CN1436862A - Production process of high-strength steel nodular cast iron - Google Patents
Production process of high-strength steel nodular cast iron Download PDFInfo
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Abstract
During the production of high-strength steely nodular cast iron, waste steel accounting for 60-95% and small amount of pig iron and returned material are used. Through high temperature smelting, gravitational cast eutectic steel-like nodular cast iron with high strength, high performance, no cast default, low carbon and low silicon is produced.
Description
A kind of manufacture method of high-strength steel nodular cast iron is characterized in that when melting iron solution input total volume 60% to a large amount of steel scrap more than 95% obtains in cupola furnace or electric furnace.The feature of high-strength steel nodular cast iron is the magnesium iron of low carbon low silicon, and chemical ingredients is an eutectic or hypoeutectic, i.e. eutectic degree≤1.The most important condition that this steely steel nodular cast iron has been emphasized since the nineteen forty-seven invention than magnesium iron is that eutectic degree 〉=1 has obvious difference.Steel nodular cast iron of the present invention has obtained than hypereutectic magnesium iron higher physicals, tensile strength height, big, the obvious characteristics that reduce of casting flaw of unit elongation are arranged under the condition of low carbon low silicon.Because a large amount of steel scraps that use, cost significantly reduces, and utilization of resources situation takes place by good the variation, and also favourable minimizing steel scrap ferric oxide is to the pollution of physical environment.The manufacture method of high-strength steel nodular cast iron of the present invention is to obtain easy, the most novel effective way low-cost, high performance ductile iron.Its feature is as follows: one, the scope of steel nodular cast iron chemical ingredients
The chemical ingredients of steel nodular cast iron of the present invention and principal element composition characteristic: carbon 1.5%-3.0%, silicon 1.8%-2.8%, sulphur＜0.6%, phosphorus＜0.07%, manganese 0.5%-1.0%.Can add molybdenum 0.2%-0.6%, copper 0.4%-0.9% or other alloying element during alloying.All the other are iron.
1, about carbon: steel nodular cast iron major control carbon equivalent of the present invention (carbon amount+1/3 silicon+1/3 phosphorus content) equals 4.3% or less than 4.3% (massfraction).Make eutectic or hypoeutectic magnesium iron, because carbon content is low, proportion is greater than common existing magnesium iron, and intensity, extensibility are higher than existing magnesium iron.For distinguishing this two kinds of magnesium irons, the magnesium iron of the steely the inventive method manufacturing of the performance of the low carbon content of a large amount of steel scrap manufacturings named be " steel nodular cast iron ".
Ferro element is that the steel scrap that adds more than the total amount 60%-95% is realized in above-mentioned chemical ingredients.Steel scrap carbon content average out to 0.5%-0.9% can add blase furnace cast iron or the foundry returns of 5%-20% in fusion process.A large amount of molten iron that adopt steel scrap can obtain carbon content 1.5%, the iron alloy free area of this low-carbon (LC) increases, crystal grain obtains refinement, when nodularization thereafter, can obtain obviously high tensile strength and extensibility, the casting flaw of this steel nodular cast iron obviously reduces, and phenomenons such as shrinkage porosite, pore, subsurface porosity, graphite floatation, slag inclusion can occur hardly.Existing hypereutectic magnesium iron, the phenomenon that the defective that a large amount of carbon atoms cause at the solid internal diffusion obviously descends material property is improved, the crystal grain of low carbon low silicon steel nodular cast iron is tiny, macroscopic property, mechanical property, erosion resistance all are greatly improved, and this manufacture method obtains steady quality, foundry goods that yield rate is high easily.Resource and waste and old material reprocessing cycle obtain fully efficient the utilization, are the effective ways of saving metallic substance.
