EP0325810A1 - Procédé de préparation de fonte à graphite sphéroidal - Google Patents

Procédé de préparation de fonte à graphite sphéroidal Download PDF

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Publication number
EP0325810A1
EP0325810A1 EP88202753A EP88202753A EP0325810A1 EP 0325810 A1 EP0325810 A1 EP 0325810A1 EP 88202753 A EP88202753 A EP 88202753A EP 88202753 A EP88202753 A EP 88202753A EP 0325810 A1 EP0325810 A1 EP 0325810A1
Authority
EP
European Patent Office
Prior art keywords
cast iron
treatment
magnesium
melt
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP88202753A
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German (de)
English (en)
Inventor
Karl Josef Reifferscheid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Evonik Operations GmbH
Original Assignee
SKW Trostberg AG
Metallgesellschaft AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SKW Trostberg AG, Metallgesellschaft AG filed Critical SKW Trostberg AG
Publication of EP0325810A1 publication Critical patent/EP0325810A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/08—Making cast-iron alloys
    • C22C33/10—Making cast-iron alloys including procedures for adding magnesium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/10—Making spheroidal graphite cast-iron

Definitions

  • the invention relates to a method for producing spheroidal graphite iron by a two-stage treatment of a cast iron melt with elements inducing spheroidal graphite formation.
  • Magnesium oxide slags have a particularly disadvantageous effect as a segregation product in thick-walled castings, since they result in structural anomalies and thus considerably reduce the dynamic properties in the casting.
  • the reaction mentioned above results in the so-called re-sulfurization of the magnesium-treated iron, which has the consequence that the spheroidal graphite already formed as a result of the magnesium erosion in vermicular or lamellar graphite is transferred and thus the metallurgical treatment goal "spheroidal graphite" is missed.
  • a Replenishment of magnesium is usually not possible due to lower temperatures and also creates reaction products of the known type again.
  • the invention is therefore based on the object to largely prevent the formation of the magnesium reaction products mentioned in the starting melt or to produce them in such a finely dispersed form that there is no structural disturbance, and also to produce workpieces from cast iron with spheroidal graphite, the improved quality properties and have clean and smooth surfaces.
  • the cast iron melt is treated at relatively high temperatures of over 1450 ° C and, if possible, at 1500 ° C.
  • the first stage of the melt treatment with rare earth metals can still be carried out in the melting furnace at 1500 ° C.
  • the manual operation of “trickling” the SE metal into the pouring stream by means of a metering vessel when tapping the cast iron melt out of the furnace is common technical practice.
  • the tapping time is only a few seconds - e.g. 1000 kg of melt in 45 seconds - and the addition of the RE metal alloy is small compared to the amount of iron, it is difficult to evenly insert the RE metal into the pouring jet in the specified period reproducible.
  • the introduction of a fine-grained SE metal alloy via a vibrating trough results in an even distribution of the SE metal.
  • a preferred, particularly safe, reproducible and also inexpensive embodiment of the method of the invention is the introduction of the SE metal into the pouring stream in wire form.
  • a steel jacket envelops the core made of powdered SE metal.
  • the sheath wire is fed into the pouring stream by means of a wire feeder (automatic dosing device) and the required exact amount added is reliably achieved.
  • the control devices of the automatic metering system enable the treatment process to be checked afterwards, just as the automatic metering system reduces the risk of accidents and reduces the adverse effects on the operating personnel due to radiant heat.
  • the RE metal can also be introduced into the cast iron melt tapped into a treatment pan by means of immersion devices.
  • the amount of RE metal is based on the analytically determined initial levels of sulfur and oxygen in the melt. A small excess of the treatment metal is expediently used.
  • the treatment metal is advantageously used in the form of a master alloy based on ferrosilicon.
  • a master alloy based on ferrosilicon Preferably an SE metal alloy of the composition 45 to 90% by weight cerium 5 to 35% by weight Lanthanum rest other SE metals used.
