DK173273B1 - Magnesium treatment method and apparatus for exercising it - Google Patents

Magnesium treatment method and apparatus for exercising it Download PDF

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Publication number
DK173273B1
DK173273B1 DK199002768A DK276890A DK173273B1 DK 173273 B1 DK173273 B1 DK 173273B1 DK 199002768 A DK199002768 A DK 199002768A DK 276890 A DK276890 A DK 276890A DK 173273 B1 DK173273 B1 DK 173273B1
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DK
Denmark
Prior art keywords
magnesium
melt
treatment
process according
reaction
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DK199002768A
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Danish (da)
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DK276890A (en
DK276890D0 (en
Inventor
Ivo Henych
Original Assignee
Fischer Ag Georg
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Priority claimed from CH4258/89A external-priority patent/CH679987A5/de
Application filed by Fischer Ag Georg filed Critical Fischer Ag Georg
Publication of DK276890D0 publication Critical patent/DK276890D0/en
Publication of DK276890A publication Critical patent/DK276890A/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00Treatment of fused masses in the ladle or the supply runners before casting
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00Refining of pig-iron; Cast iron
    • C21C1/10Making spheroidal graphite cast-iron
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00Refining of pig-iron; Cast iron
    • C21C1/10Making spheroidal graphite cast-iron
    • C21C1/105Nodularising additive agents
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/08Making cast-iron alloys
    • C22C33/10Making cast-iron alloys including procedures for adding magnesium

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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)
  • Manufacture And Refinement Of Metals (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Description

i DK 173273 B1in DK 173273 B1

Den foreliggende opfindelse angår en magnesiumbehandlings fremgangsmåde til frembringelse af en behandlet smelte med mindre end 100 g/t umetalliske indeslutninger samt et apparat til udøvelse af denne fremgangsmåde.The present invention relates to a magnesium treatment method for producing a treated melt having less than 100 g / t of nonmetallic inclusions and an apparatus for practicing this method.

5 Ved behandlingen af en jernsmelte med magnesium med det formål at påvirke grafitmorfologien således, at der dannes kuglegrafit, fremkommer større mængder af umetalliske forbindelser, f.eks. oxider, sulphider og lignende. Denne effekt forårsages af den store affinitet hos magnesium til 10 oxygen og svovl.In the treatment of an iron melt with magnesium for the purpose of affecting the graphite morphology to form spherical graphite, greater amounts of unmetallic compounds, e.g. oxides, sulphides and the like. This effect is caused by the high affinity of magnesium to 10 oxygen and sulfur.

Den største del af de umetalliske reaktionsprodukter bliver allerede under behandlingen af jernsmelten eller i tidsrummet mellem behandlingens afslutning og udstøbningen udskilt som følge af massefyldeforskellen mellem slaggepar-15 tiklerne (ca. 3000 kg/m3) og smelten (ca. 7000 kg/m3). Det er imidlertid kendt, at en del af reaktionsprodukterne -partikler, som er mindre end 12,5 /im - også efter den sædvanlige til rådighed stående tid forekommer svævende i smelten.Most of the nonmetallic reaction products are already separated during the treatment of the iron melt or in the period between the end of the treatment and the casting due to the density difference between the slag particles (about 3000 kg / m3) and the melt (about 7000 kg / m3). However, it is known that some of the reaction products - particles smaller than 12.5 microns - also float in the melt after the usual time available.

Flotationshastigheden kan med forholdsvis god nøj ag-20 tighed bestemmes ved hjælp af Stoke's ligning: d2 x (6Fe - åslagge) x g x t x 10"9 L =* -—. ............... ~ " ----- 18 x μ 25 hvor: L « flotationshøjde i mm d * partikelstørrelse i μτη 5Fe « massefylde af jern i kg/m3 (7000) åslagge = massefylde af slagge i kg/m3 (3000) 30 t = flotationstid i sekunder μ = dynamisk viskositet (0,007)The rate of flotation can be determined with relatively good accuracy by using Stoke's equation: d2 x (6Fe - yoke) xgxtx 10 "9 L = * -—. ............... ~ "----- 18 x μ 25 where: L« flotation height in mm d * particle size in μτη 5Fe «density of iron in kg / m3 (7000) of slag = density of slag in kg / m3 (3000) 30 h = flotation time in seconds μ = dynamic viscosity (0.007)

