CN103589941B - Method for preparing vermicular graphite cast iron by molten iron spheroidization - Google Patents
Method for preparing vermicular graphite cast iron by molten iron spheroidization Download PDFInfo
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- CN103589941B CN103589941B CN201310634568.4A CN201310634568A CN103589941B CN 103589941 B CN103589941 B CN 103589941B CN 201310634568 A CN201310634568 A CN 201310634568A CN 103589941 B CN103589941 B CN 103589941B
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Abstract
The invention discloses a method for preparing vermicular graphite cast iron by molten iron spheroidization. The method comprises the following steps of 1, blending raw materials, 2, preparing a mixed spheroidization agent, 3, carrying out spheroidization treatment, 4, carrying out inoculation treatment, 5, determining a ferric sulfide pouring amount, 6, taking a stokehole sample and carrying out fast metallographic examination on the stokehole sample, 7, carrying out slag removal and coverage, and 8, carrying out pouring. The vermicular graphite cast iron stably obtained by the method has a vermicularizing rate greater than or equal to 85%, matrix ferrite content greater than or equal to 90% and a heat-tolerable temperature greater than or equal to 870 DEG C. The vermicular graphite cast iron has vermicular iron performance indexes comprising tensile strength sigma b greater than or equal to 420Mpa, hardness HB of 195-210 and elongation percentage delta greater than or equal to 1.3%.
Description
Technical field
The present invention relates to cast iron materials manufacture field, be specifically related to adopt rare-earth, Mg, Ca and low silicon magnesium agglomerate mixed nodulizer, spheroidizing is carried out to molten iron, adopt iron notch ferro-silicon to pour method and once breed the method pouring method late inoculation with Si-Ba alloy in casting ladle, and pour iron sulphide alloy in employing casting ladle and increase the sulphur content of molten iron after nodularization to reach the method for residual Re and remaining Mg content in adjustment molten iron, prepare vermicular cast iron with spheroidization molten iron.
Background technology
Vermicular cast iron has not only had both castability and the high strength of spheroidal graphite cast iron, the application performance of good toughness of graphitic cast iron, this material has also possessed good damping, thermal conductivity, wear resistance simultaneously, therefore, become a kind of novel engineer applied material, be widely used in parts such as manufacturing diesel engine body, cylinder cap, cylinder sleeve, brake facing, vapor pipe.
Sulphur content, residual Re and remaining Mg content in the form of spheroidal graphite cast iron and vermicular graphite cast iron and molten iron have close relationship.Compare, in magnesium iron, sulphur content is lower than compacted iron, and residual Re and remaining Mg content are higher than compacted iron.Generally speaking, in these two kinds of cast irons, sulphur content is higher, then residual Re and remaining Mg content must be relatively low, and existence connects each other.
Different from the requirement of compacted iron to Sulfur Content in Hot Iron content, residual Re and remaining Mg content just because of magnesium iron, therefore, these two kinds of cast irons are produced respectively.
Summary of the invention
For the problems referred to above, the object of the present invention is to provide a kind of method adopting spheroidization molten iron to prepare vermicular cast iron, produce while realizing magnesium iron and compacted iron.Adopt to carry out spheroidizing by the mixed nodulizer of 50% rare-earth, Mg, Ca and 50% low silicon magnesium agglomerate alloy composition to base iron, and adopt ferro-silicon iron notch to pour method once to breed and adopt in Si-Ba alloy pouring ladle and pour method late inoculation technology, according to the detection of sulfur content of hot metal after nodularization, a certain amount of iron sulphide alloy is poured in casting ladle, with increase molten iron sulphur content, adjustment molten iron in residual Re and remaining Mg content, Absorbable organic halogens prepares the vermicular graphite iron material of nodulizing rate >=85%.
