A kind of aluminium-steel exothermic welding method
Technical field
The invention belongs to materials processing and manufacturing technology field, be specifically related to a kind of aluminium-steel exothermic welding method.
Background technology
Aluminium, as a kind of argenteous light metal, has excellent ductility, is also the maximum metallic element of content in the earth's crust simultaneously, thereby has important development prospect in fields such as aviation, building, automobiles.Steel, with its cheap price and reliable performance, becomes and uses one of maximum material, is all indispensable composition in building industry, manufacturing industry and people's life.In conjunction with excellent properties and the application prospect of aluminium and steel, the welding between For Dissimilar Materials Aluminium And just becomes a large focus naturally.But because the performance of aluminium and steel is totally different, fusing point differs greatly, therefore in the middle of actual welding, be faced with very large technological challenge.
At present, in aluminum steel welding, the maximum method of traditional use is friction welding (FW), explosive welding (EW) and soldering.In these welding methods, be inevitably faced with the technique more complicated of welding, welding cost is relatively high, the problem that energy resource consumption proportion is larger.The method of a kind of oxy-acetylene welding aluminum steel as described in patent 92113206.9, although speed of welding is fast, operates relatively simply, and the consumption rate of the energy is larger.As patent 200610152657.5 provides a kind of explosion welding method of aluminum steel dissimilar metal, although can realize the large-area aluminum steel welding of high-quality, production technology is relatively complicated.As patent 201010108154.4 provides a kind of aluminum steel welding method of flux-cored arc welding, although the strength of welded joint obtaining is high, the cost of welding is still relatively high on the whole.
In fact, traditional aluminum steel welding manner, except needs overcome above several defects, also needs to consider the associativity problem of resulting welding point.Because the thermophysical property of aluminium and steel is totally different, solid solubility is lower, when forming alloy, easily form intermetallic compound, this has just caused the hydraulic performance decline problem of aluminum steel welding point, and formed welding point is not give strong description of test in mechanical bond or this problem of metallurgical binding.Therefore, in order to improve the intensity in aluminum steel welding street corner, must improve welding procedure, in patent 200910072270.2, use the growing amount that has really reduced interface compound in the way of the preset one deck aluminium in steel surface, improved to a certain extent the quality of welding, but the welding manner of the method is used MIG welding, on cost, do not give to control.In patent 201310367501.9, utilize the mode of hot aluminizing at steel surface coverage one deck aluminium, realize aluminum steel from the metallurgical binding of spreading welding, but SnO in the formula that the method is used
2and Cu
2the economy of O is not high, does not give to control on cost.
Summary of the invention
Technical problem to be solved by this invention is the many disadvantages that overcomes conventional aluminum steel welding method, provides a kind of equipment simple, easy and simple to handle, with low cost and realize the aluminum steel welding method of aluminium-steel welded joint metallurgical binding.
Aluminium-steel exothermic welding method, comprises the following steps:
Aluminium block to be welded and the polishing of bloom cross section is clean, between the gap in aluminium block and bloom cross section to be welded, be close to aluminium block and place a steel disc of having polished in advance; Graphite crucible bottom through-hole is aimed to center, gap, solder flux is put into graphite crucible, light the pyrophoric powder on solder flux surface, the liquation that solder flux generation self-propagating reaction produces flows into the gap between aluminium block and bloom from the aperture of graphite crucible bottom, steel disc melted by heat, is cooled to the welding that completes aluminium-steel after room temperature.
Below described aluminium block and bloom, there is graphite base; Between aluminium block and bloom and graphite crucible, there is the graphite cushion block containing through hole; Graphite crucible bottom through-hole blocks with sheet metal.
Described steel disc, its thickness is 3 mm.
Described solder flux comprises the component of following mass percent: 22 ~ 28% Al powder, 62 ~ 68% Fe
2o
3powder, 4 ~ 7% Si powder and 3 ~ 6% slag former.
Described Al powder, its fineness is 200 orders.
Described pyrophoric powder is gunpowder or magnesium powder.
Described slag former is CaF
2, NaF or KF.
