CN1751134B - Cast iron billet excelling in workability and process for producing the same - Google Patents
Cast iron billet excelling in workability and process for producing the same Download PDFInfo
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- CN1751134B CN1751134B CN200480004132.6A CN200480004132A CN1751134B CN 1751134 B CN1751134 B CN 1751134B CN 200480004132 A CN200480004132 A CN 200480004132A CN 1751134 B CN1751134 B CN 1751134B
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- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 177
- 238000000034 method Methods 0.000 title claims abstract description 43
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 200
- 239000010439 graphite Substances 0.000 claims abstract description 196
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 196
- 229910001037 White iron Inorganic materials 0.000 claims abstract description 44
- 239000002245 particle Substances 0.000 claims abstract description 37
- 238000004519 manufacturing process Methods 0.000 claims abstract description 23
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 13
- 238000005266 casting Methods 0.000 claims description 145
- 238000005096 rolling process Methods 0.000 claims description 73
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 61
- 150000001875 compounds Chemical class 0.000 claims description 59
- 239000003795 chemical substances by application Substances 0.000 claims description 55
- 239000000203 mixture Substances 0.000 claims description 34
- 229910000859 α-Fe Inorganic materials 0.000 claims description 34
- 229910052742 iron Inorganic materials 0.000 claims description 30
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 26
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 23
- 150000004767 nitrides Chemical class 0.000 claims description 16
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- 239000010949 copper Substances 0.000 claims description 9
- 229910052759 nickel Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 abstract description 25
- 239000004615 ingredient Substances 0.000 abstract description 3
- 239000011265 semifinished product Substances 0.000 abstract 1
- 238000009749 continuous casting Methods 0.000 description 33
- 238000001816 cooling Methods 0.000 description 27
- 238000005098 hot rolling Methods 0.000 description 18
- 239000000463 material Substances 0.000 description 17
- 238000005097 cold rolling Methods 0.000 description 14
- 229910052751 metal Inorganic materials 0.000 description 14
- 239000002184 metal Substances 0.000 description 14
- 229910001296 Malleable iron Inorganic materials 0.000 description 13
- 238000009826 distribution Methods 0.000 description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 12
- 229910001141 Ductile iron Inorganic materials 0.000 description 11
- 230000000694 effects Effects 0.000 description 11
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 10
- 239000006185 dispersion Substances 0.000 description 10
- 238000011835 investigation Methods 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 239000010959 steel Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 7
- 238000007669 thermal treatment Methods 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 239000005864 Sulphur Substances 0.000 description 6
- 238000000137 annealing Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 229910018505 Ni—Mg Inorganic materials 0.000 description 5
- 238000005452 bending Methods 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000003754 machining Methods 0.000 description 5
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000012467 final product Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000005087 graphitization Methods 0.000 description 3
- 229910007981 Si-Mg Inorganic materials 0.000 description 2
- 229910008316 Si—Mg Inorganic materials 0.000 description 2
- NMBNQRJDEPOXCP-UHFFFAOYSA-N butofilolol Chemical compound CCCC(=O)C1=CC(F)=CC=C1OCC(O)CNC(C)(C)C NMBNQRJDEPOXCP-UHFFFAOYSA-N 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
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- 238000013016 damping Methods 0.000 description 2
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- 235000000396 iron Nutrition 0.000 description 2
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
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- 239000004576 sand Substances 0.000 description 2
- 238000010301 surface-oxidation reaction Methods 0.000 description 2
- 230000003313 weakening effect Effects 0.000 description 2
- 230000002087 whitening effect Effects 0.000 description 2
- 229910014458 Ca-Si Inorganic materials 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 101000818579 Homo sapiens Zinc finger and BTB domain-containing protein 22 Proteins 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 240000005373 Panax quinquefolius Species 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 102100021131 Zinc finger and BTB domain-containing protein 22 Human genes 0.000 description 1
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- 238000010336 energy treatment Methods 0.000 description 1
- HQFCOGRKGVGYBB-UHFFFAOYSA-N ethanol;nitric acid Chemical compound CCO.O[N+]([O-])=O HQFCOGRKGVGYBB-UHFFFAOYSA-N 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
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Abstract
The present invention provides tough cast iron and cast iron semi-finished products excellent in workability without heat treatment requiring massive heat energy and long time and a method of production enabling these to be efficiently produced, that is, cast iron of ingredients of white cast iron where particles of spheroidal graphite or flattened graphite are dispersed, cast iron where the ingredients of the white cast iron satisfy, by wt%, (%C)<=4.3-(%Si) DIVIDED 3 and C>=1.7% and where the particles of spheroidal graphite are dispersed at a density of 50 particles/mm<2> or more, or cast iron where the particles of flattened graphite have a width of 0.4 mm or less and a length of 50 mm or less.
Description
Technical field
The present invention relates to cast iron, cast iron sheet and the manufacture method thereof of excellent in workability.
Background technology
As tough cast iron, spheroidization of graphite agent such as adding Mg, Ca, Ce are arranged, carry out that resulting spheroidal graphite cast iron is handled in the graphite balling or the shape vermicular cast iron that contracts (コ Application パ Network ト バ one ミ キ ュ ラ cast iron) (following note is made C/V cast iron), in addition, also have casting by whitening that resulting white pig iron is heat-treated and the malleable iron that obtains etc.
In above-mentioned C/V cast iron, it is spherical that graphite does not reach, and exists with the graphite form of bulk of intermediate state etc.In addition, because the castibility of malleable iron is fine, and by heat-treating, will be the important materials that machinofacture is used therefore as steel excellent, the tough characteristic that is ductile.This malleable iron can be divided into that white heart malleable cast iron, black heart malleable cast iron, have the cast iron of special material etc.
Wherein, in black heart malleable cast iron, if the malleable iron foundry goods does not add processing at the cast blank state, will present white structure, this tissue is not only hard but also crisp, therefore carries out the graphitization processing that is realized by annealing in this manufacturing process.
This annealing conditions will usually be determined its time and temperature according to a lot of other castings, but this annealing generally includes the twice annealing operation.This is annealed for the first time under 900～980 ℃ temperature, needs 10 to 20 hours, and the free cementite decomposes fully in this processing; Combination is carried out turning to the slow cooling in 700～760 ℃ temperature range of purpose and making the graphited long time treatment in 700～730 ℃ scope of cementite in the perlite with direct graphite in annealing for the second time.Like this, the needed time of whole annealing operation was generally about 20～100 hours, to this record to some extent in 1982 editions p115～116 of Japanese iron and steel institute " powder metallurgy is forged in the casting of the 3rd edition iron steel brief guide V volume ".
Spheroidal graphite cast iron and malleable iron have pressure rolling to a certain degree, extend by making the casting sheet after the casting, make the rolling cast iron of cast iron slab or cast iron thin plate, cast iron bar etc., can expect being suitable for to various uses.Yet, but the condition of these cast iron pressure rollings is narrow, and it is suitable for and only rests on limited purposes.
In addition, as the method for the casting sheet that obtains to become the raw material that pressure rolling uses, thereby normally used be that the casting fused solution obtains the casting of casting sheet in casting molds such as sand mold, but in order to improve productivity situation about casting continuously is arranged also.
