EP0032282A1 - Process for manufacture of cast iron with vermicular graphite and cast iron so produced - Google Patents
Process for manufacture of cast iron with vermicular graphite and cast iron so produced Download PDFInfo
- Publication number
- EP0032282A1 EP0032282A1 EP80300136A EP80300136A EP0032282A1 EP 0032282 A1 EP0032282 A1 EP 0032282A1 EP 80300136 A EP80300136 A EP 80300136A EP 80300136 A EP80300136 A EP 80300136A EP 0032282 A1 EP0032282 A1 EP 0032282A1
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- EP
- European Patent Office
- Prior art keywords
- graphite
- cast iron
- agent
- iron
- cast
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- 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.)
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- 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
- This invention relates to a process for the manufacture of cast iron with vermicular graphite.
- Vermicular graphite is a name given to flake graphite which has become rounded, thickened and shortened compared with the normal elongated flakes commonly found in grey cast irons.
- This modified form of graphite is known by several other names including “compacted”, “quasi-flake”, “aggregate flake”, “chunky”, “stubby”, “up-graded”, “semi-nodular” “P-type” and "floccular” graphite.
- the present invention provides a process for the production of cast iron with vermicular graphite wherein molten grey cast iron optionally containing a nodular graphite inhibitor is introduced into the mould cavity by way of a conventional pouring system which additionally includes one or more intermediate chambers containing a vermicularising agent in an amount sufficient to convert the graphite at least in part to vermicular graphite under the process conditions employed.
- vermicularizing agent used herein we mean an agent which is in general an alloy but can be a metal and which leads to vermicular graphite, under appropriate process conditions.
- the formation of vermicular graphite depends to a certain extent on the process conditions, as is well known in the art, which process conditions are for example described in U.K. Patent Specification 1,427,445.
- the vermicularizing agent will be a magnesium-containing alloy.
- This alloy may contain a metal, such as, titanium which will inhibit the production of nodular graphite.
- This titanium may also be added as ferrotitanium to the metal in the ladle prior to pouring. It may also inherently be present in the iron which makes up the charge.
- vermicular graphite is obtained when the magnesium level in the finished metal is below 0.02 to 0.025% by weight based on the weight of the iron.
- a nodular- graphite inhibiting metal in particular titanium, but also zirconium higher levels of magnesium may be tolerated.
- a particularly useful additive in the vermicularizing alloy is cerium.
- the vermicularizing agent may therefore be magnesium in the form of a 5% magnesium ferrosilicon alloy containing cerium.
- a suitable base iron for the grey iron charge, excluding carbon, is:-
- the size of the intermediate chamber, the pouring rate of the molten grey iron and the amount of magnesium retained in the cast metal may be determined according to the relationship defined in our U.K. Patent Specification Serial No. 1,511,246.
- the total area of the base or bases of the chamber or chambers are equal to a "factor" x (metal pouring rate) x (total concentration of the agent in the cast metal, expressed as a proportion of the weight of the cast metal).
- the "factor” is the reciprocal of the constant "k” as defined in Specification No. 1,511,246 and is dependent on the physical form and chemical composition of the agent, preferably magnesium as described in detail in U.K. Patent Specification 1,511,246.
- the required amount of magnesium can be calculated with great accuracy.
- the factor can then be determined.
- the structure obtained is generally not totally vermicular graphite but is about 80% to 90% vermicular.
- molten metal containing a nodular graphite inhibitor enters the mould system by way of a pouring bush (not shown) down a downsprue 1 and into a reaction chamber 2 which contains the vermicularizing agent.
- a gate 3 regulates the outflow of metal from the chamber thereby ensuring a sufficient residence time for the metal in the chamber for reaction with the vermicularizing agent therein. From the gate 3 the treated molten metal flows via a runner 4 and ingate e.g. 5, to the remainder of the system comprising a riser and the mould cavity proper (not shown).
- molten iron containing a nodular graphite inhibitor passes into the casting mould it contacts the vermicularizing additive in the intermediate reaction chamber 2 and the graphite in the iron is converted into vermicular form.
- the present invention is further illustrated by the following Example which was carried out using a mould system as described above.
- the disc casting size was 50.8 cms (20 inches) x 2.54 cms (1.0 inch) and the pouring time was ten seconds.
- the intermediate chamber contained a vermicularising agent consisting of an alloy comprising 5% magnesium, 0.3 to 0.5% calcium, 0.2% cerium, 45-50% silicon with the balance being iron.
- the process parameters were selected to give a controlled magnesium content of 0.015%.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
Description
- This invention relates to a process for the manufacture of cast iron with vermicular graphite.
