PURPOSE: To reduce time required for transferring a steel pipe when it is polyethylene-coated under a T-die system, and enhance its productivity.
CONSTITUTION: In order to impart necessary hardness to a coating before a coated portion reaches a feed roll 5 at an aft step, forced gascooling devices 6 are set just behind an undercoating device 2 or a T-die 3 to cool the coating. In the case of cooling by gas, no adverse effect on the coating is caused by gas because, unlike water, gas is not dragged into the coating. Therefore, gas can be blown to the coating in the vicinity of the T-die or even before application of the polyethylene coating. Accordingly, a waiting time required for the natural cooling of the coating is substantially saved, and the processing time can greatly be reduced.
HORIKOSHI HIROMITSU
AZUMA KENICHIRO
SAN SABURO
KIYOTO YASUMITSU