  • the amount of treatment metal is added to the cast iron melt with the proviso that 10 to 150 ppm and preferably 20 to 60 ppm of ferrous metal remain in the finished cast iron.
  • the SE oxisulfides and / or SE sulfides formed by the pretreatment are globular in shape and their distribution in the matrix is intragranular and therefore does not have a negative effect on the static and dynamic properties of the material to be produced.
  • the finely dispersed particles generally have a particle size of 1 to 2 ⁇ . They act as nucleating agents for the crystallization of the graphite.
  • the phases are also so fine that when the cast iron melt treated in the first stage is experimentally filtered through a fine-pored ceramic filter which is usually used for the filtration of Mg-treated cast iron, the phases cannot be filtered out.
  • the use of an excess of treatment agent ensures that oxygen and sulfur are virtually completely removed from the melt. Therefore, in the subsequent magnesium treatment in the second stage, the formation of undesired reaction products of the magnesium, such as, in particular, MgS or MgO, is avoided and filtration of the treated cast iron melt is superfluous.
  • magnesium treatment is carried out in the second stage to form spheroidal graphite.
  • the Mg treatment of the second stage is carried out immediately after the first treatment stage, ie the cast iron which has been tapped into the treatment pan and pretreated with RE metal is immediately treated with magnesium.
  • the melt temperature is about 1470 to 1480 ° C.
  • the magnesium can be added to the melt as a magnesium metal, for example in wire form.
  • the wire can also be designed as a sheath wire, with a steel jacket encasing an inner core made of powdered treatment agent.
  • the core can consist of magnesium powder or a magnesium-containing alloy powder mixture. Such mixtures can contain, for example, powders of magnesium, iron, nickel, graphite and other components.
  • the Mg treatment of the second stage is also possible in the form of a lumpy master alloy, for example a master alloy based on ferrosilicon, copper or nickel.
  • Treatment with a nickel / magnesium master alloy, which is specifically heavier than the molten iron, is particularly advantageous.
  • a master alloy has, for example, the composition. 4 to 6% by weight magnesium 53 to 57% by weight nickel rest Iron.
  • the magnesium can also be added by pouring over the magnesium master alloy; in this case, the melt to be treated is poured onto the magnesium master alloy which is stored on the bottom of the treatment vessel and which is covered with a covering agent such as scrap iron.
  • the magnesium can also be added by another known introduction method, such as dipping, blowing or by means of "tundish". Magnesium-containing sheathed wires are preferably used in the method of the invention.
  • the respective treatment agent can be introduced into the melt in the respective stage in the same or different form. This means that one can combine immersion processes with pouring processes or wire treatment processes in the individual stages. However, in the process of the invention, the treatments are preferably carried out in both stages with sheathed wires.
  • the two-stage treatment of the cast iron melt is followed by an inoculation treatment known per se, advantageously with an inoculation alloy based on ferrosilicon.
  • the method of the invention has advantages.
  • the process of the invention enables the production of castings which are practically completely free of inclusions, have clean and smooth surfaces, have no structural anomalies and consequently also have improved dynamic quality properties, such as improved elongation at break, constriction at break, and fatigue strength.
  • the amount of magnesium added is also reduced, and melt filtration is also eliminated.
  • the method of the invention is particularly suitable for the production of cast iron from spheroidal graphite with a ferritic structure.
  • Characteristics for the toughness of the material with ferritic matrix e.g. B. GGG 40, are elongation at break and constriction at break.
  • elongation and contraction particularly with large wall thicknesses, depend on the design, size and distribution of spheroidal graphite in the ferritic iron matrix, on the ferrite grain size and the residual pearlite content.
  • Structural anomalies such as segregation, grain boundary deposits and non-metallic inclusions significantly reduce the material properties.