The manufacture method of the iron liquid of carbon content 1.5%-3.0% of the present invention has two kinds.When the first is founded, need in stove, to add the steel scrap melting of Graphite Electrodes (50 millimeters * 50 millimeters bulks) 1%-2.5% (massfraction) with mean carbon content 0.5% in electric furnace (as middle frequency furnace).It two during melting, can not add carbon in stove in cupola furnace, owing to use coke carburetting to carry out naturally in melting process, can obtain the iron liquid of 1.5% carbon amount very easily with the steel scrap of average carbon containing 0.5%.The method of producing steel nodular cast iron mainly is to change the cupola furnace air port where necessary to the distance between furnace bottom, distance is more little, iron liquid is few more to the absorption of carbon, also cupola well can be cancelled, furnace bottom is elevated to more than the line of air port, or at the fire-resistant checkers of some excessive molten iron streams of soaring masonry of well, to adjust carbon increasing amount.Because ash oontent influences carburetting in the coke, increases the coke consumption slightly, melting zone and cast iron temperature also increase thereupon, promote the carburetting of iron liquid and improve homogeneity.But adjust the carburetting of coke consumption to 1.5%-3%, do not need additionally to add carbon.The present invention advocates low-carbon-equivalent, takes as the leading factor with hypoeutectic and eutectic state.For example as cast condition crystal grain is very careful during carbon amount 1.5%, and macroscopical color is the iron oxide surface of silver bright color, no blue look, because casting flaw overheated or that chilling is common is disappeared, grain refining, mechanical property significantly improve.Only this adopts a behave of low carbon content just can improve a quality grade with having magnesium iron smelting level now.The performance of the steel nodular cast iron of the low carbon low silicon of a large amount of employing steel scraps generally can reach the above level of GB500-10.Significantly better than the performance of using the existing magnesium iron of high-quality blase furnace cast iron.
2, about silicon: the feature of the silicone content of steel nodular cast iron of the present invention is that the silicon amount is controlled between the 1.5%-2.8%.The inventive method add silicon technology be with all or 4/5 silicon be used for inoculation, in stove, only add 1/5 silicon, even in stove, do not add silicon.Because the carbon content of present method is low, the temperature of fusion height only is that the flowability, the crystal grain thinning that improve molten iron are the main purposes that adds silicon owing to add an amount of silicon that breeds.Present method is taked silicon was applied at the bag end, pours molten iron at twice, with the method that stream spreads two to three instant inoculations of thin ferrosilicon grain, will not need the ferrosilicon of preheating to add in the flowing molten iron respectively.The nodulizing agent of enumerating in big nucleating agent and present method table 1, the way that alterant adds together, it is crucial handling molten iron.
3, alloy element: in the fusion process of steel nodular cast iron, can in iron liquid, add various alloying elements.Disposable when present method is characterised in that in electric furnace the beginning melting various alloying elements are added in the lump, to reduce eutectic point, it is overheated to obtain, and reaches the purpose of crystal grain thinning.But the abundant stirring molten iron refining eutectic body behind spheroidizing reacion during the condition of high temperature obtains the high quality casting of no macroscopical local uniformly or crystallite segregation.
4, process for sulfur removal: after the iron liquid fusing, before the cast, the molten iron that pours in the casting ladle should sulphur removal in casting ladle, and molten iron per ton adds 20 kilograms of soda, can remove sulphur about 60%.Add 1/2 soda and be placed on the bag end with paper bag packing earlier.In addition 1/2 adds during molten iron 1/2 in pouring bag, react to add a small amount of lime or slagging agent slagging-off after 3 minutes, and the sparkling and crystal-clear degree of molten iron improves, the increase flowability.
5, the representative formula of one of present method embodiment following (mass component): carbon 1.822%, silicon 2.75%, sulphur 0.019%, phosphorus 0.048%, manganese 0.505%, copper 0.3%, molybdenum 0.2%, remaining magnesium 0.034%, residual Re 0.02%, all the other are iron.
Use 90% steel scrap when fusing, the mean carbon content of steel scrap is 0.5%, and steel scrap is an industrial waste.
Fusing does not add carbon and ferrosilicon in cupola furnace, breeds the soda sulphur removal with three heavy doses of ferrosilicon (silicon 75%) branch of molten iron total amount 2.6%.Use spheroidizing inoculant, spheroidizing inoculant calcic 1.45%, rare earth 7-9%, magnesium 9.47% during spheroidizing.The nodulizing agent consumption accounts for 1.8% of molten iron total amount.
Reach 1300Nm through isothermal thermal treatment (880 ℃ of heating 30 minutes, 260 ℃ of isothermals 90 minutes) tensile strength.Unit elongation 1.5% hardness HRC48 impact value 80Jcm
-2
Alterant that the inventive method is used such as subordinate list 4 be numbered 1,2,3,4 etc. four kinds, in nodulizing agent such as the subordinate list 3 cited 1,2,3,4 etc. four kinds.
Accompanying drawing 1 of the present invention is a process flow diagram.In accompanying drawing 1, the technical process of manufacture method of the present invention is added the smelting furnace downwards with the block diagram formal representation as shown in Figure 1 from steel scrap from the left side, upper end.
