Method and apparatus for continuous rolling by welding the rolled materials at an intermediate stage of a rolling line

A method for continuous rolling comprising the sequential steps of:

• successively rolling a plurality of steel billets by a first rolling mill group;
• pinching a succeeding steel billet after being rolled in the first rolling mill group by a set of pinch rolls;
• detecting the transfer speed of the succeeding steel billet and the position of a front end of the succeeding steel billet;
• detecting the transfer speed of a preceding steel billet and the position of a rear end of the preceding steel billet;
• controlling the transfer speed of the succeeding steel billet by adjusting the rotational speed of the pinch rolls so that the front end of the succeeding steel billet contacts the rear end of the preceding steel billet at a specified position in a travelling flash-butt welding machine;
• joining the rear end of the preceding steel billet with the front end of the succeeding steel billet by flash-butt welding using the travelling flash-butt welding machine to form a continuous steel billet, after the front end of the succeeding steel billet has contacted the rear end of the preceding steel billet, while the travelling flash-butt welding machine moves at a speed synchronous with the transfer speed of the continuous steel billet;
• removing burr from a welded portion on the continuous steel billet;
• and
• continuously rolling the continuous steel billet, after removing the burr, by a second rolling mill group located downstream from the burr-removing step.