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20-High Mills

Sendzimir 20-High Mills are known worldwide for their ability to roll extremely hard materials to very thin gauges with few, if any, intermediate anneals. They consistently maintain quality aspects that are difficult, if not impossible, to duplicate with other mills.

Advantages Of Using 20-High Mills

Sendzimir Cluster mills have numerous advantages over other mills. One specific advantage is that they make good jobbing mills. It is quite easy to vary the strip material, strip width and/or the strip thickness and set the mill up quickly and efficiently in a matter of minutes, not hours.

The smallest mills roll 4” (100 mm) wide strip down below 0.0001” (2.5 microns). The largest mills roll mostly intermediate gauge materials at widths up to 80” (2 meters) at speeds in excess of 3280 Fpm (1000 Mpm). The small size of the work roll permits superior reductions on very hard materials, such as stainless steel or titanium.

Most rolling mills are custom designed for a specific customer application as well.

  • Flex Backing Assemblies and Segmented Idler Rolls
  • Zero Crown Housing
  • Split Zero Crown Housing
  • Positionable Sprayboards

Sendzimir’s 20 High Mills offer crucial manufacturing advantages: quality of surface, thin gauge capability, gauge tolerance, and shape.

Quality of Surface

The Work Roll in a Sendzimir Cluster mill is non-chock supported, and thus, can easily be pulled out of the mill by hand. The larger mills will require a roll change cart due to the mass of the roll. In any event, the Work Rolls can be changed in 1 to 3 minutes depending on mill size. Most Sendzimir mills roll a multiple pass schedule (5-7 passes). On the last pass, the Work Roll can be changed out for a fresh pair, and thus, the surface quality of the strip will reflect that fine polish on a new set of Work Rolls. For this reason, most of the 400 series architectural stainless in the world is rolled on Sendzimir mills as the surface finish is paramount.

Strip Shape

The Sendzimir 20-High mill has several shape adjusting capabilities. These are:

  • Lateral movement of the Tapered (opposed) 1st Intermediate Rolls.
  • As-U-Roll control of the secondary crown eccentrics in each saddle across the width of the mill.
  • Double As-U-Roll Mill Configuration
  • Flexible Backing Assemblies and Segmented Idler Rolls

The small diameter of the work rolls also permits greater responsiveness to shape control mechanisms.

Thin Gauge Capacity and Gauge Tolerance

The cascading structure of the 20-High design allows for a very small Work Roll Diameter. The advantage of this work roll diameter is that it provides for a high specific pressure on a very small contact area. As a result, we can take higher reductions at thin gauges with up to 80%+ total reductions on stainless and 92%+ on non-ferrous.

Because of the very small contact area, the mill housing realizes a relatively small total RSF (Roll Separating Force). And therefore, because the RSF is lower, the mill appears stiffer so that there is less output variation on the strip thickness. This fact, together with our patented Zero Crown Housing, ensures good strip tolerance across the width of the strip with minimum variation from operator to drive side of the mill. This principle holds for softer materials as well as the very hard-to-roll materials.

For instance, a ZR 22-50, 50” mill has a maximum RSF is 1,675,000 Lbs (7468 kN) where a typical 4-High of the same width would be on the order of 5,000,000 lbs. (22295 kN)! The reduced rigidity of 4-High or 6-High mills caused by higher RSF, results in roll deflection and flattening, and therefore, thickness variation, especially near the center of the strip, is increased.

Materials Rolled and Thicknesses Obtained

Sendzimir’s 20-High Cluster mills can roll any metal our clients may need, and we specialize in exceptionally hard metals.

Explore some of the listed options Sendzimir offers our clients:

  • Autobody sheet
  • Deep and extra-deep drawing, low-carbon steels
  • Feedstock for the manufacture of tinplate
  • Austenitic, martensitic, and ferritic stainless steels
  • Non-oriented as well as grain-oriented silicon steels
  • High-carbon steels for items such as razor blades and saws
  • Nonferrous metals, such as brass and special alloys of brass, copper, bronze, beryllium copper, and bimetals
  • Metals, such as aluminum, zirconium, molybdenum, silver, gold, tantalum, titanium, cobalt, and nickel, and their alloys, such as aluchrom

Mill Section Nomenclature Designations

20 High Mill
20 High Mill

Standard Sendzimir Mill Models

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Mill Section Nominal Work Roll Diameter Backing Bearing Diameter Strip Width
Min – Max
Roll Separating Force
ZR 32 0.25” 1.875” 4.5 – 8.75” 5,200 lb/in
6.35 mm 47.6 mm 114 – 222 mm 93 kg/mm
ZR 34 0.400” 3.000” 7.5 – 17.5” 8,400 lb/in
10 mm 76.2 mm 190 – 445 mm 150 kg/mm
ZR 24 0.844” 4.724” 8.5 – 19.5” 13,300 lb/in
21.5mm 120mm 215 – 500mm 238 kg/mm
ZR 33 1.125” 6.299” 13 – 37” 17,700 lb/in
28.5mm 160mm 330 – 940mm 316 kg/mm
ZR 25 1.260” 13.23” 13.8 – 28” 22,000 lb/in
32mm 190mm 350 – 710mm 393 kg/mm
ZR 23 1.578” 8.858” 19 – 56” 24,900 lb/in
40mm 225mm 480 – 1425mm 445 kg/mm
ZR 22 2.125” 11.811” 25 – 80” 33,200 lb/in
54mm 300mm 635 – 2030mm 593 kg/mm
ZR 22B 2.500” 11.811” 25 – 80” 33,200 lb/in
64mm 300mm 635 – 2030mm 593 kg/mm
ZR 21B 3.543” 16.000” 36 – 90” 45,000 lb/in
90mm 406.4mm 914 – 2286mm 804 kg/mm

Our innovative staff of engineers and designers is available to discuss revamp work on your existing mill or new mills designed to your specifications.  Contact Us Today!