But, in the method for above-mentioned document, because graphitization processing needs for a long time in the malleable iron foundry goods, therefore its productivity significantly worsens, in addition owing to produce surface oxidation, decarburization by heating for a long time, therefore in order to suppress surface oxidation and decarburization the necessity that heats is just arranged in non-oxide atmosphere gas, thereby have the problem that further increases processing costs.And then, no matter anneal cycles normally whether, the graphite of separating out after the processing can nodularization.Therefore, can not be referred to as to have the graphitization processing of the characteristic that can satisfy fully.Especially aspect intensity, pressure rolling sexual balance or fatigue strength, compare the superiority that has not a particle of as malleable iron, thereby wish further to improve from these characteristic aspects with common grey cast iron.
Relative therewith, open the spy and to have showed in the flat 7-138636 communique that the short period of time carries out graphited treatment process, but the graphite of separating out after handling does not have complete balling.In addition, in rolling spheroidal graphite cast iron or the resulting rolling cast iron of malleable iron, because graphite forms laminar and layered distribution when rolling, so its processibility will worsen.
And then, in the continuous casting of plain cast iron for the purpose that prevents chill generation etc., used the mold of graphite, but because white cast iron solid-liquid coexisting region is bigger, therefore be difficult to continuous casting, shown in No. 4074747 communique of United States Patent (USP), except seldom a part of, carry out this operation hardly like that.
In addition, manufacture method as tough thin plate cast iron plate, we have also considered shown in No. 3130670 communique of Japanese Patent, be by twin-roll caster and carry out whitening casting lamellarly, it is heat-treated, thereby produce the thin plate cast iron plate that forms by malleable iron, but this situation is identical with the situation that malleable iron is made, because form blocky graphite, the balling of graphite is insufficient, therefore has the insufficient such problem points of processibility.
Summary of the invention
The present invention is conceived to such problem and invents, its purpose be to provide a kind of need not carry out need be very big heat energy and thermal treatment for a long time, the tough cast iron of excellent in workability, cast iron casting sheet and can make their manufacture method efficiently.In addition, said cast iron, casting sheet comprise cast iron itself among the present invention, by band casting resulting as cast condition cast iron sheets such as (strip costing), and rolling these cast irons or the resulting rolling cast iron sheet of cast iron sheet.Its main idea is as described below:
(1) a kind of cast iron sheet, it is by the formed cast iron of the constituent class that forms white cast iron, it is characterized in that, within it portion, disperse to have spherical independent or compoundly or extend shape graphite, described spherical or extend shape graphite outside surface a part or all covered by ferrite.
As the cast iron sheet of (1) described excellent in workability, it is characterized in that (2) globular graphite or extension shape graphite are separated into 50/mm
2Or more than it.
As the cast iron sheet of (1) described excellent in workability, it is characterized in that (3) width of globular graphite or extension shape graphite is at 0.4mm or below it, length is at 50mm or below it.
As the cast iron sheet of (1) described excellent in workability, it is characterized in that (4) it is 70% or more than it that ferritic in the cast iron occupies ratio.
(5) as the cast iron sheet of any described excellent in workability of (1)～(4), it is characterized in that, form the composition of white cast iron, is the composition in satisfied (the %C)≤4.3-of quality % (%Si) ÷ 3, C 〉=1.7%.
(6) as the cast iron sheet of (5) described excellent in workability, it is characterized in that,, further contain any a kind or more than it of Cr 〉=0.1 quality %, Ni 〉=0.1 quality % as the composition of cast iron.
(7) as the cast iron sheet of any described excellent in workability of (1)～(4), it is characterized in that, spherical or extend shape graphite, with a kind of the particulate that contains Mg, Ca or REM a kind or oxide compound, sulfide, nitride or their complex chemical compound more than it or mutually compound more than it.
As the cast iron sheet of (7) described excellent in workability, it is characterized in that (8) above-mentioned oxide compound, sulfide, nitride or their complex chemical compound a kind or its above particulate diameter are 0.05～5 μ m.
(9) as the cast iron sheet of any described excellent in workability of (1)～(4), it is characterized in that above-mentioned white cast iron sheet is thin plate cast iron, slab cast iron, strip cast iron.
As the cast iron sheet of (9) described excellent in workability, it is characterized in that (10) thickness of above-mentioned cast iron sheet is 1～400mm.
(11) a kind of manufacture method of cast iron sheet of excellent in workability, wherein, the molten iron of the composition that is made of white cast iron of nodulizing agent has been added in casting, then resulting casting sheet is rolled.
As the manufacture method of the cast iron sheet of (11) described excellent in workability, it is characterized in that (12) above-mentioned nodulizing agent contains Mg, Ca or REM a kind or more than it.
(13) a kind of manufacture method of cast iron sheet of excellent in workability is characterized in that, will be by the further heat treated of (11) resulting rolling casting sheet.
Description of drawings
Fig. 1 relates to the metal structure photo of the sheet of embodiments of the invention.Fig. 1 (a) is the metal structure photo that shows the tissue of example No.1a, and Fig. 1 (b) is the metal structure photo that shows the tissue of example No.1b, and Fig. 1 (c) is the metal structure photo that shows the tissue of comparative example No.1.
Fig. 2 relates to the enlarged photograph of the graphite in the sheet of embodiments of the invention, and Fig. 2 (a) is the enlarged photograph of the graphite of example No.1a, and Fig. 2 (b) is the enlarged photograph of the graphite of example No.1b.
Fig. 3 relates to the metal structure photo after the nitric acid ethanol corrosion of sheet of embodiments of the invention, Fig. 3 (a) is the photo that shows the metal structure of example No.1a, Fig. 3 (b) is the photo that shows the metal structure of example No.1b, and Fig. 3 (c) is the photo that shows the metal structure of example No.2b.
Fig. 4 is the figure that shows the continuous casting machine that relates to embodiments of the invention.
Embodiment
Present inventors' latest find, the molten iron that has added the white cast iron composition of nodulizing agent by casting forms the casting sheet, carried out heat treated after rolling should casting sheet, and can make through rolling cast iron and be the nodular cast iron that is dispersed with the excellent in workability of globular graphite.
Specifically, in the tissue of following such casting sheet, do not observe graphite, described casting sheet is to add nodulizing agent in the molten iron of the cast iron of white cast iron composition, and casting resulting then only is casting and without the casting sheet of other processing.Next, in the tissue of the cast iron that with lower temperature this casting sheet is carried out hot rolling, obtains to carry out heat treated then, observed the globular graphite tissue than higher temperature.If this cast iron is carried out bending machining, it is very excellent to judge processibility.Part or all of the outside surface of the globular graphite in this cast iron covered by ferrite, and it is good to judge the more cast iron processibility of this ferritic phase (Off worker ラ イ ト phase).Above result is the same in the cast iron of the different shape of thin plate, slab, strip etc.
In addition, latest find, not under the situation of cast iron of spherical, as to be dispersed with extension graphite at above-mentioned stone mill, obtained good processibility, and then become weakening and the good goods of noise reduction, make the casting sheet by the fused solution that has added nodulizing agent in the molten iron that is cast in the white cast iron composition, and this casting sheet is rolled, can make the cast iron of the graphite that is dispersed with extension.
