CA1075724A - Casting of metals - Google Patents
Casting of metalsInfo
- Publication number
- CA1075724A CA1075724A CA288,360A CA288360A CA1075724A CA 1075724 A CA1075724 A CA 1075724A CA 288360 A CA288360 A CA 288360A CA 1075724 A CA1075724 A CA 1075724A
- Authority
- CA
- Canada
- Prior art keywords
- tundish
- weight
- organic
- fibre
- lining
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/02—Linings
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Ceramic Products (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A tundish comprising an outer metal casing, a relatively permanent lining of refractory material and an expendable inner lining formed of a set of slabs of re-fractory heat insulating material of a composition comprising refractory filler, binder and fibre is improved by incorpora-ting sufficient carbonaceous material in the slab composition to increase the life of the slabs when exposed to molten metal during casting.
A tundish comprising an outer metal casing, a relatively permanent lining of refractory material and an expendable inner lining formed of a set of slabs of re-fractory heat insulating material of a composition comprising refractory filler, binder and fibre is improved by incorpora-ting sufficient carbonaceous material in the slab composition to increase the life of the slabs when exposed to molten metal during casting.
Description
J5 7;~ FoSo 1075 This invention relates to tundishes and in parti-cular to tundishes used in continuous casti g of steel having an outer metal casing, a relatively permanent re-~ractory lining in the metal casing and an expendable inner lining made of refractory heat insulating materialO
~undishes of this general type are described in British Patent Specification 13646650 During continuous casting, molten steel is poured into the tundish and flows from the tundish through one or more nozzles set in the base of the tundish into a mouldO The presence of a tundish keeps the flow of molten steel into the continuous casting mould substantially constant and any non-metallic inclusions in the molten metal tend not to be entrained in the stream or streams of molten metal leaving the nozzle(s)~ ~he relatively permanent lining may be made of refractory brick or may be cast of refractory concrete while the inner expendable lining, which is removed and thrown away whenever the tundish is emptied of metal, is usually made of a composition comprising refractor~
fibrç 9 refractory filler and binderO
One advantage of using a heat insulating refractory inner lining is that preheating of the whole interior of the tundish prior to pouring molten metal steel therein, necessary with tundishes which are simply metal casings lined with refractory bricks, is avoidedO Instead, only the nozzle(s) and areas of the interior of the tundish adjacent to the nozzle(s) need to be preheatedO
Fo~ 1075= ~L
q~
ît5'7'~
~hc use of an expendable inner lining as described in the above noted specification has become widespread in recent years on account of the various advantages such a lining affordsO As well as the avoidance of preheating the entire tundish, the inner expendable lining reduces the amount of heat lost from the molten mot~l and acts to protect the relatively permanent lining of the tun-disho Because the molten metal is kept relatively hot, the amount of skull left behind when the tundish has been emptied is reduced and such skull can easily be removed together with the expendable liningO
Although the adoption of an inner expendable lining has been widespread, there are certain diffi-culties encountered in certain areas of continuous casting using such a techniqueO First of all, there is a growing tendency to extend the length of time of a single continuous casting cycle by successively feeding the tundish from each of a plurality of ladles As soon a~ one ladle is empty, another is moved into place and molten metal tapped from the new ladle into the tundishO Working in this way, continuous casting runs of seven or eight hours duration have been achievedD
~uch long runs place very severe strains on the durability of inner liners for tundishesO The problem is par-ticularly severe in the case of certain steel types, high manganese steel leading to rapid deterioration of expendable lining materialsO
FoSo 1075 ' ' :
,' : . `,, ` .