- In U.K. Patent No. 1,278,265 a process for the production of nodular or spheroidal graphite cast iron castings in which untreated molten grey cast iron is introduced-into the mould cavity by way of a conventional pouring system which additionally includes one or more intermediate chambers containing a nodularising agent in an amount sufficient to convert the graphite to nodular or spheroidal form is described.
- It has now surprisingly been found that the pouring system described in the said prior patent enables castings of cast iron with vermicular graphite to be produced, if desired without the use of a nodular graphite inhibitor as mentioned below.
- Vermicular graphite is a name given to flake graphite which has become rounded, thickened and shortened compared with the normal elongated flakes commonly found in grey cast irons. This modified form of graphite is known by several other names including "compacted", "quasi-flake", "aggregate flake", "chunky", "stubby", "up-graded", "semi-nodular" "P-type" and "floccular" graphite.
- Most cast irons have elongated flake graphite structures and such irons are comparatively weak and brittle, but have good thermal conductivity and resistance to thermal shock. It is known however, that it is possible to produce cast irons having a nodular or spheroidal, graphite structure and these are ductile and comparatively strong. However, in some circumstances these nodular or spheroidal graphite structures have lower thermal conductivity and sometimes also poorer resistance to thermal shock. Irons with vermicular graphite structures combine the high strength and ductility often associated with nodular graphite irons whilst retaining good thermal conductivity and resistance to thermal shock.
- The manufacture of cast iron containing vermicular graphite has been well known for many years by alloying the iron with magnesium. Various investigators have devised systems in an attempt to control the magnesium content. A narrow range of magnesium content is required to produce a vermicular structure and close control of the process necessary to achieve this has been difficult. One proposed method of control involves the addition of an alloying agent, normally magnesium, and an inhibiting or suppressing agent. The major problem with such two-part systems, e.g. magnesium alloying agent and a nodular graphite inhibitor is that, in practice, it is difficult to make accurate additions at the required levels, e.g. 0.015%. One part addition agents are known, that is agents comprising a combination of a suppressing agent and magnesium. However, in practise, it is difficult to achieve the correct balance of the two components.
- We have now found that cast iron with vermicular graphite can be produced in a controllable manner if the pouring system of the prior patent referred to above is utilized wherein a vermicularizing agent is contained in the intermediate chamber or chambers and optionally a nodular graphite inhibitor is added to the molten grey cast iron charge.
- Although the pouring system of the prior patent provides a high degree of control over the casting porcess, it was not to be expected that this pouring system could be used to produce vermicular graphite containing cast iron in a reproducible manner, since the production of vermicular graphite represents a half way stage between flake and nodular graphite.
- Accordingly, the present invention provides a process for the production of cast iron with vermicular graphite wherein molten grey cast iron optionally containing a nodular graphite inhibitor is introduced into the mould cavity by way of a conventional pouring system which additionally includes one or more intermediate chambers containing a vermicularising agent in an amount sufficient to convert the graphite at least in part to vermicular graphite under the process conditions employed.
- By the term vermicularizing agent used herein we mean an agent which is in general an alloy but can be a metal and which leads to vermicular graphite, under appropriate process conditions. The formation of vermicular graphite depends to a certain extent on the process conditions, as is well known in the art, which process conditions are for example described in U.K. Patent Specification 1,427,445. In general the vermicularizing agent will be a magnesium-containing alloy. This alloy may contain a metal, such as, titanium which will inhibit the production of nodular graphite. This titanium may also be added as ferrotitanium to the metal in the ladle prior to pouring. It may also inherently be present in the iron which makes up the charge. The presence of this titanium enables one to be less strict in controlling the level of magnesium. In principle, vermicular graphite is obtained when the magnesium level in the finished metal is below 0.02 to 0.025% by weight based on the weight of the iron. In the presence however of a nodular- graphite inhibiting metal, in particular titanium, but also zirconium higher levels of magnesium may be tolerated. A particularly useful additive in the vermicularizing alloy is cerium.
- The vermicularizing agent may therefore be magnesium in the form of a 5% magnesium ferrosilicon alloy containing cerium.
- A suitable base iron for the grey iron charge, excluding carbon, is:-
- Si: - 2.17% by weight
- Al: - 0.01% by weight
- Ti: - 0.013% by weight.
- According to the present invention the size of the intermediate chamber, the pouring rate of the molten grey iron and the amount of magnesium retained in the cast metal may be determined according to the relationship defined in our U.K. Patent Specification Serial No. 1,511,246.
- That is, the total area of the base or bases of the chamber or chambers are equal to a "factor" x (metal pouring rate) x (total concentration of the agent in the cast metal, expressed as a proportion of the weight of the cast metal).
- The "factor" is the reciprocal of the constant "k" as defined in Specification No. 1,511,246 and is dependent on the physical form and chemical composition of the agent, preferably magnesium as described in detail in U.K. Patent Specification 1,511,246.