Particularly, in the fused solution of the cast iron that nodulizing agent is added to the white cast iron composition, cast then resulting, only cast and be to do in the tissue of casting sheet of cast iron of other processing, do not observe graphite.Then, carry out with comparatively high temps having observed the tissue of the graphite that is dispersed with extension in the tissue of the resulting cast iron of hot rolling will casting sheet, can judge, if this cast iron is carried out bending machining, then be easy to process, and then weakening and noise reduction are good.Part or all of the outside surface of the graphite of the extension in this cast iron covered by ferrite, judges the many cast iron excellent processabilities of this ferritic phase.Above result is same in the cast iron of different shapes such as thin plate, slab, strip.
In course of hot rolling, interrupted in the tissue of the rolling casting sheet of hot rolled, observed globular graphite and with the graphite of its flattening, having confirmed at rolling and graphite viewed extension on the cast iron plate that obtains, is that the globular graphite of separating out in the heating of casting sheet or when rolling extends to form by pressure rolling.
The present invention is based on these understanding and finishes.Below the present invention is described in detail.
At first, the cast iron that is dispersed with globular graphite in the cast iron of white cast iron composition of the present invention is in a large number described.Illustrating in passing, as cast iron as described above, is the cast iron after rolling, can exemplify thin plate cast iron, slab cast iron, strip cast iron etc.So-called strip cast iron refers to the section bar, sheet pile material of sections such as bar, wire rod, guide rail material or chevron, I shape, H shape etc.In addition, use casting mold wall and the synchronization-moving continuous casting machine of casting sheet, be not rolled and the cast iron that obtains also can be included in the thin plate cast iron.In technology in the past, there is not the cast iron that forms such proterties, by obtaining the cast iron of the such proterties of the present invention, can guarantee very good processibility.
Below, be that example describes with thin plate cast iron.
Above-mentioned thin plate cast iron plate is the cast iron that has added nodulizing agent in the molten iron of white cast iron composition to be cast make the casting sheet, and carries out heat treated obtain behind rolling this casting sheet.Detailed content for manufacture method is narrated in the back.
In globular graphite of the present invention, so-called spherical and do not mean that it must is the spheroid of standard, also can have concavo-convexly on the surface, also can partly have planar portions in addition.
Next the composition that forms white cast iron is described.C and Si are the most important elements that is used to obtain white cast iron, and graphited speed is had a significant impact.If C and Si, are preferably (%C)≤4.3-1.3 * (%Si), C 〉=1.7% in satisfied (the %C)≤4.3-of quality % (%Si) ÷ 3, C 〉=1.7%, just become white cast iron.Here, (C%) the quality % of the C in the expression white cast iron, (Si%) the quality % of the Si in the expression white cast iron.Because the amount less than 1.7 quality % of C just can't obtain white cast iron, therefore be made as 1.7 quality % or its above scope.
In addition, in order to ensure processibility, the individual number density that is preferably globular graphite is at 50/mm
2Or more than it.If the 50/mm of individual number density less than of globular graphite
2, processibility worsens slightly.
The size of this globular graphite does not have special stipulation, but mostly is usually by diameter of equivalent circle at 0.4mm or below it.
In addition, for guaranteeing processibility the ferrite content of the outside surface that covers graphite is increased, being preferably ferritic in the cast iron, to occupy ratio be 70% or its above (capacity benchmark), more preferably 80～90% or its above (capacity benchmark).Ferritic occupation ratio in the cast iron is fruit less than 70% (capacity benchmark) for example, and processibility reduces slightly.
Here, the ferritic ratio of occupying in the cast iron draws by the ferritic area occupation ratio of obtaining the cast iron section.In addition, above-mentioned area occupation ratio can wait by image analysis and obtain.
And then, as cast iron composition, preferably comprise Cr 〉=0.1 quality %, Ni 〉=0.1 quality % any one or its more than.This is because contain the generation that Cr or Ni can control the graphite when making.That is, Cr has the graphited effect when suppressing casting, and Ni has the graphited effect when promoting heat treated.But because if if the amount less than 0.1 quality % of Cr and Ni just is difficult to obtain this effect, so Cr, Ni amount are preferably 0.1 quality % or more than it.In addition, higher limit is not particularly limited, and consideration cost or desired processibility etc. are suitably set and got final product.
1 kind of the particulate of dispersive globular graphite and oxide compound, sulfide, nitride or their complex chemical compound of nodulizing agent element or mutually compound more than it.Here, so-called nodulizing agent refers to employed nodulizing agent Fe-Si-Mg, Fe-Si-Mg-Ca, Fe-Si-Mg-REM, Ni-Mg etc. in the manufacturing of nodular cast iron, but is not particularly limited.
If there is the nodulizing agent element, in cast iron, will produce oxygen in element and the iron in the nodulizing agent, sulphur, nitrogen chemical combination and the particle of the oxide compound, sulfide, nitride and their complex chemical compound that generate mutually, as nuclear, will separate out globular graphite during heat treated after rolling, generate and a kind of these particulate or compound globular graphite mutually more than it.
As the concrete element of nodulizing agent, consider preferred Mg, Ca, rare earth element (REM) from nodularization facilitation effect aspect.Wherein, especially Mg is more preferably because of its effect is good especially.Therefore, as nodulizing agent, preferably contain the material of Mg, Ca, rare earth element (REM).
Above-mentioned nodulizing agent is that any one of mixture of single-element or multiple element can be brought into play this effect.
Next, thin plate of the present invention is in the thin plate of the cast iron that is formed by the composition that forms white cast iron, is dispersed with a kind or its above particulate thin plate of oxide compound, sulfide, nitride or their complex chemical compound of nodulizing agent element.
Above-mentioned thin plate cast iron plate be will in the molten iron of white cast iron composition, add the iron casting of nodulizing agent become the casting sheet, to this casting sheet be rolled and obtain rolling after carry out thin plate cast iron plate before the heat treated.Details about manufacture method describes in the back.
Because this thin plate cast iron plate does not carry out heat treated, therefore do not separate out globular graphite.Thereby, become in the thin plate of the cast iron that forms by the composition that forms white cast iron, be dispersed with a kind or its above particulate state of oxide compound, sulfide, nitride or their complex chemical compound of nodulizing agent element.In addition, for the effect of the composition, nodulizing agent element, Cr and the Ni that form white cast iron etc., same as described above.
In addition, if these particulate number density less than 50/mm
2, the generation of the globular graphite during thermal treatment will become slowly slightly, and the density of the globular graphite of Sheng Chenging also reduces slightly simultaneously, and, because globular graphite becomes thick so damages processibility easily.Thereby a particulate number density is preferably 50/mm
2Or more than it.
And then if above-mentioned particulate diameter less than 0.05 μ m works as the nuclear of globular graphite with regard to being difficult to, if surpass 5 μ m, it is thick that the globular graphite of generation will become, and damages processibility easily, so the particulate diameter is preferably 0.05 μ m～5 μ m.Here, the meaning of so-called particulate diameter is the particulate diameter of equivalent circle.
And then, casting sheet of the present invention is identical with the thin plate of above-mentioned heat treated after not being rolled, be in the casting sheet of the cast iron that forms by the composition that forms white cast iron, be dispersed with a kind or its above particulate casting sheet of oxide compound, sulfide, nitride or their complex chemical compound of nodulizing agent element.
Above-mentioned casting sheet carries out castibility to the cast iron that has added nodulizing agent in the molten iron of white cast iron composition and becomes the casting sheet to obtain.About manufacture method, be described in detail in the back.For this casting sheet, also identical with the above-mentioned thin plate that does not carry out heat treated after rolling, do not separate out globular graphite.