1-~'7S'7;~
A further disadvantage of known expendable lining ~aterial~ ~esides in their poor resistance against s~ag sttackO This can lead to erosion about a specific hori-zontal level with subsequent penetration of metal and slag to the relatively ~ermanent lining of the tundish with advers~ affectsO Also, the known materials have poor resistance to erosion caused by turbulence in the molten metal, particularly in the region where molten metal enters the tundish in a streamO
According to the present invention there is provided a tundish comprising an outer metal casing, a relatively permanent lining of refractory material and an expendable inner lining formed of a set of slabs of refractory heat insulating material of a composition comprising refractory filler, binder and fibre and sufficient carbonaceous material to increase the life of the slabs when exposed to molten metalO
Preferably, the composition comprises by weight 60 to 93% refractory filler, 5 to 30% carbonaceous material,
~undishes of this general type are described in British Patent Specification 13646650 During continuous casting, molten steel is poured into the tundish and flows from the tundish through one or more nozzles set in the base of the tundish into a mouldO The presence of a tundish keeps the flow of molten steel into the continuous casting mould substantially constant and any non-metallic inclusions in the molten metal tend not to be entrained in the stream or streams of molten metal leaving the nozzle(s)~ ~he relatively permanent lining may be made of refractory brick or may be cast of refractory concrete while the inner expendable lining, which is removed and thrown away whenever the tundish is emptied of metal, is usually made of a composition comprising refractor~
fibrç 9 refractory filler and binderO
One advantage of using a heat insulating refractory inner lining is that preheating of the whole interior of the tundish prior to pouring molten metal steel therein, necessary with tundishes which are simply metal casings lined with refractory bricks, is avoidedO Instead, only the nozzle(s) and areas of the interior of the tundish adjacent to the nozzle(s) need to be preheatedO
Fo~ 1075= ~L
q~
ît5'7'~
~hc use of an expendable inner lining as described in the above noted specification has become widespread in recent years on account of the various advantages such a lining affordsO As well as the avoidance of preheating the entire tundish, the inner expendable lining reduces the amount of heat lost from the molten mot~l and acts to protect the relatively permanent lining of the tun-disho Because the molten metal is kept relatively hot, the amount of skull left behind when the tundish has been emptied is reduced and such skull can easily be removed together with the expendable liningO
Although the adoption of an inner expendable lining has been widespread, there are certain diffi-culties encountered in certain areas of continuous casting using such a techniqueO First of all, there is a growing tendency to extend the length of time of a single continuous casting cycle by successively feeding the tundish from each of a plurality of ladles As soon a~ one ladle is empty, another is moved into place and molten metal tapped from the new ladle into the tundishO Working in this way, continuous casting runs of seven or eight hours duration have been achievedD
~uch long runs place very severe strains on the durability of inner liners for tundishesO The problem is par-ticularly severe in the case of certain steel types, high manganese steel leading to rapid deterioration of expendable lining materialsO
FoSo 1075 ' ' :
,' : . `,, ` .
1-~'7S'7;~
A further disadvantage of known expendable lining ~aterial~ ~esides in their poor resistance against s~ag sttackO This can lead to erosion about a specific hori-zontal level with subsequent penetration of metal and slag to the relatively ~ermanent lining of the tundish with advers~ affectsO Also, the known materials have poor resistance to erosion caused by turbulence in the molten metal, particularly in the region where molten metal enters the tundish in a streamO
According to the present invention there is provided a tundish comprising an outer metal casing, a relatively permanent lining of refractory material and an expendable inner lining formed of a set of slabs of refractory heat insulating material of a composition comprising refractory filler, binder and fibre and sufficient carbonaceous material to increase the life of the slabs when exposed to molten metalO
Preferably, the composition comprises by weight 60 to 93% refractory filler, 5 to 30% carbonaceous material,
2 to 16% binder and 1 to 10% fibre, and slabs of this composition are novel and constitute a further feature of the inventionO
We have found that such co~positios in th~ for~ of tundish lining slabs are resistant to attack b~ molten steel fcr a sufficient length of time to enable sequence casting to take place without damaging the lining slabs to such an extent that substantial damage to the relativel~
OSo 1075 :- ~
~ ' ' ' .
10757;~
p~rmanent lining can take placeO This advantagc is obtained both for normal stcels and special steels such as high manganese steelO
~he carbonaceous material improves the resistance of the composition to erosion by basic slag which may be present in the tundish and also resistance to erosion caused by turbulence of molten metal in the tundish particularly in the region where the molten metal enters the tundish as a streamO At the same time all of the advantages achieved by the use of an inner expendable lining, explained in the specification referred to above, are maintained.
