CA2080490A1 - Method of determining the carbon equivalent, carbon content and silicon content of molten cast iron and estimating the physical and mechanical properties of the iron, and cooling curve measuring cup used in the method - Google Patents
Method of determining the carbon equivalent, carbon content and silicon content of molten cast iron and estimating the physical and mechanical properties of the iron, and cooling curve measuring cup used in the methodInfo
- Publication number
- CA2080490A1 CA2080490A1 CA002080490A CA2080490A CA2080490A1 CA 2080490 A1 CA2080490 A1 CA 2080490A1 CA 002080490 A CA002080490 A CA 002080490A CA 2080490 A CA2080490 A CA 2080490A CA 2080490 A1 CA2080490 A1 CA 2080490A1
- Authority
- CA
- Canada
- Prior art keywords
- iron
- cast iron
- moulding
- carbon
- cooling curve
- 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.)
- Abandoned
Links
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 42
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 35
- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 30
- 238000001816 cooling Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 25
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 22
- 239000010703 silicon Substances 0.000 title claims abstract description 22
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 21
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 238000000465 moulding Methods 0.000 claims abstract description 33
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052714 tellurium Inorganic materials 0.000 claims abstract description 17
- 239000000843 powder Substances 0.000 claims abstract description 16
- 239000000155 melt Substances 0.000 claims abstract description 14
- 238000007711 solidification Methods 0.000 claims abstract description 14
- 230000008023 solidification Effects 0.000 claims abstract description 14
- 239000004411 aluminium Substances 0.000 claims abstract description 13
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910052797 bismuth Inorganic materials 0.000 claims abstract description 13
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims abstract description 13
- 230000005496 eutectics Effects 0.000 claims abstract description 13
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052796 boron Inorganic materials 0.000 claims abstract description 12
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 11
- 239000011701 zinc Substances 0.000 claims abstract description 11
- 238000002076 thermal analysis method Methods 0.000 claims abstract description 8
- 229910001567 cementite Inorganic materials 0.000 claims abstract description 6
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims description 14
- 238000005259 measurement Methods 0.000 claims description 8
- 239000000470 constituent Substances 0.000 claims description 4
- 229940074389 tellurium Drugs 0.000 description 12
- 238000005266 casting Methods 0.000 description 11
- 235000000396 iron Nutrition 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052684 Cerium Inorganic materials 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910000805 Pig iron Inorganic materials 0.000 description 2
- NJFMNPFATSYWHB-UHFFFAOYSA-N ac1l9hgr Chemical compound [Fe].[Fe] NJFMNPFATSYWHB-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 229910002056 binary alloy Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- QMQXDJATSGGYDR-UHFFFAOYSA-N methylidyneiron Chemical compound [C].[Fe] QMQXDJATSGGYDR-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000003381 stabilizer Substances 0.000 description 2
- 229910001126 Compacted graphite iron Inorganic materials 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000010112 shell-mould casting Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/02—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering
- G01N25/04—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering of melting point; of freezing point; of softening point
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
- G01N33/202—Constituents thereof
- G01N33/2022—Non-metallic constituents
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
- G01N33/205—Metals in liquid state, e.g. molten metals
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
In measuring a cooling curve by means of thermal analysis of cast iron, a compressed powder moulding or sintered moulding of tellurium, bismuth, boron, zinc and/or aluminium is fixed to -the inner surface of a cooling curve measuring cup, and a melt is poured into said cup when primaly crystalized and eutectic temperatures based on the metastable solidification of iron, cementite and silicon cleary appear. This method allows the carbon equivalent, carbon content and silicon content of the cast iron to be determined and the physical and mechanical properties of the iron to be estimated. Additionally, said compressed metallic powder moulding or sintered moulding is arranged at and fixed to said cooling curve measuring cup used in the method, while enclosing a thermocouple.
Description
2~0~9~
SPECIFICATION
METHOD OF DETERMINING THE CARBON EQUIVALENT, CARBON CONTENT AND SILICON CONTENT OF MOLTEN
CAST IRON AND ESTIMATING THE PHYSICAL AND
MECHANICAL PROPERTIES OF THE IRON, AND
COOLING CURVE MEASURING CUP USED IN THE METHOD
Technical Field This invention relates to methods of accurately ; measuring a cooling curve of molten cast iron by thermal analysis thereby determining the carbon equivalent, carbon content and silicon content of the iron and estimating the physical and mechanical properties of the iron whereby the furnace front administration of the pre-casting processin the casting factory is suffi-ciently administered for a cupola and the melt charging from the furnace is measured, and a cooling curve measuring cup used in these methods.