Therefore, become in the thin plate of the cast iron that the composition by white cast iron forms, be dispersed with a kind or its above particulate state of oxide compound, sulfide, nitride or their complex chemical compound of nodulizing agent element.For the effect of the composition, nodulizing agent element, Cr and the Ni that form white cast iron etc., same as described above in addition.
The manufacturing of casting sheet, though ingot bar casting or continuous casting can, therefore the tendency of the more little easy more generation of speed of cooling when graphite has casting is preferably made by the continuous casting of having used the water-cooled copper mold.If because cast thickness increases in continuous casting, the speed of cooling at central part place will reduce, the thickness that therefore casts the casting sheet of gained continuously is preferably 1～400mm.
Specifically, if make with the bar strip continuous casting machine making under the situation of thin plate, just can obtain thickness and be the casting sheet about 30～120mm; And if then cast with the biobelt of the mobile casting mold that has used so-called band or roller, short band, the bitubular, a short tube casting machine, just can obtain thickness and be the casting sheet (perhaps be called thin plate also can) about 1～30mm.
Next, the manufacture method to casting sheet of the present invention describes.
At first, in the molten iron of white cast iron composition, add nodulizing agent and carry out melting.Here, the white cast iron composition as previously mentioned.In addition, if the nodulizing agent that adds preferably uses Mg, Ca or REM a kind or more than it, then can promote nodularization aspect tell on.The interpolation of nodulizing agent waits with casting ladle or tundish usually to be carried out.In addition, the addition of nodulizing agent so long as can make the thin plate of the finished product guarantee that the amount of good processibility gets final product, does not have special stipulation, suits to set by pretesting to get final product, but is about 0.02 quality % with respect to molten iron usually.
And then with respect to molten iron, preferably add Cr 〉=0.1 quality %, Ni 〉=0.1 quality % any one or its more than.For the interpolation of Cr and Ni, also same as described above, wait with casting ladle or tundish usually and carry out.
By casting the molten iron after the melting in this wise, can obtain casting sheet of the present invention.Castmethod gets final product so long as have the method that can obtain the speed of cooling of white cast iron by casting on material all, does not have special stipulation.And then speed of cooling is also influenced by casting condition, therefore is not particularly limited, and is fit to as long as set.But, because the big words of speed of cooling just generate white cast iron easily, so preferred.
Therefore, when making this casting sheet, also can use common casting molds such as sand mold to cast, but, therefore preferably make with the bigger continuous casting machine of speed of cooling because graphite has the tendency of the more little easy more generation of speed of cooling.And then by using continuous casting machine, its productivity increases, can the qurer manufacturing.
In addition, in the present invention, at first only obtaining white cast iron and be organized as prerequisite by casting, this is because the graphite that primary crystal, eutectic generated when solidifying is thicker, thereby the cause that will stop this crystal to be separated out.And then, because in the graphite that when casting, is generated, according to the speed of cooling difference, the state of the generation of graphite changes, therefore will be created in inhomogeneous on the thickness direction on the size of graphite or number, near the possibility that particularly produces thick graphite the thickness central part will be very high.
In addition, if had graphite in the casting sheet, when rolling casting sheet was made iron plate, by rolling, graphite will form laminar, and therefore this laminar graphite can damage processibility etc. with layered distribution, therefore must make the casting sheet not generate graphite.
Relative therewith, the method according to this invention, by being cast in the molten iron of the nodulizing agent that has added elements such as containing Mg, Ca, REM in the molten iron, just can indigenous graphite in resulting casting sheet, there are oxygen in element and the iron in the above-mentioned nodulizing agent, sulphur, nitrogen chemical combination and the particle of the oxide compound, sulfide, nitride and their complex chemical compound that generate mutually dispersedly.
In addition, in the continuous casting of cast iron, normally used is the casting mold of graphite or refractory body, but speed of cooling is less like this, thereby generates graphite easily, and the growth of solidified shell is also relatively slower, so the casting of white cast iron is very difficult.
That is, white cast iron because in the continuous casting of common cast iron in the employed graphite casting mould carbon can be dissolved in the molten iron, so the loss of casting mold is very violent, can't cast for a long time; Perhaps because its solid-liquid coexisting region of white cast iron is bigger, therefore in graphite casting mould the intensity of solidified shell a little less than, splash easily, be difficult to cast.
Therefore, just speed of cooling can be increased, the generation of the graphite in the sheet can be prevented to cast by using the water-cooled copper mold, thus preferred.And then, by promoting the generation of solidified shell, can be for a long time, continuous casting stably, casting speed also can increase than the casting speed of the casting mold that uses graphite or refractory body, and productivity increases.
Graphite has the big more tendency that generates of being difficult to more of the speed of cooling in when casting.Thereby, in order not generate graphite, preferably use the big continuous casting machine of speed of cooling.Specifically, the preferred continuous casting machine that has used the common water-cooled copper casting mold that in the continuous casting of steel, is adopted that utilizes, more preferably bar strip continuous casting machine, perhaps casting mold wall and the synchronization-moving continuous casting machine of casting sheet.
The thickness of casting resulting casting sheet with the continuous casting machine of the slab that used the common water-cooled copper casting mold that is adopted in the continuous casting of steel or blank is about 120～400mm, the thickness of casting resulting casting sheet with the bar strip continuous casting machine is about 30～120mm, and then, cast and the thickness of the casting sheet that obtains (perhaps be called thin plate also can) is about 1～30mm with the biobelt of the mobile casting mold that has used so-called band or roller, short band, the bitubular, short tube casting machine.
In addition, under the situation of making bar-shaped product, also can use the continuous casting machine of the steel billet of section to cast with square or circle.The foursquare length of side of section or the circular diameter of the casting sheet of this moment are about 75～250mm.
In casting sheet, can not generate graphite as described above by method manufacturing of the present invention.Therefore, above-mentioned casting sheet carry out hot rolling, according to circumstances so the rate of compression (draught) of carrying out cold rolling the time can increase.
At this, when rolling, under the situation of making thin plate cast iron, heat with process furnace with continuous casting or by the casting sheet of die casting, perhaps, also when high temperature, it is taken out, carry out hot rolling and form the band steel with roughing mill and finishing mill, batch to coiled material by reeling machine then and form hot-rolled sheet, according to circumstances different, the hot-rolled sheet that will batch sometimes to web shaped (coil shape) launches to carry out pickling, and all then cold-rolling mills carry out cold rolling, batch again to the coiled material shape forms cold-reduced sheet, thereby obtain thin plate cast iron.
In addition, under the situation of similarly making slab cast iron, to heat with process furnace by the casting sheet that continuous casting or mould etc. are cast, use heavy plate rolling machine repeat-rolling on length direction, width then as required, make the flat board of the size of regulation, cool off then and obtain slab cast iron.
And then, under the situation of making bar shaped cast iron, to heat with process furnace by the casting sheet that continuous casting or mould etc. are cast, be configured as the shape material of the section of bar-shaped, wire, guide rail shape or chevron, I shape, H shape etc. with roughing mill, intermediate rolling machine, the finishing mill of the hole shape roller of shape with regulation, cut into the length of regulation or batch and be the coiled material shape, thereby obtain strip cast iron.
In the cast iron after rolling, do not have indigenous graphite, keeping oxygen in the element that disperses to have in the above-mentioned nodulizing agent and the iron, sulphur, nitrogen chemical combination and the particulate state of the oxide compound, sulfide, nitride and their complex chemical compound that generate mutually.