Technical scheme of the present invention is achieved in the following ways: a kind of method adopting spheroidization molten iron to prepare vermicular cast iron, comprises the following steps: 1) prepare burden, 2) preparation mixed nodulizer, 3) spheroidizing, 4) inoculation, 5) the iron sulphide amount of pouring determines, 6) stokehold sample and quick metallographic examination, 7) coverings, 8 of skimming) pour into a mould; It is characterized in that:
1) prepare burden: by weight percentage, spheroidization molten iron chemical composition: C:2.5 ~ 3.1%, Si:4.7 ~ 5.2%, Mn:0.3 ~ 0.5%, Cr:0.1 ~ 0.3%, phosphorus P :≤0.07%, sulphur S :≤0.03%, Mg:0.03 ~ 0.04%, RE:0.015 ~ 0.025%, all the other are iron;
2) mixed nodulizer is prepared: be hybridly prepared into mixed nodulizer by 50% rare-earth, Mg, Ca and 50% low silicon magnesium agglomerate nodulizing agent;
Wherein: rare-earth, Mg, Ca composition is: RE:1.5 ~ 2.5%, Ca:3 ~ 5%, Mg:6 ~ 8%, Si:43 ~ 47%, all the other are iron;
Low silicon magnesium agglomerate nodulizing agent composition is: Mg:6 ~ 8%, Si :≤10%, all the other are iron.
3) spheroidizing: molten iron treatment temp is controlled at 1440 ~ 1450 DEG C, mixed nodulizer add-on is 1.3 ~ 1.4%, and spheroidizing reacion time controling was at 1.5 ~ 2 minutes; Weight of molten iron fluctuation ± 5%;
4) inoculation: adopt ferro-silicon iron notch to pour method and once breed and adopt in Si-Ba alloy pouring ladle and pour method late inoculation method.
Ferro-silicon iron notch pours method for once to breed: when adding molten iron after spheroidizing, pours ferro-silicon once breed at iron notch, and the add-on of nucleating agent is that 1.0-1.2%(is by weight of molten iron), nucleating agent granularity is 3 ~ 7 mm.
Late inoculation adopts in casting ladle and pours method: nucleating agent is placed on bottom pouring ladle, is melted when molten iron proceeds to pouring ladle by the bag that taps a blast furnace, and post inoculant adopts Si-Ba alloy, and add-on is 0.15-0.3%, and nucleating agent granularity is 0.5 ~ 1.5mm;
The composition of described silicon titanate innoculant is: Ba4-6%, Ca1-2%, Si65-70%, Al1-2%, and all the other are iron; The composition of silicon iron inoculator is: Si72-80%, Cr≤0.5%, P≤0.5%, S≤0.04%, C≤0.02%, and all the other are iron; Weight of molten iron fluctuation ± 5%.
5) the iron sulphide amount of pouring is determined: after liquid iron balling process, and sampling detects the sulphur content in molten iron, determines the amount of pouring of iron sulphide.
In magnesium iron: 0.02 ~ 0.03%S, 0.015 ~ 0.025%RE
residual, 0.03 ~ 0.04%Mg
residual; In compacted iron: 0.035 ~ 0.045%S, 0.007 ~ 0.01%RE
residual, 0.02 ~ 0.03%Mg
residual;
When sulphur content in magnesium iron is 0.02 ~ 0.025%, in casting ladle, pour iron sulphide 0.035 ~ 0.04%; When sulphur content is 0.026 ~ 0.035, in casting ladle, pour iron sulphide 0.025 ~ 0.03%.
Wherein: iron sulphide is commercial alloy, model is FeS2, index: S > 48%, Fe > 42%, As < 0.1%, Pb+Zn < 0.1%, SiO
2< 3%, H
2o < 0.5%.
6) stokehold sample and quick metallographic examination: stokehold specimen size is φ 20mm; At 2 ~ 3 minutes quick test stokehold samples, determine vermiculation effect.
