CN104962801A - Smelting method of high-strength gray cast iron - Google Patents
Smelting method of high-strength gray cast iron Download PDFInfo
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- CN104962801A CN104962801A CN201510318713.7A CN201510318713A CN104962801A CN 104962801 A CN104962801 A CN 104962801A CN 201510318713 A CN201510318713 A CN 201510318713A CN 104962801 A CN104962801 A CN 104962801A
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Abstract
The invention discloses a smelting method of high-strength gray cast iron; waste steel, pig iron and foundry returns serve as raw materials to smelt the gray cast iron; the smelting comprises the following specific steps: firstly, ferromanganese and the pig iron are added into a medium-frequency induction electric furnace; then, carburant and the waste steel are synchronously added; when the volume of molten iron in the induction electric furnace is 3/4, silicon carbide is added, and the foundry returns are synchronously added for smelting; after raw molten iron is heated up to a temperature of 1500-1520 DEG C, the raw molten iron is stood for 5-10 minutes; silicon zirconium inoculant and the raw molten iron are both fed into a tapping packet; and after slag on the surface of the molten iron is cleaned, the molten iron is cast into a molding cavity of a casting mold. The method reduces the manufacturing cost, and is convenient to manage the foundry returns; the method adopts 60% of waste steel to improve the final strength of castings, adopts the silicon carbide and burden synchronous smelting method to pretreat the molten iron to guarantee the pretreatment effect, and adopts the high-efficiency inoculant-silicon zirconium inoculant to guarantee the inoculation effect; and the gold phases of the casting bodies obtain A type graphite more than 80%.
Description
Technical field
The present invention relates to a kind of melting method of gray iron casting, particularly relate to the melting method of high-strength gray cast iron part, belong to chemical melting field.
Background technology
The cocrystallizing type alloy that graphitic cast iron is made up of iron, carbon and silicon substantially, wherein, carbon mainly exists with the form of graphite.Produce premium casting, form and the matrix metal tissue of the graphite formed when controlling cast iron solidified are vital.Inoculation is one of most important link in production technique.Good inoculation can make graphitic cast iron have satisfactory microstructure, thus ensures mechanical property and the processing characteristics of foundry goods.In liquid cast, add nucleating agent, a large amount of sub-micro-core can be formed, impel eutectic cell to generate in the liquid phase.During close to eutectic solidification temperature, first raw core place forms tiny graphite flake, and grows into eutectic cell thus.The formation of each eutectic cell, all peripherad liquid phase can discharge a small amount of heat, the eutectic cell of formation is more, and the solidification rate of cast iron is lower.The reduction of solidification rate, just contributes to solidifying by iron-graphite stable system, and can obtain A type graphite tissue.
General, good inoculation has following effect: (1) is eliminated or alleviated chilling tendency; (2) avoid occurring over-cooling structure; (3) alleviate the sectional sensitivity of ironcasting, make the difference of thin, the thick section microstructure of foundry goods little, difference in hardness is also little; (4) be conducive to the raw core of eutectic cell, Eutectic Cell Number is increased; (5) make the form of Graphite in Cast Iron mainly tiny and equally distributed A type graphite, thus improve the mechanical property of cast iron.Breed good cast iron mobility better, the contraction minimizing of foundry goods, processing characteristics improvement, residual stress reduce.
Alloy element copper or tin must be added during traditional medium-frequency induction furnace melting height trade mark gray iron casting, add manufacturing cost.
Summary of the invention
The object of this invention is to provide the melting method of high-strength gray cast iron part, to solve the high difficult problem of above-mentioned manufacturing cost, and the A type graphite of higher yields can be obtained.