The present invention adopts the self propagating high temperature synthetic reaction of aluminium and iron oxide, and this reaction produces a large amount of heats and generates a large amount of iron liquid, and iron liquid flow in welding groove, realizes the welding of aluminium-steel, and Fig. 1 is device schematic diagram used in the present invention.The Fe using in reaction
2o
3than SnO
2and Cu
2o is a kind of cheapness and efficient aluminum heat flux.In Welding Structure, at the thin bloom of the aluminium preset del in surface, effect is mainly the face of weld of protection aluminium, because the temperature of the self propagating high temperature synthetic reaction of aluminium and iron oxide is up to more than 2,000 degree, approach the boiling point of aluminium, so the iron liquid of high-temperature directly contacts with aluminium block, cause the embrittlement tendency of aluminium block seriously and easily to cause directly burning of aluminium block, make the normally combination of aluminium and steel, at the preset thin bloom in aluminium surface, absorbed the part heat of iron liquid, make the temperature on aluminium surface be unlikely to too high, reduced the embrittlement tendency of aluminium block, improved the associativity of aluminium and steel, upside-down triangle shape design meets iron liquid and flows to from top to down the thermodynamics regularity of distribution that in welding groove, temperature is successively decreased gradually.The object that adds Si powder is the mobility that increases iron liquid, realizes the good separation of slag liquid; The CaF adding
2, NaF or KF effect be mainly and react the Al generating
2o
3form loose porous and low-density slag, absorption portion heat in course of reaction, make course of reaction tend towards stability with gently; Be close to aluminium block and place a del bloom that thickness is 3mm.
The present invention, by the preset thin bloom in aluminium surface, uses self propagating high temperature synthetic technology to weld aluminum steel, the heat that utilizes reaction to produce, metal is filled in fusing, fill metal and flow in filling slot, make aluminium and steel realize metallurgical binding, aluminum steel dissimilar metal is welded together.The Fe using in reaction
2o
3relatively cheap, on cost, be under control.Experimental facilities of the present invention is simple, with low cost, and gained aluminium-steel welded joint is metallurgical binding joint.
Tool of the present invention has the following advantages and beneficial effect:
1. the present invention is reasonable in design, simple in structure.Aluminium block one is sidelong and is put the del bloom that a thickness is 3mm, has absorbed part heat, has reduced embrittlement and the scaling loss of aluminium; The design of del shape meets iron liquid and flows down the Thermodynamic Law that temperature declines gradually.
2. the present invention is simple to operate, device simple.Simple to operate, required step is for taking powder, mixed-powder, filling powder, igniting reaction.Device simple, equipment needed thereby is mainly the graphite jig of charge material, without other main equipments.
3. stable reaction of the present invention, safe and reliable.In reaction, added CaF
2whole course of reaction is tended to be steady, can be too inviolent.The iron liquid mobility that adds Si that reaction is generated is fine, can not be stuck in slag.
4. raw material of the present invention is extensive, with low cost.React required Al, Fe
2o
3, Si, CaF
2be all the more common raw material in laboratory, and be very easy to obtain, cost is also quite cheap simultaneously.
5. welding point slag inclusion of the present invention is few, metallurgical binding, and quality is good.The slag former adding in reaction, makes slag liquid well separated, has improved the quality of welding point, and has realized the metallurgical binding at aluminum steel interface.
Accompanying drawing explanation
Fig. 1 is the device schematic diagram of the embodiment of the present invention 1.
Fig. 2 is the scanning electron microscope (SEM) photograph at the aluminum steel welding point place of the embodiment of the present invention 1.
Fig. 3 is the energy spectrogram at the aluminum steel welding point place of the embodiment of the present invention 1.
The specific embodiment
Below in conjunction with embodiment, the present invention is done to further detailed description, but embodiments of the present invention are not limited to this.If no special instructions, the chemicals using in following embodiment is AR.
Embodiment 1
Aluminium block to be welded and the polishing of bloom cross section that area of section is identical is clean, between aluminium block and bloom cross section to be welded, to be close to aluminium block place and to place the steel disc being of moderate size of having polished in advance, the cross sectional shape of steel disc is del, thickness is 3 mm; Aluminium block and bloom are positioned under graphite crucible according to shown in Fig. 1, and the through hole of graphite crucible bottom is aimed at center, gap; Below aluminium block and bloom, have graphite base, have the graphite cushion block containing through hole between aluminium block and bloom and graphite crucible, graphite crucible bottom through-hole blocks with sheet metal.Mass percent is respectively to 22% Al powder (fineness is 200 orders), 68% Fe
2o
3powder, 7% Si powder and 3% CaF
2powder is loaded in meal mixer, mix formation solder flux, then solder flux is put into graphite crucible, slightly after compacting solder flux, on solder flux surface, sprinkle one deck gunpowder, with igniter, light the magnesium rod gunpowder that ignites, the liquation that solder flux generation self-propagating reaction produces flows directly into the gap between aluminium block and bloom by the aperture of crucible bottom, by steel disc fusing, be cooled to the welding that completes aluminium-steel after room temperature.By after the aluminium-steel joint sample preparation welding, carry out scanning electron microscope analysis and the power spectrum test of joint, scanning electron microscope analysis result is as shown in Figure 2, as can be seen from Figure 2, the associativity of welding point place mother metal and weld seam is good, there is no obvious crackle, and the slag inclusion of commissure is relatively less.Power spectrum test result as shown in Figure 3, can be found out by the variation of EDX relative integral intensity, realize good metallurgical binding between mother metal and weld metal.