7) to skim covering: adopt the perlite deslagging agent of the weight of molten iron of 0.2% to carry out skimming 1 ~ 2 time, the perlite insulation insulating covering agent of the weight of molten iron with 0.2 ~ 0.3% forms the thick insulation tectum of 35 ~ 40mm on molten iron surface, prevents the effusion naturally of wrapping interior molten iron fast cooling and nodularization element;
8) pour into a mould: teeming temperature 1330 ~ 1340 DEG C, the molten iron after spheroidizing is poured in 16 ~ 17 minutes.
Beneficial effect of the present invention: spheroidizing is carried out to base iron with the mixed nodulizer by 50% rare-earth, Mg, Ca and 50% low silicon magnesium agglomerate alloy composition, adopt ferro-silicon iron notch to pour method once to breed and adopt in Si-Ba alloy pouring ladle and pour method late inoculation technology, and according to the detection of sulfur content of hot metal after nodularization, the iron sulphide alloy of 0.025 ~ 0.04% is poured in casting ladle, to adjust the sulphur content of molten iron, residual Re and remaining Mg content, Absorbable organic halogens prepares nodulizing rate >=85%, the vermicular graphite iron material of ferrite content >=90% in matrix, heat resisting temperature >=870 DEG C.Compacted ferrum property index is: tensile strength sigma
b>=420 Mpa, hardness HB195 ~ 210, unit elongation δ>=1.3%.
Embodiment
Adopt spheroidization molten iron to prepare a method for vermicular cast iron, comprise the following steps:
1, prepare burden: by weight percentage, magnesium iron Hydrochemical Composition: C:2.5 ~ 3.1%, Si:4.7 ~ 5.2%, Mn:0.3 ~ 0.5%, Cr:0.1 ~ 0.3%, phosphorus P :≤0.07%, sulphur S :≤0.03%, Mg:0.03 ~ 0.04%, RE:0.015 ~ 0.025%, all the other are iron;
2, mixed nodulizer is prepared: be hybridly prepared into mixed nodulizer by 50% rare-earth, Mg, Ca and 50% low silicon magnesium agglomerate nodulizing agent;
Wherein: rare-earth, Mg, Ca (commercial alloy) composition is: RE:1.5 ~ 2.5%, Ca:3 ~ 5%, Mg:6 ~ 8%, Si:43 ~ 47%, all the other are iron;
Low silicon magnesium agglomerate nodulizing agent (commercial alloy) composition is: Mg:6 ~ 8%, Si :≤10%, all the other are iron.
3, spheroidizing: molten iron treatment temp is controlled at 1440 ~ 1450 DEG C, mixed nodulizer add-on is that 1.3 ~ 1.4%(is by weight of molten iron), spheroidizing reacion time controling was at 1.5 ~ 2 minutes; Weight of molten iron fluctuation ± 5%;
4, inoculation: adopt ferro-silicon iron notch to pour method and once breed and adopt in Si-Ba alloy pouring ladle and pour method late inoculation method.
Ferro-silicon iron notch pours method and once breeds: when adding molten iron after spheroidizing, pours ferro-silicon once breed at iron notch, and the add-on of nucleating agent is that 1.0-1.2%(is by weight of molten iron), nucleating agent granularity is 3 ~ 7 mm.
Late inoculation adopts in pouring ladle and pours method: nucleating agent is placed on bottom pouring ladle, melted when molten iron proceeds to pouring ladle by the bag that taps a blast furnace, post inoculant adopts Si-Ba alloy, and add-on is that 0.15-0.3%(is by weight of molten iron), nucleating agent granularity is 0.5 ~ 1.5mm; The composition of described silicon titanate innoculant (commercial alloy) is: Ba4-6%, Ca1-2%, Si65-70%, Al1-2%, and all the other are iron; The composition of silicon iron inoculator (commercial alloy) is: Si72-80%, Cr≤0.5%, P≤0.5%, S≤0.04%, C≤0.02%, and all the other are iron; Weight of molten iron fluctuation ± 5%.
