CN107326257B - A kind of hi-strength nodular iron profile and preparation method thereof - Google Patents
A kind of hi-strength nodular iron profile and preparation method thereof Download PDFInfo
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- CN107326257B CN107326257B CN201710520868.8A CN201710520868A CN107326257B CN 107326257 B CN107326257 B CN 107326257B CN 201710520868 A CN201710520868 A CN 201710520868A CN 107326257 B CN107326257 B CN 107326257B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
- B22D11/045—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for horizontal casting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/08—Making cast-iron alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/04—Cast-iron alloys containing spheroidal graphite
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- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention discloses a kind of hi-strength nodular iron profiles, by weight percentage consisting of: C:3.0~3.3%, Si:2.2~3.0%, Mn:0.1~0.3%, P≤0.15%, S≤0.06%, Sb:0.01~0.015%, MgIt is residual>=0.05%, REIt is residual: 0.015~0.018%, remaining is Fe, and the sum of composition described above weight percent is 100%.The invention also discloses the preparation methods of above-mentioned hi-strength nodular iron profile.The tensile strength of high-strength ductile cast iron profile of the present invention is greater than 600MPa, and hardness is uniform, surface quality is good, and dimensional accuracy is high, the casting flaws such as no burning into sand, slag inclusion, stomata, shrinkage cavity, has good machinability.Spheroidal graphite cast-iron profile center portion the number of graphite improves 20% or more than common Ductile iron bar, and diameter of graphite ball is about 6~7 grades, without apparent 4~5 grades of major diameter graphite.
Description
Technical field
The invention belongs to cast iron materials casting technology fields, are related to a kind of hi-strength nodular iron profile, the invention further relates to upper
State the preparation method of Ductile iron bar.
Background technique
Ductile iron bar is the high-quality spheroidal graphite cast-iron blank material produced using horizontal continuous-casting mode, even due to level
Continuous casting Ductile iron bar has many advantages, such as dense structure, and good product quality, comprehensive mechanical property are excellent, processing performance is excellent, because
This has been widely used in numerous areas or the industries such as mechanical, hydraulic, metallurgical, weaving, printing.
Currently, the Ductile iron bar for directlying adopt horizontal continuous-casting method production tensile strength 600MPa or more is relatively more tired
Difficulty, the method generally used are that high performance ductile iron profile is obtained by ADI isothermal hardening.Although being handled by ADI can obtain
The high tensile property Ductile iron bar of 1000MPa or more or even 1500MPa is obtained, but the window being heat-treated is relatively narrow, stability contorting rises
It is next extremely difficult, and higher cost.In addition, higher by the hardness of the ADI Ductile iron bar handled, machining property is poor,
This also results in some difficulty to following process.
However, the requirement to Ductile iron bar mechanical property is also higher and higher with the fast development of machining technique, and
In order to control production cost, user is not intended to that the noble metals such as Cu, Ni, Mo or Cr are added and is heat-treated to realize high-performance,
The hardness for also wanting to material simultaneously is not so high, and is able to carry out subsequent machining.This requires cast iron profile materials in level
It must be strictly controlled links in continuously casting production process, to realize the requirement of low-cost and high-performance.
Summary of the invention
The object of the present invention is to provide a kind of hi-strength nodular iron profile, solve that existing Ductile iron bar mechanical property is low to ask
Topic.
It is a further object of the present invention to provide the preparation methods of above-mentioned hi-strength nodular iron profile.
The technical scheme adopted by the invention is that a kind of hi-strength nodular iron profile, by weight percentage consisting of: C:
3.0~3.3%, Si:2.2~3.0%, Mn:0.1~0.3%, P≤0.15%, S≤0.06%, Sb:0.01~0.015%,
MgIt is residual>=0.05%, REIt is residual: 0.015~0.018%, remaining is Fe.