And then, by to by rolling that obtain, do not generate graphite, keep the constant cast iron of state after rolling to carry out heat treated generating globular graphite, just can produce the nodular cast iron that does not have the distribution of laminar graphite laminate ground.
After rolling, carried out in the cast iron of heat treated, with the oxygen in the element in the dispersive nodulizing agent and the iron, sulphur, nitrogen chemical combination and the particle of the oxide compound, sulfide, nitride and their complex chemical compound that generate is a nuclear mutually, generate globular graphite by thermal treatment, therefore graphite disperses equably, and granule number is more thereby more small.Like this, disperse imperceptibly, just can obtain the cast iron of excellent in workability by making globular graphite.According to the thickness or the material of desired goods, can suitably select hot rolling and cold rolling.
If under the situation that does not have the nodulizing agent element, even carry out heat treated after rolling, graphite can not become globular graphite yet, but becomes bulk or roll into a ball cotton-shaped graphite, and greying also needs for a long time.Relative therewith, can carry out globular graphiteization with the heat treated of short period of time.
In addition, explanation in the above be that heat treated keeps state after rolling not do the method for the cast iron of other processing, but for example cast and obtain with the biobelt of the mobile casting mold that has used so-called band or roller, short band, the bitubular, short tube casting machine, thickness is in the casting sheet (perhaps become thin plate also can) about 1～30mm, can be not rolling under the situation that does not have rolling necessity and carry out heat treated yet.
In the time of hot rolled, if rolling temperature surpasses 900 ℃, just cause the generation of graphite easily, therefore be preferably 900 ℃ or below it.By rolling temperature being controlled at 900 ℃ or below it, just can obtain not generating in the plate after rolling the cast iron of graphite more definitely.In addition, for the heating before rolling too,, just cause the generation of graphite easily, therefore be preferably 900 ℃ or below it if Heating temperature surpasses 900 ℃.
Next, the heat treated temperature behind cast iron rolling is described.The heat treated here, its purpose is to promote globular graphiteization, if the heat treated temperature at 900 ℃ or below it, globular graphiteization will need for a long time, and is therefore preferred above 900 ℃.Yet though the upper limit of heat treated temperature does not have special stipulation, if surpass 1150 ℃, its intensity just descends, and heat treated distortion (deformity) just increases easily, therefore preferably at 1150 ℃ or carry out heat treated below it.
And then, the heat treated time behind cast iron rolling is described.In the present invention,, therefore can carry out the globular graphiteization in the short period of time, have the heating that surpasses 60 minutes, the situation that graphite will increase owing to be added with nodulizing agent.Under the situation that has such danger,, be preferably 60 minutes or below it as the heat treated time after rolling.The method according to this invention even carried out 60 minutes or the heat treated below it, also can obtain small graphite dispersive cast iron equably.
The part of the outside surface of the graphite after the heat treated of the cast iron after in the present invention, rolling or casting sheet of thinner thickness etc. or all covered by ferrite.If the speed of cooling after the above-mentioned heat treated is very fast, before forming ferrite fully, just to cool off, ferritic amount will reduce.
Thereby, in order to increase the ferritic ratio in the cast iron, importantly guarantee to be used for time of changing to ferrite, preferably temporarily remain on 730～650 ℃ in the process of cooling after above-mentioned heat treated, for example preferably keep about 30 minutes～1 hour.In addition, as other method, in above-mentioned process of cooling, preferably slowly cool off during from 730 ℃ to 300 ℃, this speed of cooling preferably is made as 10 ℃/min or its following speed of cooling.And then, also can all carry out two aspects.
If surpass 730 ℃, ferrite just is difficult to stable existence; If, just be difficult to generate ferrite in addition less than 300 ℃.In addition, if surpass the speed of cooling of 10 ℃/min, ferritic amount just reduces easily.
Next, team's cast iron of being dispersed with the graphite of extension in the cast iron of the composition of white cast iron of the present invention in a large number describes.
The graphite that a large amount of dispersive extend, because globular graphite extends to form because of rolling, so graphite and ferritic interface be slick, each is self-existent naturally.
In the prior art, there is not the technology that forms such proterties, by obtaining cast iron, can guarantees good processibility, and then can guarantee good damping property and noise reduction as proterties of the present invention.
If thickization of graphite of extending will be damaged processibility, so the preferred 0.4mm of the width of graphite or below it, the preferred 50mm of length or below it.
Because therefore the part of the excircle of the graphite of the extension in this cast iron or all covered by ferrite can further improve processibility.In addition, for guaranteeing processibility, the ferrite content of the outside surface that covers graphite is increased, the shared ratio of the ferrite in the cast iron is preferably 70% or its above (capacity benchmark), and more preferably 80～90% or its above (capacity benchmark).If the shared ratio of the ferrite in the cast iron is less than 70% (capacity benchmark), processibility will reduce slightly.Here, the ferritic ratio of occupying in the cast iron draws by the ferritic area occupation ratio of obtaining the cast iron section.In addition, above-mentioned area occupation ratio can wait by image analysis and obtain.
In the prior art, there is not the technology that forms such proterties,, can guarantees good processibility by obtaining cast iron as proterties of the present invention.
Above-mentioned cast iron is that the fused solution that will add nodulizing agent in the molten iron of white cast iron composition is cast as the casting sheet, will cast the sheet hot rolling again and obtain.Details for manufacture method describes in the back.
In addition, form the composition of white cast iron, satisfy the composition of following condition in quality %: (%C)≤4.3-(%Si) ÷ 3, C 〉=1.7%, be preferably (%C)≤4.3-1.3 * (%Si), C 〉=1.7%, this point is identical with record content in the nodular cast iron.
And then, as cast iron composition, preferably containing any a kind or more than it of Cr 〉=0.1 quality %, Ni 〉=0.1 quality %, this point is also identical with record content in the nodular cast iron.
1 kind of the particulate of the graphite of the extension that is scattered here and there and the oxide compound of nodulizing agent, sulfide, nitride or their complex chemical compound or mutually compound more than it.Here, so-called nodulizing agent refers to employed nodulizing agent Fe-Si-Mg, Fe-Si-Mg-Ca, Fe-Si-Mg-REM, Ni-Mg etc. in the manufacturing of nodular cast iron, but is not particularly limited.
If there is the nodulizing agent element, in cast iron, will produce oxygen in element and the iron in the nodulizing agent, sulphur, nitrogen chemical combination and the particle of the oxide compound, sulfide, nitride and their complex chemical compound that generate mutually, as nuclear, heating before rolling, indigenous graphite when rolling, generate and a kind of these particulate or compound graphite mutually more than it, such and particle compound graphite mutually are extended in rolling.
As the concrete element of nodulizing agent, from the preferred Mg in nodularization facilitation effect aspect, Ca, rare earth element (REM).Wherein, because this effect of Mg is good especially thereby be more preferably.Thereby,, preferably contain the material of Mg, Ca, rare earth element (REM) as nodulizing agent.
Above-mentioned nodulizing agent is that any one of mixture of single-element or multiple element can be brought into play this effect.
In addition, for the casting fused solution and the proterties of the casting sheet that obtains, the manufacture method of casting sheet, also the situation with the cast iron that is dispersed with globular graphite is identical in the situation of the cast iron of the graphite that is dispersed with extension.
