CN1410194A - Spheroidal graphite cast iron mould cavity inoculation block and its production technology - Google Patents
Spheroidal graphite cast iron mould cavity inoculation block and its production technology Download PDFInfo
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- CN1410194A CN1410194A CN 02139260 CN02139260A CN1410194A CN 1410194 A CN1410194 A CN 1410194A CN 02139260 CN02139260 CN 02139260 CN 02139260 A CN02139260 A CN 02139260A CN 1410194 A CN1410194 A CN 1410194A
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Abstract
An in-mould inoculating block for nodular graphite cast iron contains Si (55-70 wt.%), RE (0.5-5), low-smelting-point element (2-10) and iron (the rest), and is prepared through proportioning the ferrosilicon and rare-earth elements and low-smelting-point elements, smelting at 1600-1650 deg.c in a MF induction furnace, preparing wet clay-sand mould, fast casting with pearlite for stopping slags, waiting inoculating block to cool to 300-500 deg.C, demoulding, clearing off inoculating block, and blasting sand of the surface. Its advantages are low smelting point, low density and uniform inoculation.
Description
Technical field: the invention belongs to metallic substance and technology, relate to spheroidal graphite cast iron in-mold inoculation inoculant block and production technique thereof.
Background technology: the importance of inoculation technology in Cast Iron Production is familiar with by people already, and it has become the important step of producing high quality cast iron spare, also is the effective measure of producing thin-walled, complexity, meehanite cast iron and improving the foundry goods processing characteristics.The effect of nucleating agent has ageing, and promptly pregnant effect weakens along with the prolongation of time, so nucleating agent adds the time that time of iron liquid solidifies near iron liquid more, and its effect is just good more, and the art of inoculation that adopts is current-following inoculation and mould cavity inoculation usually.Mould cavity inoculation belongs to instant inoculation, because it is effective, easy and simple to handle, be suitable for streamline production and widespread use.During mould cavity inoculation, nucleating agent be form side with inoculant block in casting mold, the fusing gradually with the inflow of molten iron is dissolved in and plays inoculation(effect) in the molten iron when cast.The employed inoculant block of mould cavity inoculation technology has molding bonded, powder metallurgy forming and casting three major types, and various moulding processs respectively have relative merits.
The inoculant block of molding bonded adopts granular nucleating agent, has the simple advantage of moulding process.The organic binder bonds that adopt in moulding process more, as paraffin, polyvinyl alcohol (PVA), stearic acid etc., experimental results show that, in casting process, organic binder bond or decomposition vaporization reduce inoculant block intensity, and be defeated and dispersed under the souring of molten iron easily, cause dissolving inhomogeneous, produce " bright spot " defective; Or, hinder the reaction of molten metal and inoculant block at nucleating agent particle surface formation carburization zone, cause and do not breed.The employing mineral binder bond that has, as water glass, in moulding process, the easy and ferrosilicon particle reaction of water glass forms compound layer, hinders the reaction of the molten iron and the nucleating agent that fill type earlier, causes and breeds hysteresis.
The conventional cast inoculant block is that ferrosilicon liquid forms through high melt and process of setting, dense structure, and its advantage is a chemical ingredients of being convenient to adjust inoculant block, suitable difference breeds the requirement of production.But in moulding process, form one deck compact oxide easily on the surface of inoculant block.In preparation process, the ferrosilicon that zone of oxidation has hindered molten metal and inside reacts, and causes the molten metal that fills type earlier to can not get breeding, and causes and breeds hysteresis; And after zone of oxidation is destroyed, the ferrosilicon surface of inner fresh densification is very fast with the molten metal speed of response, the degree that breeds of molten metal is increased, under situation about growing the duration of pouring, follow-up molten metal may breed deficiency owing to inoculant block has dissolved to finish to cause, thereby makes the different molten metals that fill type the duration of pouring of foundry goods breed inhomogeneous.
The inoculant block of powder metallurgy forming has good pregnant effect, but cost is higher, uses less aborning.
Homogeneity in order to guarantee to breed meets the needs of production, and the chemical ingredients of necessary appropriate design inoculant block reduces density, surperficial No oxided film.
Summary of the invention: the present invention proposes a kind of uniform inoculant block of dissolving and manufacture method thereof that as-cast ferrite ductile iron is produced that be used in order to solve existing inoculant block fusing point height, density height, to breed inhomogeneous or the problem that does not breed.
A kind of spheroidal graphite cast iron in-mold inoculation inoculant block, main raw material(s) are ferrosilicon, add rare earth and low melting point element simultaneously, it is characterized in that: the weight percent of described component is: Si accounts for 55～70%; RE accounts for 0.5～5%; Low melting point element accounts for 2～10%; All the other are iron.Its production technique is: A, adopt the medium-frequency induction furnace melting, material is weighed in corresponding ratio and order adds and carries out melting, smelting temperature is at 1600～1650 ℃; B, the folded case upright casting moulding of employing wet type clay-bonded sand; C, use the perlite pushing off the slag, water soon; D, pour after, treat that inoculant block is cooled to 300～500 ℃ after, shake out cleaning inoculant block carries out shot blasting on surface (sand) and handles.