- According to this embodiment of the invention, the required amount of magnesium can be calculated with great accuracy.
- For example, for a magnesium alloy agent with a grading in the range of 0.5 to 4 mm., the following constants (k) have been determined
- k (6% Mg alloy) = .0225 kg/cm2 (0.032 lb/in2) sec
- k (9% Mg alloy) = .0337 kg/cm2 (0.048 lbJin2)sec:
- We have found experimentally, using a magnesium alloy as the agent, that a product which is cast iron containing vermicular graphite can be obtained when the total concentration of the magnesium in the cast metal expressed as a proportion of the weight of the cast metal is between for example 0.01% and 0.02%.
-
- The factor can then be determined.
- The structure obtained is generally not totally vermicular graphite but is about 80% to 90% vermicular.
- We have found that the amount of magnesium required to produce vermicular graphite is dependent on the sulphur level of the metal. The tests just described were carried out with a grey iron containing 0.01 to 0.015% by weight of sulphur. Where the sulphur content is higher, the amount of magnesium required will increase and vice-versa.
- The invention is further illustrated by the accompanying drawing which illustrates one embodiment of a mould system used in the process according to the invention.
- In this embodiment, molten metal containing a nodular graphite inhibitor enters the mould system by way of a pouring bush (not shown) down a
downsprue 1 and into areaction chamber 2 which contains the vermicularizing agent. A gate 3 regulates the outflow of metal from the chamber thereby ensuring a sufficient residence time for the metal in the chamber for reaction with the vermicularizing agent therein. From the gate 3 the treated molten metal flows via a runner 4 and ingate e.g. 5, to the remainder of the system comprising a riser and the mould cavity proper (not shown). Thus, as molten iron containing a nodular graphite inhibitor passes into the casting mould it contacts the vermicularizing additive in theintermediate reaction chamber 2 and the graphite in the iron is converted into vermicular form. - The present invention is further illustrated by the following Example which was carried out using a mould system as described above.
- A base metal containing a total carbon content of 3.4%, silicon`2.4%, sulphur 0.01% and titanium 0.015%, the balance being iron, was poured to obtain a total pound weight of casting, together with riser and runner bar, of 22 kgs (50lbs). The disc casting size was 50.8 cms (20 inches) x 2.54 cms (1.0 inch) and the pouring time was ten seconds.
- The intermediate chamber contained a vermicularising agent consisting of an alloy comprising 5% magnesium, 0.3 to 0.5% calcium, 0.2% cerium, 45-50% silicon with the balance being iron.
- The process parameters were selected to give a controlled magnesium content of 0.015%.
-
- Therefore the required base area of the intermediate chamber is approximately
- 3.88 cms x 3.88 cms (1.53 inches x 1.53 inches).
- Using an intermediate chamber of these dimensions, a structure was obtained which was found to contain 90% vermicular graphite and 10% malformed nodules of graphite.
Claims (8)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE8080300136T DE3070892D1 (en) | 1980-01-15 | 1980-01-15 | Process for manufacture of cast iron with vermicular graphite and cast iron so produced |
AT80300136T ATE14455T1 (en) | 1980-01-15 | 1980-01-15 | PROCESS FOR THE MANUFACTURE OF CAST IRON WITH VERMICULAR GRAPHITE AND CAST IRON MANUFACTURED BY THE PROCESS. |
EP80300136A EP0032282B1 (en) | 1980-01-15 | 1980-01-15 | Process for manufacture of cast iron with vermicular graphite and cast iron so produced |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP80300136A EP0032282B1 (en) | 1980-01-15 | 1980-01-15 | Process for manufacture of cast iron with vermicular graphite and cast iron so produced |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0032282A1 true EP0032282A1 (en) | 1981-07-22 |
EP0032282B1 EP0032282B1 (en) | 1985-07-24 |
Family
ID=8187077
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP80300136A Expired EP0032282B1 (en) | 1980-01-15 | 1980-01-15 | Process for manufacture of cast iron with vermicular graphite and cast iron so produced |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0032282B1 (en) |