In casting sheet made according to the method for the present invention, though do not generate graphite as mentioned above, will generate graphite by heating before suitably being rolled and the heating when rolling, but therefore can make it to have the intensity of pressure rolling, make hot rolling become possibility, can make various cast irons.
Promptly, because in the time of heating, hot rolled, with the oxygen in the element in the dispersive nodulizing agent and the iron, sulphur, nitrogen chemical combination and the particle of the oxide compound, sulfide, nitride and their complex chemical compound that generate is a nuclear mutually, generate globular graphite, so it is graphite disperses equably, amounts of particles is more, therefore more small.Like this, because globular graphite is disperseed imperceptibly, therefore can carry out hot rolling at an easy rate.
And then, being dispersed with the graphite that has extended in the cast iron after rolling, they are that not get in touch ground self-existent.In addition, graphite and ferritic interface are slick.Disperse by the graphite that makes extension like this, can obtain the cast iron of excellent in workability.Can suitably select thereafter cold rolling according to the thickness of required goods and material.
If under the non-existent situation of nodulizing agent element, graphite can not form globular graphite when rolling, but become bulk or roll into a ball cotton-shaped graphite, on graphite that has extended and ferritic interface, will produce concavo-convexly when rolling or form mesh-shape, therefore will generate in the time of hot rolled and break, the processibility of milled sheet etc. will suffer damage.
In the time of hot rolled, Heating temperature and rolling temperature are under 900 ℃ or the situation below it before rolling, and the generation of graphite will be difficult to take place, and therefore is preferably above 900 ℃.Make rolling before heating or rolling temperature surpass 900 ℃, rolling before the just generation easily of generation of graphite during heating or when rolling, the graphite that can obtain extending is dispersive cast iron imperceptibly.Here, rolling before the preferred higher limit of Heating temperature and rolling temperature do not have special stipulation, as long as suitably set, but common at iron 1150 ℃ of fusing points or carry out below it.
Extension in this cast iron graphite periphery a part or all covered by ferrite, so processibility further increases.In addition, for guaranteeing processibility, the ferrite content of the outside surface that covers graphite is increased, as described above, the ferritic area occupation ratio of section is preferably 70% or more than it.
If the speed of cooling after the hot rolling is too fast, will before fully forming ferrite, just cool off, ferrite content will reduce.Thereby, in order to increase the ferritic ratio in the cast iron, importantly guarantee after hot rolling, to be used for time of changing to ferrite, preferably temporarily remain on 730～650 ℃ in the process of cooling after above-mentioned heat treated, for example preferably keep about 30 minutes～1 hour.In addition, as other method, in above-mentioned process of cooling, preferably slowly cooling during 730 ℃ to 300 ℃, this speed of cooling preferably is made as the following speed of cooling of 10 ℃/min or its.And then, also can all carry out two aspects.
If surpass 730 ℃, ferrite just is difficult to stable existence; If, just be difficult to generate ferrite in addition less than 300 ℃.In addition, if surpass the speed of cooling of 10 ℃/min, ferritic amount just reduces easily.
At the cast iron after the hot rolling is under the situation of thin plate, also can batch to be the coiled material shape, and increase in order to make ferrite content this time, because can slowly cool off by being taken as the wire rod shape at 750～550 ℃ temperature last volume, so preferred.The speed of cooling of this situation can be made as 10 ℃/min or below it usually.
If surpass 750 ℃, batch again in rolling end and just to be easy to become difficulty, on the other hand, if batch during less than 550 ℃, ferrite content just reduces easily.
In addition, also can be further carry out cold rolling to the cast iron of the above-mentioned graphite that is dispersed with extension that obtains by hot rolling like that as required.
Because the graphite that extends absorbs vibration easily, therefore can make the cast iron of comparing damping property and noise reduction excellence with nodular cast iron.
Embodiment
(embodiment 1)
The cast iron of the chemical ingredients shown in the table 1 is melted in smelting furnace, add after the nodulizing agent, the square metal block of casting 100mm.This white cast iron of team carries out hot rolling and forms the thick hot-rolled sheet of 3.5mm.And then on the hot-rolled sheet of a part, carry out cold rolling and become the thick cold-reduced sheet of 1.2mm.The part of resulting hot-rolled sheet of rolling white cast iron and cold-reduced sheet is carried out heat treated in process furnace.After heating finishes, through the temperature course cool to room temperature of regulation.
On the other hand, in comparative example, use the example of technology in the past.Specifically, cast, carry out the hot rolling of resulting casting sheet at the nodular cast iron molten iron that comparative example 1 squadron is common.In addition in comparative example 2, in the cast iron fused solution of white cast iron constituent class, do not add nodulizing agent and cast, carry out the hot rolling, cold rolling of resulting casting sheet, the heat treated after being rolled then.
Choose sample in the plate after resulting casting sheet, hot-rolled sheet, cold-reduced sheet and thermal treatment,, measure the number of precipitate in addition with SEM with the composition of SEM-EDX mensuration precipitate.And then, with form, the number of light microscope determining graphite, with nital corrosion sheet metal structure is revealed simultaneously, use observation by light microscope, measure ferritic area occupation ratio (being designated as the ferrite rate sometimes).With these as a result summary sheet be shown in table 2, the table 3.Embodiment No.1a～No.17a is in the thin plate of the cast iron that is grouped into by the one-tenth that forms white cast iron, is dispersed with the embodiment of the situation of globular graphite; Embodiment No.1b～No.17b is in the thin plate of the cast iron that is grouped into by the one-tenth that forms white cast iron, is dispersed with the embodiment of situation of the graphite of extension.
According to the result of top embodiment as can be known, in example, can make the cast iron thin plate of the graphite that is dispersed with fine globular graphite or extension.Even these cast iron thin plates can bending machining can not processed with breaking yet.Particularly, the ferrite rate be 60% or its above cast iron thin plate can guarantee processibility, the ferrite rate is 70% or its above cast iron thin plate excellent in workability.
On the other hand, the fracture of limit portion has taken place in comparative example 1 when hot rolling, and the shape of plate becomes bad, will rupture if resulting plate carries out bending machining.Fracture has taken place in comparative example 2 when bending machining.
In addition, the example of the metal structure photo of expression test specimen in Fig. 1, Fig. 1 (a) is example No.1a, and Fig. 1 (b) is example No.1b, and Fig. 1 (c) is the metal structure of comparative example No.1.According to Fig. 1, graphite is spherical in example No.1a, and graphite has extended in example No.1b.Relative therewith, in comparative example No.1, graphite forms laminar, layeredly exists.
And then Fig. 2 represents the example of enlarged photograph of the graphite of example.Fig. 2 (a) is the globular graphite of No.1a, and Fig. 2 (b) is the extension graphite of No.1b.Near the center of graphite, have inclusion particle, generate graphite as nuclear.In addition, confirmed that by SEM near the inclusion particle the center of graphite is Mg-O-S.
In addition, Fig. 3 represents the example with the metal structure photo after the nital corrosion of test specimen, and Fig. 3 (a) is example No.1a, and Fig. 3 (b) is example No.1b, and Fig. 3 (c) is the metal structure of embodiment 2b.According to Fig. 3, in example No.1a, be globular graphite around almost all covered by ferrite, in the example No.1b, almost all being covered around the graphite that has extended by ferrite.Relative with these, ferritic area occupation ratio is very low in embodiment 2b, mix the graphite have extension around all by the part around the graphite of particle that ferrite covered and extension by particle that ferrite covered.But, all covered around any one graphite by ferrite, guaranteed processibility.
