CN104498757A

CN104498757A - Antimony modification treatment method for ZL116 aluminum alloy sand casting

Info

Publication number: CN104498757A
Application number: CN201410777815.0A
Authority: CN
Inventors: 赵佩霞
Original assignee: Guizhou Anji Aviation Precision Casting Co Ltd
Current assignee: Guizhou Anji Aviation Precision Casting Co Ltd
Priority date: 2014-12-15
Filing date: 2014-12-15
Publication date: 2015-04-08

Abstract

The invention discloses an antimony modification treatment method for ZL116 aluminum alloy sand casting. By adopting Al-Sb alloy as a modifier in combination with the addition of Mg, the problem that the ZL116 alloy modified by sodium salt has serve pinholes is solved, the obtained casting has thin and short eutectic silicon and spherical modified microstructures. The difficulty in adopting the melting operation process of the antimony-modified alloy is decreased, the alloy has better fluidity than that of the alloy modified by sodium salt and the tendency of forming such defects as pinholes and the shrinkage porosity of the casting is decreased. The casting process of the alloy is increased and the casting has tensile strength greater than 300MPa and elongation after fracture greater than 2%.

Description

ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process

Technical field

The present invention relates to the sand casting process of aluminium alloy, particularly ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process.

Background technology

In producing at present, mostly Aluminum alloy modification process is to adopt Na salt, though Na salt can refining eutectic body effectively, but in technique with still there is many problems qualitatively, be mainly manifested in following two aspects: 1) Na easily and in casting mold steam produce following reaction occur: 2Na+H2O → Na2O+H2, reaction result makes to produce subsurface porosity in foundry goods; 2) adding Na makes alloy solution viscosity raise, and retardance bubble and the discharge be mingled with, cause modified alloy easily to form the defect such as pin hole, slag inclusion.Practice shows: more easily produce " white point " in the fracture of the sand mold casting after AL-Si alloy modification, alloy mechanical property is reduced.This " white point " is the air film shape pin hole be distributed on crystal boundary after deliberation, when alterant add-on and melt down doses many time, due to increasing containing sodium amount in alloy, " white point " on fracture is general also even more serious.

ZL116 alloy is can the aluminium-silicon-magnesium system cast aluminium alloy of heat treatment reinforcement, and this alloy adds titanium elements and beryllium element on the basis of ZL101, significantly improves the comprehensive mechanical property of alloy.When simultaneously beryllium can reduce alloy melting, the oxidation of magnesium, eliminates alloy fragility.But this alloy is in sodium salt degeneration process, the beryllium on alloy liquid level and sodium salt occur sharply to react, and destroy alloy liquid level zone of oxidation, cause alloy air-breathing to be inclined to and increase severely, cause foundry goods pin-hole phenomena serious.Must select more to be applicable to the alterant of ZL116 alloy sand mold casting for this reason, determine that the method for antimony metamorphic process becomes the key of ZL116 alloy sand mould casting process development.

Antimony is aluminium alloy long-acting alterant, good modification effect is had to Metal mould casting, but because antimony metamorphic agent exists susceptibility to casting section thickness or speed of cooling, seldom apply in sand mold casting, in prior art, do not find concrete ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process.

Summary of the invention

The invention provides ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process, the method, by determining the amount adding form, add opportunity and add of antimony metamorphic agent, realizes good Metamorphism treatment effect.

Concrete technical scheme of the present invention is as follows.

ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process, is characterized in that comprising following steps:

(1) first by ZL116 aluminum alloy ingot and the fusing of Sb alterant: Sb alterant adds with the form of Al-Sb alloy, and the add-on of Al-Sb alloy inoculant is that Sb composition weight accounts for 0.2% of final cast aluminium alloy weight;

(2) until ZL116 aluminum alloy ingot and Al-Sb alloy inoculant melt completely and melt temperature within the scope of 680 ~ 700 DEG C time be incorporated as the Mg of final cast aluminium alloy weight 0.55%;

(3) stir liquation and pass through C ₂cl ₆refining treatment;

(4) to stir and refining carries out sand mold casting in 670 ~ 680 DEG C of temperature ranges after completing again.

Beneficial effect of the present invention is: ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process disclosed by the invention, and solve the problem that ZL116 alloy adopts pin hole after sodium salt degeneration process serious, the foundry goods Eutectic Silicon in Al-Si Cast Alloys obtained is thin and short, and in spherical rotten tissue.After adopting antimony metamorphic, alloy melting operating procedure difficulty reduces, and alloy flowability comparatively sodium salt degeneration is good, and foundry goods forms pin hole, shrinkage defect tendency reduces.Alloy casting manufacturability improves.Foundry goods tensile strength is greater than 300MPa, and elongation after fracture is greater than 2%.

Embodiment

Below in conjunction with example, the present invention is described in detail, but should not be interpreted as that the scope of theme of the present invention is only limitted to following embodiment at this point, without departing from the idea case in the present invention described above, all make according to ordinary skill knowledge and customary means various amendments, replacement and change, include within the scope of the invention.

For solving ZL116 alloy sand mold casting pin hole problems, the invention provides sand mold casting antimony metamorphic treatment process, solve foundry goods pin hole excessive problem, casting composition is qualified, mechanical property all reaches HB962-2001 " cast aluminium alloy " sand mold-T5 standard-required.Referring specifically to following two embodiments.

