REFRACTORIES FOR THE CONSUMER

REFRACTORY OF

LININGS

CONTINUOUS

OF

BILLET

THE

TUNDISHES

CASTING

MACHINES

(A REVIEW)I Yu.

V.

Materikin

and

V.

UDC 566.76:[621.746.329. 047 : 66.043.1] :669.18.046.518

A o Molochkov

The t u n d i s h e s of c o n t i n u o u s b i l l e t e a s t i n g m a c h i n e s a r e i n t e n d e d f o r a b s o r b i n g the k i n e t i c e n e r g y of 51e s t r e a m of s t e e l flowing f r o m the s t e e l t e e m i n g l a d l e , p a r t i a l s e p a r a t i o n of the n o n m e t a l l i c i n c l u s i o n s , and t m i f o r m d i s t r i b u t i o n of the s t e e l in the m o l d . The s t e e l t e m p e r a t u r e in the t u n d i s h m u s t n o t d r o p s i g n i f i c a n t l y . I n i t i a l l y the t u n d i s h l i n i n g s w e r e m a d e of l a d l e b r i c k , which w e r e l a i d a f t e r a r e i n f o r c i n g l a y e r f l a t o r e d g e w i s e (Fig. 1). The p o i n t of i m p a c t of the s t r e a m was a d d i t i o n a l l y l a i d with r e f r a c t o r i e s in one o r m o r e lay,

ers. Recently, to ease the manual labor of the bricklayers and for economy in formed parts, Cherepovets, Donetsk, and Sarkanais Metalurgs Plants have used poured siliceous linings in tundishes used primarily for single pourings [i]. The pured lining is prepared from a fluid siliceous mixture with a binder of water glass. The mixture is poured into the space between the removable former and the reinforcing layer. After hardening of the lining (after 30-40 rain) the former is removed and the lining is dried and heated at 900-1200~ The average life of a poured lining under the conditions of Cherepovets Plant is 6.5 heats. TABLE i. Properties of the Refractory Materials for the Working Layer of the Lining of Tundishes in the Plants of the United States Steel Corporation

Weight, % Material AI~O,

SiO$

P20 a

Open A~r'en porosl- demi. ty, % ~t~sg~

!

Burnt refractory

9--i I1--23 --

The same

3--~

18--21 12,51--

/2,52

7--10 '--, 10--1312,83-2,91

Unburnt refractory

5--:

5--18

~--,

18--2212,69--

The same

3--t

7--10

~--,

18--2212,88--

Plastic mix3--~ ture The same 9--! Basic refractory with a direct bond

60*

12,73

2,98

8--11 ~--, 23--2612,56-/2,64 6- -8 23--2612,64-2,72 3]"

12--1313,33-13,39

Wt. % of MgO shown. Wt. % of CaO shown.

All-Union Refractory Institute.

108

T r a n s l a t e d f r o m O g n e u p o r y , No. 1, pp. 5 1 - 5 7 , F e b r u a r y , 1983.

0034-3102/83/0102-0108507.50

9 1983 P l e n u m P u b l i s h i n g C o r p o r a t i o n

i i i i Ii Ii i Ii iiii

ii Ill llllllll

a

Lr lO

5 \

J I i I~I ~ II I' I I I I/f

9

_

I~l

,.'[, \\\.~\\ I I\

I

I t I I I

~

~\1 \ \\\~1 \ \ I \\\ I \~\ I \ \ I \ \~\1 \

!,!