Appropriate design inoculant block chemical ingredients of the present invention adds elements such as rare earth, magnesium, aluminium in inoculant block, reduced the fusing point of inoculant block, helps the reaction of inoculant block and molten iron, and prevent decaying spheroidisation in preparation process; Adopt sand mold sand multiple mould, both satisfied batch production requirement, and reduce the density of inoculant block, make inoculant block dissolving successively in reaction process, breed evenly; Adopt shot peening, remove the high temperature oxide film on inoculant block surface, reduced molten iron and inoculant block contact reacts time, guarantee that the molten iron that fills type is earlier fully bred; Be applicable to as-cast ferrite ductile iron production, can direct production as-cast ferrite ductile iron spare, and without thermal treatment.
Description of drawings: Fig. 1 produces the metallographic structure photo of foundry goods for the inoculant block of using the present invention's making.
Embodiment: spheroidal graphite cast iron in-mold inoculation inoculant block of the present invention, main raw material(s) are ferrosilicon, add rare earth and low melting point element simultaneously, and wherein the weight percent of each component is: Si accounts for 55～70%; RE accounts for 0.5～5%; Low melting point element accounts for 2～10%; All the other are iron.Because the main raw material(s) of the nucleating agent that adopts is a ferrosilicon usually, its fusing point is at 1310～1330 ℃, and the teeming temperature of molten iron is unfavorable for the ferrosilicon fusing so generally at 1330～1380 ℃ in the industrial production owing to the fusing point of ferrosilicon is higher, thereby influences pregnant effect.The fusing point that reduces ferro-silicon is to guarantee to breed uniform important measures.On the basis of ferrosilicon, add the fusing point that rare earth and low melting point element can reduce ferro-silicon in the nucleating agent, help the fusing of nucleating agent, wherein low melting point element comprises elements such as magnesium, aluminium.Concrete composition when low melting point element is selected magnesium, aluminium for use following (weight percentage): Si is 55～70%; Al is 1.5～5%; RE is 0.5～5%; Mg is 0.5～5%; All the other are iron.
By said ratio, adopt cast shaping process, and carry out according to following processing step:
A, melting: adopt the medium-frequency induction furnace melting, material is weighed in corresponding ratio and add in proper order and carry out melting, smelting temperature is at 1600～1650 ℃.
Starting material:
75 ferrosilicon---by the GB2277-87 requirement
Rare earth ferrosilicomagnesium---contain 43.2%Si, 5～18%RE, 7～19%Mg, 2%Ca, all the other are iron
Commercial-purity aluminium---technical pure
The pig iron---by GB 718-82 requirement, select the T10 pig iron for use
75 ferrosilicon, rare earth ferrosilicomagnesium, commercial-purity aluminium, the pig iron are added in 100: 8～12: 2～6: 0.5～3 ratio, material addition sequence: add 75 ferrosilicon earlier and carry out melting, after 75 ferrosilicon melt back adding rare earth ferrosilicomagnesium heat fused fully, add industrial aluminum and pig iron adjustment composition again.
Behind material melting, note slag is scratched clean.
B, moulding: adopt the folded case upright casting moulding of wet type clay-bonded sand, like this because sand mold intensity is lower, and contain moisture in the sand mold, in liquid metal filling, process of setting, the decomposition of at high temperature vaporizing of the moisture in the sand mold, enter into molten metal, make that pore increases in the inoculant block, density reduces, and increases the ferrosilicon surface, when reacting, be unlikely to very violent, thereby guarantee the dissolution process homogeneity with molten iron.
C, cast:,, avoid contacting of metal and air simultaneously, when cast with the minimizing oxidation to guarantee that liquid metal filling is complete because ferrosilicon liquid mobile relatively poor should adopt soon and water.In casting process, adopt the perlite pushing off the slag, stop the oxide compound on ferrosilicon liquid surface in the bag to enter die cavity.
D, cleaning: after pouring, treat that inoculant block is cooled to 300～500 ℃ after, shake out cleaning inoculant block.Then the inoculant block that cleans out being carried out shot blasting on surface (sand) handles, pass through shot blasting on surface, the high temperature oxide film of the densification on inoculant block surface is removed, like this in the mould cavity inoculation process, the oxide film that molten iron does not need to destroy the inoculant block surface just can be directly and the ferrosilicon reaction, shortened inoculant block and molten iron contact reacts time, guaranteed that the molten iron that fills type is earlier fully bred.
Below in conjunction with specific embodiment the present invention is described:
Part is a dumb iron: require ferritic content to be not less than 85%, its chemical ingredients is: C is 3.6～3.8%, and Si is 2.4～2.6%, Mn＜0.3%, S, P＜0.05%.