(embodiment 2)
In the molten cast iron of C:3.4 quality %, Si:0.3 quality %, add the nodulizing agent of Ni-Mg, Mg:0.03 quality %, by tundish, usefulness has used the continuous casting machine of the vertical shape of water-cooled copper casting mold to cast the slab of thickness 200mm, width 1000mm continuously, makes the casting sheet then.The summary that in Fig. 4, shows continuous casting machine.
The part of this casting sheet is formed the thick hot-rolled sheet of 3mm 850 ℃ of following hot rollings.And then a part of hot-rolled sheet carries out the thick cold-reduced sheet of cold rolling formation 1mm.Use process furnace 1000 ℃ of times of heating 30 minutes down the hot-rolled sheet and the cold-reduced sheet that obtain like this.Heating finishes the back placement and is cooled to room temperature.Choose sample in the plate after resulting casting sheet, hot-rolled sheet, cold-reduced sheet and thermal treatment, the form and the distribution of investigation graphite.
Its result, in the plate before casting sheet and heat treated, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.On the other hand, all observe globular graphite on hot-rolled sheet, the cold-reduced sheet in the plate after heat treated.The number of this globular graphite is about 100/mm
2, fine and dispersion in large quantities.In addition, exist observed particle before heat treated in the inside of this globular graphite.
In addition, an other part of casting sheet is rolled into the thick hot-rolled sheet of 3mm under 950 ℃, under 600 ℃ temperature, batches rolling material shape.And then a part of hot-rolled sheet carries out the thick cold-reduced sheet of cold rolling one-tenth 1mm.In resulting casting sheet, hot-rolled sheet, cold-reduced sheet, choose sample, the form and the distribution of investigation graphite.
In the casting sheet, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.All observe the appearance of the graphite that is dispersed with extension in the plate after rolling on hot-rolled sheet, the cold-reduced sheet.The number of this globular graphite is about 100/mm
2, fine and dispersion in large quantities.In addition, exist observed particle in the casting sheet in the inside of this globular graphite.And then, being covered by ferrite around the graphite, ferritic area occupied rate is 98%.
(embodiment 3)
In the molten cast iron of C:2.4 quality %, Si:0.7 quality %, add the nodulizing agent of Ca-Si class, be taken as Ca:0.005 quality %, Si:1.0 quality %, by tundish, come the thin slab of cast thickness 50mm, width 900mm with the thin plate continuous casting machine that uses the water-cooled copper mold then.
The part of this casting sheet is rolled into the thick hot-rolled sheet of 3.5mm under 800 ℃, batches and be the coiled material shape.And then a part of hot-rolled sheet carries out the thick cold-reduced sheet of cold rolling formation 1.5mm.Use process furnace 1000 ℃ of times of heating 30 minutes down the hot-rolled sheet and the cold-reduced sheet that obtain like this.Heating finishes the back and is cooled to 300 ℃ with 1 ℃/minute speed of cooling from 700 ℃, places then and is cooled to room temperature.Choose sample in the plate after resulting casting sheet, hot-rolled sheet, cold-reduced sheet and thermal treatment, the form and the distribution of investigation graphite.
Its result, in the plate before casting sheet and heat treated, the oxide compound of having observed Ca and sulfide and they are the particle about compound 0.5～4 μ m mutually, but does not find graphite.On the other hand, all observe globular graphite on hot-rolled sheet, the cold-reduced sheet in the plate after heat treated.The number of this globular graphite is about 150/mm
2, fine and dispersion in large quantities.In addition, exist observed particle before heat treated in the inside of this globular graphite.And then, being covered by ferrite around the graphite, ferritic area occupied rate is 75%.
In addition, the other part of casting sheet is rolled into the hot-rolled sheet of 3.5mm under 1000 ℃, under 730 ℃ of coiling temperatures, batches rolling material shape.And then a part of hot-rolled sheet carries out the thick cold-reduced sheet of cold rolling formation 1.5mm.In resulting casting sheet, hot-rolled sheet, cold-reduced sheet, choose sample, the form and the distribution of investigation graphite.
In the casting sheet, the oxide compound of having observed Ca and sulfide and they are the particle about compound 0.5～4 μ m mutually, but does not find graphite.On hot-rolled sheet, cold-reduced sheet, all be dispersed with the graphite that has extended in the plate after rolling.The number of the graphite that this has extended is about 150/mm
2, fine and dispersion in large quantities.In addition, exist at observed particle in the casting sheet in the inside of this globular graphite.And then, being covered by ferrite around the graphite, ferritic area occupied rate is 95%.
(embodiment 4)
Add the nodulizing agent of REM class in the molten cast iron of C:3.0 quality %, Si:0.6 quality %, REM:0.01 quality % comes the plate of cast thickness 3mm then with the bitubular continuous casting machine of diameter 1000mm.The part of this plate is carried out the cold-reduced sheet of cold rolling formation 1.0mm.The plate of casting former state and cold-reduced sheet heats 45 minutes under 950 ℃ with process furnace times will be kept.Heating finishes placement and is cooled to room temperature.Choose sample in the plate after resulting casting sheet, hot-rolled sheet, cold-reduced sheet and thermal treatment, the form and the distribution of investigation graphite.
Its result, in the plate before casting sheet and heat treated, the oxide compound of having observed REM and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.On the other hand, on hot-rolled sheet, cold-reduced sheet, all observe globular graphite in the plate after heat treated.The number of this globular graphite is about 200/mm
2, fine and dispersion in large quantities.In addition, exist observed particle before heat treated in the inside of this globular graphite.
(embodiment 5)
In the molten cast iron of C:3.0 quality %, Si:0.6 quality %, add the nodulizing agent of REM class, REM:0.01 quality %, come the plate of cast thickness 3mm then with the bitubular continuous casting machine of tube diameter 1000mm, be rolled down to thickness 2.4mm with through type (in-line) roller mill.In addition, rolling temperature is made as 950 ℃.The part of this plate is carried out the cold-reduced sheet of cold rolling formation 1.0mm.From resulting hot-rolled sheet, cold-reduced sheet, choose sample, the form and the distribution of investigation graphite.
On hot-rolled sheet, cold-reduced sheet, all observe globular graphite.Fine and the dispersion in large quantities of this globular graphite.In addition, its size is width 0.01mm～0.3mm, length 0.02mm～30mm.And then the oxide compound of having observed REM in the inside of this graphite that has extended and sulfide and they are particle about compound 0.05～3 μ m mutually.
(embodiment 6)
In the molten cast iron of C:3.4 quality %, Si:0.3 quality %, add the nodulizing agent of Ni-Mg, Mg:0.03 quality %, by tundish, usefulness has used the continuous casting machine of the vertical shape of water-cooled copper mold to come the slab of cast thickness 250mm, width 1500mm, makes the casting sheet then.The summary that in Fig. 4, shows continuous casting machine.
The part of this casting sheet is rolled into the thick hot-rolled thick plank of 40mm under 850 ℃.Use process furnace 1000 ℃ of times of heating 30 minutes down the hot-rolled sheet that obtains like this.Heating finishes the back placement and is cooled to room temperature.Choose sample in the plate after resulting casting sheet, hot-rolled thick plank and heat treated, the form and the distribution of investigation graphite.