8

9

5"

b Fig. 2

Fig. 1

Fig. 1. Method of laying ladle b r i c k in the tundish edgewise (a) or fiat (b). Fig. 2. Plan of the lining of tundishes used f o r pouring a s e r i e s of h e a t s by the "heat on h e a t " method (a) and f o r pouring single heats (b) : 1) 85% alumina r e f r a c t o r y ; 2) working l a y e r of the lining; 3) t h e r m a l insulation l a y e r ; 4) p r o t e c t i v e l a y e r of the lining; 5) shell of the tundish; 6) i m p a c t projection; 7) wells for the n o z z l e s ; 8) 75% alumina r e f r a c t o r y ; 9) c h a m o t t e r e f r a c t o r y ; 10) f e e d e r n o z z l e s .

t'c

t.,~

#oo

1590;

l

~

SO0 / 2.OO

1550

Z

100 1510 0

I

I

I

f

I

I

lfl

20

SO

4,0

50

5O

Time, min Fig. 3

Fig. 4

SO

60

90

Time, rain

120

7s

Fig. 5

Fig. 3. Plan of a "cold" lining of a tundish: 1) expendable facing plate; 2) t h e r m a l insulation filler; 3) well block; 4) r e i n f o r c i n g l a y e r . Fig. 4. The change in t e m p e r a t u r e t of m o l t e n s t e e l in tundishes with a p r e v i o u s l y heated b r i c k lining (1) and with a "cold" lining (2). Fig. 5. ~he change during pouring of the t e m p e r a t u r e t of the shell of a tundish with a n o r m a l (1) and with a "cold" (2) lining. The t e m p e r a t u r e was m e a s u r e d on the r e a r side of the t h e r m a l insulation plates.

109

[ 58--65

I sa-89

} 62--70

Wt.% of AI20~

For long pours of a large number of heats in a series

For pouring single heats F o r pouring two o r t h r e e heats in a s e r i e s

slag band

reinforcing layer

insulation

Tundish lid

special

or

a r e a or stream imp act Chamotte of different configurations Chamotte Metal c a s t i n g Chamotte High alumina o r ehamotte High Metal o r lined with alumina r e f r a c t o r y concrete, The s a m e Normal The samel Lined with r e f r a c High alumina stoppe~ tory concrete, a (inter~ plastic mixture, or insulation nal) brick ~he High High alumina or baste , High The s a m e alumina same alumina working l a y e r

R e f r a c t o r i e s used for the lining of

TABLE 3. The R e f r a c t o r i e s Used for Lining Ttmdishes in the Plants of the United Steel Co.

Tundish

0;2--6,0

1a-6(]5,0) 1 4,0Z8.5r 2,5Z5.o:*

2,56--2,64 2,10--2,30 15--9 (1450) I 0,2--3,0

0,96-- I;04

~Volume contraction,o7o' Apparent Deformation under density, ]a load of g / cm3

* The t e m p e r a t u r e , ~ at which d e f o r m a t i o n o c c u r s is shown in p a r e n theses. The v o l u m e t r i c growth, %, is shown.

brick High alumina mixture High alumina concrete

Special high alumina insulating

Material

T A B L E 2. P r o p e r t i e s of Materials Used for Lining the Lids of Tundishes in the Plants of the United States Steel Co.

Slide valve {external)

Normal stopper (internal) N o r m a l stopper o r slide valve (external)

the flow

Control of

T A B L E 4. C h a r a c t e r i s t i c s of the R e f r a c t o r y Materials Used for Lining the W o r k i n g ~; "er of Tundishes in the Plants of the United States Steel Co.

wo,~.~o

Material

~1l~ II~~l l"~ ~

A~o~ s~o, F~o, c~o Mgo

Normal expanding in set vice Normal nonexpanding in service Expanding

]~ 1~o i ~- t~ ~i~,~,~ ~-~ ,

.'~'~'~ ~or.olo~o~to.~,~o~l~

R,ol~/,~l~,~l~o~

IO

5~176176 511"1"1~176 601351,,210,110,1 1 72 I 23 11,5 /0,2 10,2 I I0 ~ I:0 o~:l 0:~

Nonexpanding High purity Standard Improved With 85 wt.% A12Oa

I/Ill

2'~176176 ~176 0,2/~:~/.,2j0258 Io,5 [

Plate

/ j 5.

20,6 [ 0,085

io,~l~,~l,~,~lo,,,o

15

3,480/,,~30~1.3,022, 3,480 1 4,0 12.8 4,404j 1,2 j.

