A kind of aldural and melting thereof and castmethod
Technical field
The present invention relates to a kind of aldural, also relate to its melting and castmethod.
Background technology
The duraluminum that deep processing is used often need at first be cast as large-scale ingot blank; Like slab ingot, pole etc.; Through means such as rolling, extruding, forgings, be processed into various finished products again, these processes all will combine with heat treatment phase basically; If to the finished product that can directly use, then also will be through operations such as over-segmentation, surface working, Passivation Treatment.These processing means need aluminum alloy materials itself to possess good deep processing performance, comprise castability, press working deformation performance, heat treatment reinforcement performance, corrosion resistance, antifatigue destructive characteristics, surface working and coating property etc.Wherein, founding performance is the basis of duraluminum deep processing performance.Large-scale ingot blank; Especially the above above pole of slab ingot, slab and diameter 500mm of thickness 500mm; Can be the representative base material of large-scale efficient deep processing, and be prefabricated into large-scale ingot blank, also be the technology critical point, first road whether test aluminum alloy materials itself is fit to carry out deep processing.
Because the big one-tenth branch of density is deposited in the foundry goods bottom in alloying constituent or the compound, float on top on the little composition of density.For example add this refractory metal of Ti and Al and form dystectic flaky compound Al for crystal grain thinning
3Ti can early crystallize out from alloy liquid; When growing up to greatly, just sink to producing the gravity segregation of local rules easily; Can on the foundry goods fracture, see the compound of the white bright ash of surfacing when segregation is serious, primary silicon thick in the hypereutectic Al-Si duraluminum also forms segregation easily owing to density is less.
In addition when this alloy liquid before cast owing to stir the inhomogeneous eutectic segregation that causes, concentrate the place in Eutectic Silicon in Al-Si Cast Alloys, the high fragility of hardness is big, the process tool wearing and tearing are greatly; The position that Eutectic Silicon in Al-Si Cast Alloys is few forms α (Al) sosoloid soft spots, and intensity is low, adds not only sticking cutter in man-hour, worsens processing characteristics, under the effect of cutting force, can make the distortion of α (Al) sosoloid cause machined surface hickie to occur.When magnesium content was less than 0.6% (massfraction) in ZL108 (ZAlSi12Cu2Mg1) duraluminum, hickie also appearred in finished surface easily.
There is Cu elements segregation in the Al-Si-Cu duraluminum to cause that thick Al appears in regional area again
2Cu is net distribution mutually and along crystalline substance, even if adopt thermal treatment can not it is dissolved in α (Al) sosoloid fully and remain in intergranular, thereby makes this kind alloy fragility increase.
Simultaneously, when adopting this duraluminum to cast, the normal appearance mainly contains oxide inclusion, molding material and flux slag inclusion etc. various being mingled with in the foundry goods that casting is accomplished.Wherein, be mingled with al oxide the most general.Especially in containing the duraluminum of Mg, majority is mingled with and is aluminum oxide and magnesian mixture, so in the aluminium alloy smelting process, the content of oxide inclusion is one of important mark matter of reflection aluminium liquid metallurgical quality.
This shows: the forming property of present aluminum alloy materials during except the large-scale ingot blank of founding is relatively poor; Large-scale ingot blank is not high in the hardening capacity of heat treatment process, tempering resistance is relatively poor and can not satisfy higher mechanical property requirements or some property (as heat-resisting, anti-corrosion) etc., is significant deficiency yet.These defectives make it in the process of strong materials of weight such as field of engineering technology instead of steel goods and structure, form the technological breakpoint that is difficult to cross over.
Summary of the invention
In order to overcome the deficiency of prior art, the present invention provides a kind of aldural and melting and castmethod, can overcome the deficiency of existing aluminium alloy capability, improves its obdurability, plasticity and hardening capacity, for efficient deep processing provides high-end base material.
A kind of aldural is characterized in that by percentage to the quality, comprises 0.6~0.9% Si; Fe smaller or equal to 0.35%, the Cu smaller or equal to 0.1%, Mn smaller or equal to 0.1%; 0.4~0.6% Mg, the Cr smaller or equal to 0.1%, Zn smaller or equal to 0.1%; Ti smaller or equal to 0.1%, 1.8~2.7% Ni and 0.14~0.21% N, surplus is Al and unavoidable impurities; The content of said single impurity is no more than 0.05% of total mass per-cent; Content of impurities is no more than 0.15% of total mass per-cent.