The technical solution used in the present invention is: the melting method of high-strength gray cast iron part, is characterized in that: the pig iron that the steel scrap being with trade mark Q235, the trade mark are Q10 and gray iron foundry returns carry out the melting of gray iron casting for raw material; Described melting concrete steps are:
(1) pig iron being first Q10 by 0.8 ~ 1% ferromanganese and 10% trade mark together adds in medium-frequency induction furnace, and the carburelant and 60% trade mark that then add 2.5% are the steel scrap of Q235 simultaneously, finally add 30% gray iron foundry returns melting;
(2) cast iron melting to induction furnace volume 3/4 time, the silicon carbide adding 0.6 ~ 0.7% add simultaneously gray iron foundry returns full to stove after carry out melting and form molten iron;
(3) by step 2 be heated to 1440 ~ 1460 DEG C time, use carbon sulphur instrument to measure C content in molten iron 3.00 ~ 3.10%;
(4) after the molten iron in step 3 being heated to 1500 ~ 1520 DEG C, induction furnace is adjusted to keeping warm mode, molten iron leaves standstill 5 ~ 10 minutes and forms base iron;
(5) the silicon zirconium nucleating agent of 0.5 ~ 0.6% and base iron are together poured tap a blast furnace wrap in form whole molten iron, subsequently whole molten iron drossing clean after pour into casting mold die cavity, setting pouring temperature is 1380 ~ 1410 DEG C, and pouring time is 1 ~ 2 minute.
Further, in described step 1, the trade mark is that the massfraction of each moiety in the pig iron of Q10 is respectively C:4.45 ~ 4.50%, Si:0.75 ~ 0.80%, Mn:0.12 ~ 0.15%, P:0.023 ~ 0.027%, S:0.012 ~ 0.015%, Cr:0.033 ~ 0.040%, Ti:0.02 ~ 0.030%, V:0.010 ~ 0.020%, surplus is Fe.
Further, in described step 1, the trade mark is that the massfraction of each moiety in the steel scrap of Q235 is respectively C:0.23 ~ 0.28%, Si:0.15 ~ 0.18%, Mn:0.43 ~ 0.55%, P:0.02 ~ 0.025%, S:0.021 ~ 0.030%, Cr:0.017 ~ 0.020%, Ti:0.001 ~ 0.003%, V:0.001 ~ 0.004%, surplus is Fe.
Further, in described step 1, each constituent mass mark of carburelant is respectively nitrogen :≤0.02%, carbon: 98 ~ 100%, impurity 0 ~ 1.68%.
Further, in described step 2, the massfraction of silicon carbide is 88 ~ 90%, wherein silicon: 60 ~ 63%, carbon: 27%, impurity 10 ~ 13%; Granularity 1 ~ the 5mm of described silicon carbide.
Further, in described step 5, each constituent mass mark of silicon zirconium nucleating agent is respectively Si:73.1%, Zr:2.42%, and surplus is Fe.
Further, in described step 5, the granularity of silicon zirconium nucleating agent is 0.2 ~ 0.6mm.
Beneficial effect: alloy element copper or tin must be added when method of the present invention instead of traditional medium-frequency induction furnace melting height trade mark gray iron casting, reduce manufacturing cost, and be convenient to the management of foundry returns; Present method adopts the method for silicon carbide and furnace charge melting simultaneously to carry out pre-treatment to molten iron, ensure that pretreated effect; Adopt effective inoculation agent silicon zirconium nucleating agent to ensure that the effect bred, make the A type graphite obtaining more than 80% in foundry goods body metallographic, foundry goods body tensile strength reaches between 270 ~ 300, body surface E type graphite≤20%, centre≤5%.
Accompanying drawing explanation
Fig. 1 is A type graphite distribution plan in the structure of body coupon of the present invention.
Fig. 2 is the perlite figure of body coupon of the present invention.
Embodiment
Implementation column below can make those skilled in the art more fully understand the present invention, but does not therefore limit the present invention among described scope of embodiments.