12,5

4 464 I 19 O

_

o~oo I ~

j O.l j2,~o i I,,O j 0.213 ~6,3~

The t e m p e r a t u r e o f v o l u m e t r i c g r o w t h , ~ T A B L E 5.

~o

I

4,1

,o ~o

is shown in p a r e n t h e s e s .

Chemical Composition of the Thermal Insulation Plates Wei ht %

SiO2

AlcOa

CaO

MgO

FeO

Fe~O~

MnO

Na20

K~O

anZcalc

I

A

86,4

0,52

0,01

0,1

0,71

B

83--86

2--4

3--6

1--2

No.info,

0,17

1

021

O,Ol [ O,Ol No info. i

No information

3--5

T A B L E 6. P h y s i c o t e c h n i c a l P r o p e r t i e s of t h e T h e r m a l I n s u l a t i o n P l a t e s Indices

Values of the indices of plate A

B

Apparent density, g/cm s 0,96-- 1,02 0,85--1,10 Compressive strength, MPa 2,5--3,2 2,0 Thermal conduetivit in the 100-40022 range, W/(m 9 "K) No info. 3.209--0,260 Gas permeability, m2 1,53--3,6 No info. Contraction at 140022 with. a 60 1--3 No info. min hold, % T h e p r i m a r y d i s a d v a n t a g e o f p o u r e d l i n i n g s is t h e f a c t that t h e y a r e t h i c k e r than b r i c k o n e s , b r e a k ha r e m o v a l o f the s c r a p , and a t the s a m e t i m e a r e d i f f i c u l t to b r e a k up ha r e l i n i n g . The e x p e r i e n c e ha N o v o l i p e t s k M e t a l l u r g i c a l P l a n t in the u s e o f h i g h a l u m i n a p o u r e d m i x t u r e s f o r the l i n hag o f t u n d i s h e s h a s n o t o b t a i n e d w i d e u s e [2]. ~he l i n i n g w a s d o n e with p n e u m a t i c t a m p e r s with a c o m p r e s s e d a i r p r e s s u r e of 0 . 5 - 0 . 6 M P a , d r i e d , and h e a t e d with a g a s t o r c h with g r a d u a l r a i s i n g of the t e m p e r a t u r e to 1200~ with a 5 h h o l d a t this t e m p e r a t u r e . T h e a v e r a g e l i f e of the t a m p e d l i n i n g r e a c h e d 25 h e a t s . H o w e v e r , in c o n n e c t i o n with the f a c t t h a t the q u e s t i o n o f m e c h a n i z a t i o n of t h e w o r k ha p r e p a r i n g the t a m p e d h i g h a l u m i n a l i n i n g w a s n o t s o l v e d , and a l s o a s the r e s u l t o f e a r l y f a i l u r e s o f t h e m in r e m o v a l o f the s c r a p , the u s e o f s u c h l i n i n g s was d e e m e d u n d e s i r a b l e . At p r e s e n t a h i g h a l u m i n a m i x t u r e with a b o u t 70 wt. % o f A1203 with a p h o s p h a t e b i n d e r is u s e d o n l y f o r r a m m i n g the w e l l f o r t h e n o z z l e a n d , in c e r t a i n c a s e s , f o r l i n i n g the r o u n d e d p o r t i o n s in t u n d i s h e s of c o m p l e x configuration. E x p e r i e n c e in the p l a n t s o f the United S t a t e s Steel C o r p o r a t i o n in the u s e o f r a m m e d m o n o l i t h i c l i n i n g s with a w e i g h t p e r c e n t a g e of 85% a l u m i n a and a p h o s p h a t e b i n d e r , and a l s o o f l i n i n g s with a l a m e l l a r a l u m i n a b a s e and a s i l i c a t e b i n d e r , h a s shown t h a t a s t h e r e s u l t of t h e i r f a i l u r e in r e m o v a l of t h e s c r a p , the c o s t s f o r r e f r a c -