Another technical solution of the present invention is a kind of preparation method of hi-strength nodular iron profile, specifically by following
Step is implemented:
Step 1, cast iron melting:
According to the weight percent of setting, the silicon amount that inovulant is brought into is deducted, casting magnesium iron needed for weighing base iron
The pig iron, steel scrap, foundry returns, 75% ferrosilicon and SiC, are molten into molten iron in induction furnace, take base iron to carry out stokehold ingredient quick
Analysis adjusts the content of each element in base iron, wherein C:3.0~3.3%, Si:1.1~1.8%, Mn:0.1%~0.3%,
P≤0.15%, S≤0.06%, remaining is Fe, and the sum of composition described above weight percent is 100%, tapping；
Step 2, the molten iron that step 1 obtains is subjected to spheroidising using dam-type molten ductile iron packet and bred；
Step 3, molten iron casting step 2 obtained enters holding furnace, and carries out horizontal continuous-casting to get high-intensitive ball is arrived
Swage material.
Feature of the present invention also resides in,
Charging sequence is melted successively in step 1 are as follows: it is first put into a part casting magnesium iron pig iron, is advisable with covering furnace bottom, to
SiC is added after this batch of pig iron fusing, the remaining pig iron, steel scrap and foundry returns is then added, and be pressed in above SiC.
The dosage of SiC is the 0.8~1.1% of weight of molten iron in step 1, and granularity is 3~10mm.
Fusion temperature is 1550~1580 DEG C, and tapping temperature is 1500~1550 DEG C, and pouring temperature is 1360~1420 DEG C.
It is bred in step 2 to breed twice, breeds carried out simultaneously with spheroidising for the first time, breed at nodularization for the second time
Reason is completed, and is carried out after skimming, inovulant is placed in the upper surface of molten iron in ladle, to pour into holding furnace with stream.
Spheroidising in step 2 specifically: molten iron is poured into the ladle of pre- roasted mistake, Sb nodulizer will be contained, dike is added
It in dam, and is covered on nodulizer, then be covered on nodulizer using low-sulfur iron filings, consolidates by inovulant used is once bred
The thickness of iron filings coating is not less than 2~3cm afterwards, covers ladle lid rapidly after tapping, finishes to spheroidizing reacion, removes iron
Water backpack cover, skims.
The granularity of inovulant is 3~5mm, and the dosage of an inovulant is the 0.3~0.4% of molten iron total weight；Two
The granularity of secondary inovulant is 1~3mm, and the dosage of post inoculant is the 0.4~0.5% of molten iron total weight.
Nodulizer dosage is 1.1~1.6% in step 2, and granularity is 15~30mm；The dosage of inovulant is weight of molten iron
0.7~0.9%.
Horizontal continuous-casting uses "~stopping~is drawn to draw " processing method in step 3, the revolving speed of traction electric machine in casting process
For 800~1200rpm, the drawing time is 0.2~2.0s, and the residence time is 1~35s, and length of mould is 200~600mm, into
Coolant-temperature gage is room temperature, and leaving water temperature is 50~70 DEG C, and profile crystallizer outlet temperature is controlled at 900~1050 DEG C.
The invention has the advantages that the tensile strength of high-strength ductile cast iron profile material of the present invention is greater than 550MPa,
Hardness is uniform, surface quality is good, and dimensional accuracy is high, the casting flaws such as no burning into sand, slag inclusion, stomata, shrinkage cavity.Spheroidal graphite cast-iron profile material
Expect that center portion the number of graphite improves 20% or more than common Ductile iron bar, diameter of graphite ball is about 6~7 grades, without obvious
4~5 grades of major diameter graphite；Ductile iron bar hardness of the invention is HB200~260, and the machinability of Ductile iron bar is good
Good, resistance to cutting is small, can be with High speed finish machining, and processed surface smoothness relative fluctuation is small.
Specific embodiment
The present invention is described in detail With reference to embodiment.
The present invention provides a kind of hi-strength nodular iron profiles, by weight percentage consisting of: C:3.0~3.3%, Si:
2.2~3.0%, Mn:0.1~0.3%, P≤0.15%, S≤0.06%, Sb:0.01~0.015%, MgIt is residual>=0.05%,
REIt is residual: 0.015~0.018%, remaining is Fe, and the sum of composition described above weight percent is 100%.
