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Flexible Rolling of Tailor Rolled Blanks- innovative light weight design in steel -
Dr.-Ing. Michael RehseMuhr und Bender KG
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During the past 5 years, lightweight construction potential, feasibility, competitiveness and volume production capability of Flexible Rolling have been verified.
Tailor Rolled Blanks
- a light weight design opportunity -
• Flexible Rolling is a continuous rolling process with periodically varying thickness.
• Mubea developed the complete process chain for a steel component made of TRB
• The adoption of TRB in the automotive industry offers great potential for the optimization of weight, function, cost and complexity.
• Verification of competitiveness: supply orders with Audi, BMW, DCX, GM & Skoda ( 31 parts)
• Ongoing launches in Europe and North America
• Serial production of Tailor Rolled Tubes with an annual capacity of 1 million tubes
• Application studies for multiple car and truck bodies
• Verification of volume production capability: 16,500 to / 5.75 million blanks up to now
Side Member Reinforcement Rocker Cross Member Rear Axle
Heel Cross Member Side Member Rear Seat Cross Member
Front Seat Cross Member Cockpit Cross Member Connection Member
Bumper Reinforcement Safety Belt Side Member
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Mubea – as a lightweight design specialist – supplies automotive OEM‘s worldwide with steel based products. Using Mubea lightweight innovations, a weight reduction of 20 kg per vehicle can be achieved.
SuspensionComponents
System ComponentsSuspension
Stabilizer Bars
Suspension Coil Springs
Engine Components
Hose ClampsValve Springs CamshaftsBelt Tensioner systems Body &Interior
Head Rests
Tailor Rolled Tubes
Tailor Rolled BlanksTransmission Components
Transmission Disc Springs Drive and Transmission Shafts
Mubea Group
Product Range
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Mubea Group
Worldwide presence
Over 4,200 employees @ 15 production sites enable us to serve the customers worldwide.
Taubaté, Brazil
Taicang, China
Warnstedt, GermanyAttendorn, Germany
Production plant
Development Center
Florence, KY, USA Zebrák, Czech Republic
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Mubea Group
Sales development
Mubea strives for a continuous growth in the coming years.
2000 2002 2004 2006 2010
Sale
s in
M €
Target 2010:1 billion €
368445
547
689
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Mubea has a long experience in cold rolling.
Mubea Cold Rolling Mill
Many years of experience in the cold rolling area
Annual production of 30.000 t / year
Core competence in the following materials
- Spring steels- Mild and higher-tensile steels
Expansion of the cold rolling mill in two steps
Flexible rolling facility I: 10.000 t / yearFlexible rolling facility II: 60.000 t / yearMaterials:- Deep-draw grades- Micro-alloyed steels- Higher-tensile steels
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Mubea is convinced that lasting success can only be achieved in partnerships.
Principle of Flexible Rolling
• Defined sheet metal thickness contours
• Uniform thickness transition areas
• High efficiency as strip rolling process
• Can be applied to all rollable metals
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Flexible Rolling allows to produce components with almost all thinkable thickness changes.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 100 200 300 400 500 600 700Meßweg in mm
Ban
ddic
ke in
mm
gewalzte BandkonturSollprofil
0,00,20,40,60,81,01,21,41,6
0 200 400 600 800 1000Meßweg in mm
Ban
ddic
ke in
mm
gewalzte BandkonturSollprofil
strip length in mm
strip length in mm
Strip
thic
knes
s in
mm
Strip
thic
knes
s in
mm
Varying sheet metal thickness with smooth
transitions
50% max. thickness reduction
Slope between 1/3000 up to 1/100
Thickness tolerances 50µm
Optimized sheet thickness dependent upon
the load
The cost of the component does not
depend on number of thickness steps
Reduction of sheet and component weight
TRB Properties
Feasible Profile Shapes
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0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 100 200 300 400 500 600 700
Meßweg in mm
Ban
ddic
ke in
mm
gewalztes Bandprofil
Sollprofil
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
TRB PropertiesSt
rip th
ickn
ess
in m
m
strip length in mm
Varying sheet metal thickness with smooth
transitions
50% max. thickness reduction
Slope between 1/3000 up to 1/100
Thickness tolerances 50µm
Optimized sheet thickness dependent upon
the load
The cost of the component does not depend
on number of thickness steps
Reduction of sheet and component weight
0 200 400 600 800 1000strip length in mm
Strip
thic
knes
sin
mm
gewalzte BandkonturSollprofil
Flexible Rolling allows to produce components with almost all thinkable thickness changes.