The method of the described aldural of a kind of melting claim 1 is characterized in that step is following:
Step 1: aluminium ingot is added in the smelting furnace heating make it to melt fully, add the Si of total product mass percent 0.6~0.9% then by prescription, Fe smaller or equal to 0.35%; Cu smaller or equal to 0.1%; Mn smaller or equal to 0.1%, 0.4~0.6% Mg, Cr smaller or equal to 0.1%; Zn smaller or equal to 0.1% and smaller or equal to 0.1% Ti dissolves fully and melts; Said melting process is accomplished in enclosed environment;
Step 2:, obtain alloy melt 700~1000 ℃ of insulations down;
Step 3: adopt mixed gas that aluminium alloy melt is carried out the degassing and purifying operation, and will account for the Ni of total product mass percent 1.94~2.91%
3The N powder joins in the aluminium alloy melt with above-mentioned gas with the fluidization mode and mixes, and makes Ni
3N is evenly distributed in aluminium alloy melt, and lasting ventilation finishes until reaction; Said mixed gas is: nitrogen or rare gas element or nitrogen mix according to arbitrary proportion with rare gas element and obtain;
Step 4: temperature adjustment to 680 after reaction finishes~730 ℃ obtains the aluminium alloy melt that melting is accomplished.
Aluminium ingot in the step 1 is replaced with molten aluminum liquid.
A kind of method that described aldural is cast; It is characterized in that: the aluminium alloy melt longshore current groove of claim 2 melting is toppled over come out of the stove; To vertical water cooling casting machine system; Casting processing is used ingot blank, particularly above large-scale slab ingot and the above pole of diameter 500mm of cast thickness 500mm.
A kind of method that described aldural is cast; It is characterized in that: the aluminium alloy melt metaideophone of claim 2 melting is gone in the mold of foundry goods; Use metal mold, sand mold or mixed type casting mode; Adopt gravitational casting, pressure die casting or counter-pressure casting technology, the aluminum alloy casting of y alloy y foundry goods, particularly casting large-scale, thin-walled or complex construction.
Aldural provided by the invention and melting thereof and castmethod, in wrought aluminium alloy with the Ni of Powdered adding 1.94~2.91%
3N adds in the aluminium alloy melt process with protective gas with the fluidization form, has the specific surface area more much bigger than general cake mass, can realize disperseing fast and fully contacting with melt, has significantly shortened and has disperseed and the uniform time.Adopt aldural of the present invention simultaneously in castingprocesses, can in alloy graining process, effectively increase heterogeneous forming core core, thereby reach the effect of grain refining, strengthen alloy strength; And the element that adds can promote to form interstitial atom and gap mutually; During high temperature in α (Al) sosoloid solubleness big, and very little when room temperature, thereby make alloy have higher heat-treatability matter; After the thermal treatment, its intensity and hardness all have significant improvement.
Make a concrete analysis of as follows:
Without before adding above-mentioned element, except that the common solution that form various elements, also contain compound phase that more following intermetallics form in the melt at this alloy:
Mg
2Si phase, N phase (Al
7Cu
2Fe), α phase (Al1
2Fe
3Si), S phase (Al
2CuMg);
These metallic compounds when melt cools off because the minimum free energy principle of system, can not stable existence in the crystal grain that forms; Will be under the driving that lattice distortion can differ from move and concentrate to crystal boundary, simultaneously, because the saturation solubility of alloying element in aluminum substrate descends along with temperature and significantly reduces; So along with the cooling of melt, oversaturated melt is constantly separated out the intermetallic compound that is rich in alloying element, these compounds are in the intergranular enrichment; Be difficult for to each other merging, in microtexture, become thick intergranular compound group, alloy is produced crisp sclerosis influence; Worsen the alloy casting forming property, reduce its homogeneity, toughness, solidity to corrosion and through hardening performance.So; When alloy graining becomes the substruction of supersaturated solid solution matrix+intergranular metallic compound; Be commonly referred to pure as-cast structure, the alloy with this tissue just can have the mechanical property and other technical indicator of satisfying the demand after must passing through the thermal treatment of " solid solution+timeliness ".
Though, can improve through the thermal treatment of formulation optimization processing and raising alloy property, still still there are a lot of defectives in alloy itself: insufficient strength is high, can not cast big specification type ingot etc.