Background Technique The principle for the measuxement of carbon equivalent is such of monitoring~ as of pseudobinary system, originally the elements of iron, carbon and silicon basically of ternary system at the~initial thermal arrest temperature (primaly crystal to be liquidus) when the melt of cast iron .. :
;~, :
- : , .
- . : :
" 208~90 solidifies thereby to make it carbon equivalent. Though carbon equivalent is expressed in various ways the most general application thereof is to define it as the total percent of carbon plus one-third (Si% plus P%). There is a further application in which eutectic temperature is measured, interrelation of the temperature with liquid, liquid plus solid, and solid is reviewed thereby to determine the silicon and carbon contents, and the physical and mechanical properties of the cast iron can be estimated on the basis, as function, of the ~ime until solidification of the melt. It is known that according to the application, the numerical values thus obtained are corrected and analyzed depending on the modification of practical profile, material and the like of the casting, it is possible to know the state of the melt accurately and more quickly and field-like than any other analyzing method by means of a cup which is manufactured by a known technique and pre-arranged before the pouring of the melt to allow the melt to be administered before casting, and in case the constituents and variOus propertleS of the molten cast iron differ from those intended a s~itable pretreatment can be carried out. ~hese known techniques are disclosed in U.S. Patent No. 3,267,732 and Japanese Patent No. 820,206 based thereon, bu-t neither of them can sufficiently achieve the ob~ect.
:: : :
.. .
. :: :,. ' ,'~ . : .,',.. , .: . .. .
2~8~g~
Compared with the time when said known techniques were proposed the casting materials are selected in a greater range in the present casting industires High technology has now been desired as compacted graphite iron (so-called CV cast iron) or austempered ductile iron (so-called ADI
cast iron) has appeared and cast iron alloys have been improved and developed whereby a technique of administering the in-situ furnace front melt is required correctly and more quickly. That is, iron and carbon system is a binary system whereas iron, carbon and silicon system is a ternary system. In binary system the eutectic temperature is constant whereas in the ternary system it is maximum or minimum, and con-ditions have become diverse such that cast irons are greatly affected by the silicon content, and according lS to the additive elements for cast iron alloys the eutectic temperature rises for some elements and is lowered for some others. A further complicated phenomenon is that in the solidification of the basic elements iron, carbon and silicon of ternary system there are two ~0 equilibriums of completely stable solidification of iron-carbon (graphite)-silicon system and metastable soli-dification o iron-carbon (cementite)-silicon system.
Additionally, as the cooling rate changed or the additive elements dlffer the two equilibriums alternately ` 25 occur in the same melt in some occasions. Such a multi-:~:
:~
: :
- , .,, ~: .
-- 2~0~0 equilibrium problem causes the complication of solidifi-cation of cast iron system. Under the existing circum-stances where operation by cupola is gradually shifting these days to the melting by electric furnace because of the control to the environmental contamination, serious problems are presented not only to steels but also to cast irons, as the problems not only for the characteristic change of the melt caused with time after melting and the simple change of the constituents of the melt but also for the oxygen content, oxide or solved oxygen content in the meIt.
This makes known thermal analysis method unsatis-factory. It is therefore necessary to accurately measure not only the primaly crystalized temperature but also the eutectic temperature, so that, it is required to measure the cooling curve in a safe white pig iron state (iron and cementite system), and the measurement by semi-stable solidification becomes necessaryt as requisite condition, not only for the cooling curve but also for samples for mechanical analysis such as in emission spectrum analysiS method, X-ray analysis metho~d or the like.
The inventor of this invention has made extensively his research in~an attempt to solve the above problems. ~ -~5 As a method of adding graphltization-hindering elements ' ` ' ', ' ,' '.,' ' ~ '; ' 2 ~ 9 ~
such as tellurium, bismuth and boron as metastable solidification promotors according to prior art there can be mentioned the one of adding, as a paint for chill wash or the li~e, metal tellurium powder or the like in a measuring cup, which method bases on the above-referred patent inventions. However, it is questionable in those inventions whether said elements are accurately added always in a constant proportion, and it is doubtful whether correct primalycrystalized and eutectic temperatures are always obtained from the samples of melts of cast irons.