Embodiment 1
The melting method of high-strength gray cast iron part: take the trade mark as the steel scrap of Q235, the trade mark pig iron that is Q10 and foundry returns carry out the melting of gray iron casting for raw material; Melting concrete steps are:
(1) pig iron being first Q10 by 0.8% ferromanganese and 10% trade mark together adds in medium-frequency induction furnace, and the carburelant and 60% trade mark that then add 2.5% are the steel scrap of Q235 simultaneously, finally add the foundry returns melting of 30%;
(2) cast iron melting to induction furnace volume 3/4 time, the silicon carbide adding 0.6% in induction furnace add simultaneously gray iron foundry returns full to stove after carry out melting and form molten iron;
(3) by step 2 be heated to 1440 ~ 1460 DEG C time, use carbon sulphur instrument to measure C content in molten iron 3.00 ~ 3.10%;
(4) after the base iron in step 2 being heated to 1500 ~ 1520 DEG C, induction furnace is adjusted to keeping warm mode, molten iron leaves standstill 5 ~ 10 minutes and forms base iron;
(5), in the silicon zirconium nucleating agent of 0.5% and base iron together being poured and tapping a blast furnace and wrap, pour in casting mold die cavity more subsequently simultaneously and cast, arranging pouring temperature is 1380-1410 DEG C, and pouring time is 1 ~ 2 minute.
According to the melting method of the present embodiment, each component concentration of base iron of melting meets: C:3.00-3.10%, Si:1.30-1.40%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%;
The each component concentration of whole molten iron of melting meets: C:3.00-3.10%, Si:1.70-1.80%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%.
The assay of the present embodiment melting gray iron casting is that tensile strength reaches 276, and surface hardness reaches 220, and content of pearlite in alloy is 98%.
Embodiment 2
Be 0.9% by the ferromanganese amount added, Silicon carbide addition is 0.65%, and silicon zirconium innoculant adding quantity is 0.55%, carries out melting according to the melting method described in embodiment 1.
According to the melting method of the present embodiment, each component concentration of base iron of melting meets: C:3.00-3.10%, Si:1.30-1.40%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%;
The each component concentration of whole molten iron of melting meets: C:3.00-3.10%, Si:1.70-1.80%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%.
The assay of the present embodiment melting gray iron casting is that tensile strength reaches 281, and surface hardness reaches 228, and content of pearlite in alloy is 98.5%.
Embodiment 3
Be 1% by the ferromanganese amount added, Silicon carbide addition is 0.7%, and silicon zirconium innoculant adding quantity is 0.6%, carries out melting according to the melting method described in embodiment 1.
According to the melting method of the present embodiment, each component concentration of base iron of melting meets: C:3.00-3.10%, Si:1.30-1.40%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%;
The each component concentration of whole molten iron of melting meets: C:3.00-3.10%, Si:1.70-1.80%, Mn:0.6%-0.9%, P≤0.05%, S:0.08-0.010%.
The assay of the present embodiment melting gray iron casting is that tensile strength reaches 277, and surface hardness reaches 236, and content of pearlite in alloy is 98.9%.
Claims (5)
1. the melting method of high-strength gray cast iron part, is characterized in that: the pig iron that the steel scrap being with trade mark Q235, the trade mark are Q10 and gray iron foundry returns carry out the melting of gray iron casting for raw material; Described melting concrete steps are:
(1) pig iron being first Q10 by 0.8 ~ 1% ferromanganese and 10% trade mark together adds in medium-frequency induction furnace, and the carburelant and 60% trade mark that then add 2.5% are the steel scrap of Q235 simultaneously, finally add 30% gray iron foundry returns melting;
(2) cast iron melting to induction furnace volume 3/4 time, the silicon carbide adding 0.6 ~ 0.7% add simultaneously gray iron foundry returns full to stove after carry out melting and form molten iron;
(3) by step 2 be heated to 1440 ~ 1460 DEG C time, use carbon sulphur instrument to measure C content in molten iron 3.00 ~ 3.10%;
(4) after the molten iron in step 3 being heated to 1500 ~ 1520 DEG C, induction furnace is adjusted to keeping warm mode, molten iron leaves standstill 5 ~ 10 minutes and forms base iron;
(5), in the silicon zirconium nucleating agent of 0.5 ~ 0.6% and base iron together being poured and tapping a blast furnace and wrap, form whole molten iron, pour into casting mold die cavity after whole molten iron drossing is clean, setting pouring temperature is 1380 ~ 1410 DEG C, and pouring time is 1 ~ 2 minute;
In described step 1, the trade mark is that the massfraction of each moiety in the pig iron of Q10 is respectively C:4.45 ~ 4.50%, Si:0.75 ~ 0.80%, Mn:0.12 ~ 0.15%, P:0.023 ~ 0.027%, S:0.012 ~ 0.015%, Cr:0.033 ~ 0.040%, Ti:0.02 ~ 0.030%, V:0.010 ~ 0.020%, surplus is Fe;
In described step 1, the trade mark is that the massfraction of each moiety in the steel scrap of Q235 is respectively C:0.23 ~ 0.28%, Si:0.15 ~ 0.18%, Mn:0.43 ~ 0.55%, P:0.28 ~ 0.025%, S:0.021 ~ 0.030%, Cr:0.017 ~ 0.020%, Ti:0.001 ~ 0.003%, V:0.001 ~ 0.004%, surplus is Fe.