The preparation method of above-mentioned hi-strength nodular iron profile is specifically implemented according to the following steps:
Step 1, cast iron melting:
Molten iron is melted using intermediate frequency furnace, according to the weight percent composition of setting, long-acting ferrosilicon is pregnant when deduction is bred
The silicon amount that agent is brought into is educated, the low manganese casting magnesium iron pig iron, steel scrap, foundry returns, 75% ferrosilicon and SiC etc. needed for weighing base iron are calculated
Amount, carry out cast iron melting.Melt charging sequence successively are as follows: be put into a part of low manganese casting magnesium iron pig iron, first to cover furnace bottom
Be advisable, be added at one time the SiC that granularity is 3~10mm after this batch of pig iron melts, weight by every furnace weight of molten iron 0.8~
1.1% calculates, and then adds the remaining pig iron, steel scrap and foundry returns, and be pressed in above SiC, complete to furnace charges all in furnace
Fusing；The ferroalloy being added in intermediate frequency furnace is calculated according to 10% scaling loss amount；To the end of all ferroalloys melt
After take base iron to carry out stokehold fast analyzing constituent, determine and the ball that supplements 75% ferrosilicon or carburant, and produce as needed
The diameter of swage material adjusts the content of each element in base iron, wherein C:3.0~3.3%, Si:1.1~1.8%, Mn:
0.1~0.3%, P≤0.15%, S≤0.06%, remaining is Fe, prepares to come out of the stove.Fusion temperature is 1550~1580 DEG C, tapping
Temperature is 1500~1550 DEG C.
Step 2, it spheroidising and once breeds:
Dam-type molten ductile iron packet is selected to carry out spheroidising, ladle requires height/diameter >=1.6.Before spheroidising first
It carries out scalding packet processing, molten iron is poured into the ladle of pre- roasted mistake, then molten iron is toppled in telegram in reply furnace, be repeated three times.
Then, molten iron total weight 1.1~1.6%, the nodulizer containing Sb that granularity is 15~30mm are added in dykes and dams, and will once bred
Inovulant used is covered on nodulizer, and dosage is that the 0.3~0.4% of molten iron total amount is again covered on nodularization using low-sulfur iron filings
In agent, the thickness of iron filings coating is not less than 2~3cm after tamping.Wherein, the granularity of an inovulant is 3~5mm.After tapping
It is covered with dedicated molten iron backpack cover rapidly, the absorptivity of Mg and RE is ensured with this, Mg is indirectly controlled with thisIt is residual>=0.05%, REIt is residualFor
0.015~0.018%.It is finished to spheroidizing reacion, removes dedicated molten iron backpack cover, then skim, in case of late inoculation and pour again
Note.
Step 3, late inoculation:
According to the weight of every iron clad water, the long-acting silicon iron inoculator containing Sr and Ba is weighed according to the Si amount of required supplement, one
Secondary and post inoculant total amount is 0.7~0.9% of molten iron gross weight in ladle.The molten iron of spheroidising is after skimming, button
Except the amount of an inovulant, the dosage of remaining post inoculant is the 0.4~0.5% of molten iron total amount, the granularity of inovulant is 1~
3mm places it in the upper surface of molten iron in ladle, to pour into holding furnace with stream.
Step 4, it is poured:
Using atomized diesel fuel nozzle by holding furnace internal protecting wall 30~40min of baking to shiny red before casting, in a crystallizer
It is inserted into dummy bar head, dummy bar head is connected with dummy bar, and passes through traction machine travel drawing.By pouring for the warm furnace of the molten iron handled well
Mouth pours into holding furnace.
Step 5, horizontal continuous-casting:
It is stopped 1~4 minute after molten iron casting is entered holding furnace, the molten iron into crystallizer is made to wrap dummy bar head, to
Start dummy ingot traction after crystallization and freezing, with "~stopping~is drawn to draw " technological level continuous casting.Wherein, during horizontal continuous-casting
The revolving speed of traction electric machine is 800~1200rpm, and the drawing time is 0.2~2.0s, and the residence time is 1~35s, length of mould
For 200~600mm, inflow temperature is room temperature, and leaving water temperature is 50~70 DEG C, the control of profile crystallizer outlet temperature 900~
1050 DEG C to get arrive spheroidal graphite cast-iron profile material.
Drawing speed and profile outlet temperature are controlled, runout is prevented, control molten iron casting interval is no more than 10 minutes, to prevent
Only liquid iron balling and inoculation fade and occur graphite form variation and carbide.