~ he reason for this reason this remarkable improve-ment in performance is not fully understood though it is belie~ed that the principal effect of including a carbonaceous material in the composition of the inner - expendable liner is substantially to diminish the rate of chemical attack between the slag on top of the molten metal surface and the usuall~ siliceous filler constituting a principal ingredient of the liningO
~ he refractory filler which constitutes the principal component of the composition for the inner liner may be an~ highly refractor~ particulate filler material known for use in refractor~ heat insulating compositions~ for example silica sand, quartz~ alumina, magnesia, magnesite, chamotte, grog, mullite, chromite and zirconO ~he composition should contain at least FoSo 1075 1(1757;~
60% by weight refractory filler sincc if the amount of refractory filler is less the lining slabs tend to be too porous and become impregnated with molten steel and slag, which is disadvantageous and can shorten the life of the inner liningO
~he carbonaceous material which is included in the composition preferably consists of elemental carbonO
Among the materials which may be used are coke, graphite, carbon electrode scrap, pitch, tar, carbon black, anthracite dust and charcoal powderO ~he materials of choice are graphite and carbon electrode scrapO ~he content of carbonaceous material in the composition of the expendable inner lining should be at least 5% by weight in order to ensure an increase in durability relative to a similar composition but comprising wholly non-carbona-ceous fillerO It is undesirable to incorporate more than 30% by weight of such material into the inner lining composition since it reduces the strength of the compo-sition and its heat insulation valueO ~here is also a risk, particularly in the case of low carbon steel and other steels where the carbon content is critical,of carbon pickup by the molten metal which is undesirableO
~he binder used may be organic, inorganic or a mixture of the twoO Preferably the binder is wholly organic or a mixture of organic and inorganic binder, the organic binder contributing 2 to 10% by weightO
~ess than 2% of organic binder is insufficient to give the slabs ade~uate strengthO As organic binders there ~ -1075~
are preferred thermosetting resins~ pa~ticularly phenol form~ldehyde resins, urea formaldehyde resins and furane resinsO Inorganic binders which may be used in admixture therewith are for example colloidal silica sol, coll~idal alumina sol, various phosphate binders, hydraulic and refractory cements, bonding clays such as ball clay and bentoniteO
The inclusion of a proportion of fibre in the composition of the slabs leads to a number of advantageous properties of the slabO It improves the heat insulation value; it raises the strength of the slab and it addi-tionally lowers the density of the slabO The fibre used may be all organic, all inorganic, or a mixture of the twoO Suitable inorganic fibres which may be used are for example asbestos, glass wool, aluminium silicate fibre and calcium silicate fibreO The latter may be used in their commercially available impure forms of slag wool and rock woolO Preferably the composition of the slabs includes not more than 6% by weight of inorganic fibreO ~his is because of the relatively low melting point of any of these inorganic fibres compared with the casting temperature of molten steelO During long casting periods, such fibres may melt and the molten material thereby generated may form a complex system with other ingredients of the composition, notably siliceous filler, also of melting point lower than the casting temperature of the molten metal~ ~his would ~oSo_l075 ~ 0757;~
lead to progrossive erosion of the conposition which is undesiredO mese adverse effccts may be avoided by ensuring that the conposition contains not nore than 6%
of inorganic fibreO
Suitable organic fibres which nay be used include paper pulp~either natural or formed of waste paper,and a wide variety of natural and synthetic fibrous DaterialsO
Cotton and various synthetic fibres such as rayon, nylon, polyacrylonitrile and polyethylene terephthalate fibre may be mentionedO Preferably the content of organic fibre in the composition does not exceed 4% by weight since quantities above that percentage tend to lead to substantial porosity in the lining slab which tends to reduce the erosion resistance of the slab over a long period of ~imeO
~ he slabs of refractory heat insulating naterial of the co~position specified abovs ~ay be made by ar.y ~ethod convenient and methods for naking such ~aterials are known and widely practicedO ~he preferred nethod is to for~ an a~ueous slurry of the ingredients of the slab and then to dewater portions of this slurry in an appropriate mould to leave a damp slab of the required shape and sizeO On drying such a slab, eOg~ in an oveD, a rigid, strong bonded shape is obtained which nay be asse~bled in the tundish in known fashion to form the expendable liningO Drying is usually carried out at 150 to 200C for a sufficient length of ti~e to drive off substantially all of the waterO
- 8 - F~So 1075 10757'~
~ he rvllowing exa~ples will serve to illustrate the invention~ All percentages are by weightO
l~:XA~IE 1 The conposition for the slabs was;
silica sand 63%
asbestos fibre 3%
paper pulp 2%
crushed graphite 26%
phenol.formaldehyde resin 3%
colloidal silica sol 3%
~ hese ingredients in the proportions stated were mixed with sufficient water to forn a slurry of appro-priate consistencyO Portions of this slurry were poured into patterns the base of which was for~ed by netal gauze through which the slurry was dewatered to leave shapes of thickness 30 ~O ~he shapes were thereafter dried at 150 to 200C, various shapes being produced in order to constitute a complete i~ner lining for a tundish when assenbledO
