US 12,459,021 B2
Method for mitigating the effects of coil collapse on hot strip mill coils
Yuefa Xiao, Tinley Park, IL (US)
Assigned to ArcelorMittal, Luxembourg (LU)
Filed by ArcelorMittal, Luxembourg (LU)
Filed on May 2, 2024, as Appl. No. 18/653,153.
Application 18/653,153 is a continuation of application No. 17/044,411, granted, now 11,998,966, previously published as PCT/IB2019/052600, filed on Mar. 29, 2019.
Claims priority of application No. PCT/IB2018/052328 (WO), filed on Apr. 4, 2018.
Prior Publication US 2024/0269724 A1, Aug. 15, 2024
Int. Cl. B21C 47/04 (2006.01); B21C 47/02 (2006.01); B21C 47/06 (2006.01); B21C 47/08 (2006.01); B21C 47/24 (2006.01)
CPC B21C 47/04 (2013.01) [B21C 47/02 (2013.01); B21C 47/063 (2013.01); B21C 47/08 (2013.01); B21C 47/24 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for mitigating the effects of coil collapse on hot strip mill coils without insertion of a mechanical means into the coil eye to limit sagging, the method comprising the steps of:
producing a hot rolled steel sheet in a hot strip mill;
forming a hot strip coil by coiling the hot rolled steel sheet around a mandrel on a downcoiler;
orienting the hot strip coil such that the coil eye axis of the hot strip coil is in a horizontal direction;
removing the hot strip coil from the mandrel/downcoiler;
pre-sagging the hot strip coil to create an initial sag by allowing gravity to cause the coil to sag in a first specific direction for a first period of time;
without inserting a mechanical means into the coil eye to limit sagging, modifying a direction of the sag caused by the force of gravity to a direction perpendicular to the first specific direction and allowing gravity to sag the coil in the modified direction for a second period of time;
the hot strip coil being cooled enough by the end of the second period of time such that the rate of sagging of the hot strip coil has become negligible thereby mitigating the initial sag;
wherein the first period of time and the second period of time are chosen such that the initial sag created during the first period of time is mitigated by the perpendicular sag during said second period of time; and
wherein the pre-sagging step the coil becomes pre-sagged without rotation about said coil eye axis, for said first period of time, and wherein the without inserting step is performed without additional rotation upon said coil eye axis for said second period of time,
wherein the step of pre-sagging the hot strip coil includes the steps of:
placing the hot strip coil onto a coil car, the coil car having a coil stand to hold and support the coil, the coil resting on a coil bottom;
holding the hot strip coil, without rotation about said coil eye axis, for the first period of time, wherein the first period of time is between 2 and 6 minutes, the pre-sagging creating a maximum coil eye diameter (Dmax) dimension in the direction perpendicular to the force of gravity.