Embodiment 2
Aluminium block to be welded and the polishing of bloom cross section that area of section is identical is clean, between aluminium block and bloom cross section to be welded, to be close to aluminium block place and to place the steel disc being of moderate size of having polished in advance, the cross sectional shape of steel disc is del, thickness is 3 mm; Aluminium block and bloom are positioned under graphite crucible according to shown in Fig. 1, and the through hole of graphite crucible bottom is aimed at center, gap; Below aluminium block and bloom, have graphite base, have the graphite cushion block containing through hole between aluminium block and bloom and graphite crucible, graphite crucible bottom through-hole blocks with sheet metal.Mass percent is respectively to 24% Al powder (fineness is 200 orders), 66% Fe
2o
3powder, 6% Si powder and 4% NaF powder are loaded in meal mixer, mix formation solder flux, then solder flux is put into graphite crucible, slightly after compacting solder flux, on solder flux surface, sprinkle one deck magnesium powder, with igniter, light the magnesium rod magnesium powder that ignites, the liquation that solder flux generation self-propagating reaction produces flows directly into the gap between aluminium block and bloom by the aperture of crucible bottom, by steel disc, be cooled to the welding that completes aluminium-steel after room temperature.
Embodiment 3
Aluminium block to be welded and the polishing of bloom cross section that area of section is identical is clean, between aluminium block and bloom cross section to be welded, to be close to aluminium block place and to place the steel disc being of moderate size of having polished in advance, the cross sectional shape of steel disc is del, thickness is 3 mm; Aluminium block and bloom are positioned under graphite crucible according to shown in Fig. 1, and the through hole of graphite crucible bottom is aimed at center, gap; Below aluminium block and bloom, have graphite base, have the graphite cushion block containing through hole between aluminium block and bloom and graphite crucible, graphite crucible bottom through-hole blocks with sheet metal.Mass percent is respectively to 26% Al powder (fineness is 200 orders), 64% Fe
2o
3powder, 5% Si powder and 5% KF powder are loaded in meal mixer, mix formation solder flux, then solder flux is put into graphite crucible, slightly after compacting solder flux, on solder flux surface, sprinkle one deck gunpowder, with igniter, light the magnesium rod gunpowder that ignites, the liquation that solder flux generation self-propagating reaction produces flows directly into the gap between aluminium block and bloom by the aperture of crucible bottom, by steel disc fusing, be cooled to the welding that completes aluminium-steel after room temperature.
Embodiment 4
Aluminium block to be welded and the polishing of bloom cross section that area of section is identical is clean, between aluminium block and bloom cross section to be welded, to be close to aluminium block place and to place the steel disc being of moderate size of having polished in advance, the cross sectional shape of steel disc is del, thickness is 3 mm; Aluminium block and bloom are positioned under graphite crucible according to shown in Fig. 1, and the through hole of graphite crucible bottom is aimed at center, gap; Below aluminium block and bloom, have graphite base, have the graphite cushion block containing through hole between aluminium block and bloom and graphite crucible, graphite crucible bottom through-hole blocks with sheet metal.Mass percent is respectively to 28% Al powder (fineness is 200 orders), 62% Fe
2o
3powder, 4% Si powder and 6% NaF powder are loaded in meal mixer, mix formation solder flux, then solder flux is put into graphite crucible, slightly after compacting solder flux, on solder flux surface, sprinkle one deck gunpowder, with igniter, light the magnesium rod gunpowder that ignites, the liquation that solder flux generation self-propagating reaction produces flows directly into the gap between aluminium block and bloom by the aperture of crucible bottom, by steel disc fusing, be cooled to the welding that completes aluminium-steel after room temperature.
Above embodiments of the present invention are explained in detail, but ratio of the present invention is not limited to above-mentioned embodiment, in the ken that one skilled in the relevant art possesses, can also under the prerequisite that does not depart from aim of the present invention, makes a variety of changes.