Development of Sheet Bar Milling Technology for High Temperature Steel.

Fully continuous hot finishing line, so called "Endless hot strip rolling process", has started in operation for the first time in the world at our works. In this process, sheet bars are joined at the entry side of the hot finishing mill and then rolled continuously. If a joint with a raised area is rolled, an overlap defect will occur in the initial stage of rolling. To prevent this problem, a method of removing the raised portion on joined sheet bars simultaneously using milling was developed This paper describes the main technologies which were developed in realizing the milling of high temperature steel surface over 900 °C. The following experimental results which used saw type cutter made by S55C are confirmed (1) Forming of chip adhesion on the cutting edge depend on the milling speed, and good milling achieved under the speed over 80 m/s. (2) Under the milling condition mentioned above, wearing progress speed of cutting edge is extremely slow and the milling of 6500 cycles achieved under milling length of 300 mm/cycle. (3) Under this specification of milling speed, the production plant has installed in 1995 and it is operating satisfactorily without trouble.