Slabs so nade were used to line a 6-tonne capacity tundish consisting of a ~etal casing lined internall~ with a relatively perD~ent lining of fire- ~-brickO The lining slabs were used to line the floor and sidewalls of the tundish save for the i~nediate vicinity of the nozzlesO After lining~ the nozzles were haated for 30 ~inutes by gas burnersO ~hereafter the So 10~5 ' :
10 75~7'~
tundish wns put to use in continuous casting pl~in carbon steel~ Sequence casting was enployed, 6 ladle-fuls, each of 60-tonn~,being passed through the tun-dish over a ti~e of 6 hoursO At the end of casting, which had been troublefree, the tundish was allowed to e~pty and the tundish then visually inspectedO ~he quantity of skull re~aining in the tundish was substan-tially less than nor~al for the steelworks in questionO
Cn inversion of the tundish, the little skull present fell out together with the remains of the expendable lining. ~here was substantially no damage to the rela-tively per~anent firebrick liningO
30 ~m thick lining slabs were ~ade using the method of Exa~ple 1 but using a conposition as follows:
silica sand 80%
crushed waste paper 1%
phenolfor~aldehyde resin 4%
graphite particles (crushed electrode scrap)l~%
carbon black 2%
~he lining was used inside a 5-tonne capacity tundish which had a relatively per~anent monolithic lining formed of a cast refractory co~positionO ~he tundish was put to service casting plain carbon steel over a period of 7O5 hoursO During this ti~e eight 40-tonne ladlefuls of steel were passed through the tundishO
~0 SO 10 - '-- .: . -10757;~
Results were satisfactory and similar to those Qbtained in Example lo 35 mm thick liner slabs were made USiDg the 5 method of Example 1 but using the following composition:
magnesia 73%
asbestos fibre 2%
aluminosilicate fibre2%
particulate graphite 14%
coke powder 4%
phenol formaldehyde resin 4%
colloidal silica sol 1%
~ he slabs so made were used to line a tundish having a relatively permanent lining of firebrick and a capacity of 8 tonnesO High mangaDese steel (11.5% manganese) was then cast through this bndish for a period of 6 hours 20 minutes. ~uring this time 5 ladlefuls each of 100 tonDe -were passed through the tundishO After casting, it was observed that little erosion o~ the liner had taken place and that the little skull present and expendable liner could be removed easily from the tundishO During casting molten metal flow was maintained through all the nozzles without difficulty at all timesO
.
10757~
A mixture was made up of silica sand 88%
asbestos fibre 1%
particulate graphite 6%
phenol formaldehyde resin 5%
This mixture was formed to a thick paste by the additie;. of one part by weight water per 5 parts by weight mixtureO ~he paste was then pressed into slab shapes each 40 mm thick and the shapes subsequently driedO
~ tuDdish of the type noted in Example 3 was then lined with such slabs and used for casting low carbon (002%) steel for 6 hoursD During this time 5 ladlefuls each of 100 tonnes of metal were passed through the tundishO
After casting, the expendable lining was examined and found to be substantially of the original thickness prior to 5~stingO ~he expendable lining and skull were easily removed from the tundish and D0 difficulty was ex-perienced during casting with nozzle blockagesO
hXAMP~E 5 ~undash.lining slabs were made of the following composition silica flour 5701%
silica sand 26~0%
urea for~aldehyde resin 100%
phenol formaldehyde resin 300~
paper pulp 20 9%
carbon electrode scrap (p~article size less than 1000%
0025 mm) FoSo lO
.
.
.' - - ~ .
: :
1075'7;~
Thc slabs were made by forming an aqueous slurry of the above ingredients and dewatoring portions of that slurry on to a metal for~er to for~ damp slabs. ~hese slabs were then dried in an ovenO
Dry slabs were then used to form an inner lining on the walls of a refractory brick lined tundish for a two-strand bloom casting machineO In the area of the walls which, when the tundish was in use, would be adjacent the stream of molten metal entering the tundish, the slabs were used as a replacement for high alumina re-fractory ~ricks which would normally be used to with- ~-stand the highly erosive e~fects of the impinging molten metal streamO
~he so lined tundish was used for casting 006 manganese steel for 2 hours 20 ninutesO During this time, three 80-tonne ladlefuls of molten steel were passed through the tundish, the steel being at 1560a in the ladles and 1525C in the tundishO
After the end of casting, the lining was examined and it was found that the lining slabs according to the present invention had suffered no significant erosion, even adjacent the area of the inco~ing molten netal streanO
Identical slabs were also used to line a tundish used for 1 hour 38 minutes to cast two 60-tonne ladlesof normal steelO ~adle temperature was 1570C and tundish te~perature 1530Co Sinilar results were obtained in that after use the lining slabs showed no significant - FoSo 1075 ~0757;~
erosioD~ In both cas~s, it was particularly noticeable that ~ery little sintering of the ~aterial of the slabs had taken place~
- 14 _ F9So 107 .. . .. ~.
- . . .
- -. . : - - -' .
We have found that such co~positios in th~ for~ of tundish lining slabs are resistant to attack b~ molten steel fcr a sufficient length of time to enable sequence casting to take place without damaging the lining slabs to such an extent that substantial damage to the relativel~
OSo 1075 :- ~
~ ' ' ' .
