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 PDF

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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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iron
molten iron
profile
furnace
temperature
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CN107326257A (en
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徐春杰
徐信锋
王弋丹
赵振
马萌
李倩
淡江雷
李翠芹
张忠明
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Shaanxi Xili Huazhu New Material Technology Co Ltd
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Xian University of Technology
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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
    • 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
    • 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
    • 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
    • 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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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • 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

A kind of hi-strength nodular iron profile and preparation method thereof
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)

1.一种高强度球铁型材的制备方法，其特征在于，具体按以下步骤实施：1. a preparation method of high-strength ductile iron profile, is characterized in that, is specifically implemented according to the following steps: 步骤1，铁水熔炼：Step 1, molten iron smelting: 按照设定的重量百分比，扣除孕育剂所带入的硅量，称量原铁水所需的铸造球铁生铁、废钢、回炉料、75％硅铁及SiC，在感应炉中熔化为铁水，According to the set weight percentage, after deducting the amount of silicon brought in by the inoculant, weigh the cast ductile iron pig iron, scrap steel, returning charge, 75% ferrosilicon and SiC required for the original molten iron, and melt it into molten iron in the induction furnace. 所述熔化加料顺序依次为：先放入一部分铸造球铁生铁，以盖住炉底为宜，待该批生铁熔化后加入SiC，然后加入剩余的生铁、废钢和回炉料，并压在SiC上面，The sequence of melting and feeding is as follows: first put a part of cast ductile iron pig iron, preferably to cover the bottom of the furnace, add SiC after the batch of pig iron is melted, then add the remaining pig iron, scrap steel and returning charge, and press it on the SiC , 所述SiC的用量为铁水重量的0.8～1.1％，粒度为3～10mm，The dosage of the SiC is 0.8-1.1% of the molten iron weight, and the particle size is 3-10 mm. 取原铁水进行炉前成分快速分析，调整原铁水中各元素的含量，其中C：3.0～3.3％，Si：1.1～1.8％，Mn：0.1％～0.3％，P≤0.15％，S≤0.06％，其余为Fe，以上组成重量百分比之和为100％，出铁；Take the raw molten iron for quick analysis of the composition before the furnace, and adjust the content of each element in the raw molten iron, among which C: 3.0-3.3%, Si: 1.1-1.8%, Mn: 0.1%-0.3%, P≤0.15%, S≤0.06 %, the rest are Fe, the sum of the above composition weight percentages is 100%, and the iron is tapped; 步骤2，将步骤1得到的铁水采用堤坝式球铁铁水包进行球化处理和孕育In step 2, the molten iron obtained in step 1 is spheroidized and incubated with a dam-type ductile iron ladle. 所述孕育为两次孕育，第一次孕育与球化处理同时进行，第二次孕育在球化处理完成，扒渣后进行，孕育剂置于铁水包中铁水的上表面，待随流浇入保温炉中，Described inoculation is twice inoculation, the first inoculation is carried out simultaneously with spheroidizing treatment, and the second inoculation is carried out after spheroidizing treatment is completed, after slag removal, the inoculant is placed on the upper surface of the molten iron in the ladle, and is to be poured along into the holding furnace, 一次孕育剂的粒度为3～5mm，一次孕育剂的用量为铁水总重量的0.3～0.4％；二次孕育剂的粒度为1～3mm，二次孕育剂的用量为铁水总重量的0.4～0.5％；The particle size of the primary inoculant is 3～5mm, and the dosage of the primary inoculant is 0.3～0.4% of the total weight of the molten iron; the particle size of the secondary inoculant is 1～3mm, and the dosage of the secondary inoculant is 0.4～0.5% of the total weight of the molten iron %; 所述球化处理具体为：将铁水浇入预烤焙过的铁水包中，将含Sb球化剂加入堤坝内，并将一次孕育所用的孕育剂覆盖在球化剂上，再采用低硫铁屑覆盖在球化剂上，捣实后铁屑覆盖层的厚度不小于2～3cm，出铁后迅速盖上铁水包盖子，待球化反应完毕，移除铁水包盖子，扒渣；The spheroidizing treatment is specifically as follows: pouring molten iron into the pre-baked ladle, adding Sb-containing spheroidizing agent into the dam, covering the spheroidizing agent with the inoculant used for one inoculation, and then using low-sulfur spheroidizing agent. The iron filings are covered on the nodularizing agent, and the thickness of the iron filings covering layer after tamping is not less than 2-3 cm. After tapping, the lid of the ladle is quickly covered. After the spheroidization reaction is completed, the lid of the ladle is removed and the slag is removed; 球化剂用量为1.1～1.6％，粒度为15～30mm；The amount of nodulizer is 1.1-1.6%, and the particle size is 15-30mm; 步骤3，将步骤2得到的铁水浇注入保温炉，并进行水平连续铸造，即得到高强度球铁型材，所述高强度球铁型材按重量百分比其组成为：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％，Mg残≥0.05％，RE残：0.015～0.018％，其余为Fe，以上组成重量百分比之和为100％。Step 3, pour the molten iron obtained in step 2 into the holding furnace, and perform horizontal continuous casting to obtain a high-strength ductile iron profile. : 2.2～3.0%, Mn: 0.1～0.3%, P≤0.15%, S≤0.06%, Sb: 0.01～0.015%, Mg residue ≥0.05%, RE residue : 0.015～0.018%, the rest is Fe, the above composition The sum of the weight percentages is 100%. 2.根据权利要求1所述的一种高强度球铁型材的制备方法，其特征在于，所述熔化温度为1550～1580℃，出铁温度为1500～1550℃，浇注温度为1360～1420℃。2. The method for preparing a high-strength ductile iron profile according to claim 1, wherein the melting temperature is 1550-1580°C, the tapping temperature is 1500-1550°C, and the pouring temperature is 1360-1420°C . 3.根据权利要求1所述的一种高强度球铁型材的制备方法，其特征在于，所述步骤3中水平连续铸造采用“拉～停～拉”加工方式，铸造过程中牵引电机的转速为800～1200rpm，拉拔时间为0.2～2.0s，停留时间为1～35s，结晶器长度为200～600mm，进水温度为室温，出水温度为50～70℃，型材结晶器出口温度控制在900～1050℃。3. The method for preparing a high-strength ductile iron profile according to claim 1, wherein in the step 3, the horizontal continuous casting adopts the "pull-stop-pull" processing method, and the rotational speed of the traction motor during the casting process It is 800～1200rpm, the drawing time is 0.2～2.0s, the residence time is 1～35s, the length of the crystallizer is 200～600mm, the temperature of the inlet water is room temperature, the temperature of the outlet water is 50～70℃, and the outlet temperature of the profile crystallizer is controlled at 900～1050℃.
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