2. the melting method of high-strength gray cast iron part according to claim 1, is characterized in that: in described step 1, each constituent mass mark of carburelant is respectively nitrogen :≤0.02%, carbon: 98 ~ 100%, impurity 0 ~ 1.68%.
3. the melting method of high-strength gray cast iron part according to claim 1, is characterized in that: in described step 2, the massfraction of silicon carbide is 88 ~ 90%, wherein silicon: 60 ~ 63%, carbon: 27%, impurity 10 ~ 13%; Granularity 1 ~ the 5mm of described silicon carbide.
4. the melting method of high-strength gray cast iron part according to claim 1, is characterized in that: in described step 5, each constituent mass mark of silicon zirconium nucleating agent is respectively Si:73.1%, Zr:2.42%, AL:0.82%, and surplus is Fe.
5. the melting method of high-strength gray cast iron part according to claim 1, is characterized in that: in described step 5, the granularity of silicon zirconium nucleating agent is 0.2 ~ 0.6mm.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105401065A (en) * | 2015-11-28 | 2016-03-16 | 西峡县西泵特种铸造有限公司 | Production process of high-strength alloyed gray iron hydraulic valve body part |
| CN105950813A (en) * | 2016-06-23 | 2016-09-21 | 含山县清溪德胜铸造厂 | Production process of high-strength bearing gear cast iron |
| CN110157975A (en) * | 2019-06-28 | 2019-08-23 | 含山县兴达球墨铸铁厂 | A kind of preparation method of high-strength thin-walled gray iron casting |
| CN112589054A (en) * | 2020-12-20 | 2021-04-02 | 十堰市泰祥实业股份有限公司 | Sand-lined casting method for gray cast iron automobile engine main bearing cap iron mold |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101649396A (en) * | 2009-07-31 | 2010-02-17 | 湖南有色金属研究院 | Methods of removing F and Cl in secondary zinc oxide dust effectively and producing electrolytic zinc |
| CN103882279A (en) * | 2014-03-31 | 2014-06-25 | 江苏力源金河铸造有限公司 | Method for smelting high-strength grey-iron cast |
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- 2015-06-06 CN CN201510318713.7A patent/CN104962801A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101649396A (en) * | 2009-07-31 | 2010-02-17 | 湖南有色金属研究院 | Methods of removing F and Cl in secondary zinc oxide dust effectively and producing electrolytic zinc |
| CN103882279A (en) * | 2014-03-31 | 2014-06-25 | 江苏力源金河铸造有限公司 | Method for smelting high-strength grey-iron cast |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105401065A (en) * | 2015-11-28 | 2016-03-16 | 西峡县西泵特种铸造有限公司 | Production process of high-strength alloyed gray iron hydraulic valve body part |
| CN105950813A (en) * | 2016-06-23 | 2016-09-21 | 含山县清溪德胜铸造厂 | Production process of high-strength bearing gear cast iron |
| CN110157975A (en) * | 2019-06-28 | 2019-08-23 | 含山县兴达球墨铸铁厂 | A kind of preparation method of high-strength thin-walled gray iron casting |
| CN112589054A (en) * | 2020-12-20 | 2021-04-02 | 十堰市泰祥实业股份有限公司 | Sand-lined casting method for gray cast iron automobile engine main bearing cap iron mold |
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Application publication date: 20151007 |