Embodiment one: casting composition is 6.5 ~ 8.5% by weight Si; Mg is 0.35 ~ 0.55%; Ti is 0.1 ~ 0.3%; The ZL116 alloy of Be0.15 ~ 0.4, the large-scale sand mold casting of plate shape of casting section thickness 13mm, adopt antimony metamorphic treatment process method, it is characterized in that: aluminium antimony master alloy together adds as long-acting alterant and aluminium ingot, other master alloy, after all dissolving, be warmed up to 680 ~ 700 DEG C and be incorporated as weight alloy 0.55% MAG block, (noting Sb:Mg ≈ 1:3) stirs 2 ~ 3 minutes; After composition adjustment is qualified, the refining under temperature is 710 ~ 760 DEG C of conditions of the C2Cl6 with 0.3 ~ 0.5%, refining time controlled at 8 ~ 13 minutes.After refining static 10 minutes.Control teeming temperature 680 DEG C cast.

Adopt the present embodiment method, foundry goods Eutectic Silicon in Al-Si Cast Alloys is thin and short, is obvious spherical silicon rotten tissue mutually.Aluminium alloy pin hole grade is 1 grade, and foundry goods tensile strength is: foundry goods tensile strength is: σ b=308MPa; Unit elongation δ 5=2.2%; Hardness HB=107

Embodiment two: casting composition is 6.61% by weight Si; Mg is 0.39%; Ti is 0.18%; Be is 0.23%; Fe is 0.15%; Cu is the ZL116 alloy of 0.07%, the template sand mold casting of casting section thickness 3.5mm, adopt antimony metamorphic treatment process method, it is characterized in that: aluminium antimony master alloy together adds as long-acting alterant and aluminium ingot, other master alloy, after all dissolving, be warmed up to 680 ~ 700 DEG C and be incorporated as weight alloy 0.55% MAG block, (noting Sb:Mg ≈ 1:3) stirs 2 ~ 3 minutes; After composition adjustment is qualified, the refining under temperature is 710 ~ 760 DEG C of conditions of the C2Cl6 with 0.3 ~ 0.5%, refining time controlled at 8 ~ 13 minutes.After refining static 10 minutes.Control teeming temperature 720 DEG C cast.

Adopt the present embodiment method, foundry goods Eutectic Silicon in Al-Si Cast Alloys is thin and short, is obvious spherical silicon rotten tissue mutually.Aluminium alloy pin hole grade is 1 grade, and foundry goods tensile strength is: σ b=327MPa; Unit elongation δ 5=2.2%; Hardness HB=95.0.

After adding micro-antimony and magnesium in aluminium alloy solution, obtain good rotten tissue and (do not add the ZL116 alloy eutectic structure of any alterant element, the silicon distribution in long slab strip mutually, branch is thick at random, after adding antimony 0.2%+0.55%Mg, silicon attenuates mutually and shortens, and has occurred obvious silicon mutually in spherical rotten tissue.

When only adding antimony in cocrystallized Al-Si alloy, from Al-Sb phasor, a kind of compound and AlSb high melting compound is only there is in melt, the eutectic temperature of AlSb and α (Al) is about 625 DEG C, higher than the eutectic temperature 577 DEG C of silicon phase and α (Al), the two component eutectic reaction of AlSb and α (Al), α (Al) is impelled to separate out in advance, compared with unmetamorphosed aluminum silicon alloy, the quantity showed increased of α (Al), dendritic crystal is many and fine and closely woven, growing up of α (Al) crystal encloses AlSb phase, make its Dispersed precipitate, now silicon is separated out due to the precipitation concentration increase of α (Al), so α (Al) growth suppresses silicon to grow mutually soon, silicon is made to obtain refinement mutually.

After addition element magnesium, Mg3Sb2 will be generated greatly in 658 DEG C of alloy melts eutectic reaction will occur, and impel α (Al) to separate out, distribute in fine and closely woven shape, split the distribution of silicon phase on the one hand, inhibit silicon to grow mutually on the other hand, make silicon Entropy density deviation fine and closely woven, therefore obtain rotten tissue.Because the add-on of magnesium and antimony (is respectively 0.55% and 0.2%, and the atomic molar ratio antimony of magnesium is much smaller) instruct, the atomicity of magnesium is much larger than the atomicity of antimony in the melt, so magnesium atom is except participation antimony formation compound, also there is unnecessary magnesium atom, because magnesium is very easily in Mg3Sb2 surface attachment, reduce the interfacial free energy of this compound on the one hand, add wettability, make silicon mutually easy at the raw core in its surface.On the other hand, be the absorption at compound surface, change its interface structure, form a transition layer, this layer allows to cross silicon interpromoting relation in five elements nucleus growth under cool condition at not forming core, makes Mg3Sb2 serve the effect of heterogeneous nucleus.Therefore first adding antimony, then to add the modification effect of magnesium good.

Claims

1.ZL116 aluminium alloy sand mould casting antimony metamorphic treatment process, is characterized in that comprising following steps:

(1) first by ZL116 aluminum alloy ingot and the fusing of Sb alterant: Sb alterant adds with the form of Al-Sb alloy, and the add-on of Al-Sb alloy inoculant is that Sb component accounts for 0.2% of final cast aluminium alloy weight;

(3) stir liquation and pass through C ₂cl ₆refining treatment;