Present method can obtain the flawless foundry goods of the refrigerative of the layering gradually gravity casting of proportion 7.2-7.7 different specific weight with the method for the different iron flow of control.Do not produce the feeding phenomenon in cast part cast gate, at this moment only proportion slightly reduces, and has realized no pressure head, no rising head, no shrinkage porosite, has not needed the very high process for manufacturing cast article of molten iron utilization ratio of feeding.As shown in Figure 2, accompanying drawing 2 medium castings 1 are big stream cast faster, when the flowing molten iron 2 among Fig. 2 is poured into a mould.Because high temperature liquid iron chilling in sprue cup is shrunk to the deep valley shape, be the shape of useless sprue foundry goods, obviously waste a large amount of molten iron.Accompanying drawing 2 medium castings 3 are the shapes of watering the foundry goods of the complete no shrinkage porosite that is full of die cavity that beam 4 obtains through certain hour with the less molten iron of limiting the quantity of, and can realize not having rising head, the gravity casting of no pressure head cast gate.
Two, the method that prevents of chilling tendency: use the hypoeutectic of low carbon low silicon of steel scrap or the steel nodular cast iron of eutectic composition in a large number, chilling tendency appears in theory easily, cementite can form in a large number, but the inventive method be characterised in that to molten iron is melting adopt exceed the very high high temperature of traditional method and overheated, temperature of fusion is high, pouring temperature is high, high temperature liquid iron discharges the temperature that a large amount of heats has directly improved metal mold or sand mold type wall in type.The pyritous result is that foundry goods obtains a large amount of ferrite and pearlitic structure, has in fact promoted graphited process.Never with high temperature liquid iron heating die cavity wall, foundry goods iron liquid temp is low spoken parts in traditional operas to occur again by the casting mold Quench to traditional method, and subsurface porosity waters not congruent multiple casting flaw and is inevitable.When the inventive method adopts steel scrap in a large number in the iron liquid a spot of carbide, nitride be distributed on the austenitic crystal boundary, the obstruction austenite crystal is grown up, the weak carbide that alloy element forms, carbon content is set in after a little while and is easier to be dissolved in the austenitic solid solution phase under the high temperature action, and making crystal grain obtain special refinement, macrofracture is the spitting image of steel.Because carbon content is few, the graphite of free state is spherical, and the hole of formation greatly reduces, and notch sensitivity also significantly reduces.Because a spot of carbon is under the encirclement of a large amount of iron atoms, under the effect of a large amount of nucleus of element such as silicon, manganese, the graphite precipitate is by refinement rapidly, the very tiny densification of crystallization, there is not the crystallization of macroscopical pomegranate shape, unlike magnesium iron and fracture the spitting image of " steel " is arranged, this steely steel nodular cast iron has very high physicals, outward appearance and inner quality are all the spitting image of steel.And in the chemical ingredients conclusive carbon than steel height, lower than cast iron, be a kind of iron-carbon between iron and steel, and comprehensive physicals is higher than iron and steel.For example a kind of carbon equivalent of steel nodular cast iron of the inventive method manufacturing is 3.07, be with 90% carbon containing 0.4% steel scrap, add silicon 2.8%, blase furnace cast iron 7%, a little copper, the rotten processing of molybdenum fusing back nodularization and obtain.Tensile strength reaches 980Nm, the high-quality steel nodular cast iron of unit elongation 3.2%.