The present invention is through relatively selecting; The nitride of having developed transition element is handled the mode of melt; Through adding 1.8~2.7% Ni and 0.6~0.9% N element, the atomic state M metal that the nitride after the decomposition produces has not had under the simple substance state between atoms metal with the d/f/s electronics potential barrier that the lattice energy of tightly packed generation between the powerful metal bond energy that produces and similar atom forms of combining closely; Merge with " naked attitude " and a large amount of on every side matrix atoms; Form solution and metallic compound altogether, and the leading phase when becoming crystallization and grain refining are mutually, the while also is the High-Temperature Strengthening phase.Therefore, nitride has solved refractory metal and in aluminium liquid, has dissolved difficult, the difficult problem of uniform distribution with the decomposition under the generation high temperature in the fluidization adding melt and the disperse state of formation, has realized the microcosmic homogenizing distribution of lattice distortion ability and the refinement of crystal grain.
The nitrogen that in fusion process, charges in addition helps aluminium synthetic AlN in 800~1000 ℃ nitrogen atmosphere.Because the AlN that N and Al reaction generates is an atomic crystal, genus quasi-diamond nitride the highlyest is stabilized to 2200 ℃; Room temperature strength is high, and intensity is slower with the rising decline of temperature, can effectively improve the hot strength and the resistance to corrosion of alloy; Thermal conductivity is good, and thermal expansivity is little, can improve the body material thermal shock resistance.Therefore, work as N
2When charging into the high temperature aluminium alloys melt, itself has just had the activity that reacts with multiple metallic gold.So the concentration of temperature when suitably regulating the cleaning molten operation and protectiveness nitrogen, the content of AlN in the adjustable melt, this further provides method for the content of regulating transition metal in the melt.
Joining the degree that the nitride in the melt decomposes in addition, change along with the different of the stability of nitride itself and melt temperature, promptly react and have certain reversibility, is a kind of dynamic balance.The saturation solubility of most of transition element in molten aluminium is less, and the maximum solid solution degree of dechromisation, titanium, vanadium, zirconium occurs in outside the peritectic temperature, and the maximum solid solution degree of other elements all occurs in eutectic temperature; Solubleness at room temperature is all less than 0.1%wt.
It is thus clear that: because the means of using the fluidization nitride to handle in the present invention; Integrate the multiple effects of strengthening matrix and crystal grain thinning; Replace master alloy, make duraluminum manufacturing concern no longer be limited by the master alloy manufacturer, help creating the green production line of " nearly moulding, short flow process, intensification "; Energy-saving and cost-reducing, reduce comprehensive cost; Simultaneously, in heat treatment process, owing to formed excellent material microstructure; The unrelieved stress of ingot blank is less; Therefore can significantly improve thermal treatment usefulness, improve the hardening capacity of ingot blank, when comparing with similar alloy; Can produce thicker blank (bar that sheet material that thickness 500mm is above and diameter 500mm are above) with " casting+heat treatment mode ", (realize " rolling " on the plate manufacturing technology of thickness 15~200mm) to cast generation at series specification.
Generally speaking, the invention has the beneficial effects as follows:
In molten aluminium, caused multiple grain refining element, particle, thickization that prevents matrix and strengthening phase had good result.In cooled aluminum substrate, caused stable high interstitial atom and gap mutually, become new efficient strengthening phase, the intensity of material and hardness are improved.
Below in conjunction with embodiment the present invention is further specified.
Embodiment
Embodiment 1:
A kind of aldural by percentage to the quality, comprises 0.6% Si, 0.35% Fe; 0.1% Cu, 0.1% Mn, 0.4% Mg, 0.1% Cr; 0.1% Zn, 0.1% Ti, 1.8% Ni, 0.6% N; Surplus is Al and unavoidable impurities, and the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.15% of total mass per-cent.
The present invention also provides the preparation method of said aldural, adds Ni with the Combined Processing mode
3N may further comprise the steps:
Step 1: the component according to said aldural is got the raw materials ready, and comprises the Si that accounts for total product mass percent 0.6%, 0.35% Fe, 0.1% Cu, 0.1% Mn, 0.4% Mg, 0.1% Cr, 0.1% Zn, 0.1% Ti;
Step 2: in smelting furnace, add aluminium ingot or molten aluminum liquid earlier, heating makes it to melt fully, adds getting the raw materials ready of step 1 earlier by formula rate, makes it to dissolve fully and melt, and 700~1000 ℃ of insulations down, obtains alloy melt after the refining; Melting process is accomplished in enclosed environment;
Step 3: use the mixed gas of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion that alloy melt is carried out the degassing and purifying operation, and lasting ventilation finishes until reaction; To account for the Ni of total product mass percent 0.6% simultaneously
3The N powder joins in the alloy melt with above-mentioned gas with the fluidization mode; Stir, make Ni
3N is evenly distributed in alloy melt, and fully reacts with alloy melt; Leave standstill, temperature adjustment to 680~730 ℃, obtain the aluminium alloy melt that melting is accomplished.