De praktiske målinger viste, at ved de sædvanlige behandlingsmetoder ligger mængden af svævende partikler 35 mellem 200 og 600 g/t behandlet jern, hvilken så med støbestrålen indstøbes i den form, som skal udstøbes. Undersøgelserne viste ligeledes, at disse indeslutninger, som forbliver DK 173273 B1 2 i støbegodset, væsentlig kan formindske de dynamiske egenskaber af støbegodset.The practical measurements showed that in the usual treatment methods, the amount of floating particles 35 is between 200 and 600 g / h of treated iron, which is then cast with the casting jet in the form to be cast. The studies also showed that these inclusions, which remain DK 173273 B1 2 in the castings, can significantly diminish the dynamic properties of the castings.

For at muliggøre flotationen af reaktionsprodukterne må smelten henstå i længere tid i støbeskeen. Dette har 5 imidlertid betydelige, i regelen prohibitive, temperaturtab (6 til 15eC/min) til følge.In order to allow the flotation of the reaction products, the melt must remain in the mold for a longer period. However, this results in significant, generally prohibitive, temperature loss (6 to 15 ° C / min).

Anvendelse af den fra stålfremstillingen kendte fremgangsmåde med spuling af smelten med indifferent gas (N, Ar osv.) forårsager en stærk oxidering af magnesiummet, der 10 fører til dannelse af yderligere, nye indeslutninger, hvorfor det ønskede formål ikke kan opnås med denne fremgangsmåde.Use of the method known in steel making with flushing the melt with inert gas (N, Ar, etc.) causes a strong oxidation of the magnesium, which leads to the formation of additional new inclusions, and therefore the desired purpose cannot be achieved with this method.

Den foreliggende opfindelse har som formål at foreslå en fremgangsmåde og et apparat, med hvis hjælp behandlingsreaktionen kan styres således, at de umetalliske indeslut-15 ninger i den behandlede smelte reduceres til et minimum.The object of the present invention is to propose a method and apparatus with which the treatment reaction can be controlled so as to minimize the non-metallic inclusions in the treated melt.

Dette formål opnås ved at udøve den indledningsvis nævnte fremgangsmåde som angivet i den kendetegnende del af krav 1 og ved at indrette det indledningsvis nævnte apparat som angivet i den kendetegnende del af krav 9.This object is achieved by practicing the method mentioned in the preamble as set forth in the characterizing part of claim 1 and by arranging the device mentioned in the preamble as stated in the characterizing part of claim 9.

20 Yderligere foretrukne foranstaltninger i forbindelse med fremgangsmåden fremgår af de uselvstændige krav 2 til 8, mens yderligere foretrukne træk hos apparatet ifølge opfindelsen er angivet i de uselvstændige krav 10 til 12.Further preferred measures in connection with the method are set forth in the dependent claims 2 to 8, while further preferred features of the apparatus according to the invention are set forth in the dependent claims 10 to 12.

På grund af den kontrollerede spuling af smirelten i 25 en reducerende atmosfære over overfladen af jernsmelten allerede under magnesiumbehandlingen koagulerer de ved behandlingen frembragte reaktionsprodukter og transporteres ved hjælp af de opstigende magnesiumdampbobler som slagge til overfladen af smelten, og koagulationen af reaktionspro-30 dukterne bevirkes på grund af den frembragte dampmængde og ved hjælp af blandingsenergien. Erfaringerne viser, at intensiteten af koagulationen forstærkes væsentligt ved sammenstød af de umetalliske partikler på tidspunktet for deres dannelse, dvs. på stedet for reaktionen. Blandingsenergien kan 35 bestemmes ved hjælp af følgende ligning: DK 173273 B1 3Due to the controlled flushing of the smelt melt in a reducing atmosphere over the surface of the iron melt already during the magnesium treatment, the reaction products produced in the treatment coagulate and are transported by the ascending magnesium vapor bubbles as slag to the surface of the melt and the coagulation of the reaction products is effected. due to the amount of steam generated and by the mixing energy. Experience shows that the intensity of the coagulation is greatly enhanced by the collision of the unmetallic particles at the time of their formation, ie. at the site of the reaction. The mixing energy can be determined by the following equation: DK 173273 B1 3

