Cold Z-high® Mills
The Cold Z-high® mill was developed by Sendzimir to preserve the advantages of both the high-performance 20-high cluster mill and the economical 4-high mill during the milling process. It can roll superior products with stricter criteria for thickness, strength, or gauge accuracy measurements, making the Cold Z-high® mills particularly ideal for manufacturing automobile panels and aircraft shells.
How Cold Z-high® Mills Achieve Superior Results
The essential characteristics of the Cold Z-high® mill permit superior strip quality. Small work rolls are supported not by chocks, but instead by lateral support rolls, eliminating lateral flexure. The Cold Z-high® mill’s small work roll diameter also results in reduced roll separating forces, producing less deflection of the mill structure. Consequently, variation in “mill spring”, which occurs when the incoming strip gauge varies, is greatly lessened, causing inherently less variation in strip gauge and profile.
Our Cold Z-high® mills are equipped with both roll bending and axial shifting controls, with axial shifting being yet another engineering innovation that was pioneered and perfected by Sendzimir over 50 years ago. Both of these features provide excellent shape controllability.
The Sendzimir Cold Z-high® mill has outstanding operating flexibility. It can roll a great range of materials, gauges, and widths without needing to change rolls. Even when the work rolls are changed, the time required for this process is usually only two minutes or less. In addition, the small rolls can be cycled through the roll grinding process very quickly, providing our customers with time-saving results.
Lastly, this new configuration allows the cold Z-high® mill to take on heavier reductions per pass and makes thinner gauges possible. Harder materials can be rolled without the use of intermediate anneals, and a better surface can be produced when using our cold Z-high® mills.
Sendzimir Cold Z-high® Mill for Aluminium
Sendzimir mills have traditionally been associated with the superior cold rolling of hard-to-roll materials such as stainless steel. What is not as well known is that this concept can be profitably applied to hard aluminium alloys, such as those containing 3 to 5 percent magnesium. A version of the Sendzimir Cold Z-high® mill has been optimized for aluminium rolling by incorporating slightly larger work rolls. This change allows for greater draft reductions, with draft being a common hindrance that occurs when aluminium begins to break down.
Cold Z-high® Mill Installation Configuration Possibilities
There are 5 major cold Z-high® installation configurations as follows:
- As a retrofit into an existing 4-High mill, the “Cold Z-high® Package” is adapted to an operating mill where the mill can be reconverted back into a 4-High by withdrawing the “Z-high® Insert” and replacing the 4-High work rolls, chocks and drive spindles within 20 minutes.
- As a conversion of a 4-High mill to a “dedicated” cold Z-high® mill, optionally widening the mill at the same time.
- As a new cold Z-high® mill with smaller diameter back-up rolls, smaller chocks and smaller mill housings due to reduced RSF requirements of the Cold Z-high®, as compared to 4-High mill of the same width.
- As a new cold Z-high® / 4-High convertible mill similar to (3) above and built according to new mill specifications.
- As a tandem mill either in a process line, in-line with the other process line equipment, or, in a stand-alone single pass tandem mill configuration.
The versatility in installation configuration of a Z-high® results in a smaller capital investment than other alternatives.
Z-High Mill Section Specifications
| Mill Section | Nominal Work Roll Diameter | Intermediate Roll Diameter (Max/Min) | Max Strip Width | RSF |
|---|---|---|---|---|
| ZR 62 | 1.12” | 2.75 – 2.5” | 10” | 12,000 lb/in |
| 28.4mm | 70 – 64 mm | 254mm | 214 kg/mm | |
| ZR 63 | 1.35” | 3.3 – 3” | 12” | 14,000 lb/in |
| 34.3mm | 84 – 76 mm | 305mm | 250 kg/mm | |
| ZR 64 | 1.8” | 4.4 – 4” | 16” | 19,000 lb/in |
| 45.7mm | 112 – 102 mm | 406mm | 339 kg/mm | |
| ZR 65 | 2.25” | 5.5 – 5” | 20” | 24,000 lb/in |
| 57.2mm | 140 – 127 mm | 508mm | 429 kg/mm | |
| ZR 66 | 2.7” | 6.6 – 6” | 24” | 29,000 lb/in |
| 68.6mm | 168 – 152 mm | 610mm | 518 kg/mm | |
| ZR 67 | 3.15” | 7.7 – 7” | 30” | 33,000 lb/in |
| 80.0mm | 196 – 178 mm | 762mm | 589 kg/mm | |
| ZR 68 | 3.6” | 8.8 – 8” | 32” | 37,000 lb/in |
| 91.4mm | 224 – 203 mm | 813mm | 661 kg/mm | |
| ZR 69A | 3.6” | 9.7 – 9” | 39” | 37,000 lb/in |
| 91.4mm | 246 – 229 mm | 991mm | 661 kg/mm | |
| ZR 73 | .846” | 2.992 – 2.717” | 8” | |
| 21.5mm | 76 – 69 mm | 203mm | ||
| ZR 610A | 4.1” | 10.7 – 10” | 40” | 44,000 lb/in |
| 104.1mm | 272 – 254 mm | 1016mm | 786 kg/mm | |
| ZR 611A | 4.625” | 11.75 – 11” | 48” | 53,000 lb/in |
| 117.5mm | 298 – 279 mm | 1219mm | 946 kg/mm | |
| ZR 612A | 5.0” | 13 – 12” | 52” | 58,000 lb/in |
| 127.0mm | 330 – 300 mm | 1321mm | 1,036 kg/mm | |
| ZR 613A | 5.1” | 14 – 13” | 64” | 61,000 lb/in |
| 129.5mm | 356 – 330 mm | 1626mm | 1,089 kg/mm | |
| ZR 614A | 6.3” | 15.1 – 14” | 68” | 65,000 lb/in |
| 160.0mm | 384 – 356 mm | 1727mm | 1,161 kg/mm | |
| ZR 615A | 5.9” | 16.2 – 15” | 72” | 68,000 lb/in |
| 149.9mm | 411 – 381 mm | 1829mm | 1,214 kg/mm | |
| ZR 616A | 6.1” | 17.2 – 16” | 76” | 70,000 lb/in |
| 154.9mm | 437 – 406 mm | 1930mm | 1,250 kg/mm | |
| ZR 617A | 6.1” | 18.3 – 17” | 76” | 72,000 lb/in |
| 154.9mm | 465 – 432 mm | 1930mm | 1,286 kg/mm | |
| ZR 618A | 6.3” | 18.6 – 17.3” | 85” | 75,000 lb/in |
| 160.0mm | 472 – 439 mm | 2159mm | 1,339 kg/mm |