111

t o r y m a t e r i a l s for lining tundishes i n c r e a s e [3, 4]. ~lhe p r o p e r t i e s of the r e f r a c t o r y m a t e r i a l s used in the work~ ing l a y e r of the lining of tundishes used in pouring s e r i e s consisting of m o r e than two h e a t s in the plants of ~ i s company a r e shown in Table 1. In single pourings c h a m o t t e ladle b r i c k is used. At the point of i m p a c t of the s t r e a m of m e t a l with the bottom of the tundish, pads of dense h i g h - a l u m i n a or a l u m i n a - c h r o m i t e blocks, and, in s o m e c a s e s , h i g h - a l u m ina blocks produced by isostatic p r e s s i n g , a r e used. The use of s m a l l b r i c k s at this point is not r e c o m m e n d e d as a r e s u l t of the increased e r o s i o n of the joints. Long action of the molten m e t a l on the tundish lining c a u s e s i n c r e a s e d w e a r of the lining and o v e r h e a t i n g of the shell, and t h e r e f o r e the design of the linings of tundishes used for pouring a s e r i e s of heats includes the use of insulation protecting the shell f r o m overheating and also a thicker working l a y e r of m o r e - e x p e n s i v e w e a r r e s i s t a n t m a t e r i a l s providing the n e c e s s a r y r e l i a b i l i t y of the lining in long pourings (Fig. 2a). The s e r v i c e life of such linings r e a c h e s 100 h e a t s and the r e f r a c t o r y consumption is 0.7-0.9 kg p e r ton of s t e e l melted. The pads a r e r e p l a c e d a f t e r pouring each s e r i e s of heats. 'Ihe s e r v i c e life of the lining with single pourings (Fig. 2b) is about 30 h e a t s , and the consumption of r e f r a c t o r i e s 1.6-1.9 kg p e r ton of s t e e l melted. Such a high tundish lining life is obtained as a r e s u l t of the fact that the r e s i d u e s of m e t a l and slag a r e e a s i l y r e m o v e d in molten f o r m b e c a u s e of the sloped bottom of the tundish and the r o o f b u r n e r s in the lid. Tundish lids a r e used in the continuous b i l l e t - c a s t i n g m a c h i n e s of p r a c t i c a l l y all c o u n t r i e s . They a r e intended to provide t h e r m a l insulation and protection of the o p e r a t o r f r o m s p l a s h e s in filling of the tundish. D e pending upon the pouring t i m e , m e t a l lids or lids lined with various r e f r a c t o r y m a t e r i a l s m a y be used. In the plants of the United States Steel Company r e f r a e t o r y m a t e r i a l s [5], the c h a r a c t e r i s t i c s of which a r e shown in Table 2 , a r e used for lining the lids. In selecting the optimum profile of the tundish lining, the United States Steel Comp any has developed a c o m p u t e r p r o g r a m which takes into consideration the following e x p e r i m e n t a l p a r a m e t e r s : time of p r e l i m i n a r y heating and t e m p e r a t u r e to which the tundish is heated b e f o r e pouring; t i m e n e c e s s a r y for pouring a single heat; n u m b e r of s u c c e s s i v e h e a t s ; methods of r e m o v a l of the s c r a p ; production cycle (turnover t i m e and methods of p r e paring the s t e e l teeming ladle f o r the next heat). The s p e c i a l i s t s ofthe f i r m a s s u m e that the t e m p e r a t u r e of the m e t a l shell and the p o s s i b i l i t y of f o r m a t i o n of s c r a p a r e the deciding c r i t e r i a in selection of the o p t i m u m lining profile. The r e f r a c t o r y m a t e r i a l s used f o r lining the tundishes in the plants of the United Steel Comp any a r e given in Tables 3 and 4. It should be noted that in all plants with long pouring of a l a r g e n u m b e r of h e a t s in a s e r i e s a slide valve is used in the ladle instead of n o r m a l s t o p p e r . For the conditions of continuous b i l l e t - c a s t i n g m a c h i n e s of d o m e s t i c s t e e l p l a n t s , it m a y be a s s u m e d that based on the life of existing s t o p p e r rod a s s e m b l i e s , it is d e s i r a b l e to use slide valves in tandishes in pouring not l e s s than ten 300-ton heats in a s e r i e s . For p r o t e c t i o n of the lining f r o m f a i l u r e during r e m o v a l of the s c r a p , the British Steel Corporation has conducted investigations on the development of s p e c i a l lining coatings [6]. For the m a t e r i a l s of the coatings the following r e q u i r e m e n t s a r e specified: s i m p l i c i t y in application; insignificant c r a c k formation and low contraction in firing; peeling r e s i s t a n c e in p r e l i m i n a r y heating; r e s i s t a n c e to erosion and c o r r o s i o n during pouring; high r e f r a c t o r i n e s s ; and low adhesion c a p a c i t y with the r e f r a c t o r y l i n ing on the interface at o p e r a t i n g t e m p e r a t u r e s , which m a k e s it p o s s i b l e to s e p a r a t e the coating in r e m o v a l of the scrap. Basic {developed in the USA) and siliceous coatings, which a r e widely used for protection of the lining of s t e e l teeming l a d l e s , w e r e tested. The siliceous coating r e v e a l e d a tendency toward fusing with the lining, e s pecially in the p r e s e n c e of iron oxide. Magnesite and m a g n e s i t e - c h r o m i t e m i x t u r e s w e r e used in s e r v i c e . The p r o t e c t i v e m i x t u r e was applied both by guniting and m a n u a l l y (with a trowel). In the f i r s t c a s e m o r e rapid a p plication of the coating was provided, but it was m o r e difficult to obtain a uniform coating l a y e r thickness and the p r o b l e m of dust f o r m a t i o n a r o s e . Coatings applied b y this method had a higher tendency toward c r a c k i n g . T h e r e f o r e , application of a (10-15)-ram-thick coating with a trowel was p r e f e r r e d . With the u s e of p r o t e c t i v e coatings it was p o s s i b l e to i n c r e a s e the s e r v i c e life of the tundish lining to 12 p o u r s , which is 6 to 9 pours m o r e than the service life of an improtected lining. However, the effectiveness of the protective layer systematically became poorer as the result of its cracking in drying and preliminary heating.