10757;~
p~rmanent lining can take placeO This advantagc is obtained both for normal stcels and special steels such as high manganese steelO
~he carbonaceous material improves the resistance of the composition to erosion by basic slag which may be present in the tundish and also resistance to erosion caused by turbulence of molten metal in the tundish particularly in the region where the molten metal enters the tundish as a streamO At the same time all of the advantages achieved by the use of an inner expendable lining, explained in the specification referred to above, are maintained.
~ he reason for this reason this remarkable improve-ment in performance is not fully understood though it is belie~ed that the principal effect of including a carbonaceous material in the composition of the inner - expendable liner is substantially to diminish the rate of chemical attack between the slag on top of the molten metal surface and the usuall~ siliceous filler constituting a principal ingredient of the liningO
~ he refractory filler which constitutes the principal component of the composition for the inner liner may be an~ highly refractor~ particulate filler material known for use in refractor~ heat insulating compositions~ for example silica sand, quartz~ alumina, magnesia, magnesite, chamotte, grog, mullite, chromite and zirconO ~he composition should contain at least FoSo 1075 1(1757;~
60% by weight refractory filler sincc if the amount of refractory filler is less the lining slabs tend to be too porous and become impregnated with molten steel and slag, which is disadvantageous and can shorten the life of the inner liningO
~he carbonaceous material which is included in the composition preferably consists of elemental carbonO
Among the materials which may be used are coke, graphite, carbon electrode scrap, pitch, tar, carbon black, anthracite dust and charcoal powderO ~he materials of choice are graphite and carbon electrode scrapO ~he content of carbonaceous material in the composition of the expendable inner lining should be at least 5% by weight in order to ensure an increase in durability relative to a similar composition but comprising wholly non-carbona-ceous fillerO It is undesirable to incorporate more than 30% by weight of such material into the inner lining composition since it reduces the strength of the compo-sition and its heat insulation valueO ~here is also a risk, particularly in the case of low carbon steel and other steels where the carbon content is critical,of carbon pickup by the molten metal which is undesirableO
~he binder used may be organic, inorganic or a mixture of the twoO Preferably the binder is wholly organic or a mixture of organic and inorganic binder, the organic binder contributing 2 to 10% by weightO
~ess than 2% of organic binder is insufficient to give the slabs ade~uate strengthO As organic binders there ~ -1075~
are preferred thermosetting resins~ pa~ticularly phenol form~ldehyde resins, urea formaldehyde resins and furane resinsO Inorganic binders which may be used in admixture therewith are for example colloidal silica sol, coll~idal alumina sol, various phosphate binders, hydraulic and refractory cements, bonding clays such as ball clay and bentoniteO
The inclusion of a proportion of fibre in the composition of the slabs leads to a number of advantageous properties of the slabO It improves the heat insulation value; it raises the strength of the slab and it addi-tionally lowers the density of the slabO The fibre used may be all organic, all inorganic, or a mixture of the twoO Suitable inorganic fibres which may be used are for example asbestos, glass wool, aluminium silicate fibre and calcium silicate fibreO The latter may be used in their commercially available impure forms of slag wool and rock woolO Preferably the composition of the slabs includes not more than 6% by weight of inorganic fibreO ~his is because of the relatively low melting point of any of these inorganic fibres compared with the casting temperature of molten steelO During long casting periods, such fibres may melt and the molten material thereby generated may form a complex system with other ingredients of the composition, notably siliceous filler, also of melting point lower than the casting temperature of the molten metal~ ~his would ~oSo_l075 ~ 0757;~
lead to progrossive erosion of the conposition which is undesiredO mese adverse effccts may be avoided by ensuring that the conposition contains not nore than 6%
of inorganic fibreO
Suitable organic fibres which nay be used include paper pulp~either natural or formed of waste paper,and a wide variety of natural and synthetic fibrous DaterialsO
Cotton and various synthetic fibres such as rayon, nylon, polyacrylonitrile and polyethylene terephthalate fibre may be mentionedO Preferably the content of organic fibre in the composition does not exceed 4% by weight since quantities above that percentage tend to lead to substantial porosity in the lining slab which tends to reduce the erosion resistance of the slab over a long period of ~imeO