Referring to a method of obtaining a cooling curve Japanese Patent No. 820,206 describes in its claims to add into the melt bismuth, boron, cerium, lead, magnesium and tellurium, and compounds and mixtures thereof as stabilizer. However, cerium and magnesium are spherification reaction agents and spherification stabilizers for typical ductile cast irons, and they disturb the equilibriUm state of metal-stable solidification of iron-cementitet system to make the measurement of respective primalycrystalized and ~0 eutectic temperatures. It is naturallY not until the measurement of the equilibrium state that the primaly crystali~ed and eutectic temperatures are measuled.
Cerium and magnesium necesSarlly pass through deoxidatlon, desulfuration and decarburizatiOn processes before the spherification of graphite; a-d it w111 be c~ea~ it lS
2 ~ 9 0 inconvenient to use elements which obtain a decarburi-zation action, in measuring the carbon equivalent and carbon content.
3isclosure of the Invention In the present invention various studies and experiments have been carried out to remove the above demerits of the known techniques. The technical constitution of the invention lies in a method of measuring a cooling curve by means of thermal analysis of moltén cast iron, in which onto the inner surface of a cooling curve measuring cup there is fixed a compressed powder moulding or sintered moulding prepared of a metallic powdery body of tellurium, bismuth, boron, zinc or aluminium or a mixture thereof a melt of cast iron is poured into said measuring cup when primaly crystalized and eutectic temperatures based on the metastable solidification of iron, cementite and silicon clearly appear on the Cooling curve of the cast iron whereby the carbon equivalentl carbon content and silicon content of the iron are determined and also the physical and mechanical propertieS thereof are estimated. On the other hand, the present lnvention relates to a cooling curve measuring cup by meanS Of thermal analysis of cast iron, characterized in that a;compressed metallic powder moulding or sintered moulding of tellurium, bismuth, , ~:
': , ,~ ` . . ' . . ,:
-.- , . , . . .
2 ~ 0 boron, zinc or aluminium or a mix-ture thereof is arranged at and fixed onto the inner bottom surface of said cup, while enclosing a thermocouple.
As described above, in view that a surfficient deoxidative effect is produced if used even in a small amount and the primaly crystalized and eutectic tempera-tures of cast iron are not reversely affected evenremained as an alloy element, the inventor of this invention has paid his attention to aluminium. He has also noticed that by adding a small amount of zinc to enhance the effect of the metastable solidification promotors such as tellu-rium, bismuth and boron and to control a little exothermic phenomenon which occurs due to the deoxidation reaction of aluminium, it is possible to cancel the heat generation by the evaporation latent heat to allow the effect of the metastable solidification to be improved, and to completely remove the affection caused by the oxide or solved oxygen content~ According to the invention, therefore, a powdery body of tellurlum~ bismuth or boron ~ .
is mixed with that of aluminium, the mixture is formed as a compressed powder moulding or sintered moulding, and the moulding is fiXed to the inside of the cooling curve measuring cup. ~The mi~ture as a moulding well reacts with the pourlng mel~t of the cast iron~so~that lt ~ :
is possible to quickly and accurately measure the:carbon~
~: :
: ~ : :: : :
:
~ ~ , , :- , . :: : :
.
- . . . ' ': : : :
2 ~
equivalent, carbon content and silicon content of the iron and to determine the physical and mechanical pro-perties of the cast iron.
Brief Description of the Drawings Fig. 1 is a plan view of a cooling curve measuring cup of the invention; and Fig. 2 is a vertical sectional view taken along the line II-II of Fig. 1.
Best Embodiment for Carrying out the Invention The method of the invention has been carried out by using a cooling curve measuring cup (13 shown in Figs. 1 and 2. A ring-like moulding (2) of the invention is arranged, while enclosing a thermocouple (3), at the bottom surface within said cup (1). Said moulding (2) is prepared in such a manner that metalliC powder of tellu-rium, bismuth, boron, zinc or aluminium or a powdery mixture thereof is compressed or sintered for moulding.
A suitable composition thereof may be in the following range because of the above reasons:
20 Aluminium .. ...3 - 20% by weight Zinc ....... ....3 - 20% by weight Tellurium .. --. The rest Further, bismuth and boron can be substituted for part of said tellurium content up to 50% by weight.