112

To p r o t e c t tundish linings, in the F e d e r a l Republic of G e r m a n y the Rubenit m i x t u r e of the Didier Werke Company is used. Tee c h a r a c t e r i s t i c s of the m i x t u r e a r e 75 wt. % MgO, 3 wt. %, Cr203,: r e f r a c t o r i n e s s 1720~ growth at 1500~ 1.5%, and binder c h e m i c a l . The m i x t u r e includes g r a i n s of the 0 - 5 m m f r a c t i o n s . For the p u r p o s e of eliminating c r a c k i n g of m a g n e s i a coatings and i n c r e a s i n g their c o r r o s i o n r e s i s t a n c e , The Kawasaki Rodzai KK c o m p a n y of Japan u s e s as a binder a m i x t u r e of the condensed salt of orthophosphoric acid and slaked l i m e , and as the addition a powder of fused quartz [7]. The c h a r a c t e r i s t i c s of the coating used by the Kawasaki Rodzai KK c o m p a n y a r e : Weight %: MgO Cr203 Content, %, of the f r a c t i o n , # m : ->1000 1000-350 350-74 %74 Moisture content, % A p p a r e n t density, g / c m 3, a f t e r h e a t t r e a t m e n t at, ~ 110 1500 C o m p r e s s i v e s t r e n g t h , MPa, a f t e r h e a t t r e a t m e n t at, ~ 110 1500 L i n e a r c o n t r a c t i o n , ~0, a f t e r h e a t t r e a t m e n t a t , ~ 110 900 1300 1500 Coefficient of t h e r m a l expansion, a , 10-~~ -i

