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Cold Rolling Mill

Lineup of HCM and UCM Mills

In order to meet the diverse range of customer needs regarding cold rolling, we have developed various types of HC and UCM mills that are in use for actual production. The first type we developed was a 6Hi HCM mill with intermediate roll shift function, to which we then added further intermediate roll bender functions. By adding work roll shift functions, various roll bender functions, and other functions, we created a UCM mill with smaller roll diameters, as well as the rest of our current lineup of 7 types, which are in use in all kinds of rolling operations.

Lineup of HCM and UCM Mills

  • HCM: 6-high IMR shift type HC-MILL
  • HCW: 4-high WR shift type HC-MILL
  • HCMW: 6-high WR & IMR shift type HC-MILL
  • UCM: 6-high IMR shift type HC-MILL with IMR bender
  • UCMW: 6-high WR & IMR shift type HC-MILL with IMR bender

6Hi UCM Mill

We offer the 6Hi UCM mill to meet a broad range of customer needs. This mill provides the high quality, improved productivity, energy savings, and other characteristics that are demanded in cold rolling, as well as superior shape control and stable operation. By reducing the diameter of the work rolls, this UCM mill achieves both high reduction rolling and lower rolling energy consumption. The rolling mill adds roll coolant control to the 3 existing types of control (intermediate roll bender, intermediate roll shift, work roll bender) to deliver superior shape control capability. This machine is in wide use in all types of cold rolling fields, including tandem cold mills and reversing cold mills.

Photo of the 6Hi UCM Mill
6Hi UCM Mill

Schematic of the 6Hi UCM Mill
Schematic of the 6Hi UCM Mill

Principle of UCM Mill Shape Control

With conventional 4Hi mills, the rolling reaction force results in deflection of the backup roll (BUR) and work roll (WR), flattening of the WR, and other problems during rolling. This leads to unevenness in the rolled material strip thickness and to shape problems. A UCM mill shifts an intermediate roll (IMR) in the axial direction according to the strip width of the rolled material. This reduces the portion where the WR bending load acts outside the strip width (harmful contact area), reducing WR deflection and providing superior shape control performance and stable rolling.

4Hi-MILL
4Hi-MILL

IDEAL-MILL
IDEAL-MILL

UCM-MILL
UCM-MILL

Changes in the Strip Thickness (Strip Width) During Continuous Rolling

Continuous rolling mills require functions which allow constant, stable supply of a strip with good shape when there are rolling schedule changes such as strip thickness or strip width (flying schedule changes), and in cases of changes to the thermal crown. If the strip width is changed while the mill is running, the rolling conditions also change. With 4Hi mills, it is extremely difficult to make flying changes to the strip width without causing large disruption in the strip shape and product shape problems. However the UCM mill shifts the IMR position according to the strip width, allowing stable and easy flying changes to the strip thickness or strip width without any shape disruption.

Flying Shape Width Change

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20Hi Sendzimir Mill, HZ Mill

Our company produces the Sendzimir mill under license from the U.S. company, Sendzimir Inc. The Sendzimir mill utilizes ultra-small diameter work rolls to efficiently roll high-hardness materials such as stainless steel, magnetic steel strips, and phosphor bronze.

To the original high rolling reduction capacity of the mill, we have added the double AS-U (shape control mechanism) that was developed originally by our company. This provides shape control capability that is superior to that of an ordinary Sendzimir mill. With the HZ mill where the housing is divided into an upper and lower housing, a large roll gap can be created for threading, and this mill has been particularly well evaluated for rolling of magnetic steel strip materials.

Double AS-U
Double AS-U (Shape Control Mechanism)


HZ Mill

New Sendzimir (KZR) Mill

The Sendzimir (ZR) mill is a mill for the cold rolling of hot-rolled coils of stainless steel and other hard materials to the designated product thickness and strip shape accuracy. The ultra-small diameter rolls are firmly supported in a 20Hi roll cluster arrangement.
With a conventional Sendzimir (ZR) mill, the bending system for the backing bearing shafts that control the shape (the AS-U system) contains only 2 (shafts B, C) of the 4 upper backing bearing shafts (shafts A, B, C, D). As a result, the strip shape control capability is insufficient, and there are problems which make high-speed rolling with high rolling reduction difficult. To resolve this, we developed and produced the new Sendzimir (KZR) mill. This mill is equipped with a double AS-U system for two upper backing bearings shafts A and B, together with bearing shafts C and D, and also includes new automatic shape control that utilizes fuzzy logic control. Because this KZR mill is capable of high-speed rolling with high rolling reduction, it can deliver a boost to productivity for rolling of stainless steel and other hard materials.

Detailed View of Double AS-U Section

Detailed View of Double AS-U Section

Schematic of the New Sendzimir (KZR) Mill

New Sendzimir (KZR) Mill

New Sendzimir (KZR) Mill

HZ Mill (New Sendzimir Mill with Split Housing)

Because the housing is split into upper and lower sections, there is a large gap between the upper and lower work rollers. This makes threading and the strip cutting cobble process easier.

In a conventional Sendzimir (ZR) mill, the 20Hi rollers are supported in a cluster arrangement and are contained inside a mono-block structure housing. Although this structure is compact, the gap between the upper and lower work rolls is small, and extra work is required in some cases for the threading and the strip cutting cobble processes.
For this reason, we developed and produced the new split housing Sendzimir (HZ) mill which splits the mono-block housing into an upper and lower section, supported by 2 outer housings. Because this HZ mill has a housing that is split into an upper and lower section, the gap between the upper and lower work rolls is large, facilitating the threading and the strip cutting cobble processes. In addition, unlike the mono-block ZRM, the work rolls can be used in nearly their full range regardless of the diameter of intermediate rolls 1 and 2, for greater operability.

HZ Mill Internal Structure
HZ Mill Internal Structure
HZ Mill (New Split-Housing Sendzimir Mill)
HZ Mill (New Split-Housing Sendzimir Mill)

12Hi CR Mill

The 12Hi CR mill is a mill developed independently by Mitsubishi-Hitachi Metals Machinery for the rolling of stainless steel, copper alloys, and nickel alloys. Compared with a Sendzimir mill, the number of roll steps is fewer and it provides greater shape control performance. In addition, the work roll diameter range is significantly broader, allowing high accuracy rolling of soft, medium, and hard materials.

The upper/lower backup roll frame is split, allowing automated work roll changes and offering good threading performance and maintenance characteristics. It is also possible to use the housing of an existing 4Hi mill and modify the system. An addition, an oscillation function has been added to the intermediate roll, preventing the backup bearing mark from being transferred to the strip, and this mill is used as a rolling mill for materials which have strict surface requirements.

  • 12-roll arrangement (Work roll x 2, IMR x 4, BUR x 6)
  • Split-type BUR
  • Exceptional shape control
  • Small-diameter work rolls provide high rolling reduction.
  • Modification of a conventional mill using the existing housing is also possible.

Photo Inside Plant

Basic Structure of CR MILL

Photo of CR Mill
CR Mill

Photo of CR Mill
CR Mill

4Hi Mill

This product represents the starting point for our more-than 50 years of rolling mill design and development. At present, this mill is used in large numbers in the skinpass mill and temper mill fields.

  • Work roll shift mill
  • Pair cross mill
  • Conventional-type mill

System Diagram