Continuous casting method and corresponding apparatus

Patent metadata

Field	Value
Publication number	US-10758972-B2
Application number	US-201816333781-A
Country	US
Kind code	B2
Filing date	Jun 15, 2018
Priority date	Jun 16, 2017
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

Method for the continuous casting of a product (P) along a curved casting line (18), provided with a crystallizer (11) having a tubular cavity (12) with a polygonal cross section defined by a determinate number of sides (n). The product (P) exiting from the crystallizer (11) is curved along the casting line (18) by support and curving rollers (19) and without the aid of lateral containing sectors of the cross section of the product (P).

First claim

The invention claimed is:

1. Method for the continuous casting of a product (P), chosen from billets or blooms, along a curved casting line ( 18 ), said method providing to cast a liquid metal (M) in a crystallizer ( 11 ) that is provided with a tubular cavity ( 12 ) having a polygonal cross section defined by a determinate number of sides (n), wherein said product (P) exiting from said crystallizer ( 11 ) is curved along said casting line ( 18 ) by support and curving rollers ( 19 ) and without the aid of lateral containing sectors of the cross section of said product (P), in that said method comprises setting a productivity (P r ) of said casting line ( 18 ) chosen inside a work field delimited by a first achievable maximum productivity (P rmaxb ), and by a second achievable maximum productivity (P rmaxt ), said first achievable maximum productivity (P rmaxb ) being defined by the expression:

P
rmaxb

=

0.9
*
ρ
*

K
2

*

(

n

tan
⁡

(

π
n

)

)

wherein:
ρ: is the density of the solid metal,
K: is a constant comprised between 0.04 and 0.05; and
n: is the number of sides of said polygon of the tubular cavity ( 12 );
and said second achievable maximum productivity (P rmaxt ) being defined by the expression:

P
rmaxt

=

0.9
*
ρ
*

D
2

*

(

K
s

t
min

)

2

*
n
*

tan
⁡

(

π
n

)

wherein
ρ: is the density of the solid metal;
D: is a size of the cross section of said product (P);
K S : is a solidification constant determined as a function of the material of said liquid metal (M);
t min : is a preset minimum thickness of said product (P);
n: is the number of sides of said polygon of the tubular cavity ( 12 );
in that said productivity (P r ) is set so that it is less than or equal to the minimum value between said first maximum productivity (P rmaxb ) and said second maximum productivity (P rmaxt ), and in that said method comprises supplying said crystallizer ( 11 ) having a number of sides (n) determined so as to obtain said set productivity (P r ).

2. Method as in claim 1 , wherein it provides to determine an optimal number of sides (n ott ) suitable to optimize said productivity (P r ), said optimal number of sides (n ott ) being determined by the expression:

n
ott

=

int
(

π

arctan
⁡

(

K

K
s

*

t
min

D

)

)

wherein
int: represents the integer number approximated by defect of the expression comprised between the brackets;
K: is a constant comprised between 0.04 and 0.05;
K S : is a solidification constant determined as a function of the material of said liquid metal (M);
D: is a size of the cross section of said product (P);
t min is a preset minimum thickness of said product (P).

3. Method as in claim 2 , wherein if said crystallizer ( 11 ) has a number of sides (n) fewer than said number of optimal sides (n ott ), the method provides to cast said product (P) at a casting speed expressed by the relation:
V c ≤( K/W ){circumflex over ( )}2

wherein W is the length of the side of said polygon.

4. Method as in claim 2 , wherein if said crystallizer ( 11 ) has a number of sides (n) bigger than said number of optimal sides (n ott ), the method provides to cast said product (P) at a casting speed expressed by the relation:

V
c

≤

(

K
s

t
min

)

2

.

5. Method as in claim 1 , wherein said number of sides (n) is chosen from between 4, 6 and 8.

6. Method as in claim 1 , wherein said casting line ( 18 ) has a productivity (P r ) greater than or equal to 60 t/h.

7. Method as in claim 1 , wherein said tubular cavity ( 12 ) is defined by a plurality of walls ( 14 ) defining the sides of the crystallizer ( 11 ), and in that the walls ( 14 ) of the crystallizer ( 11 ) are all the same size.

8. Method as in claim 1 , wherein said safety minimum thickness t min is comprised between 7 mm and 9 mm, even more preferably about 8 mm.

Assignees

• Danieli Off Mecc

Inventors

• Andreatta Daniele
• De Luca Andrea
• Entesano Luca
• Isera Massimiliano
• Flumian Fabio

Classifications

• B22D11/0406 Primary

  Moulds with special profile · CPC title

• B22D11/009 Primary

  of work of special cross-section, e.g. I-beams, U-profiles · CPC title

• B22D11/142

  for curved casting · CPC title

• B22D11/18 Primary

  for pouring (B22D11/20 takes precedence) · CPC title

• B22D11/1246

  Nozzles; Spray heads · CPC title