6,2 x 10-3 x Q x T(1-273/T) x ln p/pO6.2 x 10-3 x Q x T (1-273 / T) x ln p / pO

E - --E - -

VV

hvor:where:

5 E = blandingsenergi i W/tn3 Q gasmængde i NI/min T = temperatur i °K5 E = mixing energy in W / tn3 Q gas quantity in NI / min T = temperature in ° K

pO *« tryk på overfladen af smelten i bar p * pO + ferrostatisk tryk i bar 10 V * volumen af smelten i m3pO * «pressure on the surface of the melt in bar p * pO + ferrostatic pressure in bar 10 V * volume of the melt in m3

De praktiske forsøg viste, at mængden af umetalliske indeslutninger i smelten kan reduceres til værdier under 100 g/t, når blandingsenergien er større end 1000 W/m3, 15 magnesiumdampene fremkommer i en dybde på mindst 200 mm under overfladen af smelten, og atmosfæren ovenover smelten er overmættet med magnesiumdamp.The practical tests showed that the amount of unmetallic inclusions in the melt can be reduced to values below 100 g / h when the mixing energy is greater than 1000 W / m3, the magnesium vapors appear at a depth of at least 200 mm below the surface of the melt, and the atmosphere above the melt is supersaturated with magnesium vapor.

Dette skal beskrives i det følgende ved hjælp af et eksempel.This will be described in the following by way of example.

2020

Eksempel:Example:

Pra en jernsmelte med legeringssammensætningen: C - 3,72%Pra an iron melt with the alloy composition: C - 3.72%

Si =» 2,3% 25 Mn - 0,27% S = 0,08% P » 0,05% blev efter en behandling med renmagnesium i en lukket behandlingsbeholder med en åbning på 30 cm2, hvor fire reak-30 tionsåbninger, som forbinder reaktionsrummet med smelten, har et samlet tværsnit på 1250 mm2, efter en reaktionstid på 60 sekunder udtaget en prøve. Analysen viste 3 ppm oxygen og 50 ppm svovl. Der blev beregnet en mængde på 20 g/t umetalliske indeslutninger. Den kvantitative metallografiske , 35 analyse viste en mængde af umetalliske indeslutninger på 23 g/t.Si = »2.3% 25 Mn - 0.27% S = 0.08% P» 0.05% became after a treatment with pure magnesium in a closed treatment vessel with an opening of 30 cm 2, with four reaction openings, which connects the reaction chamber to the melt, has a total cross section of 1250 mm 2, after a 60 second reaction time, a sample is taken. The analysis showed 3 ppm oxygen and 50 ppm sulfur. An amount of 20 g / t of nonmetallic inclusions was calculated. The quantitative metallographic analysis showed a quantity of unmetallic inclusions of 23 g / h.

Claims (12)