  • a base iron with the following composition (in% by weight) was melted at 1450 ° C from special pig iron and deep-drawn sheet metal scrap with the addition of electrode graphite as carburizing agent and lumpy FeSi 75 as a siliconizing agent in an acidic mains frequency induction furnace with a content of 3 t: C. Si Mn P Ti Cr 3.60 1.35 0.12 0.030 0.02 0.03 Cu Ni V Pb Sn S 0.02 0.01 0.01 0.002 0.002 0.010 a) In a comparative experiment, a partial amount of 1000 kg of the iron overheated to 1460 ° C.
  • this portion was poured into the casting jet 1 kg piece, commercially available silico mixed metal of the composition (in% by weight) 15.1% rare earth metals, 45.3% Si, 0.7% Al, 0.4% Ca, rest of iron added via a downpipe.
  • the subsequent Mg treatment was carried out using 1.4% by weight of a commercially available master alloy, containing 5.7% Mg, 2.1% Ca, 1.02% Al, 45.8% Si, balance Fe.
  • a base iron of the following composition (in% by weight) was melted from special pig iron and deep-drawn sheet metal scrap with the addition of electrode graphite as the carburizing agent and lumpy FeSi 75 as the siliciding agent in an acidic mains frequency induction furnace.
  • Example 2 The analytical and metallographic results of these experiments in Example 2 are shown in Table 2. From this it can be seen that a perfect graphite formation in a ferritic / pearlitic matrix was achieved with all three melts.
  • Table 3 contains the strength values determined on so-called proportional bars. It becomes clear that with a magnesium master alloy additive reduced from 0.70 to 0.55% by weight, even norm-compliant minimum values for the cast iron grade GGG 40 with increased yield strength and tensile strength are achieved, while with the single-stage melt a) the minimum value for elongation at break of a GG 40 has not been reached.
  • a base iron made of special pig iron, steel scrap and circuit material with the addition of electrode graphite as a carburizing agent and lumpy FeSi 50 as a siliciding agent was melted in an acidic supplied mains frequency induction furnace with a useful content of 6 t with the following initial analysis (in% by weight): C. Si Mn P Ti Cr Cu Ni S 3.70 2.10 0.20 0.040 0.025 0.030 0.020 0.01 0.016
  • a steel-sheathed sheath wire with an outer diameter of 5 mm was introduced into the pouring jet at a speed of 0.60 m / sec using a wire feed device.
  • the sheath wire contained a powdered SE metal alloy of the composition 32.0% by weight of SE, 38.0% by weight of Si, 0.9% by weight of Al, the rest iron, in an amount of 40 g per m of sheathed wire.
  • the temperature of the melt was determined to be 1480 ° C.
  • An analysis sample gave the following values (in% by weight) for C, Si and S: C. Si S 3.68 2.15 0.016
  • the subsequent magnesium treatment of the melt to produce spheroidal graphite cast iron was also carried out with a sheath wire of 9 mm outside diameter.
  • the steel-coated treatment wire contained 33 g / m of metallic magnesium powder and was introduced into the melt pretreated with RE metal alloy at a feed rate of 20 m / min. The introduction took 60 seconds, corresponding to a wire quantity of 20 m.
  • With a weight of the filled sheath wire of 225 g / m an addition of 4.5 kg sheath wire is calculated, corresponding to 0.75% by weight addition to the treated amount of iron of 600 kg.
  • an analysis sample gave the following values (in% by weight), which clearly show the success of the treatment: C. Mg S 3.63 0.053 0.008
  • the melt was partly cast into Y2 samples according to DIN 1693 and partly into castings, the inoculation of the samples and castings being carried out exclusively as a mold vaccination with 0.15% FeSi 70.
  • the metallographic examinations carried out on Y2 samples and castings in the cast state showed perfect graphite formation of over 90% spheroidal graphite in a ferritic matrix with 3 to 5% residual pearlite.
  • a metallurgical explanation for this is that the ceroxysulfides formed in the first treatment stage by the addition of the SE metal alloy are not influenced by the magnesium metal treatment and the formation of magnesium sulfide does not occur. Furthermore, the formation of complex reaction products such as MgOSiO2, MgOCaO, MgOAl2O3 in the second treatment stage is avoided due to the absence of silicon, calcium and aluminum in the treatment agent.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
EP88202753A 1988-01-23 1988-12-01 Procédé de préparation de fonte à graphite sphéroidal Withdrawn EP0325810A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3801917A DE3801917A1 (de) 1988-01-23 1988-01-23 Verfahren zur herstellung von gusseisen mit kugelgraphit
DE3801917 1988-01-23