~ he slabs of refractory heat insulating naterial of the co~position specified abovs ~ay be made by ar.y ~ethod convenient and methods for naking such ~aterials are known and widely practicedO ~he preferred nethod is to for~ an a~ueous slurry of the ingredients of the slab and then to dewater portions of this slurry in an appropriate mould to leave a damp slab of the required shape and sizeO On drying such a slab, eOg~ in an oveD, a rigid, strong bonded shape is obtained which nay be asse~bled in the tundish in known fashion to form the expendable liningO Drying is usually carried out at 150 to 200C for a sufficient length of ti~e to drive off substantially all of the waterO
- 8 - F~So 1075 10757'~
~ he rvllowing exa~ples will serve to illustrate the invention~ All percentages are by weightO
l~:XA~IE 1 The conposition for the slabs was;
silica sand 63%
asbestos fibre 3%
paper pulp 2%
crushed graphite 26%
phenol.formaldehyde resin 3%
colloidal silica sol 3%
~ hese ingredients in the proportions stated were mixed with sufficient water to forn a slurry of appro-priate consistencyO Portions of this slurry were poured into patterns the base of which was for~ed by netal gauze through which the slurry was dewatered to leave shapes of thickness 30 ~O ~he shapes were thereafter dried at 150 to 200C, various shapes being produced in order to constitute a complete i~ner lining for a tundish when assenbledO
Slabs so nade were used to line a 6-tonne capacity tundish consisting of a ~etal casing lined internall~ with a relatively perD~ent lining of fire- ~-brickO The lining slabs were used to line the floor and sidewalls of the tundish save for the i~nediate vicinity of the nozzlesO After lining~ the nozzles were haated for 30 ~inutes by gas burnersO ~hereafter the So 10~5 ' :
10 75~7'~
tundish wns put to use in continuous casting pl~in carbon steel~ Sequence casting was enployed, 6 ladle-fuls, each of 60-tonn~,being passed through the tun-dish over a ti~e of 6 hoursO At the end of casting, which had been troublefree, the tundish was allowed to e~pty and the tundish then visually inspectedO ~he quantity of skull re~aining in the tundish was substan-tially less than nor~al for the steelworks in questionO
Cn inversion of the tundish, the little skull present fell out together with the remains of the expendable lining. ~here was substantially no damage to the rela-tively per~anent firebrick liningO
30 ~m thick lining slabs were ~ade using the method of Exa~ple 1 but using a conposition as follows:
silica sand 80%
crushed waste paper 1%
phenolfor~aldehyde resin 4%
graphite particles (crushed electrode scrap)l~%
carbon black 2%
~he lining was used inside a 5-tonne capacity tundish which had a relatively per~anent monolithic lining formed of a cast refractory co~positionO ~he tundish was put to service casting plain carbon steel over a period of 7O5 hoursO During this ti~e eight 40-tonne ladlefuls of steel were passed through the tundishO
~0 SO 10 - '-- .: . -10757;~
Results were satisfactory and similar to those Qbtained in Example lo 35 mm thick liner slabs were made USiDg the 5 method of Example 1 but using the following composition:
magnesia 73%
asbestos fibre 2%
aluminosilicate fibre2%
particulate graphite 14%
coke powder 4%
phenol formaldehyde resin 4%
colloidal silica sol 1%
~ he slabs so made were used to line a tundish having a relatively permanent lining of firebrick and a capacity of 8 tonnesO High mangaDese steel (11.5% manganese) was then cast through this bndish for a period of 6 hours 20 minutes. ~uring this time 5 ladlefuls each of 100 tonDe -were passed through the tundishO After casting, it was observed that little erosion o~ the liner had taken place and that the little skull present and expendable liner could be removed easily from the tundishO During casting molten metal flow was maintained through all the nozzles without difficulty at all timesO
.
10757~
A mixture was made up of silica sand 88%
asbestos fibre 1%
particulate graphite 6%
phenol formaldehyde resin 5%
This mixture was formed to a thick paste by the additie;. of one part by weight water per 5 parts by weight mixtureO ~he paste was then pressed into slab shapes each 40 mm thick and the shapes subsequently driedO
~ tuDdish of the type noted in Example 3 was then lined with such slabs and used for casting low carbon (002%) steel for 6 hoursD During this time 5 ladlefuls each of 100 tonnes of metal were passed through the tundishO
After casting, the expendable lining was examined and found to be substantially of the original thickness prior to 5~stingO ~he expendable lining and skull were easily removed from the tundish and D0 difficulty was ex-perienced during casting with nozzle blockagesO
hXAMP~E 5 ~undash.lining slabs were made of the following composition silica flour 5701%
silica sand 26~0%
urea for~aldehyde resin 100%
phenol formaldehyde resin 300~
paper pulp 20 9%
carbon electrode scrap (p~article size less than 1000%
0025 mm) FoSo lO
.
.
.' - - ~ .