For preventing spoken parts in traditional operas, in breeding metamorphic process, add a large amount of silicon, produced the silicate particle that many disperses distribute, its lattice parameter and graphite hexagonal lattice constant are very approaching, are easy to generate a large amount of nucleus.The concentration fluctuations of the silicon-rich areas in these hypoeutectic molten iron is equivalent to the molten iron of eutectic area or the outer reason of hypereutectic district process nodularization, can when solidifying, separate out globular graphite immediately, these free carbons do not have enough carbon to remove to generate cementite under the high temperature heat kinetics function, a large amount of ferrites account for essential factor, thereby have avoided the generation of chilling tendency.Add CaC2 and promote graphited effect more obvious, avoided chilling tendency owing to made a large amount of " artificial nucleus " rotten processing and nodularization process, topmost feature is that hyperthermia and superheating makes said process more abundant, has prevented chilling tendency.Foundry goods needn't be annealed and can be carried out mechanical workout.The process indigenous graphite or the cementite of graphite direct crystallization in solution or solid solution, because the molten iron solution of present method hyperthermia and superheating is also used higher temperature when cast, 1460 ℃ in cupola furnace, 1650 ℃ to 1700 ℃ on electric furnace a spot of carbon atom under high temperature action has like this absorbed very few iron atom and it combines, the pyritous intensity of activation makes bonding force between a spot of carbon atom greater than the bonding force of foreign atom, make carbon atom can't be in a large number and iron atom combine, destroyed the condition that forms cementite, and its diffusion process of effect owing to nodulizing agent when carbon is separated out in solution is a control process, atom evenly flows into from every side can crystallize into carbon the garden ball shape, and seldom form cementite, such foundry goods processing characteristics is good, can remove graphitizing annealing from.If certainly because casting mold or technological reason when spoken parts in traditional operas occurring, the high-strength steel nodular cast iron foundry goods of present method also can carry out mechanical workout after graphitizing annealing, and high-intensity characteristic is not had bad influence.Can reduce more than 1/2 than the annealing time of prior art as its annealing time of iron liquid foundry goods with electric furnace hyperthermia and superheating fusing more than 1600 ℃, can all eliminate cementite, annealing time obviously reduces, and save energy is remarkable.
Three, about " hyperthermia and superheating " of melting and teeming temperature
Add silicon after the steel nodular cast iron carburetting and breed the height that the molten iron temperature when going bad nodularization will be tried one's best.For example cupola furnace is come out of the stove for 1500 ℃, and this moment, available hot-blast stove or oxygen blast improved furnace temperature, and about 1450 ℃ of teeming temperatures, more efficient methods are to smelt with electrosmelting of intermediate frequency or with the duplex that electric furnace heats.Make tapping temperature be not less than 1500 ℃, will adopt high temperature when melting is overheated as far as possible, for example the hyperthermia and superheating between 1600 ℃-1760 ℃.Through the iron liquid casting quality remarkable especially that hyperthermia and superheating like this is handled, be the simple and effective key method of gravity casting zero defect casting.High temperature liquid iron has the watery flowability of picture, can instantaneously be full of casting mold, the brilliant tendency that forms reduces between branch, high temperature liquid iron scour cast wall, greying is abundant when helping casting solidification, the foundry goods of complex thin-wall can be filled rapidly under the effect of high temperature liquid stream high reynolds number, mistake subsequently is cold not only avoided spoken parts in traditional operas again especially refinement crystal grain, improved the quality and the yield rate of foundry goods.The finite energy that high temperature consumes, and nearly hundred-percent yield rate and no rising head do not have the molten iron utilization ratio of gating system of pressure head apparently higher than existing casting technique.Present method at first breaks through " high temperature forbidden zone " and has obtained obvious effects, and high temperature obviously improves casting quality.Mobile correlation data sees attached list 2.
Usually molten iron graphite when 1500 ℃ of spheroidizings is more spherical, when then being increased to 1550 ℃ of processing again, graphite pebbles is alabastrine irregularity garden sphere, degradation, and present method is when adopting 1600 ℃-1700 ℃ pyroprocessing, and flakes graphite is activated post crystallization by high temperature heat and becomes more tiny shaped graphite pebbles.Sphere diameter is 20 μ-350 μ during low temperature, and the sphere diameter of refinement can reach 1 μ to 20 μ during high temperature.
Another benefit of high temperature cast is that the molten iron flowability is good especially, and impurity and bubble are easy to come-up in the high temperature iron liquid, and slag inclusion obviously reduces, and dispersed shrinkage reduces, and is the simple and effective method of obtaining closely knit zero defect casting.For example the high temperature liquid iron quality degassing effect in electric furnace is good, and molten iron easily absorbed gas when common saying was high temperature, and in fact the gas in the iron liquid is squeezed to atmosphere by the high specific gravity of molten iron and suffered during high temperature.When the furnace melting molten iron, a large amount of bubble floatings appears between 1500 ℃-1600 ℃, boiling during as to boil water boiling, bubble takes place incessantly repeatedly, but bubble and boiling phenomenon have stopped in the temperature-rise period of continuation, molten iron presents tranquil mirror status, obviously molten steel quality at this moment is very even, and inclusion-free does not have macroscopic view and crystallite segregation yet, and the molten iron that clear thorough crystalline substance melts is significantly better than brilliant between the easy raised growth branch of low temperature, coarse " gluing ", mobile bad molten iron.