84-87 9-10 32-42 20-42 14-18 24-26 12-14 2.5-2.55 2.65-2.7 4 35 1.0 1.2 2.2 3.5 1.2

Data on the life of tundishes with this coating is not p r e s e n t e d . It should be noted that despite the significant quantity of work done on coatings of tundish linings, the m a j o r i t y of authors h a v e c o m e to the conclusion that coatings developed for the p u r p o s e of easing r e m o v a l of the s c r a p have not proven t h e m s e l v e s . More effective h a s been protection of tundish linings with t h e r m a l insulation plates [3, 4, etc.]. With the use of such plates it b e c o m e s possible to eliminate or significantly reduce p r e l i m I n a r y heating of the tundish b e f o r e pouring, as a r e s u l t of which this lining h a s r e c e i v e d the n a m e "cold." In p r e p a r i n g a cold lining in a tundish with a rei/nforcing lining of b r i c k or of a tamped o r poured m i x t u r e , t h e r m a l insulation plates with a thickness of about 30 ~ a r e installed (Fig. 3). The physicotechnical p r o p e r t i e s and c h e m i c a l composition of c e r t a i n t h e r m a l insulation plates a r e p r e s e n t e d in Tables 5 and 6. The plates w e r e m a d e of a finely ground f i l l e r a n d a r e i n f o r c i n g fiber (asbestos, s i l i c a t e s , c a l c i u m , a l u m inum). Silica, alumina, m a g n e s i u m oxide, and s i l i c a t e s m a y be used as the f i l l e r , and colloidal silica sol, sodium s i l i c a t e , s t a r c h , and p h e n o l - f o r m a l d e h y d e or u r e a - f o r m a l d e h y d e r e s i n s * as the binder. In d e t e r m i n i n g the r a tio between the f i l l e r , the r e i n f o r c i n g f i b e r , and the binder, the governing f a c t o r is obtaining the o p t i m u m c o m bination of the following p r o p e r t i e s : s t r e n g t h , specific h e a t , t h e r m a l conductivity, and r e s i s t a n c e to the action of molten m e t a l and slag. The use of plates of different compositions also depends upon the type of s t e e l and the c h a r a c t e r of continuous casting (individual heats or a s e r i e s of heats) [8]. In the Yawata, Japan plant of the Sin Nippon Seitetsu company, m e a s u r e m e n t s w e r e m a d e of the t e m p e r a ture of the s t e e l in a s i x - s t r a n d e o n t i n u o u s b i l l e t - c a s t i n g m a c h i n e during pouring in a p r e v i o u s l y heated tundish with a b r i c k lining and in a tundish with t h e r m a l insulation plates (Fig. 4) [9]. In the tundishes with the "cold" lining there is only s o m e reduction in t e m p e r a t u r e in the f i r s t minutes of pouring, while in the tundishes with the b r i c k lining the t e m p e r a t u r e d r o p s by 10-15~ during the whole pouring p r o c e s s . Data c h a r a c t e r i z i n g the reduction in t e m p e r a t u r e of s t e e l was also obtained in m e a s u r i n g the t e m p e r a t u r e of the tundish shell (Fig. 5). With the use of a b r i c k lining in 70 rain of pouring the shell t e m p e r a t u r e reached about 400~ while with the t h e r m a l insulation plate lining it was 3.5-4 times l e s s . + Patent No. 1469513

(Great Britain), 1977.