Spheroidal graphite cast-iron profile material of the invention, tensile property index have been more than LZQT600-3 standard (JB/T 10854-
2008 horizontal continuous-casting cast iron profile materials, Chinese machinery industry standard) it requires.
The tensile strength of hi-strength nodular iron profile material of the invention is greater than 550MPa, and hardness is uniform, surface quality is good, ruler
Very little precision is high, the casting flaws such as no burning into sand, slag inclusion, stomata, shrinkage cavity.Spheroidal graphite cast-iron profile material center portion the number of graphite is than common
Ductile iron bar improves 20% or more, and diameter of graphite ball is about 6~7 grades, without apparent 4~5 grades of major diameter graphite；This hair
The hardness of bright Ductile iron bar is HB200~260, and the machinability of Ductile iron bar is good, and resistance to cutting is small, can high speed
Finishing, processed surface smoothness relative fluctuation are small.
The preparation method of ball cast iron profile material material of the present invention, is mainly characterized by: being added in electric furnace during cast iron melting
SiC is conducive to the content for improving Si and C, while the addition of SiC can be used as the core of heterogeneous forming core, can also be improved graphite
The core amounts of forming core, it is thus possible to improve the quantity of graphite nodule.Simultaneously as the raising of the number of graphite, is conducive to avoid
Kish ball overgrowth and there is major diameter kish ball.The inside and outside difference organized of profile is advantageously reduced in this way, is mentioned
The hardness of high profile center portion reduces the hardness on surface layer, and improves the machining property of profile.In addition, due to the fusing point of SiC
It is 2800 DEG C, density is much smaller than iron, thus its Adding Way is very crucial, can not melt if being directly added in molten iron,
And the absorptivity of SiC is extremely low, is removed when cannot function as the core of heterogeneous forming core, and being likely to become field trash or skim.Cause
This, present invention employs distinctive preparation methods.
The low rare-earth nodularizer of low magnesium containing 1%Sb is used in nodularization, guarantees that the content of Sb in casting is about after nodularization
0.01~0.015%, MgIt is residual>=0.05%, REIt is residualIt is 0.015~0.018%, the roundness of graphite nodule can be improved, is conducive to mention
High-performance.
The amount of the long-acting silicon iron inoculator containing Sr and Ba is increased in preparation process, and uses late inoculation method, can be improved
Pregnant effect and extension incubation time avoid major diameter spheroidal graphite cast-iron profile in process of production because breeding caused by setting time length
It fails and carbide occurs.
In process of production that the noble metals such as Cu, Ni, Mo or Cr are not added, therefore the more common Ductile iron bar of production cost does not have
There is significant change.In addition, due to not using these precious metal alloys elements, the harden ability of Ductile iron bar of the invention and common
Ductile iron bar is almost the same, does not have complicated carbide and needle austenite in tissue, therefore the hardness of material is far below at ADI
The hardness of reason, and the machinability of material is excellent.
Embodiment 1
Φ 35mm spheroidal graphite cast-iron profile material and its preparation.
By weight percentage consisting of C:3.3%, Si:3.0%, Mn:0.1%, P:0.10%, S:0.06%, Sb:
0.01%, MgIt is residual: 0.05%, REIt is residual: 0.015%, remaining is Fe.
Long-acting silicon iron inoculator band is deducted according to above-mentioned weight percent composition using 2T intermediate frequency furnace fusing molten iron
The silicon amount entered, the amount of foundry iron needed for calculating base iron, steel scrap, foundry returns and 75% ferrosilicon, fusing charging sequence are followed successively by
It is first put into a part of low manganese casting magnesium iron pig iron, is advisable with covering furnace bottom, being added at one time granularity after this batch of pig iron melts is
The SiC of 3mm, weight are calculated by the 0.8% of every furnace weight of molten iron, then add the remaining pig iron, steel scrap and foundry returns, and
It is pressed in above SiC, is completely melt to furnace charges all in furnace；The ferroalloy being added in intermediate frequency furnace according to 10% scaling loss
Amount calculates；It takes base iron to carry out stokehold fast analyzing constituent after melting to all ferroalloys, determine and supplements 75% silicon
Iron or carburant, and produce the diameter of Ductile iron bar as needed, adjust the C, Si, Mn in base iron, the ingredient of P, S with
Reach requirement, prepares to come out of the stove.Fusion temperature is 1550 DEG C, and tapping temperature is 1520 DEG C.It is fast that a stokehold is carried out before coming out of the stove every time
Speed analysis and composition adjustment, require supplementation with carburant when appropriate.