1. Magnesiumbehandlingsfremgangsmåde til frembringelse af en behandlet smelte med mindre end 100 g/t umetalliske indeslutninger, kendetegnet ved, at behandlings - 5 reaktionen med magnesiummet styres i en dybde af mindst 200 mm under overfladen af smelten således, at mængden af det fordampede magnesium frembringer en blandingsenergi på mindst 1000 W/m3, hvorhos der ovenover overfladen af smelten i behandlingsbeholderen er tilvejebragt en ikke-oxiderende 10 atmosfære.1. A magnesium treatment process for producing a treated melt with less than 100 g / t of nonmetallic inclusions, characterized in that the treatment reaction with the magnesium is controlled at a depth of at least 200 mm below the surface of the melt to produce the amount of the evaporated magnesium. a mixing energy of at least 1000 W / m 3, where a non-oxidizing atmosphere is provided above the surface of the melt in the treatment vessel. 2. Fremgangsmåde ifølge krav 1, kendeteg net ved, at der som behandlingsmiddel anvendes stykformigt renmagnesium.Process according to Claim 1, characterized in that the purified magnesium is used as a treatment agent. 3. Fremgangsmåde ifølge krav 1, kendete g- 15 net ved, at der som behandlingsmiddel anvendes magnesiumgranulat .3. A process according to claim 1, characterized in that magnesium granulate is used as the treatment agent. 4. Fremgangsmåde ifølge krav 1, kendeteg net ved, at der som behandlingsmiddel anvendes en blanding af renmagnesiumgranulat med et reaktionsneutralt materiale, 20 f.eks. jernspåner osv., med mindst 40 vægtprocent magnesium.Process according to claim 1, characterized in that a mixture of pure magnesium granulate with a reaction-neutral material, e.g. iron shavings, etc., containing at least 40% by weight of magnesium. 5. Fremgangsmåde ifølge ethvert af kravene l til 4, kendetegnet ved, at magnesiumudnyttelsen ikke ligger højere end ved 75 procent.Process according to any one of claims 1 to 4, characterized in that the magnesium utilization is not higher than at 75 percent. 6. Fremgangsmåde ifølge ethvert af kravene 1 til 5, 25 kendetegnet ved, at udgangssmelten har et svovlindhold mellem 0,001 og 0,30 vægtprocent.Process according to any one of claims 1 to 5, characterized in that the starting melt has a sulfur content between 0.001 and 0.30% by weight. 7. Fremgangsmåde ifølge ethvert af kravene 1 til 6, kendetegnet ved, at behandlingstemperaturen indstilles mellem 1400 og 1530°C.Process according to any one of claims 1 to 6, characterized in that the treatment temperature is adjusted between 1400 and 1530 ° C. 8. Fremgangsmåde ifølge ethvert af kravene 1 til 7, kendetegnet ved, at basiciteten af behandlingsslaggen ligger højere end l.Process according to any one of claims 1 to 7, characterized in that the basicity of the treatment slag is higher than 1. 9. Apparat til udøvelse af fremgangsmåden ifølge ethvert af kravene 1 til 8, kendetegnet ved, at 35 der er tilvejebragt en reaktionsbeholder, der har et fra - smelten adskilt reaktionsrum, som er forsynet med mindst to DK 173273 B1 åbninger, ved hjælp af hvilke forbindelsen mellem reaktionsrummet og smelten tilvejebringes.Apparatus for carrying out the method according to any one of claims 1 to 8, characterized in that a reaction vessel is provided which has a separated space of reaction, which is provided with at least two openings, by means of which the connection between the reaction chamber and the melt is provided. 10. Apparat ifølge krav 9, kendetegnet ved, at åbningerne har et samlet tværsnitsareal på mindst 5 500 mm^.Apparatus according to claim 9, characterized in that the openings have a total cross-sectional area of at least 5 500 mm 2. 11. Apparat ifølge krav 9, kendetegnet ved, at den øvers te åbning er anbragt mindst 200 mm under overfladen af smelten.Apparatus according to claim 9, characterized in that the upper opening of the upper part is arranged at least 200 mm below the surface of the melt. 12. Apparat ifølge krav 9, kendetegnet 10 ved, at reaktionsbeholderen i sin øvre del er forsynet med en åbning, som tilvejebringer en forbindelse med den omgivende atmosfære og herved sikrer et overtryk af magnesiumdamp på mindst 0,01 bar over overfladen af smelten. βApparatus according to claim 9, characterized in that the reaction vessel is provided in its upper part with an opening which provides a connection with the ambient atmosphere and thereby ensures an overpressure of magnesium vapor of at least 0.01 bar above the surface of the melt. β
DK199002768A 1989-11-28 1990-11-21 Magnesium treatment method and apparatus for exercising it DK173273B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH4258/89A CH679987A5 (en) 1989-11-28 1989-11-28
CH425889 1989-11-28

Publications (3)

Publication Number Publication Date
DK276890D0 DK276890D0 (en) 1990-11-21
DK276890A DK276890A (en) 1991-05-29
DK173273B1 true DK173273B1 (en) 2000-06-05

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Country Status (5)

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DK (1) DK173273B1 (en)
ES (1) ES2028563A6 (en)
RU (1) RU2127320C1 (en)
SE (1) SE506027C3 (en)
ZA (1) ZA909520B (en)

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Publication number Publication date
ES2028563A6 (en) 1992-07-01
ZA909520B (en) 1991-09-25
RU2127320C1 (en) 1999-03-10
DK276890A (en) 1991-05-29
DK276890D0 (en) 1990-11-21
SE9003756L (en) 1991-05-29
SE9003756D0 (en) 1990-11-26
SE506027C3 (en) 1997-12-22
SE506027C2 (en) 1997-11-03

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