Publications (1)

Publication Number Publication Date
EP0325810A1 true EP0325810A1 (fr) 1989-08-02

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EP88202753A Withdrawn EP0325810A1 (fr) 1988-01-23 1988-12-01 Procédé de préparation de fonte à graphite sphéroidal

Country Status (3)

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US (1) US4874576A (fr)
EP (1) EP0325810A1 (fr)
DE (1) DE3801917A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0439244A1 (fr) * 1990-01-16 1991-07-31 The International Meehanite Metal Company Limited Procédé de nodularisation
EP0524444A1 (fr) * 1991-07-20 1993-01-27 SKW Trostberg Aktiengesellschaft Agent pour le traitement de fontes
FR2701717A1 (fr) * 1993-02-17 1994-08-26 Peugeot Procédé d'élaboration de fonte grise pour traitement de refusion superficielle.
WO2001090425A1 (fr) * 2000-05-26 2001-11-29 Pechiney Electrometallurgie Procede de production de fonte a graphite spheroidal
DE10340994A1 (de) * 2003-09-05 2005-03-31 Mahle Ventiltrieb Gmbh Verfahren zur Herstellung eines hochlegierten Stahlgusswerkstoffes mit feiner Kornstruktur.
CN105364415A (zh) * 2015-11-20 2016-03-02 燕山大学 一种球墨铸铁表层石墨球细化的方法

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6024804A (en) * 1997-05-02 2000-02-15 Ohio Cast Products, Inc. Method of preparing high nodule malleable iron and its named product
US7081151B2 (en) * 1999-12-17 2006-07-25 Sintercast Ab Alloy and method for producing same
SE9904668D0 (sv) * 1999-12-17 1999-12-17 Sintercast Ab New alloy and method for producing same
US6508981B1 (en) * 2001-05-24 2003-01-21 Wescast Industries, Inc. High temperature oxidation resistant ductile iron
DE502005005681D1 (de) † 2004-11-12 2008-11-27 Winter Fritz Eisengiesserei Verfahren zum Herstellen von Kompaktgraphit aufweisendem Gusseisen
SE529445C2 (sv) * 2005-12-20 2007-08-14 Novacast Technologies Ab Process för framställning av kompaktgrafitjärn
MC200111A1 (fr) * 2007-12-05 2008-07-02 Luca Cattaneo Procédé de détersion de la fonte à l'état liquide
US7846381B2 (en) * 2008-01-29 2010-12-07 Aarrowcast, Inc. Ferritic ductile cast iron alloys having high carbon content, high silicon content, low nickel content and formed without annealing
CN103924148A (zh) * 2014-03-18 2014-07-16 中信重工机械股份有限公司 一种大断面低温球墨铸铁及其铸造方法
CN110814304B (zh) * 2019-12-03 2023-06-16 西安瑞森金属复合材料有限公司 蠕墨铸铁的生产方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3492118A (en) * 1966-05-24 1970-01-27 Foote Mineral Co Process for production of as-cast nodular iron
FR2323761A1 (fr) * 1975-09-11 1977-04-08 Int Nickel Ltd Alliages d'addition servant a introduire du magnesium dans un bain de fer ou d'alliage
FR2466507A2 (fr) * 1979-10-05 1981-04-10 Acetylene Electrometall Cie Un Perfectionnements au procede de preparation d'alliage ferreux permettant d'ameliorer notamment leurs proprietes mecaniques grace a l'emploi de lanthane et alliage ferreux obtenu par ce procede
DE3447244C1 (de) * 1984-12-22 1986-05-15 Walter Hundhausen GmbH & Co KG, 5840 Schwerte Verfahren zur Erzeugung von Gußeisen mit Kugelgraphit und Gußeisen mit Vermiculargraphit