AT (1) | ATE14455T1 (en) |
DE (1) | DE3070892D1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3321312A1 (en) * | 1983-06-13 | 1984-12-13 | Klöckner-Humboldt-Deutz AG, 5000 Köln | METHOD FOR PRODUCING A CAST IRON WITH VERMICULAR GRAPHITE |
EP0249897A1 (en) * | 1986-06-11 | 1987-12-23 | O.E.T.-METALCONSULT S.r.l. | Process for the degassing, refining or filtering treatment of liquid metals or alloys and related apparatus |
WO2001054844A1 (en) * | 2000-01-26 | 2001-08-02 | Novacast Ab | Gating system |
EP1458518A2 (en) * | 2001-11-27 | 2004-09-22 | Tupy Fundiçoes Ltda. | Graphitic cast iron of high mechanical strength |
EP3519602A4 (en) * | 2016-09-29 | 2020-04-01 | Tupy S.A. | Vermicular cast iron alloy for internal combustion engine block and head |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH665851A5 (en) * | 1986-03-20 | 1988-06-15 | Fischer Ag Georg | METHOD FOR PRODUCING PERLITIC CAST IRON TYPES. |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1069058A (en) * | 1965-05-04 | 1967-05-17 | Int Nickel Ltd | Cast iron |
GB1278265A (en) * | 1968-07-17 | 1972-06-21 | Materials & Methods Ltd | Improved process for the manufacture of nodular cast iron |
GB1427445A (en) * | 1974-01-15 | 1976-03-10 | British Cast Iron Res Ass | Cast iron |
DE2705630A1 (en) * | 1976-02-10 | 1977-08-11 | Bcira Co | METHOD FOR TREATMENT OF A CARBONIC FELT |
GB1511246A (en) * | 1974-04-29 | 1978-05-17 | Materials & Methods Ltd | Process for the manufacture of cast iron |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2926020A1 (en) * | 1979-06-28 | 1981-01-08 | Buderus Ag | METHOD FOR PRODUCING A CAST IRON WITH VERMICULAR GRAFIT AND USE OF THE CAST IRON |
-
1980
- 1980-01-15 AT AT80300136T patent/ATE14455T1/en not_active IP Right Cessation
- 1980-01-15 EP EP80300136A patent/EP0032282B1/en not_active Expired
- 1980-01-15 DE DE8080300136T patent/DE3070892D1/en not_active Expired
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1069058A (en) * | 1965-05-04 | 1967-05-17 | Int Nickel Ltd | Cast iron |
GB1278265A (en) * | 1968-07-17 | 1972-06-21 | Materials & Methods Ltd | Improved process for the manufacture of nodular cast iron |
GB1427445A (en) * | 1974-01-15 | 1976-03-10 | British Cast Iron Res Ass | Cast iron |
GB1511246A (en) * | 1974-04-29 | 1978-05-17 | Materials & Methods Ltd | Process for the manufacture of cast iron |
DE2705630A1 (en) * | 1976-02-10 | 1977-08-11 | Bcira Co | METHOD FOR TREATMENT OF A CARBONIC FELT |
Non-Patent Citations (2)
Title |
---|
GIESSEREI, Vol. 66, No. 15, 23 July 1979, Dusseldorf, * Page 590, right column, lines 30 to 60 * * |
GIESSEREI-PRAXIS, No. 23-24, 1979 Berlin J.B. v. NESSELRODE "Gusseisen mit Vermiculargraphit, ein Werkstoff fur Zylinderkopfe" pages 445 to 449 * page 446 * * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3321312A1 (en) * | 1983-06-13 | 1984-12-13 | Klöckner-Humboldt-Deutz AG, 5000 Köln | METHOD FOR PRODUCING A CAST IRON WITH VERMICULAR GRAPHITE |
EP0131092A2 (en) * | 1983-06-13 | 1985-01-16 | Klöckner-Humboldt-Deutz Aktiengesellschaft | Process for producing vermicular graphite cast iron |
EP0131092A3 (en) * | 1983-06-13 | 1986-09-10 | Klöckner-Humboldt-Deutz Aktiengesellschaft | Process for producing vermicular graphite cast iron |
EP0249897A1 (en) * | 1986-06-11 | 1987-12-23 | O.E.T.-METALCONSULT S.r.l. | Process for the degassing, refining or filtering treatment of liquid metals or alloys and related apparatus |
WO2001054844A1 (en) * | 2000-01-26 | 2001-08-02 | Novacast Ab | Gating system |
US6863114B2 (en) | 2000-01-26 | 2005-03-08 | Novacast Ab | Gating system |
EP1458518A2 (en) * | 2001-11-27 | 2004-09-22 | Tupy Fundiçoes Ltda. | Graphitic cast iron of high mechanical strength |
EP1458518A4 (en) * | 2001-11-27 | 2004-12-15 | Tupy Fundicoes Ltda | Graphitic cast iron of high mechanical strength |
EP3519602A4 (en) * | 2016-09-29 | 2020-04-01 | Tupy S.A. | Vermicular cast iron alloy for internal combustion engine block and head |
Also Published As
Publication number | Publication date |
---|---|
ATE14455T1 (en) | 1985-08-15 |
DE3070892D1 (en) | 1985-08-29 |
EP0032282B1 (en) | 1985-07-24 |
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