5) the iron sulphide amount of pouring is determined: after liquid iron balling process, and sampling detects the sulphur content in molten iron, determines the amount of pouring of iron sulphide.Generally, in magnesium iron: 0.02 ~ 0.03%S, 0.015 ~ 0.025%RE
residual, 0.03 ~ 0.04%Mg
residual; In compacted iron: 0.035 ~ 0.045%S, 0.007 ~ 0.01%Re
residual, 0.02 ~ 0.03%Mg
residual;
When sulphur content in magnesium iron is 0.02 ~ 0.025%, in casting ladle, pour iron sulphide 0.035 ~ 0.04%; When sulphur content is 0.026 ~ 0.035, in casting ladle, pour iron sulphide 0.025 ~ 0.03%.Wherein: iron sulphide is commercial alloy, model is FeS2, index: S > 48%, Fe > 42%, As < 0.1%, Pb+Zn < 0.1%, SiO
2< 3%, H
2o < 0.5%.
6, stokehold sample and metallographic examination fast: stokehold specimen size is φ 20mm; At 2 ~ 3 minutes quick test stokehold samples, determine vermiculation effect.
7, to skim covering: adopt the perlite deslagging agent of the weight of molten iron of 0.2% to carry out skimming 1 ~ 2 time, the perlite insulation insulating covering agent of the weight of molten iron with 0.2 ~ 0.3% forms the thick insulation tectum of 35 ~ 40mm on molten iron surface, prevents the effusion naturally of wrapping interior molten iron fast cooling and nodularization element;
8, pour into a mould: teeming temperature 1330 ~ 1340 DEG C, the molten iron after spheroidizing is poured in 16 ~ 17 minutes.
Embodiment 1:
Industrial furnace grate casting, normal working temperature scope is 820 ~ 850 DEG C.Former employing RTcr heat resisting iron manufactures, and work-ing life is about 12 months.When 860 ~ 880 DEG C of contrasts use, be only 9 ~ 10 months work-ing life with the fire grate of RTcr heat resisting iron manufacture, and adopt the grate casting of material manufacture of the present invention to reach about 24 ~ 26 months work-ing life.
Embodiment 2:
Chain furnace fire grate accessory, normal working temperature scope is 840 ~ 860 DEG C.Former employing RTcr heat resisting iron manufactures, and work-ing life is 12 ~ 14 months.When 870 ~ 900 DEG C of contrasts use, be only about 10 months work-ing life with the fire grate of RTcr heat resisting iron manufacture, and adopt the grate casting of material manufacture of the present invention to reach about 23 ~ 25 months work-ing life.
Claims (3)
1. adopt spheroidization molten iron to prepare a method for vermicular cast iron, comprise the following steps: 1) prepare burden, 2) preparation mixed nodulizer, 3) spheroidizing, 4) inoculation, 5) the iron sulphide amount of pouring determines, 6) stokehold sample and quick metallographic examination, 7) coverings, 8 of skimming) pour into a mould; It is characterized in that:
1) prepare burden: by weight percentage, spheroidization molten iron chemical composition: C:2.5 ~ 3.1%, Si:4.7 ~ 5.2%, Mn:0.3 ~ 0.5%, Cr:0.1 ~ 0.3%, phosphorus P :≤0.07%, sulphur S :≤0.03%, Mg:0.03 ~ 0.04%, RE:0.015 ~ 0.025%, all the other are iron;
2) mixed nodulizer is prepared: be hybridly prepared into mixed nodulizer by 50% rare-earth, Mg, Ca and 50% low silicon magnesium agglomerate nodulizing agent;
Wherein: rare-earth, Mg, Ca composition is: RE:1.5 ~ 2.5%, Ca:3 ~ 5%, Mg:6 ~ 8%, Si:43 ~ 47%, all the other are iron;
Low silicon magnesium agglomerate nodulizing agent composition is: Mg:6 ~ 8%, Si :≤10%, all the other are iron;