It has been confirmed from the result of experiments . :
;'` ` ` : . ' 2 ~ 9 ~
that with a composition less than the above range it is incapable of achieving the desired object of the invention while with an additive amount exceeding the upper limit it is no more than a waste of e~pensive elements.
Additionally, the arrangement of the moulding (2) within the measuring cup, which is shown in the drawings, just shows the best embodiment, and the arrangement is not restricted to the one as shown in the drawings.
Example 1 Moulding composition Aluminium .......... 7.3~ by weight Zinc ............... 9.7% by weight Tellurium .......... The rest Conditions for moulding compressed powder A powdery body of said composition was uniformly mixed, the mixed powder was charged in a powder metall-urgical die having a desired size, and it was moulded to be a ring-like moulding of about 1 mm thickness by a powder metallurgical press. In the preparation of such a moulding, binder is not used at all for the powdery body, but it makes no hindrance to employ a small amount of a volatile binder aCcordlng to the mixing proportion of the powder. As shown ln Fig. 2, a ring-like mouldlng thus prepared is pressed-in to the bottom center of a measuring cup manufactured by shell moulding sand while :: :
2 ~
making a pocket suited to the outside diameter and thickness of the moulding so as to be fixed there. Since naturally the inside diameter of the moulding is made a little larger than the outside diameter of a thermocouple protective pipe any trouble does not occur ~or inserting the thermo-couple. Samples of cast irons to be measured, in various compositions, being at 1400 - 1405C, were poured into the cups, and the following result was obtained.
Hypo-eutectic cast Hyper-eutectic cast iron iron (1) (2) (1) (2) Proeutectic 1,169C 1,154C 1,131.5C 1,111.5C
temperature (2~l36oF)(2,110F) (2,069F) (2,033F) Eutectic1,115C 1,116C 1,112.5C 1,107C
temperature (2,039F)(2,041F) (2,035F) (2,025F) Carbon equivalent4.17 4.30 4.48 4.71 Carbon content 3.52 3.66 3.78 3.9l Silicon content 1.94 1.89 2.08 2.39 Example 2 Aluminium ....... .....6.94~ by weight Zinc ............... ... 9.72~ by weight Bismuth ............ ...10.50% by weight Tellurium .......... ...... The rest ~ : ~
A mixture of the above cOnstituents was moulded in ~:
the same manner as ln Example 1, and the same operatlon :
- , , , : ~," :
was e~fected by using the moulding when the result almost same as in Example 1 was obtained.
The function and effect of the present invention are as lollows:
(1) Measurement can be made in a broad range from hypo-eutectic side to hyper-eutectic side and even to cast iron alloys.
(2~ Different from conventional methods of coating chill wash or metallic powder of tellurium or the like to the inner surface of a measuring cup it is possible to correctly add a binder of predetermined composition.
Unlike chill wash,cooling i.e. so-called recalescence often does not appear on the cooling curvej being sometimes great and sometimes small in the tellurium content in the respective measuring cups. Said recalescence enables the measurement to be difficult.
Due to the development of~the compound binder it is capable of positively grasping the lower limit value of ternary eutectic temperature therebY to know always the stable primaly crystalized and eutectic temperatures in the metastable solidification region of iron-cementite system.
SPECIFICATION
METHOD OF DETERMINING THE CARBON EQUIVALENT, CARBON CONTENT AND SILICON CONTENT OF MOLTEN
CAST IRON AND ESTIMATING THE PHYSICAL AND
MECHANICAL PROPERTIES OF THE IRON, AND
COOLING CURVE MEASURING CUP USED IN THE METHOD
Technical Field This invention relates to methods of accurately ; measuring a cooling curve of molten cast iron by thermal analysis thereby determining the carbon equivalent, carbon content and silicon content of the iron and estimating the physical and mechanical properties of the iron whereby the furnace front administration of the pre-casting processin the casting factory is suffi-ciently administered for a cupola and the melt charging from the furnace is measured, and a cooling curve measuring cup used in these methods.
Background Technique The principle for the measuxement of carbon equivalent is such of monitoring~ as of pseudobinary system, originally the elements of iron, carbon and silicon basically of ternary system at the~initial thermal arrest temperature (primaly crystal to be liquidus) when the melt of cast iron .. :
;~, :
- : , .
