst, and belongs to the field of catalysts and fine chemical engineering. According to the method, gamma-type aluminum oxide is infiltrated by the solution of soluble titanium compounds, dried and roasted to obtain composite support TiO2 / Al2o3, and is then impregnated in the solution of soluble ruthenium compounds in an equivalent-volume impregnation mode, the obtained impregnant is dried and roasted to obtain the synthetic natural gas low-ruthenium methanation catalyst, and the carrying capacity of Ru is 0.3-2.0% by weight. The prepared Ru / TiO2-Al2O3 catalyst gets a good result in a CO methanation reaction evaluation. The synthetic natural gas low-ruthenium methanation catalyst has big specific surface area, is high in catalytic activity,low in sensibility to poisons, good in stability, low in starting temperature, simple in preparation process, feasible economically and used for the inlet of a synthetic natural gas one-stage methanator, can reduce synthetic natural gas preheating temperature, and reduces heat energy consumption.

The invention discloses a gas dual-cycle radiant tube heating device. The part in a furnace of the device is a closed inner-ring gas circulating line composed of a first straight tube, a first bend, a second straight tube, a second bend, a third straight tube, a third bend, a fourth straight tube and an added smoke return tube, and the part outside the furnace of the device is an outer-ring gas circulating line composed of an empty smoke switching device, a mixed gas conveying tube and a nozzle. The heating device overcomes the defects that the temperature distribution of a radiant tube along the length direction is non-uniform and the local temperature is high. Returned smoke and combustion flame are mixed through inner-ring gas circulating so as to reduce the core temperature of flame, enhance the uniformity of the surface temperature distribution of the radiant tube, prolong the service life, and reduce the generation of thermal NOx; since the smoke return tube is added, the effective radiation heat exchange area in the furnace is enlarged, and the outer-ring gas circulating is capable of effectively improving the pre-heating temperature of gas, reducing the oxygen content in air and realizing low-temperature combustion, thereby increasing the heat efficiency while alleviating pollution.

The invention provides a joint shape design method for realizing equal bending bearing of low-match butt-joint joint with base metal and relates to a butt-joint joint design method. The method comprises the following steps that 1, the yield strength matching ratio of a low-match joint is calculated; 2, the height h of the welding seam surplus height is obtained through calculation by a material mechanical formula according to the equal bending bearing condition; 3, the cover surface weld pass half width w is determined; 4, the weld toe radius r is determined; and 5, the low-match joint geometrical shape parameter required by the equal bending bearing is obtained according to the solved height h of the welding seam surplus height, the cover surface weld pass half width w and the weld toe radius r. The joint shape design method is suitable for the low-match flat plate butt-joint joint of the X-shaped grooved double-side welding. The high-intensity welding structure can adopt the low-match joint assembly mode. The high-intensity welding adopts the low-match welding joint, the bending bearing capability can be enabled to be not lower than that of the base metal, and in addition, the ductility and toughness and the like are obviously improved through being compared with those of a matched welding joint.

The invention discloses a production process of active lime. The process comprises the following steps of (1) screening and pretreatment of limestone, (2) mixing, (3) preheating, (4) calcining, (5) cooling and (6) post-treatment. Firstly, an additive used in the production process reduces underfiring and overburning of the lime, increases the decomposition speed of CaCO3, shortens the calcining time, correspondingly reduces the energy consumption and is beneficial to industrial popularization. Furthermore, carbon is also added, decompression operation is adopted after preheating and before cooling separately, correspondingly the elements sulfur and carbon which remain in lime raw materials can be volatilized out more thoroughly, and the recombination of the elements with calcium oxide is avoided, so that the purity of the active lime is improved, and the activity degree of quicklime is further improved.

The invention discloses a composite welding method for different-strength jointed connectors of Q370qE and Q690qE bridge structural steel in the technical field of welding. According to the compositewelding method, firstly, chamfering is carried out on two faces at the position of a joint of two steel plates, the two faces of grooves are in an X shape on the whole, the small groove angle on one side is 29 degrees-31 degrees, the large groove angle on the other side is 39 degrees-41 degrees, and the truncated edge is 1.5 mm-2.5 mm; and the depth ratio of the small-angle groove to the large-angle groove is (2-2.5): 1; then, gas shielded welding is adopted to weld 2-4 lines on the side of the small-angle groove, bottoming welding lines are formed, welding grooves are welded fully through union melt welding on the same side of the small-angle groove, the steel plates are turned over, carbon arc gouging finishing is carried out on the side of the large-angle groove, union melt welding is adopted to weld the large-angle groove, and the groove is welded fully; and finally, heat preservation is carried out, and slow cooling is carried out until the normal temperature. The welding joints are excellent in mechanical performance, good in welding quality and cable of being used in bridge building.