Existing casting industry popular processing method is " high temperature is come out of the stove, cast cold ", and the new processing method of the present invention is it to be changed into " very high temperature is come out of the stove, high temperature pour into a mould " change the matrix crystallization condition is changed.Because high temperature cast, the raising of mold temperature has improved curing condition, avoid chilling tendency again refinement crystal grain, a large amount of heat of molten iron directly influence the formation of the crystalline substance of coming into being when cold in casting mold, has promoted greying.In austenitic iron liquid nodularization graphite when cooling later, do not change the shape of graphite.The fluid temperature height, surface tension reduces, good fluidity.Viscosity factor is little, makes casting forming easy, and high temperature makes cooling slowly, crystallization invert point and speed have been reduced, can make austenite divide the dispersiveness of Jie's product to increase and obtain the steel nodular cast iron of structure refinement, its as-cast structure is amount of ferrite and perlite, does not have cementite.The carbon that quantity is few, molten Jie's carbon also obviously reduces in the quantity of separating out in liquid after the cast during high temperature, and this is reduced casting flaw, and the homogeneity of metal increases, intensity and plasticity are improved.Along with the rising of smelting temperature, the tensile strength of foundry goods also improves thereupon between 1400 ℃-1760 ℃, and temperature and quality are linear, are one of principal characters of present method.Related data sees attached list 2 and subordinate list 1.
The present invention's existing casting magnesium iron of method of adding a large amount of smelting scrap steel high-strength steel nodular cast irons uses the method for blast furnace high duty pig iron that tangible difference is arranged in a large number in sum.The topmost high-quality steel nodular cast iron foundry goods of high-quality zero defect that can obtain when being characterised in that a large amount of use steel scrap when using blase furnace cast iron.Making a general survey of the home and abroad does not almost have the city or the rural area of steel scrap, and a large amount of useless steel scraps are used manufacture method of the present invention, and can to become more good foundry goods be the topmost feature of the present invention.
In a word, the manufacture method of rigidity ball nodular cast iron of the present invention is effective ways of making product innovation 21 century, and very easy processing method uses that waste and old resource obtains but is good high quality, foundry goods cheaply.
We can say that present method is an important achievement of " iron-steel unification " project in this century, have obvious social and very high economic benefit, popularizing application prospect is very wide.
Table 1 steel nodular cast iron and GB magnesium iron salient features are relatively
| Sequence number | Test item | Common hypereutectic magnesium iron | Steel nodular cast iron of the present invention | Remarks | ||
| As cast condition | Isothermal quenching | As cast condition | Isothermal quenching | |||
| ????1 | Tensile strength sigma b/Mpa | ??400-600 | ????800-1300 | ??600-900 | ??900-1500 | |
| ????2 | Unit elongation σ % | ??10-16 | ????2 | ??6-3.5 | ??2-1 | |
| ????3 | Impact value ak (J ' cm -2) | ??32-17 | ????82-120 | ??30-100 | ??80-150 | |
| ????4 | Hardness HRC | ??18-28 | ????32-48 | ??20-32 | ??38-49 | |
| ????5 | Nodule number/millimeter | ??＜500 | ????＜600 | ??600-900 | ??600-1200 | |
| ????6 | Proportion | ??7.25 | ????7.25-7.35 | ??7.3-7.7 | ??7.3-7.7 | |
| ????7 | Casting yield | ??60-70％ | ????60-75％ | ??90-95 | ??92-98 | |
| ????8 | The molten iron utilization ratio | ??65-75％ | ????65-75％ | ??90％ | ??90％ | |
| ????9 | Production cost | ??100％ | ????120％ | ??60％ | ??65-70％ | |
Table 2 steel nodular cast iron temperature and mobile relation
| Sequence number | Molten iron temperature | The macroscopic view color | The fire door flat state | The liquid level state | Thickness coefficient flowability (gram/centimetre. second) | Minimum wall thickness (MINI W.) (millimeter) | Smelting furnace |
| ??1 | ??1420℃ | Red white | Tranquil | Convex | ????0.04 | ????3 | Cupola furnace |
| ??2 | ??1500℃ | Bai Hong | Tranquil | The plane | ????0.035 | ????2 | Cupola furnace |
| ??3 | ??1600℃ | Bai Liang | The boiling bubble | Rise and fall | ????0.02 | ????1 | Electric furnace |