Its result, in the plate before casting sheet and heat treated, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.On the other hand, observed globular graphite in the plate after heat treated.The number of this globular graphite is about 180/mm
2, fine and dispersion in large quantities.In addition, exist observed particle before heat treated in the inside of this globular graphite.
In addition, the other part of casting sheet is rolled into the hot-rolled sheet of 40mm under 950 ℃.From resulting casting sheet, hot-rolled thick plank, choose sample, the form and the distribution of investigation graphite.
In the casting sheet, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.Observe the appearance of the graphite that is dispersed with extension in the plate after rolling.The number of the graphite that this has extended is about 180/mm
2, fine and dispersion in large quantities.In addition, exist at observed particle in the casting sheet in the inside of this globular graphite.
(embodiment 7)
In the molten cast iron of C:2.4 quality %, Si:1.0 quality %, add the nodulizing agent of Ni-Mg, Mg:0.03 quality %, pass through tundish then, continuous casting machine with the crooked shape of the arc radius 10.5m that uses the water-cooled copper casting mold casts the square baslled iron of thickness 160mm continuously, makes the casting sheet.
The part of this casting sheet is rolled into the bar of diameter 20mm under 850 ℃.Use process furnace 1000 ℃ of times of heating 30 minutes down the cast iron bar that obtains like this.Heating finishes the back placement and is cooled to room temperature.From the cast iron bar after resulting casting sheet, iron staff and the heat treated, choose sample, the form and the distribution of investigation graphite.
Its result, in the cast iron bar before casting sheet and heat treated, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.On the other hand, observed globular graphite in the bar after heat treated.The number of this globular graphite is about 180/mm
2, fine and dispersion in large quantities.In addition, exist observed particle before heat treated in the inside of this globular graphite.
In addition, the other part of casting sheet is rolled into the cast iron bar of diameter 15mm under 950 ℃.From resulting casting sheet, cast iron bar, choose sample, the form and the distribution of investigation graphite.
In the casting sheet, as described above, the oxide compound of having observed Mg and sulfide and they are the particle about compound 0.1～3 μ m mutually, but does not find graphite.In addition, in cast iron bar, observe the appearance of the graphite that is dispersed with extension.The number of the graphite that this has extended is about 180/mm
2, fine and dispersion in large quantities.In addition, exist observed particle in the casting sheet in the inside of this globular graphite.
Prospects for commercial application
According to rolling cast iron of the present invention, thin plate cast iron plate and manufacture method, need not carry out need to be very big heat energy and for a long time heat treatment, just can make rolling cast iron. Thus, can obtain cast iron slab, thin plate cast iron plate, strip cast iron of excellent in workability etc., can provide various goods with it, consuming little energy, CO can be provided2The steel that discharge less, carrying capacity of environment are low.
Claims (8)
1. excellent in workability cast iron sheet, it is characterized in that, it is by formed thin plate cast iron, slab cast iron or the strip cast iron after rolling of the composition that satisfies %C≤4.3-1.3 * %Si, C 〉=1.7% in quality %, and its thickness is 1～140mm, and portion disperses to have 50/m m independent or compoundly within it
2Or part or all extension shape graphite that extends to form by pressure rolling by globular graphite that ferrite covered or globular graphite of its above outside surface.
2. the cast iron sheet of excellent in workability as claimed in claim 1 is characterized in that, the width of described extension shape graphite is at 0.4mm or below it, and length is at 50m m or below it.
3. the cast iron sheet of excellent in workability as claimed in claim 1 is characterized in that, it is 70% or more than it that ferritic in the cast iron occupies ratio.
4. the cast iron sheet of excellent in workability as claimed in claim 1 is characterized in that, as the composition of cast iron, further contains any a kind or more than it of Cr 〉=0.1 quality %, Ni 〉=0.1 quality %.
5. as the cast iron sheet of any described excellent in workability of claim 1～3, it is characterized in that, spherical or extend shape graphite, with a kind of particulate as described below or mutually compound more than it, described particle is a kind or the particle of its above oxide compound, sulfide, nitride or their complex chemical compound that contains Mg, Ca or REM.
6. the cast iron sheet of excellent in workability as claimed in claim 5, it is characterized in that the described Mg of containing, Ca or REM a kind or its above oxide compound, sulfide, nitride or their complex chemical compound a kind or its above particulate diameter are 0.05～5 μ m.
7. manufacture method that is used to make the cast iron sheet of the described excellent in workability of claim 1, wherein, the molten iron of the composition that the white cast iron by satisfy %C≤4.3-1.3 * %Si, C 〉=1.7% in quality % that has added nodulizing agent is constituted casts continuously with the water-cooled Copper casting mould, and resulting casting sheet is rolled under the temperature more than 900 ℃, perhaps after being rolled under 750～900 ℃, carry out heat treated.
8. the manufacture method of the cast iron sheet of excellent in workability as claimed in claim 7 is characterized in that, above-mentioned nodulizing agent contains Mg, Ca or REM a kind or more than it.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP033201/2003 | 2003-02-12 | ||
| JP2003033201 | 2003-02-12 | ||
| JP203083/2003 | 2003-07-29 | ||
| JP2003203083 | 2003-07-29 | ||
| JP004357/2004 | 2004-01-09 | ||
| JP2004004357A JP4523776B2 (en) | 2003-02-12 | 2004-01-09 | Cast iron and manufacturing method thereof |
| PCT/JP2004/001386 WO2004072314A1 (en) | 2003-02-12 | 2004-02-10 | Cast iron billet excelling in workability and process for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1751134A CN1751134A (en) | 2006-03-22 |
| CN1751134B true CN1751134B (en) | 2010-09-08 |
Family
ID=36606011
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200480004132.6A Expired - Lifetime CN1751134B (en) | 2003-02-12 | 2004-02-10 | Cast iron billet excelling in workability and process for producing the same |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN1751134B (en) |
| ZA (1) | ZA200506151B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE534626C2 (en) * | 2009-09-08 | 2011-10-25 | Scania Cv Ab | Method for determining the compactness of a compact graphite iron |
| WO2017164382A1 (en) * | 2016-03-24 | 2017-09-28 | 日立金属株式会社 | Spherical graphite cast iron, cast article and automobile structural component comprising same, and method for manufacturing cast article comprising spherical graphite cast iron |
| CN112143956A (en) * | 2020-09-28 | 2020-12-29 | 昆明理工大学 | Preparation method of wear-resistant high-thermal-conductivity graphite white cast iron |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1104562A (en) * | 1993-12-30 | 1995-07-05 | 北京科技大学 | Process for rolling white iron blades of ball thrower |
-
2004
- 2004-02-10 CN CN200480004132.6A patent/CN1751134B/en not_active Expired - Lifetime
-
2005
- 2005-08-02 ZA ZA200506151A patent/ZA200506151B/en unknown
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1104562A (en) * | 1993-12-30 | 1995-07-05 | 北京科技大学 | Process for rolling white iron blades of ball thrower |
Non-Patent Citations (1)
| Title |
|---|
| 陈富茂,邓永良.大量流水生产球墨可锻铸铁.汽车科技 1.1985,(1),23-26. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1751134A (en) | 2006-03-22 |
| ZA200506151B (en) | 2006-04-26 |
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