Title:
【発明の名称】長尺鋼材を連続的に熱間圧延する方法
Document Type and Number:
Japanese Patent JP2857279
Kind Code:
B2
Abstract:
A method and apparatus for continuously hot rolling ferrous long products which employs a "post finishing" block of roll stands downstream from the finishing stands of the mill. Water boxes or other like cooling devices are preferably interposed between the last mill finishing stand and the postfinishing block. The post finishing block includes at least two reduction stands followed by at least two sizing stands. The reduction stands have an oval-round pass sequence, and the sizing stands have a round-round pass sequence. Clutches or other equivalent means are employed in the drive train to permit changes to be made between the interstand drive speed ratios of at least the reduction stands, and also between some or all of the remaining sizing stands. A fixed rolling schedule is provided for all roll stands in advance of the finishing stands. Thus, the finishing group is supplied with a first process section having a substantially constant cross sectional area and configuration. The first process section is passed through the finishing group and rolling occurs in either none, some, or all of the finishing roll stands, depending on the size of the desired end product. The product then continues through water cooling boxes to the post finishing block as a second process section. The interstand drive speed ratios of the roll stands in the post finishing block are appropriately adjusted to accommodate rolling of the second process section. The total reductions affected in the initial reduction stands of the post finishing block are well above 14%, thereby producing an increased energy level in the product sufficient to create a substantially uniform distribution of fine grains. Typically, such total initial reductions will be on the order of about 20-50%. Significantly lighter reductions on the order of 2-15% are taken in the final round-round pass sequences of the post finishing block to obtain the desired close sizing tolerances in the finished product. The time interval between the higher reduction affected in the oval-round pass sequence and the lighter reductions affected during sizing in the round-round pass sequence is such that the resulting grain size throughout the product cross section will not vary by more than 2, and in most cases by less than 1 ASTM grain size number.
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Inventors:
TERENSU EMU SHOOA
HARORUDO II UTSUDORO
MERICHEA PUTSUCHOSUKII
HARORUDO II UTSUDORO
MERICHEA PUTSUCHOSUKII
Application Number:
JP11366792A
Publication Date:
February 17, 1999
Filing Date:
May 06, 1992
Export Citation:
Assignee:
MORUGAN KONSUTORAKUSHON CO
DAIDO TOKUSHUKO KK
DAIDO TOKUSHUKO KK
International Classes:
B21B1/10; B21B1/16; B21B1/18; B21B35/02; B21B13/00; B21B45/02; B21B; (IPC1-7): B21B1/18; B21B1/16
Attorney, Agent or Firm:
Hidekazu Miyoshi (1 outside)