Adopt current-following inoculation, foundry goods need be heat-treated just can reach design requirements, but scrap rate is higher.
Adopt 3 tons of cupola melting molten iron, 1460～1480 ℃ of tapping temperatures adopt 250 kilograms of casting ladles, pour the Fa Baonei nodularization, use rare earth magnesium nodularizer (Mg:5～8%, RE:3～5%, Si:40.3%), the nodulizing agent add-on accounts for 1.7% of weight of molten iron; Adopt late inoculation technology, adding 0.3% 75 ferrosilicon account for weight of molten iron when subcontracting breeds, adopt inoculant block of the present invention to carry out mould cavity inoculation during cast, inoculant block weight is 70 grams, accounts for 0.125% of casting mold weight of molten iron, and the chemical ingredients of inoculant block is (weight percentage): 55～70% Si, 1.5～5% Al, 0.5～5% RE, 0.5～5% Mg, all the other are iron.Be 8～12 seconds the duration of pouring, poured into a mould 17000 casees foundry goods altogether, all do not have spoken parts in traditional operas, and casting hardness is less than HB200, and cast ferrite content is greater than 85%, metallographic structure photo such as Fig. 1.In production technique, reduced heat treatment step.
Claims (6)
1, a kind of spheroidal graphite cast iron in-mold inoculation inoculant block, main raw material(s) is a ferrosilicon, adds rare earth and low melting point element simultaneously, it is characterized in that: the weight percent of described component is: Si accounts for 55～70%; RE accounts for 0.5～5%; Low melting point element accounts for 2～10%; All the other are iron.
2, spheroidal graphite cast iron in-mold inoculation inoculant block as claimed in claim 1, it is characterized in that: described low melting point element comprises elements such as magnesium, aluminium.
3, spheroidal graphite cast iron in-mold inoculation inoculant block as claimed in claim 2, it is characterized in that: each weight percentages of components was when described low melting point element was magnesium, aluminium: Si is 55～70%; Al is 1.5～5%; RE is 0.5～5%; Mg is 0.5～5%; All the other are iron.
4, the production technique of spheroidal graphite cast iron in-mold inoculation inoculant block as claimed in claim 1 is:
A, the melting of employing medium-frequency induction furnace are weighed material in corresponding ratio and melting is carried out in the order adding, and smelting temperature is at 1600～1650 ℃;
B, the folded case upright casting moulding of employing wet type clay-bonded sand;
C, use the perlite pushing off the slag, water soon;
D, pour after, treat that inoculant block is cooled to 300～500 ℃ after, shake out cleaning inoculant block carries out shot blasting on surface (sand) and handles.
5, the production technique of spheroidal graphite cast iron in-mold inoculation inoculant block as claimed in claim 4 is characterized in that: to be 75 ferrosilicon, rare earth ferrosilicomagnesium, commercial-purity aluminium, the pig iron add in 100: 8～12: 2～6: 0.5～3 ratio described material's proportion.
6, the production technique of spheroidal graphite cast iron in-mold inoculation inoculant block as claimed in claim 4, it is characterized in that: described material addition sequence is to add 75 ferrosilicon earlier to carry out melting, melts fully at 75 ferrosilicon to add industrial aluminum and pig iron adjustment composition after the back adds the rare earth ferrosilicomagnesium heat fused again.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB021392609A CN1189271C (en) | 2002-11-07 | 2002-11-07 | Spheroidal graphite cast iron mould cavity inoculation block and its production technology |
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| CNB021392609A CN1189271C (en) | 2002-11-07 | 2002-11-07 | Spheroidal graphite cast iron mould cavity inoculation block and its production technology |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100372635C (en) * | 2005-05-27 | 2008-03-05 | 刘明 | Method for manufacturing magnesium alloy wheel hub and product thereof |
| CN101979186A (en) * | 2010-11-16 | 2011-02-23 | 昆明理工大学 | Method for controlling graphite distortion of large-sized nodular iron casting |
| CN111318644A (en) * | 2020-03-16 | 2020-06-23 | 宁夏新顺成特种合金有限公司 | Inoculation block production process for coated sand mold |
-
2002
- 2002-11-07 CN CNB021392609A patent/CN1189271C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100372635C (en) * | 2005-05-27 | 2008-03-05 | 刘明 | Method for manufacturing magnesium alloy wheel hub and product thereof |
| CN101979186A (en) * | 2010-11-16 | 2011-02-23 | 昆明理工大学 | Method for controlling graphite distortion of large-sized nodular iron casting |
| CN101979186B (en) * | 2010-11-16 | 2012-08-29 | 昆明理工大学 | Method for controlling graphite distortion of large-sized nodular iron casting |
| CN111318644A (en) * | 2020-03-16 | 2020-06-23 | 宁夏新顺成特种合金有限公司 | Inoculation block production process for coated sand mold |
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| CN1189271C (en) | 2005-02-16 |
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