: :
1075'7;~
Thc slabs were made by forming an aqueous slurry of the above ingredients and dewatoring portions of that slurry on to a metal for~er to for~ damp slabs. ~hese slabs were then dried in an ovenO
Dry slabs were then used to form an inner lining on the walls of a refractory brick lined tundish for a two-strand bloom casting machineO In the area of the walls which, when the tundish was in use, would be adjacent the stream of molten metal entering the tundish, the slabs were used as a replacement for high alumina re-fractory ~ricks which would normally be used to with- ~-stand the highly erosive e~fects of the impinging molten metal streamO
~he so lined tundish was used for casting 006 manganese steel for 2 hours 20 ninutesO During this time, three 80-tonne ladlefuls of molten steel were passed through the tundish, the steel being at 1560a in the ladles and 1525C in the tundishO
After the end of casting, the lining was examined and it was found that the lining slabs according to the present invention had suffered no significant erosion, even adjacent the area of the inco~ing molten netal streanO
Identical slabs were also used to line a tundish used for 1 hour 38 minutes to cast two 60-tonne ladlesof normal steelO ~adle temperature was 1570C and tundish te~perature 1530Co Sinilar results were obtained in that after use the lining slabs showed no significant - FoSo 1075 ~0757;~
erosioD~ In both cas~s, it was particularly noticeable that ~ery little sintering of the ~aterial of the slabs had taken place~
- 14 _ F9So 107 .. . .. ~.
- . . .
- -. . : - - -' .
Claims (17)
1. A tundish comprising an outer metal casing, a permanent lining of refractory material and an expendable inner lining formed of a set of slabs of refractory heat insulating material of a composition comprising by weight 60 to 92% refractory filler, 2 to 16% binder, 1 to 10% fibre and 5 to 30% non-fibrous carbonaceous material.
2. A tundish according to claim 1 wherein the carbonaceous material consists of elemental carbon.
3. A tundish according to claim 1 wherein the carbonaceous material is graphite.
4. A tundish according to claim 1 wherein the composition comprises 2 to 10% by weight organic binder and 0 to 6% by weight inorganic binder.
5. A tundish according to claim 4 wherein the organic binder is a thermosetting resin.
6. A tundish according to any of claims 1-3, wherein the composition comprises a maximum of 6% by weight of inorganic fibre and a maximum of 4% by weight of organic fibre.
7. A tundish according to claim 1 wherein the composition of the slab comprises siliceous refractory filler, elemental carbon, organic and inorganic binding agents and organic and inorganic fibre.
8. A tundish lining slab formed of a refractory heat insulating material of a composition comprising, by weight, 60 to 92% refractory filler, 5 to 30% non-fibrous carbonaceous material, 2 to 16% binder and 1 to 10% fibre.
9. A slab according to claim 8 wherein the carbonaceous material is elemental carbon.
10. A slab according to claim 8 wherein the carbonaceous material is graphite.
11. A slab according to claim 8 and including 2-10% by weight organic binder and 0-6% by weight inorganic binder.
12. A slab according to claim 11 wherein the organic binder is a thermosetting resin.
13. A slab according to any of claims 10-12 and comprising at most 6% by weight inorganic fibre and at most 4% by weight of organic fibre.
14. A slab according to claim 8 and comprising siliceous refractory filler, elemental carbon, organic and inorganic binding agents and organic and inorganic fibre.
15. A method of continuous casting in which molten metal is passed through a tundish, wherein the tundish used is according to claim 1.
16. A method according to claim 15 wherein successive ladlefuls of molten metal are passed through the tundish in sequence casting.
17. A method according to claim 15 or 16 wherein the molten metal is a manganese steel.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12163476A JPS5346310A (en) | 1976-10-08 | 1976-10-08 | Refractory heattinsulating lining material for tandish |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075724A true CA1075724A (en) | 1980-04-15 |
Family
ID=14816110
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA288,360A Expired CA1075724A (en) | 1976-10-08 | 1977-10-07 | Casting of metals |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5346310A (en) |
| AT (1) | AT358753B (en) |
| BE (1) | BE859506A (en) |