| ??4 | ??1700℃ | Bright as silver | Tranquil | Like horizontal plane | ????0.015 | ????0.5 | Electric furnace |
| ??※ | 20 ℃ of water | Transparent | Tranquil | Horizontal plane | ????0.0102 | Reference data |
Table 3 steel nodular cast iron is used nodulizing agent main component per-cent always
| Sequence number | Title | Silicon | Rare earth | Magnesium | Calcium | Other | Purposes |
| ??1 | A nodulizing agent | ?40-45 | ???7.18 | ???9.47 | ????1.45 | Surplus Fe | General foundry goods |
| ??2 | No. two nodulizing agents | ??55 | ????3 | ????10 | ????4.5 | Surplus Fe | Medium foundry goods |
| ??3 | No. three nodulizing agents | ?35-44 | ???7-9 | ????7-9 | ???＜2.5 | Surplus Fe | High strength casting |
| ??4 | No. four nodulizing agents | ?35-44 | ????8 | ???10-13 | ???＜2.5 | Surplus Fe | High strength casting |
Table 4 steel nodular cast iron is used alterant main component per-cent always
| Sequence number | Each claims | Silicon | Calcium | Bismuth | Aluminium | Barium | Manganese | Add-on | Other |
| ????1 | No. one, electric furnace | ???50 | ??18 | ??0.01 | ???1.2 | ??16 | ????0.4 | Surplus Fe | |
| ????2 | No. two, electric furnace | ???75 | ??2.75 | ???2 | ??5 | ??10 | ????0.5 | Surplus Fe | |
| ????3 | General No. one | ???73.5 | ??1.9 | ??0.01 | ???0.55 | ??0.28 | ????0.8 | Surplus Fe | |
| ????4 | No. one, cupola furnace | ???68 | ??2.1 | ???2.7 | ??2.5 | ????0.8 | Surplus Fe |
Claims (9)
1, the principal character of the manufacture method of high-strength steel nodular cast iron is a large amount of steel scraps that adopt when smelting ferroalloy solution, obviously distinguishes the method that prior art adopts the high-quality blase furnace cast iron in a large number.Steel scrap is meant waste materials such as waste and old steel equipment in industrial offal or the daily life, crate, boats and ships, munitions, steel construction.Through the material piece of fragmentation less than the smelting furnace diameter, the steel nodular cast iron that alloying element pyrotic smeltings such as adding carbon silicon obtain.The high-quality steel nodular cast iron foundry goods of present method is at first selected the carbon steel steel scrap for use, the structural alloy steel steel scrap.Be meant with steel scrap and adopt the steel scrap that is no less than the above gross weight of 60%-95% when the melting.When most of steel scrap is done raw material, can obtain the high quality casting more outstanding than the high-quality blase furnace cast iron.Steel nodular cast iron intensity is apparently higher than existing magnesium iron intensity.The present invention adopts cheap steel scrap to make the breakthrough that outstanding foundry goods has obtained materialogy in a large number.Two combine into one to make " steel-iron ", and the appearance of high-strength steel nodular cast iron makes iron that the performance of steel be arranged, and the steely this novel material of steel nodular cast iron of low-carbon (LC) can be as the important spare part of implementation Foundry Production easily of iron.The effect of isolating that causes the carbon of stress concentration in the steel nodular cast iron endobasal-body tissue of low carbon content reduces, and crystallization range is wide, primary austenite dendrite is flourishing and make intensity be higher than hypereutectic magnesium iron.
2, according to the manufacture method of specification sheets and the described high-strength steel nodular cast iron of claim 1, when adopting smelting scrap steel in a large number, the steel scrap mean carbon content is respectively 0.2%-0.9%.Need carburetting when melting.Present method carburetting by regulating the coke consumption, can be satisfied the scope of carburetting to 1.5%-3.0% in cupola furnace; The carbon amount that melting then needs prescription is required in electric furnace is calculated the back with the block that adds Graphite Electrodes 50 millimeter, is placed on crucible bottom with furnace charge when the beginning melting.Carbon through the breeding of the inventive method, go bad, spheroidizing and hyperthermia and superheating can be dissolved in matrix fully, obtains the high-intensity rigidity spheroidal graphite cast iron of any carbon content.Silicon content should be at 1.2%-2.8%, manganese 0.5%-1.2%, sulphur＜0.6%, phosphorus＜0.09 and more a spot of residual Re and remaining magnesium.Control carbon equivalent≤4.3 generally.When iron liquid answers carbon containing more than 1.5% during for hypoeutectic.Carbon equivalent can be controlled between the 2.0-4.3.
