Method of continuously hot-rolling steel pieces

Claim 1

A continuous steel hot-rolling method in which flexible hot steel pieces of a thickness of between 30-60 mm, a predetermined length, and maintained at a high temperature, are successively bonded in series to form a continuous train of hot steel pieces for a continuous rolling by a rolling mill, the method comprising the steps of: bringing the trailing end of a preceding hot steel piece and the leading end of a succeeding hot steel piece in close proximity to each other while said hot steel pieces are at a temperature of from 1,000° C. to 1,100° C. and travelling on the upstream side of said rolling mill; shearing the trailing end portion of said preceding hot steel piece and the leading end portion of said succeeding hot steel piece while they are held in close proximity to each other; immediately after shearing, heating the trailing end of said preceding hot steel piece and the leading end of said succeeding hot steel piece by a high frequency heating means to a desired temperature of 1,250° C. to 1,450° C. while said hot steel pieces are travelling; pressing the heated leading end surface of said succeeding hot steel piece against the heated trailing end surface of said preceding hot steel piece to bond said hot steel pieces within about 20-35 seconds while said hot steel pieces are travelling to thereby form a continuous train of the hot steel pieces; said heating and pressing being conducted at a heating temperature and a pressing force in a range determined in dependence upon the material of the hot steel pieces to be bonded; storing a predetermined length of said preceding hot steel piece on an upstream side of said rolling mill to absorb a difference between a speed at which said preceding hot steel piece is introduced into said rolling mill and a speed at which said hot steel piece end surfaces are moved during bonding thereof; and leading said continuous train of hot steel pieces into said rolling mill thereby continuously rolling said hot steel pieces.