带钢张力拉伸矫直机原理(FATA)

• Clam shell, 4-high, 6-high and solid frame levelers
• During the last 40 years supplied state-of-the-art continuous stretchers and tension levelers to the metals industry
• Downside
– Expensive – Customized cartridges with commercial bearings – No capability of adjustment if an alignment
problem occurs such as foundati1o0n0 msemttlement – No "on-line" roll surface maintenance capability
MEMBER OF FATA GROUP
PRINCIPLES OF TENSION LEVELING
During Tension Leveling . . .
• Unequal strip stresses causing shape defects are equalized • The strip is alternately bent under tension over small rolls,
EXIT BRIDLE
ENTRY BRIDLE
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FATA HUNTER
MEMBER OF FATA GROUP
PRINCIPLES OF TENSION LEVELING
PROGRESSIVE ELONGATION AS STRIP PASSES AROUND EACH
BRIDLE ROLL
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• Subsequent development provided a more economic solution by adding a non-driven roller leveler, first with large rolls (6”diameter) - later with smaller rolls
subsequent foundation settlement and misalignment – Commercial bearings, no pillow blocks
• Downside
– Expensive
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FATA HUNTER
MEMBER OF FATA GROUP
DRIVE SYSTEMS
• Tension Leveling Theory • FATA Hunter History in Tension Leveling • Design Alternates • Process Issues • Flatness and Performances
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FATA HUNTER
MEMBER OF FATA GROUP
FLATNESS PARAMETERS
• Coil flatness may appear acceptable after rolling under high tension
• A flatness defect may develop after cutting, due to generation by rolling of high non-homogeneous stresses within the strip
FATA HUNTER
MEMBER OF FATA GROUP
TENSION LEVELING PRINCIPLES AND DESIGN
presented by
Prabhaka FATA GROUP
PRESENTATION OUTLINE
AMPLIFIER
The Amplifier Consists of . . .
• (2) Flex Roll Zones • (1) Anti-Crossbow Zone
AFNLTAIT-CTRENOISNSGBZOOWNZEONE
• (1) Flattening Zone #1 FLEX ZONE
• 47 units supplied for:
– Aluminum and Steel – Can Stock, Appliances and Construction Grade
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FATA HUNTER
MEMBER OF FATA GROUP
DESIGN ALTERNATES
• Tension Bridles • Drive Systems • Leveling Amplifiers • Electrical Drives
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FATA HUNTER
MEMBER OF FATA GROUP
TENSION BRIDLE - TYPE "B"
• Design
– Bearings / pillow blocks mounted on vertical member – Standard FATA Hunter design
INCOMING STRIP
( = 2)
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FATA HUNTER
MEMBER OF FATA GROUP
OPERATING PRACTICES
• High Yield Strength Materials (Non Ductile)
– Reduced tension to prevent surface lines
Behaves as a motor to maintain and successively reduce the leveling tension
• Benefits
– Adjustment capability – Cost effective – Commercial bearings and pillow blocks
• Downside
– Non-vertical roll change – Residual moment in frame
#2 FLEX ZONE
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FATA HUNTER
MEMBER OF FATA GROUP
METHOD OF CONTROL
• By maintaining a velocity ratio between the entry and exit bridles
• For a given velocity ratio elongation stays constant regardless of . . .
I = ( 2 /4) x 2 x 10
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FATA HUNTER
MEMBER OF FATA GROUP
FLATNESS PARAMETERS
ELONGATION SETTING OF 0.25 GRAPH LINE
RESIDUAL DEFECT OF 25 I-UNITS IN OUTGOING STRIP
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FATA HUNTER
MEMBER OF FATA GROUP
TENSION BRIDLES
• BRIDLE ARRANGEMENTS – Two Roll – Three Roll – Four Roll
• 3-BRIDLE TYPES – Type A – Type B – Type C
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– Strip Size
– Mechanical Properties
– Metallurgical Properties
– Line Speed
• Work roll penetration is dictated by strip alloy
(yield strength), thickness and incoming flatness
• Excessive Elongation
– May create cross-bow or canoe-shape
– Removal by slight additional reverse bending
• Bending Over Small Rolls
– May create coil set
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FATA HUNTER
MEMBER OF FATA GROUP
TENSION BRIDLE - TYPE "C"
• Design
– Precision machined frame – Bearing blocks mounted on angle pads
• Benefits
– Excellent rigidity – Vertical roll maintenance – Maximum adjustment flexibility for
causing stress amplification beyond the elastic limit • These stresses being greater than the yield strength, cause
permanent elongation of the longitudinal fiber lengths
• Bridle Drive Configurations
– Rigid Drive: Mechanical
– Hybrid:
Combination of mechanical/electrical drives
– All Electrical: Individual electrical drives
– Removal by series of bends/reverse bends over larger diameter rolls