When 3, reaching 60%-95% according to a large amount of employing steel scraps of claim 1, use melting method carburetting of the present invention more than 3%, make carbon equivalent be equal to or greater than the steel nodular cast iron of acquisition in 4.3 o'clock, intensity is lower slightly than the hypoeutectic steel nodular cast iron, can on massive casting, use, at this moment proportion is near 7.3, and cavity filling ability, mobile better, dense materials are principal characters.
4, when the steel-smelting nodular cast iron, a small amount of ferrosilicon is put into the stove melting, and will be all or 4/5 ferrosilicon as nucleating agent, add in the bag end and cast flowing molten iron respectively after molten iron is come out of the stove that a large amount of to breed the silicon nucleogenesis strong, the special refinement of crystal grain.Employing simultaneously effectively avoids three times of chilling tendency to breed, instant inoculation, tiny ferrosilicon grain adds fashionable effect under the high temperature iron stream mode be neither to melt also can not be gathered into impurity, be uniformly distributed in the molten metal, form the solid phase nucleus, the effect of refining eutectic body is obvious.
The formulation content of the nucleating agent that the inventive method is used is reinforcement nucleating agent or the rotten ternary combination of use spheroidization and inoculation of silicon about 50%, calcium 10%-18%, aluminium 1.2%-2.2%, barium 5%-16%.
5, in the rotten treating processes of nodularization, fully stir pyrosol.Have only abundant stirring just may destroy the solute zone at interface, effectively prevent segregation, promote the graphite bead constantly to separate out rapidly from molten metal simultaneously, and impurity and bubble also float strongly because of stirring, stirring makes the different element of proportion be in uniform state as far as possible in liquid, effectively prevent gravity segregation, destroy dendrite simultaneously and form, impel equiax crystal to grow up, utilize temperature fluctuation, make the dendrite remelting, obtain the effect of dynamic crystal grain thinning.Prior art is not emphasized the effect of stirring.The feature of the inventive method is the needs when having sufficiently high molten iron temperature can supply fully to stir in high temperature liquid iron, and can overslaugh high temperature cast afterwards.Calm iron liquid and removing the gred after the vigorous stirring, the row cast again of insulation liquid level.Stirring can make full use of breeds temperature fluctuation raising molten iron flowability, the even crystal grain thinning in the solution when going bad spheroidizing reacion, obtains the steel nodular cast iron as-cast structure based on perlite and ferrite of no spoken parts in traditional operas.
6, the high melt described in the inventive method such as the specification sheets, the principal character of high temperature cast is that temperature is apparently higher than the prior art level, can significantly improve the quality of material by the molten iron of 1500 ℃ of-1760 ℃ of hyperthermia and superheatings processing, change its original performance, the novel method that obtains the gravity casting zero defect casting is one of feature of the inventive method.Because the rapid contraction of high temperature cooling in when cast fusing can obtain not have shrinkage cavity, no cold shut, no bubble, the complete densification that is full of complex-shaped surface mould of no slag inclusion, the foundry goods of clear-cut.High temperature melting can have the calm molten iron of time enough, molten iron purification in casting ladle when cast, the solid particle fusing of indissoluble, Rong particle and gas do not have an opportunity to float, and the flowability of molten iron, homogeneity increase reduce crystal grain simultaneously and block running channel, avoid watering infull phenomenon and take place.
7, present method there is no clear and definite requirement to the chemical ingredients of steel scrap.Because the alloying element in the steel scrap obviously is diversified.The chemical ingredients of high-strength steel nodular cast iron at first should be hypoeutectic or eutectic.
8, steel scrap can not carry out degreasing and rust removal, because hyperthermia and superheating is the principal character of present method, ferric oxide can aggravate the burn-off rate in stove in high temperature, and many impurity all stirs in the calm process behind high temperature and eliminates, and obtains high-quality iron liquid.
9, the process stratiform that is poured into by the more tiny molten iron stream of the careful calculation Design of quantitative warp is cooled off and the complete foundry goods of the no cast gate riser feeding of acquisition effect.The handy rate of molten iron can reach more than the 90%-95%.