- . : :
" 208~90 solidifies thereby to make it carbon equivalent. Though carbon equivalent is expressed in various ways the most general application thereof is to define it as the total percent of carbon plus one-third (Si% plus P%). There is a further application in which eutectic temperature is measured, interrelation of the temperature with liquid, liquid plus solid, and solid is reviewed thereby to determine the silicon and carbon contents, and the physical and mechanical properties of the cast iron can be estimated on the basis, as function, of the ~ime until solidification of the melt. It is known that according to the application, the numerical values thus obtained are corrected and analyzed depending on the modification of practical profile, material and the like of the casting, it is possible to know the state of the melt accurately and more quickly and field-like than any other analyzing method by means of a cup which is manufactured by a known technique and pre-arranged before the pouring of the melt to allow the melt to be administered before casting, and in case the constituents and variOus propertleS of the molten cast iron differ from those intended a s~itable pretreatment can be carried out. ~hese known techniques are disclosed in U.S. Patent No. 3,267,732 and Japanese Patent No. 820,206 based thereon, bu-t neither of them can sufficiently achieve the ob~ect.
:: : :
.. .
. :: :,. ' ,'~ . : .,',.. , .: . .. .
2~8~g~
Compared with the time when said known techniques were proposed the casting materials are selected in a greater range in the present casting industires High technology has now been desired as compacted graphite iron (so-called CV cast iron) or austempered ductile iron (so-called ADI
cast iron) has appeared and cast iron alloys have been improved and developed whereby a technique of administering the in-situ furnace front melt is required correctly and more quickly. That is, iron and carbon system is a binary system whereas iron, carbon and silicon system is a ternary system. In binary system the eutectic temperature is constant whereas in the ternary system it is maximum or minimum, and con-ditions have become diverse such that cast irons are greatly affected by the silicon content, and according lS to the additive elements for cast iron alloys the eutectic temperature rises for some elements and is lowered for some others. A further complicated phenomenon is that in the solidification of the basic elements iron, carbon and silicon of ternary system there are two ~0 equilibriums of completely stable solidification of iron-carbon (graphite)-silicon system and metastable soli-dification o iron-carbon (cementite)-silicon system.
Additionally, as the cooling rate changed or the additive elements dlffer the two equilibriums alternately ` 25 occur in the same melt in some occasions. Such a multi-:~:
:~
: :
- , .,, ~: .
-- 2~0~0 equilibrium problem causes the complication of solidifi-cation of cast iron system. Under the existing circum-stances where operation by cupola is gradually shifting these days to the melting by electric furnace because of the control to the environmental contamination, serious problems are presented not only to steels but also to cast irons, as the problems not only for the characteristic change of the melt caused with time after melting and the simple change of the constituents of the melt but also for the oxygen content, oxide or solved oxygen content in the meIt.
This makes known thermal analysis method unsatis-factory. It is therefore necessary to accurately measure not only the primaly crystalized temperature but also the eutectic temperature, so that, it is required to measure the cooling curve in a safe white pig iron state (iron and cementite system), and the measurement by semi-stable solidification becomes necessaryt as requisite condition, not only for the cooling curve but also for samples for mechanical analysis such as in emission spectrum analysiS method, X-ray analysis metho~d or the like.
The inventor of this invention has made extensively his research in~an attempt to solve the above problems. ~ -~5 As a method of adding graphltization-hindering elements ' ` ' ', ' ,' '.,' ' ~ '; ' 2 ~ 9 ~
such as tellurium, bismuth and boron as metastable solidification promotors according to prior art there can be mentioned the one of adding, as a paint for chill wash or the li~e, metal tellurium powder or the like in a measuring cup, which method bases on the above-referred patent inventions. However, it is questionable in those inventions whether said elements are accurately added always in a constant proportion, and it is doubtful whether correct primalycrystalized and eutectic temperatures are always obtained from the samples of melts of cast irons.
Referring to a method of obtaining a cooling curve Japanese Patent No. 820,206 describes in its claims to add into the melt bismuth, boron, cerium, lead, magnesium and tellurium, and compounds and mixtures thereof as stabilizer. However, cerium and magnesium are spherification reaction agents and spherification stabilizers for typical ductile cast irons, and they disturb the equilibriUm state of metal-stable solidification of iron-cementitet system to make the measurement of respective primalycrystalized and ~0 eutectic temperatures. It is naturallY not until the measurement of the equilibrium state that the primaly crystali~ed and eutectic temperatures are measuled.