3) spheroidizing: molten iron treatment temp is controlled at 1440 ~ 1450 DEG C, mixed nodulizer add-on is 1.3 ~ 1.4%, and spheroidizing reacion time controling was at 1.5 ~ 2 minutes; Weight of molten iron fluctuation ± 5%;
4) inoculation: adopt ferro-silicon iron notch to pour method and once breed and adopt in Si-Ba alloy pouring ladle and pour method late inoculation method;
5) the iron sulphide amount of pouring is determined: after liquid iron balling process, and sampling detects the sulphur content in molten iron, determines the amount of pouring of iron sulphide;
In magnesium iron: 0.02 ~ 0.03%S, 0.015 ~ 0.025%RE
residual, 0.03 ~ 0.04%Mg
residual; In compacted iron: 0.035 ~ 0.045%S, 0.007 ~ 0.01% RE
residual, 0.02 ~ 0.03%Mg
residual;
When sulphur content in magnesium iron is 0.02 ~ 0.025%, in casting ladle, pour iron sulphide 0.035 ~ 0.04%; When sulphur content is 0.026 ~ 0.035, in casting ladle, pour iron sulphide 0.025 ~ 0.03%;
Wherein: iron sulphide is commercial alloy, model is FeS2, index: S > 48%, Fe > 42%, As < 0.1%, Pb+Zn < 0.1%, SiO
2< 3%, H
2o < 0.5%;
6) stokehold sample and quick metallographic examination: stokehold specimen size is φ 20mm; At 2 ~ 3 minutes quick test stokehold samples, determine vermiculation effect;
7) to skim covering: adopt the perlite deslagging agent of the weight of molten iron of 0.2% to carry out skimming 1 ~ 2 time, the perlite insulation insulating covering agent of the weight of molten iron with 0.2 ~ 0.3% forms the thick insulation tectum of 35 ~ 40mm on molten iron surface, prevents the effusion naturally of wrapping interior molten iron fast cooling and nodularization element;
8) pour into a mould: teeming temperature 1330 ~ 1340 DEG C, the molten iron after spheroidizing is poured in 16 ~ 17 minutes.
2. a kind of method adopting spheroidization molten iron to prepare vermicular cast iron according to claim 1, it is characterized in that: in described step 4) inoculation, the method that pours ferro-silicon iron notch once breeds: when adding molten iron after spheroidizing, pour ferro-silicon at iron notch once to breed, the add-on of nucleating agent is 1.0-1.2%, nucleating agent granularity is 3 ~ 7mm, the composition of silicon iron inoculator is: Si72-80%, Cr≤0.5%, P≤0.5%, S≤0.04%, C≤0.02%, and all the other are iron; Weight of molten iron fluctuation ± 5%.
3. a kind of method adopting spheroidization molten iron to prepare vermicular cast iron according to claim 1, it is characterized in that: in described step 4) inoculation, pouring method late inoculation in Si-Ba alloy pouring ladle is: nucleating agent is placed on bottom pouring ladle, melted when molten iron proceeds to pouring ladle by the bag that taps a blast furnace, post inoculant adopts Si-Ba alloy, add-on is 0.15-0.3%, and nucleating agent granularity is 0.5 ~ 1.5mm; The composition of silicon titanate innoculant is: Ba4-6%, Ca1-2%, Si 65-70%, Al1-2%, and all the other are iron.
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| CN106929747B (en) * | 2017-03-30 | 2018-06-19 | 广西玉柴机器股份有限公司 | A kind of solution strengthening ferrite vermicular cast iron and its production method |
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| CN102676906B (en) * | 2012-06-20 | 2013-06-19 | 丹阳市锦雄机械制造有限公司 | Preparation method of compacted graphite cast iron |
| CN102796939B (en) * | 2012-08-29 | 2014-05-07 | 丹阳市锦雄机械制造有限公司 | Method for vermicular cast iron by using mixed vermiculizer |
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