It is 300kg that iron will be gone out before tapping, and height/diameter is pre- more roasted than the dam-type molten ductile iron packet progress for 1.6, then into
The boiling hot packet processing of row；Nodulizer containing Sb is selected in nodularization, and dosage is the 1.1% of molten iron gross weight, granularity 15mm.Dike is added in nodulizer
It in dam, and is covered on inovulant used is once bred on nodulizer, dosage is the 0.3% of molten iron gross weight, then uses low-sulfur
Iron filings are covered on nodulizer, and the thickness of iron filings coating is not less than 2cm after tamping.Wherein, the granularity of an inovulant is
3mm.It is covered with dedicated molten iron backpack cover rapidly after tapping, the absorptivity of Mg and RE is ensured with this, Mg is indirectly controlled with thisIt is residualFor
0.05~0.06%, REIt is residualIt is 0.016~0.018%.It is finished to spheroidizing reacion, removes dedicated molten iron backpack cover, skim, in case
Casting.
According to the weight of every iron clad water, the long-acting silicon iron inoculator containing Sr and Ba is weighed according to the Si amount of required supplement, one
Secondary and post inoculant total amount is 0.7% of molten iron total amount in ladle, and the granularity of post inoculant is 1mm.Spheroidising
Molten iron after skimming, deduct the amount of an inovulant, remaining 0.4% inovulant is placed in the upper surface of molten iron in ladle.
Holding furnace atomized diesel fuel nozzle is toasted into 30min, after being inserted into dummy bar head in a crystallizer, by the warm furnace of the molten iron handled well
Cast gate pour into holding furnace, pouring temperature is 1420 DEG C.
It is stopped 1 minute after molten iron casting is entered holding furnace, the molten iron into crystallizer is made to wrap dummy bar head, it is to be crystallized
Start dummy ingot traction after solidification, with "~stopping~is drawn to draw " technological level continuous casting.Wherein drawn during horizontal continuous-casting
The revolving speed of motor is 800rpm, and the drawing time is 0.2s, and residence time 1s, length of mould 200mm, inflow temperature is room
Temperature, leaving water temperature be 50~70 DEG C, profile crystallizer outlet temperature control 900 DEG C to get arrive spheroidal graphite cast-iron profile material.
Drawing speed and profile outlet temperature are controlled, runout is prevented, control molten iron casting interval is no more than 10 minutes, to prevent
Only liquid iron balling and inoculation fade and occur graphite form variation and carbide.
Φ 35mm spheroidal graphite cast-iron profile material prepared by embodiment 1, samples at center, and tensile strength 620MPa stretches
Long rate is 3.5%, and hardness is HB225~245, and tensile property index has been more than LZQT600-3 standard (JB/T 10854-2008
Horizontal continuous-casting cast iron profile material, Chinese machinery industry standard) it requires.
Embodiment 2
Φ 145mm spheroidal graphite cast-iron profile material and its preparation.
By weight percentage consisting of: C:3.2%, Si:2.6%, Mn:0.2%, P:0.13%, S:0.04%, Sb:
0.012%, MgIt is residual: 0.06%, REIt is residual: 0.016%, remaining is Fe.
Long-acting silicon iron inoculator band is deducted according to above-mentioned weight percent composition using 3T intermediate frequency furnace fusing molten iron
The silicon amount entered, the amount of foundry iron needed for calculating base iron, steel scrap, foundry returns and 75% ferrosilicon, fusing charging sequence are followed successively by
It is first put into a part of low manganese casting magnesium iron pig iron, is advisable with covering furnace bottom, being added at one time granularity after this batch of pig iron melts is
The SiC of 10mm, weight are calculated by the 0.9% of every furnace weight of molten iron, then add the remaining pig iron, steel scrap and foundry returns,
And be pressed in above SiC, it is completely melt to furnace charges all in furnace；The ferroalloy being added in intermediate frequency furnace according to 10% burning
Damage amount calculates；It takes base iron to carry out stokehold fast analyzing constituent after melting to all ferroalloys, determine and supplements 75%
Ferrosilicon or carburant, and the diameter of the Ductile iron bar produced as needed, adjust base iron in C, Si, Mn, P, S at
Divide to reach requirement, prepares to come out of the stove.Fusion temperature is 1550 DEG C~1580 DEG C, and tapping temperature is 1500~1530 DEG C.Go out every time
Stokehold carries out a stokehold fast analyzing constituent and composition adjustment, and carburant is required supplementation with when appropriate.