Embodiment 2:
A kind of aldural by percentage to the quality, comprises 0.75% Si, 0.3% Fe; 0.08% Cu, 0.08% Mn, 0.5% Mg, 0.08% Cr; 0.08% Zn, 0.08% Ti, 2.4% Ni, 0.8% N; Surplus is Al and unavoidable impurities, and the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.15% of total mass per-cent.
The present invention also provides the preparation method of said aldural, adds Ni with the Combined Processing mode
3N may further comprise the steps:
Step 1: the component according to said aldural is got the raw materials ready, and comprises the Si that accounts for total product mass percent 0.75%, 0.3% Fe, 0.08% Cu, 0.08% Mn, 0.5% Mg, 0.08% Cr, 0.08% Zn, 0.08% Ti;
Step 2: in smelting furnace, add aluminium ingot or molten aluminum liquid earlier, heating makes it to melt fully, adds getting the raw materials ready of step 1 earlier by formula rate, makes it to dissolve fully and melt, and 700~1000 ℃ of insulations down, obtains alloy melt after the refining; Melting process is accomplished in enclosed environment;
Step 3: use the mixed gas of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion that alloy melt is carried out the degassing and purifying operation, and lasting ventilation finishes until reaction; To account for the Ni of total product mass percent 0.8% simultaneously
3The N powder joins in the alloy melt with above-mentioned gas with the fluidization mode; Stir, make Ni
3N is evenly distributed in alloy melt, and fully reacts with alloy melt; Leave standstill, temperature adjustment to 680~730 ℃, obtain the aluminium alloy melt that melting is accomplished.
Embodiment 3:
A kind of aldural by percentage to the quality, comprises 0.9% Si, 0.2% Fe; 0.05% Cu, 0.06% Mn, 0.6% Mg, 0.05% Cr; 0.07% Zn, 0.03% Ti, 2.7% Ni, 0.9% N; Surplus is Al and unavoidable impurities, and the content of every kind of impurity is no more than 0.05% of total mass per-cent, and the content of all impurity is no more than 0.15% of total mass per-cent.
The present invention also provides the preparation method of said aldural, adds Ni with the Combined Processing mode
3N may further comprise the steps:
Step 1: the component according to said aldural is got the raw materials ready, and comprises the Si that accounts for total product mass percent 0.9%, 0.2% Fe, 0.05% Cu, 0.06% Mn, 0.6% Mg, 0.05% Cr, 0.07% Zn, 0.03% Ti;
Step 2: in smelting furnace, add aluminium ingot or molten aluminum liquid earlier, heating makes it to melt fully, adds getting the raw materials ready of step 1 earlier by formula rate, makes it to dissolve fully and melt, and 700~1000 ℃ of insulations down, obtains alloy melt after the refining; Melting process is accomplished in enclosed environment;
Step 3: use the mixed gas of nitrogen or rare gas element or nitrogen and rare gas element arbitrary proportion that alloy melt is carried out the degassing and purifying operation, and lasting ventilation finishes until reaction; To account for the Ni of total product mass percent 0.9% simultaneously
3The N powder joins in the alloy melt with above-mentioned gas with the fluidization mode; Stir, make Ni
3N is evenly distributed in alloy melt, and fully reacts with alloy melt; Leave standstill, temperature adjustment to 680~730 ℃, obtain the aluminium alloy melt that melting is accomplished.
After the aldural liquid of employing the inventive method melting is come out of the stove, carry out the Foundry Production of different goods respectively along following two kinds of flow processs.
Flow process one: the longshore current groove is toppled over and is come out of the stove, and to vertical water cooling casting machine system, casting processing use ingot blank, particularly above large-scale slab ingot of cast thickness 500mm and the pole more than the diameter 500mm.
Flow process two: metaideophone is gone in the mold of foundry goods, uses metal mold, sand mold or mixed type casting mode, adopts gravitational casting, pressure die casting or counter-pressure casting technology, the aluminum alloy casting of y alloy y foundry goods, particularly casting large-scale, thin-walled or complex construction.