113

With the use of thermal insulation plates from the Foseco International company in plants of the U. S. Steel Corp., it was shown that the level of heat content of the thermal insulation plates is so low that at the temperatures of the surrounding medium it is thermally equivalent to the heat content of ladle brick previously heated to 1000~ [3]. It was also found that thermal insulation properties of the lining are maintained for the whole pouring cycle. For full thermal insulation of the metal in the tundish, thermal insulation mixtures, which are an integral element of the system, including the "cold" lining and bearing the name of'the "Carnex" system, are used in place of normal lids. The thermal insulation protective mixture is poured on the pool of metal immediately after filling of the ladle. Variations in the level of metal do not influence the thermal protection properties of the cover. After pouring, the scrap, together with the plates, is removed by overturning the ladle until full cooling of it, or after cooling it is removed with the use of a crane. With the use of thermal insulation plates in the plants of the U. S. Steel Corp., the life of the ladle lining has reached 40 heats and more [3]. In Sweden, with the use of thermal insulation plates of the Foseco-E-Boks company, the life of a lining has increased from 10-20 to 60-100 heats [8]. According to the data of the Foseeo Steel Mills International company (Great Britain), the Carnex system reduces the requirement for refractory brick to half, doubling the service life of the lining, i.e., the service life of the tundish lining increases to 50 to i00 heats [i0]. With the use of fused refractories, which are a recent accomplishment of the Foseco company, an even longer campaign of the permanent lining (more than 200 heats) is provided [ii]. In a plant of the British Steel Corporation the life of a lining with thermal insulation plates was increased from 3-6 to 40 heats. A record life result, 60 heats, was also reached [6]. For the purpose of eliminating splashing of metal in the tundish and the formation of crusts in filling of it, a special tubular splash protection device immersed into the bath of metal for 50-100 mm is used together with the thermal insulation plates. This device also makes it possible to partially eliminate turbulent flows [II]. Also known is the use of an antisplashing device of the Foseco Steel Mills International company which is a hollow box of refractory panels, which is placed withthe use of a crosspiece mounted on the edges of the ladle [12]. The device is immersed below the level of the pool of metal in the ttmdish to decrease the turbulence of the flows of metal. The advantages of the use of a "cold" lining in comparison with a normal one include a decrease in the specific consumption of refractories and power consumption, an improvement in the working conditions in the pouring area, a reduction in the costs for preparation of lids,simplification of the repair of tundishes, and the possibility of pouring metal with a reduced temperature. Therefore, the basic tendencies in world practice in the area of improving the lining of the tundishes of continuous billet-casting machines are the use of the computer in development of methods of lining with consideration of a multitude of pouring factors, a differentiated approach to the use of a design of lining in relation to the quantity of steel to be poured, and the use of a system of "cold" lining with the use of a thermal insulation cover instead of tundish lids.

LITERATURE

CITED

1. 2. 3. 4.

A.A. L.A. D.H. K.K.

5.

D.H. Hubile and R. L. Wessel, "Selection of refractories for continuous casting," in: Continuous Casting of Steel Proceedings of Anganter National, Biarritz, France, 3 May - 2 June 1976, Bradford (1977). C.W. Hardu, "Lining protection for continuous casting tundishes," in: Continuous Casting of Steel Proceedings of the International Conference, London-Biarritz, 1976, London (1977), pp. 3-6. T. Hanaoka, T. Yamamoto, M. Ioshimura, et al., Taikabutsu, 28, No. 227,561-564 (1976). I.O. Beekmann, "Carnex-ettnyttinfordringssystem for giutlador," Bergsmannen, No. 4,102-104 (1975). M. Nisivaki, T. Kosuge, and T. Takahashi, Taikabutsu, 28, No. 276 (11), 532-541 (1976)o D. Vinsent and I. H. Courtenay, "Carnex cold tundish system," in: Continuous Casting of Steel Proceedings of Anganter National, Btarritz, France, i [sic] May - 2 June 1976, Bradford (1977). I.H. Courtenay, Steel Times, 20~_5, 165-170 (February, 1977). Metal Bulletin Monthly, No. 73, 47 (1977).

6. 7. 8. 9. i0. ii. 12.

114

Alymov, M. I. Sokolov, A. M. Kruglikov, et al., Ogneupory, No. 2, 24-26 0-977). Tseitlin, K. N. Repenko, A. K. Mendelenko, et al., Ogneupory, No. 11,4-7 0-971). Houseman, Steel Times, 205, 174-177 (February, 1977). Koppmeyer and D. H. Hubile, Ironmaking and Steelmaking, No. 3(8), 113 (1976).