It is 600kg that iron will be gone out before tapping, and height/diameter is pre- more roasted than the dam-type molten ductile iron packet progress for 1.6, then into
The boiling hot packet processing of row；Nodulizer containing Sb is selected in nodularization, and dosage is the 1.6% of molten iron gross weight, granularity 20mm.Dike is added in nodulizer
It in dam, and is covered on inovulant used is once bred on nodulizer, dosage is the 0.4% of molten iron gross weight, then uses low-sulfur iron
Bits are covered on nodulizer, and the thickness of iron filings coating is not less than 2cm after tamping.Wherein, the granularity of an inovulant is 5mm.
It is covered with dedicated molten iron backpack cover rapidly after tapping when nodularization, the absorptivity of Mg and RE is ensured with this, Mg is indirectly controlled with thisIt is residualFor
0.05~0.06%, REIt is residualIt is 0.016~0.018%.It is finished to spheroidizing reacion, removes dedicated molten iron backpack cover, skim, in case
Casting.
According to the weight of every iron clad water, the long-acting silicon iron inoculator containing Sr and Ba is weighed according to the Si amount of required supplement, one
Secondary and post inoculant total amount is 0.9% of iron water amount in ladle, and the granularity of inovulant is 5mm.The molten iron of spheroidising
After skimming, the amount of an inovulant is deducted, remaining 0.5% inovulant is placed in the upper surface of molten iron in ladle.It will heat preservation
Furnace toasts 40min with atomized diesel fuel nozzle, after being inserted into dummy bar head in a crystallizer, by the cast gate of the warm furnace of the molten iron handled well
Holding furnace is poured into, pouring temperature is 1400 DEG C.
4min is stopped after molten iron casting is entered holding furnace, the molten iron into crystallizer is made to wrap dummy bar head, it is to be crystallized
Start dummy ingot traction after solidification, with "~stopping~is drawn to draw " technological level continuous casting.Wherein drawn during horizontal continuous-casting
The revolving speed of motor is 900rpm, and the drawing time is 2.0s, residence time 35s, length of mould 350mm, and inflow temperature is
Room temperature, leaving water temperature be 70 DEG C, profile crystallizer outlet temperature control 1050 DEG C to get arrive spheroidal graphite cast-iron profile material.
Drawing speed and profile outlet temperature are controlled, runout is prevented, control molten iron casting interval is no more than 10min, to prevent
Only liquid iron balling and inoculation fade and occur graphite form variation and carbide.
Φ 145mm spheroidal graphite cast-iron profile material prepared by embodiment 2, samples at 1/2 radius, and tensile strength is
600MPa, elongation 4%, hardness are HB225~250, and tensile property index has been more than LZQT600-3 standard (JB/T
10854-2008 horizontal continuous-casting cast iron profile material, Chinese machinery industry standard) it requires.
Embodiment 3
Φ 320mm spheroidal graphite cast-iron profile material and its preparation.
By weight percentage consisting of: C:3.0%, Si:2.3%, Mn:0.3%, P:0.10%, S:0.03%, Sb:
0.015%, MgIt is residual: 0.07%, REIt is residual: 0.018%, remaining is Fe.