Cerium and magnesium necesSarlly pass through deoxidatlon, desulfuration and decarburizatiOn processes before the spherification of graphite; a-d it w111 be c~ea~ it lS
2 ~ 9 0 inconvenient to use elements which obtain a decarburi-zation action, in measuring the carbon equivalent and carbon content.
3isclosure of the Invention In the present invention various studies and experiments have been carried out to remove the above demerits of the known techniques. The technical constitution of the invention lies in a method of measuring a cooling curve by means of thermal analysis of moltén cast iron, in which onto the inner surface of a cooling curve measuring cup there is fixed a compressed powder moulding or sintered moulding prepared of a metallic powdery body of tellurium, bismuth, boron, zinc or aluminium or a mixture thereof a melt of cast iron is poured into said measuring cup when primaly crystalized and eutectic temperatures based on the metastable solidification of iron, cementite and silicon clearly appear on the Cooling curve of the cast iron whereby the carbon equivalentl carbon content and silicon content of the iron are determined and also the physical and mechanical propertieS thereof are estimated. On the other hand, the present lnvention relates to a cooling curve measuring cup by meanS Of thermal analysis of cast iron, characterized in that a;compressed metallic powder moulding or sintered moulding of tellurium, bismuth, , ~:
': , ,~ ` . . ' . . ,:
-.- , . , . . .
2 ~ 0 boron, zinc or aluminium or a mix-ture thereof is arranged at and fixed onto the inner bottom surface of said cup, while enclosing a thermocouple.
As described above, in view that a surfficient deoxidative effect is produced if used even in a small amount and the primaly crystalized and eutectic tempera-tures of cast iron are not reversely affected evenremained as an alloy element, the inventor of this invention has paid his attention to aluminium. He has also noticed that by adding a small amount of zinc to enhance the effect of the metastable solidification promotors such as tellu-rium, bismuth and boron and to control a little exothermic phenomenon which occurs due to the deoxidation reaction of aluminium, it is possible to cancel the heat generation by the evaporation latent heat to allow the effect of the metastable solidification to be improved, and to completely remove the affection caused by the oxide or solved oxygen content~ According to the invention, therefore, a powdery body of tellurlum~ bismuth or boron ~ .
is mixed with that of aluminium, the mixture is formed as a compressed powder moulding or sintered moulding, and the moulding is fiXed to the inside of the cooling curve measuring cup. ~The mi~ture as a moulding well reacts with the pourlng mel~t of the cast iron~so~that lt ~ :
is possible to quickly and accurately measure the:carbon~
~: :
: ~ : :: : :
:
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.
- . . . ' ': : : :
2 ~
equivalent, carbon content and silicon content of the iron and to determine the physical and mechanical pro-perties of the cast iron.
Brief Description of the Drawings Fig. 1 is a plan view of a cooling curve measuring cup of the invention; and Fig. 2 is a vertical sectional view taken along the line II-II of Fig. 1.
Best Embodiment for Carrying out the Invention The method of the invention has been carried out by using a cooling curve measuring cup (13 shown in Figs. 1 and 2. A ring-like moulding (2) of the invention is arranged, while enclosing a thermocouple (3), at the bottom surface within said cup (1). Said moulding (2) is prepared in such a manner that metalliC powder of tellu-rium, bismuth, boron, zinc or aluminium or a powdery mixture thereof is compressed or sintered for moulding.
A suitable composition thereof may be in the following range because of the above reasons:
20 Aluminium .. ...3 - 20% by weight Zinc ....... ....3 - 20% by weight Tellurium .. --. The rest Further, bismuth and boron can be substituted for part of said tellurium content up to 50% by weight.
It has been confirmed from the result of experiments . :
;'` ` ` : . ' 2 ~ 9 ~
that with a composition less than the above range it is incapable of achieving the desired object of the invention while with an additive amount exceeding the upper limit it is no more than a waste of e~pensive elements.
Additionally, the arrangement of the moulding (2) within the measuring cup, which is shown in the drawings, just shows the best embodiment, and the arrangement is not restricted to the one as shown in the drawings.