The invention relates to a method for welding and repairing copper surface defects of an aluminum-copper composite board transition joint. The method comprises the following steps of: before welding, preheating a part to be welded at the temperature of 20020 DEG C so as to slow down heat loss of a welding area; filling and welding pit defects on a copper surface by utilizing an inert gas arc welding method, wherein the inert gas is a mixed gas of argon and helium; and introducing cooling water to an aluminum surface of the aluminum-copper composite board transition joint so as to reduce the heat introduced to a combination area interface of the aluminum-copper composite board transition joint. The welding method of the invention is simple and practical, not only improves the work environment, reduces the labor intensity of workers and the production cost, but also ensures that the partial peeling phenomenon does not occur in the welded aluminum-copper composite board transition joint.

The invention discloses a technique and equipment for a forged steel roll neck high-chrome cast iron composite roller. Materials comprise, by mass, 2.4-3.3% of C, 0.60-1.0% of Si, 0.50-1.20% of Mn, 0.8-1.2% of Ni, 15-20.0% of Cr, 0.80-2.2% of Mo, 0.5-1% of W, 0-0.05% of P, 0-0.03% of S, 1-3% of Sb, 0.02-0.18% of N, 0.1-0.3% of Y, and the balance Fe and inevitable trace elements. The rare earth Y and silicon iron are adopted for composite inoculation; grain refinement treatment is conducted by adding the Sb and the N, so that the mechanical properties of the roller are improved; the strength of the roller is improved by the adoption of a forged steel roll neck; integral in-mold heating and casting are conducted on a mandril through an induction heater, and a water-cooling crystallizer is used for formation. The interface of a composite layer can be dynamically controlled, the technique is simple, the cost is low, composition segregation is avoided, and the service life of the roller is long.

The invention provides an ultralow-carbon austenitic welding wire material for the welding of stainless steel. According to percentage in weight, the specific chemical components of the welding wire material are as follows: less than or equal to 0.023 percent of C; 3.87 to 4.45 percent of Si; 0.57 to 0.89 percent of Mn; less than or equal to 0.023 percent of P; less than or equal to 0.013 percent of S; 18.59 to 19.32 percent of Cr; 13.57 to 14.87 percent of Ni; less than or equal to 0.33 percent of Mo; less than 0.044 percent of N; 0.09 to 0.29 percent of Cu; and the balance of Fe and inevitable impurities; and the welding wire material also comprises 0.02 to 0.042 percent by weight of rare-earth element Re. The welding wire material has the beneficial effects that: the component design is scientific, the welding wire material is convenient to use, the cold-cracking sensitivity of metal at the weld is low after welding, the performance result of the metal at the weld is near to the performance result of parent metal, and moreover, the welding wire material has high low-temperature impact toughness and corrosion resistance; and in particular, the ultralow-carbon austenitic welding wire material for the welding of stainless steel can resist the corrosion of concentrated nitric acid.

The invention belongs to the technical field of welding, and relates to a process for overlaying a copper layer with high-strength steel. The welding process includes the steps: performing metal inert-gas welding; and controlling welding temperature by preheating before welding to reach 200-250 DEG C and keeping the temperature of each layer or each bead the same as preheating temperature during welding. By the aid of the metal inert-gas welding, the process is fine in welding protection, low in preheating temperature, easy in welding temperature control and stable in welding quality. Moreover, labor intensity is greatly reduced, production efficiency is improved, and production cost is reduced.

The invention discloses a high-temperature thermal extrusion moulding method of a TiAl intermetallic compound material, which relates to a thermal extrusion moulding method of a TiAl intermetallic compound material. The invention aims to solve the problems of rapid heat radiation from blank to a die, large temperature reduction of blank, large deformation resistance, serious die damage and difficult extrusion moulding existing in the process of extruding the TiAl intermetallic compound material by adopting a traditional thermal extrusion technology. The method comprises the following steps of: firstly, manufacturing an extrusion sheath and a sheath cover; secondly, placing the extrusion sheath in an inner cavity of an extrusion female die and heating both the extrusion sheath and the extrusion female die at the temperature of 200-600 DEG C; thirdly, heating the extrusion blank of a TiAl intermetallic compound to 1150-1300 DEG C, then taking out and rapidly placing into the extrusion sheath; fourthly, covering the sheath cover; and fifthly, extruding after die assembly so that the extrusion blank of the TiAl intermetallic compound is extruded and moulded in the complete cover of the extrusion sheath and the sheath cover. The invention is used for the high-temperature thermal extrusion moulding of TiAl intermetallic compound materials.