Method and installation for introducing a cored wire into a bath of molten metal
A method for introducing a cored wire into a bath of molten metal includes extracting the cored wire from a reel, and making it run into the molten metal bath, one part of the path traveled by the cored wire being formed in a guide tube with a distal end at a defined height above the metal bath's surface. The cored wire is driven and straightened under conditions practically not altering its substantially circular cross section and allowing it to be vertically introduced and penetrate into the depth of the bath. Elements for driving the cored wire from a reel, a guide tube for guiding the cored wire, and elements for straightening the cored wire are placed in front of its entry into the guide tube, the straightening elements giving the cored wire a straight direction without altering its circular cross section.
1. A method for introducing a cored wire ( 2 ) into a bath of molten metal ( 3 ), comprising:
extracting the cored wire from a reel ( 9 ); and
making the cored wire run into the bath of metal ( 3 ), one part of the path travelled by the cored wire being formed in a guide tube ( 13 ), a distal end ( 32 ) of which is at a defined height (H) above a surface (PP′) of the bath of metal ( 3 ),
wherein the cored wire ( 2 ) is driven and subjected to a straightening operation, under conditions practically not altering a substantially circular cross-section of the cored wire and allowing the cored wire to be introduced and penetrate into a depth of the bath of metal ( 3 ) in a vertical direction.
2. The method according to claim 1 , wherein the guide tube ( 13 ) is disposed vertically above the bath, the straightening operation is carried out by passage of the cored wire ( 2 ), before entry of the cored wire into the guide tube ( 13 ), through a plurality of sets ( 18 ) of two press rolls ( 19 , 20 ), contact between the cored wire and each press roll being along a contact surface or along at least two lines of contact.
3. The method according to claim 2 , wherein the press rolls ( 19 , 20 ) comprise contact faces ( 21 , 22 ) with said cored wire ( 2 ), the contact faces ( 21 , 22 ) being concave.
4. The method according to claim 3 , wherein the concave contact faces ( 21 , 22 ) have a radius of curvature, and the radius of curvature of the concave contact faces ( 21 , 22 ) of the press rolls is substantially the same as that of the cored wire ( 2 ).
5. The method according to claim 2 , characterized in that the cored wire is held laterally during passage of the cored wire between the sets ( 18 ) of press rolls ( 19 , 20 ) by interposed guide tubes ( 30 ).
6. The method according to claim 1 , wherein the driving of the cored wire is carried out at the same time as its straightening, some of the press rolls ( 19 ) being drive rolls.
7. Method according to claim 1 , wherein the driving of the cored wire is carried out upstream and independently of its straightening, and in that during the straightening operation the cored wire ( 2 ) extends in a vertical direction.
8. The method according to claim 1 , wherein ratio between an inside diameter of the guide tube, and optionally of the interposed tubes, and an outside diameter of the cored wire is of the order of 1.5:1 to 5:1.
9. The method according to claim 1 , further comprising:
protecting the distal end ( 32 ) of the guide tube ( 13 ) on a path beyond said end ( 32 ), in proximity to the bath ( 3 ), by a protective end-piece ( 34 ).
10. The method according to claim 1 , wherein the cored wire is extracted from a core of the reel ( 9 ).
11. The method according to claim 1 , further comprising:
protecting the distal end ( 32 ) of the guide tube ( 13 ), and the cored wire ( 2 ) on its path beyond said end ( 32 ), in proximity to the bath ( 3 ), by a protective end-piece ( 34 ).