Method and apparatus for cutting and welding steel strips

Claim 1

In a continuous processing line, in which facing ends of preceding and succeeding steel strips are cut and the cut end surfaces are caused to abut as butt surfaces and are welded along the butt line formed by the abutting, a method of cutting and welding steel strips, in which, when cutting, abutting and welding facing ends of the steel strips, at the time of the cutting or abutting prior to the welding, either said preceding steel strip or said succeeding steel strip is attracted by an electromagnetic chuck in at least one work table in said continuous processing line, and said electromagnetic chuck is moved to pull said preceding or succeeding steel strip until it strikes a reference block disposed parallel to the center line of said continuous processing line to align one edge of said preceding or succeeding steel strip to be parallel to said center line.

Claim 15

A method for butt-welding preceding and succeeding steel strips using a laser beam, at a continuous processing line, in which a trailing end of said preceding strip and a leading end of said succeeding steel strip are cut to form a trailing end edge and a leading edge, respectively, and then said trailing end edge and said leading end edge are butted against each other, thereby forming a butting line between said trailing end edge and said leading end edge and thereafter said preceding and succeeding steel strips are butt-welded by running a laser beam torch along a torch running line in conformity with said butting line, characterized in that said method comprises the steps of: aligning one side edge of said preceding or succeeding steel strip to be parallel to a center line existing in said continuous processing line, by aligning an electromagnetic chuck, which is moved to pull said preceding or succeeding steel strip until it is brought into contact with a reference block disposed parallel to the center line of said continuous processing line, said aligning unit being provided at a position adjoining at least one work table in said continuous line; cutting said trailing end of said preceding steel strip to form a trailing end edge and cutting said leading end of said succeeding steel strip to form a leading end edge; forming a butting line between said trailing end edge and said leading end edge comprising the steps of positioning said trailing end registor with said torch running line, magnetizing said trailing end edge by means of an electromagnetic chuck existing beneath said laser beam torch so as to generate a magnetic attraction in said trailing end, directing said leading end edge downwardly and obliquely toward said trailing end edge having magnetic attraction therein, and approaching and butting said leading end edge against said trailing end edge; and butt-welding said trailing end edge and said leading end edge along said butting line by running said laser beam torch along said torch running line.

Claim 16

A method for butt-welding preceding and succeeding steel strips using a laser beam, at a continuous processing line, in which a trailing end of said preceding strip and a leading end of said succeeding steel strip are cut to form a trailing end edge and a leading edge, respectively, and then said trailing end edge and said leading end edge are butted against each other, thereby forming a butting line between said trailing end edge and said leading end edge and thereafter said preceding and succeeding steel strips are butt-welded by running a laser beam torch along a torch running line in conformity with said butting line, characterized in that said method comprises the steps of: aligning one side edge of said preceding or succeeding steel strip to be parallel to a center line existing in said continuous processing line, by aligning an electromagnetic chuck, which is moved to pull said preceding or succeeding steel strip until it is brought into contact with a reference block disposed parallel to the center line of said continuous processing line, said aligning unit being provided at a position adjoining at least one work table in said continuous line; cutting said trailing end of said preceding steel strip to form a trailing end edge and cutting said leading end of said succeeding steel strip to form a leading end edge; forming a butting line between said trailing end edge and said leading end edge comprising the steps of positioning said trailing end registor with said torch running line, magnetizing said trailing end edge by means of an electromagnetic chuck existing beneath said laser beam torch so as to generate a magnetic attraction in said trailing end, directing said leading end edge downwardly and obliquely toward said trailing end edge having magnetic attraction therein, and approaching and butting said leading end edge against said trailing end edge; and butt-welding said trailing end edge and said leading end edge along said butting line by running said laser beam torch along said torch running line.