Long-acting silicon iron inoculator band is deducted according to above-mentioned weight percent composition using 5T intermediate frequency furnace fusing molten iron
The silicon amount entered, the amount of foundry iron needed for calculating base iron, steel scrap, foundry returns and 75% ferrosilicon, fusing charging sequence are followed successively by
It is first put into a part of low manganese casting magnesium iron pig iron, is advisable with covering furnace bottom, being added at one time granularity after this batch of pig iron melts is
The SiC of 7mm, weight are calculated by the 0.9% of every furnace weight of molten iron, then add the remaining pig iron, steel scrap and foundry returns, and
It is pressed in above SiC, is completely melt to furnace charges all in furnace；The ferroalloy being added in intermediate frequency furnace according to 10% scaling loss
Amount calculates；It takes base iron to carry out stokehold fast analyzing constituent after melting to all ferroalloys, determine and supplements 75% silicon
Iron or carburant, and the diameter of the Ductile iron bar produced as needed adjust C, Si, Mn in base iron, the ingredient of P, S
To reach requirement, prepare to come out of the stove.Fusion temperature is 1565 DEG C, and tapping temperature is 1515 DEG C.A stokehold is carried out before coming out of the stove every time
Fast analyzing constituent and composition adjustment, require supplementation with carburant when appropriate.
It is 1000kg that iron will be gone out before tapping, and height/diameter is pre- more roasted than the dam-type molten ductile iron packet progress for 1.6, then
It carries out scalding packet processing；Nodulizer containing Sb is selected in nodularization, and dosage is the 1.3% of molten iron gross weight, granularity 23mm.Nodulizer is added
It in dykes and dams, and is covered on once inovulant is bred on nodulizer, dosage is the 0.35% of molten iron gross weight, then uses low-sulfur iron filings
It is covered on nodulizer, the thickness of iron filings coating is not less than 2.5cm after tamping.Wherein, the granularity of an inovulant is 4mm.
It is covered with dedicated molten iron backpack cover rapidly after tapping when nodularization, the absorptivity of Mg and RE is ensured with this, Mg is indirectly controlled with thisIt is residualFor
0.05~0.06%, REIt is residualIt is 0.016~0.018%.It is finished to spheroidizing reacion, removes dedicated molten iron backpack cover, skim, in case
Casting.
According to the weight of every iron clad water, the long-acting silicon iron inoculator containing Sr and Ba is weighed according to the Si amount of required supplement, one
Secondary and post inoculant total amount is 0.8% of iron water amount in ladle, and the granularity of post inoculant is 2mm.Spheroidising
Molten iron deducts the amount of an inovulant after skimming, and remaining 0.45% inovulant is placed in the upper surface of molten iron in ladle.It will
Holding furnace toasts 35min with atomized diesel fuel nozzle, after being inserted into dummy bar head in a crystallizer, by the warm furnace of the molten iron handled well
Cast gate pours into holding furnace, and pouring temperature is 1380 DEG C.
It is stopped 2 minutes after molten iron casting is entered holding furnace, the molten iron into crystallizer is made to wrap dummy bar head, it is to be crystallized
Start dummy ingot traction after solidification, with "~stopping~is drawn to draw " technological level continuous casting.Wherein drawn during horizontal continuous-casting
The revolving speed of motor is 1200rpm, and the drawing time is 1.6s, residence time 18s, length of mould 600mm, and inflow temperature is
Room temperature, leaving water temperature be 60 DEG C, profile crystallizer outlet temperature control 975 DEG C to get arrive spheroidal graphite cast-iron profile material.
Drawing speed and profile outlet temperature are controlled, runout is prevented, control molten iron casting interval is no more than 10min, to prevent
Only liquid iron balling and inoculation fade and occur graphite form variation and carbide.
Φ 320mm spheroidal graphite cast-iron profile material prepared by embodiment 3, samples at 1/2 radius, and tensile strength is
600MPa, elongation 3.5%, hardness are HB215~260, and tensile property index has been more than LZQT600-3 standard (JB/T
10854-2008 horizontal continuous-casting cast iron profile material, Chinese machinery industry standard) it requires.