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Publication number Priority date Publication date Assignee Title
GB718177A (en) * 1951-01-16 1954-11-10 British Cast Iron Res Ass Improvements in the production of cast iron
US2841490A (en) * 1952-02-27 1958-07-01 Int Nickel Co Method for making improved gray cast iron
JPS5112443B1 (fr) * 1965-12-13 1976-04-20
US3467167A (en) * 1966-09-19 1969-09-16 Kaiser Ind Corp Process for continuously casting oxidizable metals
US3955973A (en) * 1974-05-20 1976-05-11 Deere & Company Process of making nodular iron and after-treating alloy utilized therein
JPH06115910A (ja) * 1992-10-01 1994-04-26 Shikoku Chem Corp 熱安定性を改善した不溶性硫黄及びこれを用いたゴム組成物

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3492118A (en) * 1966-05-24 1970-01-27 Foote Mineral Co Process for production of as-cast nodular iron
FR2323761A1 (fr) * 1975-09-11 1977-04-08 Int Nickel Ltd Alliages d'addition servant a introduire du magnesium dans un bain de fer ou d'alliage
FR2466507A2 (fr) * 1979-10-05 1981-04-10 Acetylene Electrometall Cie Un Perfectionnements au procede de preparation d'alliage ferreux permettant d'ameliorer notamment leurs proprietes mecaniques grace a l'emploi de lanthane et alliage ferreux obtenu par ce procede
DE3447244C1 (de) * 1984-12-22 1986-05-15 Walter Hundhausen GmbH & Co KG, 5840 Schwerte Verfahren zur Erzeugung von Gußeisen mit Kugelgraphit und Gußeisen mit Vermiculargraphit

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
FOSECO, "Note Technique", Nr. 48, Seiten 1-17: "Fonte à graphite nodulaire" *
INDUSTRIAL APPLICATIONS OF RARE EARTH ELEMENTS, 180TH ACS NATIONAL MEETING, Las Vegas, Nevada, 25.-26. August 1980, Seiten 19-42, Herausgeber K.A. Gschneidner, Jr., American Chemical Society, Washington, D.C., US; H.F. LINEBARGER et al.: "The role of the rare earth elements in the production of nodular iron" *
PATENT ABSTRACTS OF JAPAN, Band 10, Nr. 161 (C-352)[2217], 10. Juni 1986; & JP-A-61 15 910 (KUSAKA REAMETARU KENKYUSHO K.K.) 24-01-1986 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0439244A1 (fr) * 1990-01-16 1991-07-31 The International Meehanite Metal Company Limited Procédé de nodularisation
EP0524444A1 (fr) * 1991-07-20 1993-01-27 SKW Trostberg Aktiengesellschaft Agent pour le traitement de fontes
FR2701717A1 (fr) * 1993-02-17 1994-08-26 Peugeot Procédé d'élaboration de fonte grise pour traitement de refusion superficielle.
EP0613956A1 (fr) * 1993-02-17 1994-09-07 Automobiles Peugeot Procédé d'élaboration de fonte grise pour traitement de refusion superficielle
WO2001090425A1 (fr) * 2000-05-26 2001-11-29 Pechiney Electrometallurgie Procede de production de fonte a graphite spheroidal
DE10340994A1 (de) * 2003-09-05 2005-03-31 Mahle Ventiltrieb Gmbh Verfahren zur Herstellung eines hochlegierten Stahlgusswerkstoffes mit feiner Kornstruktur.
CN105364415A (zh) * 2015-11-20 2016-03-02 燕山大学 一种球墨铸铁表层石墨球细化的方法

Also Published As

Publication number Publication date
DE3801917A1 (de) 1989-08-03
US4874576A (en) 1989-10-17

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