Example 1 Moulding composition Aluminium .......... 7.3~ by weight Zinc ............... 9.7% by weight Tellurium .......... The rest Conditions for moulding compressed powder A powdery body of said composition was uniformly mixed, the mixed powder was charged in a powder metall-urgical die having a desired size, and it was moulded to be a ring-like moulding of about 1 mm thickness by a powder metallurgical press. In the preparation of such a moulding, binder is not used at all for the powdery body, but it makes no hindrance to employ a small amount of a volatile binder aCcordlng to the mixing proportion of the powder. As shown ln Fig. 2, a ring-like mouldlng thus prepared is pressed-in to the bottom center of a measuring cup manufactured by shell moulding sand while :: :
2 ~
making a pocket suited to the outside diameter and thickness of the moulding so as to be fixed there. Since naturally the inside diameter of the moulding is made a little larger than the outside diameter of a thermocouple protective pipe any trouble does not occur ~or inserting the thermo-couple. Samples of cast irons to be measured, in various compositions, being at 1400 - 1405C, were poured into the cups, and the following result was obtained.
Hypo-eutectic cast Hyper-eutectic cast iron iron (1) (2) (1) (2) Proeutectic 1,169C 1,154C 1,131.5C 1,111.5C
temperature (2~l36oF)(2,110F) (2,069F) (2,033F) Eutectic1,115C 1,116C 1,112.5C 1,107C
temperature (2,039F)(2,041F) (2,035F) (2,025F) Carbon equivalent4.17 4.30 4.48 4.71 Carbon content 3.52 3.66 3.78 3.9l Silicon content 1.94 1.89 2.08 2.39 Example 2 Aluminium ....... .....6.94~ by weight Zinc ............... ... 9.72~ by weight Bismuth ............ ...10.50% by weight Tellurium .......... ...... The rest ~ : ~
A mixture of the above cOnstituents was moulded in ~:
the same manner as ln Example 1, and the same operatlon :
- , , , : ~," :
was e~fected by using the moulding when the result almost same as in Example 1 was obtained.
The function and effect of the present invention are as lollows:
(1) Measurement can be made in a broad range from hypo-eutectic side to hyper-eutectic side and even to cast iron alloys.
(2~ Different from conventional methods of coating chill wash or metallic powder of tellurium or the like to the inner surface of a measuring cup it is possible to correctly add a binder of predetermined composition.
Unlike chill wash,cooling i.e. so-called recalescence often does not appear on the cooling curvej being sometimes great and sometimes small in the tellurium content in the respective measuring cups. Said recalescence enables the measurement to be difficult.
Due to the development of~the compound binder it is capable of positively grasping the lower limit value of ternary eutectic temperature therebY to know always the stable primaly crystalized and eutectic temperatures in the metastable solidification region of iron-cementite system.
(3) As a result, accordlng~to the lnventlon, lt lS
possible to achieve a sufficient object with only the addltive amount 0.2 - 1 0~by weight~of said cDmpressed ,:
-: . . . , . ~ .
, . : .
- . ,. , . , :
,, . . ~ , . . .
2 ~
powder moulding or sintered moulding to said cast iron.
As a result of the measurement it has become to be able to make an accurate measurement almost by 100% within the ranges of ~0.05~ for carbon equivalent, '0.05% for carbon content and +0.15% even for silicon content. This results in demonstrating sufficiently the ability of the cup as a tool for administering the furnace front melt in field in a casting factory, and the invention will contribute to management of melting working to cope with advance and devélopment of future casting technology.
Industrially Possible Ap ~ ion According to the present invention, a cooling curve can be accurately measured by thermal analysis of cast iron thereby determining the carbon equivalent, carbon content and silicon content in the iron and estimating the physical and mechanical properties of the iron whereby the furnace front administration of the pre-casting processeS in a casting factory is easily effected. Additionally, an effectiVe analyzing means in field is provided for distribution and delivery of the melt for from a blast furnace and for sorting of steel making pig iron and varlous kinds of plg irons for casting.
; :
' j :' : :
: . : -: ~ .. . , .. : ~ . .--: - : :. . :
.~ . ~ : :: : ~ :
possible to achieve a sufficient object with only the addltive amount 0.2 - 1 0~by weight~of said cDmpressed ,:
-: . . . , . ~ .
, . : .
- . ,. , . , :
,, . . ~ , . . .
2 ~
powder moulding or sintered moulding to said cast iron.