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| CN 02102965 CN1436862A (en) | 2002-02-08 | 2002-02-08 | Production process of high-strength steel nodular cast iron |
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| CN 02102965 CN1436862A (en) | 2002-02-08 | 2002-02-08 | Production process of high-strength steel nodular cast iron |
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| CN102034700A (en) * | 2009-09-28 | 2011-04-27 | 东京毅力科创株式会社 | Method of recycling silicon component for plasma etching apparatus and silicon component for plasma etching apparatus |
| CN102652967A (en) * | 2012-03-09 | 2012-09-05 | 山西银光华盛镁业股份有限公司 | Method for manufacturing high-magnesium-alloy solid cored wire |
| CN102732664A (en) * | 2012-07-17 | 2012-10-17 | 长沙金龙铸造实业有限公司 | Ductile cast iron production method and production device |
| CN103924167A (en) * | 2014-04-29 | 2014-07-16 | 长沙金龙铸造实业有限公司 | High-strength rigid nodular iron and manufacturing method thereof |
| CN104195414A (en) * | 2014-08-18 | 2014-12-10 | 成都宏源铸造材料有限公司 | Preparation method and application of silicon granule nucleating agent |
| CN106086588A (en) * | 2016-06-16 | 2016-11-09 | 含山县天翔铸造有限公司 | A kind of high intensity hub cast formula and preparation technology thereof |
| CN107385311A (en) * | 2017-07-18 | 2017-11-24 | 宁波日星铸业有限公司 | The method for improving spheroidal graphite cast-iron melt iron degree of purity |
| CN112553395A (en) * | 2020-12-09 | 2021-03-26 | 大连瑞谷科技有限公司 | Spheroidizing process for nodular cast iron for production of retainer |
| CN113355588A (en) * | 2021-05-11 | 2021-09-07 | 南通虹冈铸钢有限公司 | High-strength hypoeutectic cast iron material and manufacturing method thereof |
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| US9290391B2 (en) | 2009-09-28 | 2016-03-22 | Tokyo Electron Limited | Silicon component for plasma etching apparatus |
| CN102034700B (en) * | 2009-09-28 | 2013-08-14 | 东京毅力科创株式会社 | Method of recycling silicon component for plasma etching apparatus and silicon component for plasma etching apparatus |
| CN102034700A (en) * | 2009-09-28 | 2011-04-27 | 东京毅力科创株式会社 | Method of recycling silicon component for plasma etching apparatus and silicon component for plasma etching apparatus |
| US8785214B2 (en) | 2009-09-28 | 2014-07-22 | Tokyo Electron Limited | Method of recycling silicon component for plasma etching apparatus and silicon component for plasma etching apparatus |
| US9399584B2 (en) | 2009-09-28 | 2016-07-26 | Tokyo Electron Limited | Silicon focus ring |
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| CN102732664A (en) * | 2012-07-17 | 2012-10-17 | 长沙金龙铸造实业有限公司 | Ductile cast iron production method and production device |
| CN103924167A (en) * | 2014-04-29 | 2014-07-16 | 长沙金龙铸造实业有限公司 | High-strength rigid nodular iron and manufacturing method thereof |
| CN104195414A (en) * | 2014-08-18 | 2014-12-10 | 成都宏源铸造材料有限公司 | Preparation method and application of silicon granule nucleating agent |
| CN106086588A (en) * | 2016-06-16 | 2016-11-09 | 含山县天翔铸造有限公司 | A kind of high intensity hub cast formula and preparation technology thereof |
| CN107385311A (en) * | 2017-07-18 | 2017-11-24 | 宁波日星铸业有限公司 | The method for improving spheroidal graphite cast-iron melt iron degree of purity |
| CN112553395A (en) * | 2020-12-09 | 2021-03-26 | 大连瑞谷科技有限公司 | Spheroidizing process for nodular cast iron for production of retainer |
| CN112553395B (en) * | 2020-12-09 | 2022-06-24 | 大连瑞谷科技有限公司 | Spheroidizing process for nodular cast iron for production of retainer |
| CN113355588A (en) * | 2021-05-11 | 2021-09-07 | 南通虹冈铸钢有限公司 | High-strength hypoeutectic cast iron material and manufacturing method thereof |
| CN115537642A (en) * | 2022-10-30 | 2022-12-30 | 北京工业大学 | Method for refining hypereutectic high-chromium cast iron primary carbide |
| CN115537642B (en) * | 2022-10-30 | 2023-05-02 | 北京工业大学 | Refining method of hypereutectic high-chromium cast iron primary carbide |
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