| BR (1) | BR7706717A (en) |
| CA (1) | CA1075724A (en) |
| DE (1) | DE2745271C2 (en) |
| ES (1) | ES463027A1 (en) |
| FR (1) | FR2366902A1 (en) |
| GB (1) | GB1575124A (en) |
| IT (1) | IT1091429B (en) |
| SE (1) | SE436844B (en) |
| ZA (1) | ZA776026B (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2451789A1 (en) * | 1979-03-22 | 1980-10-17 | Daussan & Co | THERMALLY INSULATING COATING FOR METALLURGICAL CONTAINERS AND METHOD THEREOF |
| JPS5650172A (en) * | 1979-09-28 | 1981-05-07 | Harima Refractories Co Ltd | Formless refractories |
| JPS5732857A (en) * | 1980-07-12 | 1982-02-22 | Foseco Trading Ag | Tundish |
| DE3119548C1 (en) * | 1981-05-16 | 1982-12-09 | Chamotte- u. Tonwerk Kurt Hagenburger, 6719 Hettenleidelheim | Wear layer of a metallurgical vessel lined with permanent lining with a layer not sintered towards the permanent lining |
| US4407969A (en) * | 1981-07-16 | 1983-10-04 | The Babcock & Wilcox Company | Flexible refractory composition |
| US4623131A (en) * | 1981-12-24 | 1986-11-18 | Foseco Trading A.G. | Molten metal handling vessels |
| CA1194894A (en) * | 1982-02-09 | 1985-10-08 | Masaru Takashima | Core for blow-forming the lining of vessel for molten metal, a lining method using said core, and a lining composition used in said lining method |
| US4618079A (en) * | 1982-12-01 | 1986-10-21 | Foseco Trading A.G. | Refractory, heat-insulating slabs |
| GB2134234B (en) * | 1983-01-21 | 1987-07-15 | Labate Michael D | Blast furnace trough and liner combination |
| US4640336A (en) * | 1984-10-01 | 1987-02-03 | Toshiba Ceramics Co., Ltd. | Refractory for continuous casting |
| DE8700542U1 (en) * | 1987-01-13 | 1988-05-11 | Chamotte- und Tonwerk Kurt Hagenburger, 6718 Grünstadt | Moulded part for the bottom lining of metallurgical melting vessels |
| GB2350810B (en) | 2000-03-17 | 2001-04-25 | Daniel James Duffey | Improvements in and relating to investment casting |
| AU2001237621A1 (en) | 2000-03-17 | 2001-09-24 | Daniel James Duffey | Improvements in and relating to investment casting |
| US7004230B2 (en) | 2000-11-10 | 2006-02-28 | Buntrock Industries, Inc. | Investment casting shells and compositions including rice hull ash |
| US7048034B2 (en) | 2000-11-10 | 2006-05-23 | Buntrock Industries, Inc. | Investment casting mold and method of manufacture |
| CN113843411B (en) * | 2021-09-01 | 2023-03-28 | 鞍山钢铁冶金炉材科技有限公司 | Low-cost composite dry material working lining for two-flow plate blank continuous casting tundish and construction method |
| CN116921660A (en) * | 2023-09-19 | 2023-10-24 | 山东国茂冶金材料有限公司 | Pouring forming die and method for tundish lining |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3637412A (en) * | 1968-09-16 | 1972-01-25 | Combustion Eng | Ladle lining refractory |
| FR1597113A (en) * | 1968-12-24 | 1970-06-22 | ||
| GB1469513A (en) * | 1973-07-30 | 1977-04-06 | Foseco Trading Ag | Tundishes |
| JPS4879733A (en) * | 1972-01-31 | 1973-10-25 | ||
| JPS4981413A (en) * | 1972-12-08 | 1974-08-06 | ||
| JPS5047825A (en) * | 1973-08-30 | 1975-04-28 | ||
| US3955721A (en) * | 1974-09-12 | 1976-05-11 | Bate Micheal Donald | Expendable tundish liner |
-
1976
- 1976-10-08 JP JP12163476A patent/JPS5346310A/en active Pending
-
1977
- 1977-09-20 GB GB39134/77A patent/GB1575124A/en not_active Expired
- 1977-10-07 ZA ZA00776026A patent/ZA776026B/en unknown
- 1977-10-07 BR BR7706717A patent/BR7706717A/en unknown
- 1977-10-07 DE DE2745271A patent/DE2745271C2/en not_active Expired
- 1977-10-07 BE BE181563A patent/BE859506A/en not_active IP Right Cessation
- 1977-10-07 ES ES463027A patent/ES463027A1/en not_active Expired
- 1977-10-07 CA CA288,360A patent/CA1075724A/en not_active Expired
- 1977-10-07 IT IT69240/77A patent/IT1091429B/en active
- 1977-10-07 SE SE7711284A patent/SE436844B/en unknown
- 1977-10-10 AT AT720077A patent/AT358753B/en not_active IP Right Cessation
- 1977-10-10 FR FR7730375A patent/FR2366902A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2366902A1 (en) | 1978-05-05 |
| IT1091429B (en) | 1985-07-06 |
| ES463027A1 (en) | 1978-07-01 |
| AT358753B (en) | 1980-09-25 |
| BE859506A (en) | 1978-02-01 |
| FR2366902B1 (en) | 1980-03-14 |
| JPS5346310A (en) | 1978-04-25 |
| DE2745271C2 (en) | 1982-07-15 |
| GB1575124A (en) | 1980-09-17 |
| BR7706717A (en) | 1978-06-27 |
| SE7711284L (en) | 1978-04-09 |
| DE2745271A1 (en) | 1978-04-13 |
| SE436844B (en) | 1985-01-28 |
| ZA776026B (en) | 1978-06-28 |
| ATA720077A (en) | 1980-02-15 |
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