As a result of the measurement it has become to be able to make an accurate measurement almost by 100% within the ranges of ~0.05~ for carbon equivalent, '0.05% for carbon content and +0.15% even for silicon content. This results in demonstrating sufficiently the ability of the cup as a tool for administering the furnace front melt in field in a casting factory, and the invention will contribute to management of melting working to cope with advance and devélopment of future casting technology.
Industrially Possible Ap ~ ion According to the present invention, a cooling curve can be accurately measured by thermal analysis of cast iron thereby determining the carbon equivalent, carbon content and silicon content in the iron and estimating the physical and mechanical properties of the iron whereby the furnace front administration of the pre-casting processeS in a casting factory is easily effected. Additionally, an effectiVe analyzing means in field is provided for distribution and delivery of the melt for from a blast furnace and for sorting of steel making pig iron and varlous kinds of plg irons for casting.
; :
' j :' : :
: . : -: ~ .. . , .. : ~ . .--: - : :. . :
.~ . ~ : :: : ~ :
Claims (4)
1. A method of measuring a cooling curve by means of thermal analysis of cast iron, characterized in that a compressed powder moulding or sintered moulding made of a metallic powdery body of tellurium, bismuth, boron, zinc or aluminium or a mixture of said elements is fixed to the inner surface of a cup for said cooling curve measurement, a melt of cast iron is poured into said cup, and primaly crystalized and eutectic temperatures based on the metastable solidification of iron, cementite and silicon are clearly displayed on the cooling curve of the cast iron thereby to determine the carbon equivalent, carbon content and silicon content in the iron and to estimate the physical and mechanical properties of the iron.
2. A method of determing the carbon equivalent, carbon content and silicon content of cast iron and estimating the physical and mechanical properties of the iron as claimed in Claim 1 wherein the composition of said compressed powder moulding or sintered moulding is in the range of 3 - 20% by weight of aluminium, 3 - 20%
by weight of zinc, and the rest of tellurium.
by weight of zinc, and the rest of tellurium.
3. A method of determing the carbon equivalent, carbon content and silicon content of cast iron and estimating the physical and mechanical properties of the iron as claimed in Claim 1 wherein bismuth or boron is substituted for part of tellurium which is one of the constituents of said compressed powder moulding or sintered moulding.
4. A cup for measuring a cooling curve by means of thermal analysis of cast iron characterized in that a compressed metallic powder moulding or sintered moulding prepared from tellurium, bismuth, boron, zinc and/or aluminium is arranged at and fixed to the inner bottom surface of said cup, while enclosing a thermocouple.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002080490A CA2080490A1 (en) | 1990-05-16 | 1990-05-16 | Method of determining the carbon equivalent, carbon content and silicon content of molten cast iron and estimating the physical and mechanical properties of the iron, and cooling curve measuring cup used in the method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002080490A CA2080490A1 (en) | 1990-05-16 | 1990-05-16 | Method of determining the carbon equivalent, carbon content and silicon content of molten cast iron and estimating the physical and mechanical properties of the iron, and cooling curve measuring cup used in the method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2080490A1 true CA2080490A1 (en) | 1991-11-17 |
Family
ID=4150544
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002080490A Abandoned CA2080490A1 (en) | 1990-05-16 | 1990-05-16 | Method of determining the carbon equivalent, carbon content and silicon content of molten cast iron and estimating the physical and mechanical properties of the iron, and cooling curve measuring cup used in the method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2080490A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103698331A (en) * | 2013-09-06 | 2014-04-02 | 内蒙古科技大学 | Experimental method and device for determining high temperature solidification phase transition rule |
| CN117250220A (en) * | 2023-11-15 | 2023-12-19 | 河南钱潮智造有限公司 | Hot metal thermal analysis method and device |
-
1990
- 1990-05-16 CA CA002080490A patent/CA2080490A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103698331A (en) * | 2013-09-06 | 2014-04-02 | 内蒙古科技大学 | Experimental method and device for determining high temperature solidification phase transition rule |
| CN117250220A (en) * | 2023-11-15 | 2023-12-19 | 河南钱潮智造有限公司 | Hot metal thermal analysis method and device |
| CN117250220B (en) * | 2023-11-15 | 2024-01-30 | 河南钱潮智造有限公司 | Hot metal thermal analysis method and device |
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