Claims (3)
1. a kind of preparation method of hi-strength nodular iron profile, which is characterized in that specifically implement according to the following steps:
Step 1, cast iron melting:
According to the weight percent of setting, the silicon amount that inovulant is brought into is deducted, the casting magnesium iron pig iron needed for weighing base iron,
Steel scrap, foundry returns, 75% ferrosilicon and SiC, are molten into molten iron in induction furnace,
The fusing charging sequence is successively are as follows: is first put into a part casting magnesium iron pig iron, is advisable with covering furnace bottom, to this batch of pig iron
SiC is added after fusing, the remaining pig iron, steel scrap and foundry returns is then added, and be pressed in above SiC,
The dosage of the SiC is the 0.8~1.1% of weight of molten iron, and granularity is 3~10mm,
It takes base iron to carry out stokehold fast analyzing constituent, adjusts the content of each element in base iron, wherein C:3.0~3.3%,
Si:1.1~1.8%, Mn:0.1%~0.3%, P≤0.15%, S≤0.06%, remaining is Fe, composition described above weight percent
The sum of be 100%, tapping；
Step 2, the molten iron that step 1 obtains is subjected to spheroidising using dam-type molten ductile iron packet and bred
It is described to breed to breed twice, it breeds carried out simultaneously with spheroidising for the first time, breed completed in spheroidising for the second time,
It being carried out after skimming, inovulant is placed in the upper surface of molten iron in ladle, to be poured into holding furnace with stream,
The granularity of inovulant is 3~5mm, and the dosage of an inovulant is the 0.3~0.4% of molten iron total weight；It is secondary pregnant
The granularity for educating agent is 1~3mm, and the dosage of post inoculant is the 0.4~0.5% of molten iron total weight；
The spheroidising specifically: molten iron is poured into the ladle of pre- roasted mistake, Sb nodulizer will be contained and be added in dykes and dams, and
The inovulant for once breeding used is covered on nodulizer, then is covered on nodulizer using low-sulfur iron filings, iron filings after tamping
The thickness of coating is not less than 2~3cm, covers ladle lid rapidly after tapping, finishes to spheroidizing reacion, removes molten iron backpack cover
Son is skimmed；
Nodulizer dosage is 1.1~1.6%, and granularity is 15~30mm；
Step 3, molten iron casting step 2 obtained enters holding furnace, and carries out horizontal continuous-casting to get hi-strength nodular iron type is arrived
Material, the hi-strength nodular iron profile by weight percentage consisting of: C:3.0~3.3%, Si:2.2~3.0%, Mn:0.1~
0.3%, P≤0.15%, S≤0.06%, Sb:0.01~0.015%, MgIt is residual>=0.05%, REIt is residual: 0.015~0.018%,
Remaining is Fe, and the sum of composition described above weight percent is 100%.
2. a kind of preparation method of hi-strength nodular iron profile according to claim 1, which is characterized in that the fusion temperature
It is 1550~1580 DEG C, tapping temperature is 1500~1550 DEG C, and pouring temperature is 1360~1420 DEG C.
3. a kind of preparation method of hi-strength nodular iron profile according to claim 1, which is characterized in that in the step 3
Horizontal continuous-casting uses "~stopping~is drawn to draw " processing method, and the revolving speed of traction electric machine is 800~1200rpm in casting process,
The drawing time is 0.2~2.0s, and the residence time is 1~35s, and length of mould is 200~600mm, and inflow temperature is room temperature, out
Coolant-temperature gage is 50~70 DEG C, and profile crystallizer outlet temperature is controlled at 900~1050 DEG C.
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| CN109604533B (en) * | 2019-02-15 | 2020-07-14 | 莱州鸿源台钳制造有限公司 | Preparation method of austempered ductile iron bench vice |
| CN110284050A (en) * | 2019-07-29 | 2019-09-27 | 河北恒工机械装备科技有限公司 | A kind of Large-cross-section nodular cast iron profile and technique preventing chunky graphite formation |
| CN113416886B (en) * | 2021-05-14 | 2022-05-03 | 西安理工大学 | Thermal shock fatigue-resistant glass mold iron section and preparation method thereof |
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| JP2010156003A (en) * | 2008-12-26 | 2010-07-15 | Nippon Piston Ring Co Ltd | Cast-iron member with cast-in spray deposit film, method for manufacturing the same, cylinder liner with cast-in spray deposit film, and wear-resistant ring with cast-in spray deposit film |
| CN102560231A (en) * | 2011-12-23 | 2012-07-11 | 昆明理工大学 | Ferrite nodular cast iron liquid for wind-power castings and preparation method thereof |
| CN103882282A (en) * | 2014-03-28 | 2014-06-25 | 日月重工股份有限公司 | Molten iron of hundred-tonnage ferritic nodular cast iron casting and preparation method of molten iron |
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