Feasible Profile Shapes
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Mubea has developed the complete process chain for a steel componentmade of Flexibly Rolled Parts.
Flexible Rollingcoil to coil
hood-typeannealing furnace
stripgalvanizing
profile levellingand cutting
profile forminginto a part
part with differentSheet thicknesses
Process chain of Tailor Rolled Blanks
Principle and Status of TRB
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Cold Rolling Plant in Attendorn
Start of construction work: Ma `03Completion of building: Jan `04Start of equipment installation: Feb `04First Coil: Aug `04Capacity: 60.000 t/year
FlexWalze 1Prinzip und Status von TRB
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Process chain of Tailor Rolled Parts
Principle and Status of TRB
Mubea developed the complete process chain for a steel component made of Flexible Rolled Blanks.
Flexible Rollingcoil to coil
hood-typeannealing furnace
stripgalvanizing
Coil Component manufacturing part with differentSheet thicknesses
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Process Chain
Production Technology TRB Pressed Parts Mubea Press Shop Application Example: Steering Link
0,00
1,00
2,00
3,00
4,00
0 100 200 300 400 500 600
Platinenlänge in mmBlank Length in mm
Wal
l Thi
ckne
ssin
mm
Mechanical press,Press force: 1.100 tonnes
Max. length pressed parts: 1450mm Max. length developed blanks:
2500mm
Fully automated part / developed blank production from coil
Fully automated blank orientation(lengthwise or across the rollingdirection), independent of die
In-house processing of Tailor RolledBlanks
Decoiling Cutting Forming PartRotationTransport +
Short processing time: raw material coil to the finished, flexibly rolled component in one plant.
Cost reduction due to omittance of storing and one production step (stackling of blanks).
New Mubea Press Shop
Principle and Status of TRB
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The material and forming properties of Tailor Rolled Blanks are comparable to conventionally rolled metal.
Properties of TRB
• Continuous transition
• Harmonic tension distribution throughout the thickness transition area
• Homogeneous surface
• No disturbed fibre pattern
• No notch effect
• No detrimental effects on microstructure caused by welding
• Can be modelled for simulation
• Forming properties are comparable to conventionally rolled metal
TWB
Analysis of the deep drawing performance
TRB
Source: RWTH Aachen, Institut für Bildsame Formgebung
Tension distribution: Weld seam vs. continuous transition
Forming behaviour
w w w . a u t o s t e e l . o r gEasy contour optimization due to the flexibility of the process.
0,00
0,40
0,80
1,20
1,60
0 200 400 600 800 1000 12000,00
0,40
0,80
1,20
1,60
0 200 400 600 800 1000 1200
contour changes
length in mm
shee
t met
al th
ickn
ess
in m
m
Process flexibility
• The flexible rolling process enables
non tool-related production
• Simple software programming
allows contour changes from one
coil to
the other
• Cost efficient manufacturing of
derivates or product variants
– Without set-up costs
– No additional body shop costs
Features of TRB
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1,851,35
1,00
1,35 1,85
• Front crash demands local up-gauging at load exposed front and below x-member
• Improvement of crash performance
Functional improvement
Side memberCross member
With local sheet metal thickness adaptations to the load Tailor Rolled Blanks provide best performance at minimum weight.
• Part design requires increased thickness
• Optimized distribution of stiffness in outer areas by matching of sheet thickness (NVH)
0,40
0,80
1,20
1,60
0 200 400 600 800 1000 1200length in mm
shee
t met
al th
ickn
ess
in m
m
0,50
1,00
1,50
2,00
0 200 400 600 800 1000length in mm
shee
t met
al th
ickn
ess
in m
m
1,35
1,20
1,00
1,501,00
Features of TRB
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0,50
1,00
1,50
2,00
2,50
0 500 1000 1500 2000
length in mm
shee
t met
al
thic
knes
s in
mm
Integration of components
• Conventional design:1 component4 reinforcements 5 parts
• TRB – design: 1 part
Opportunities:– production costs– tool costs / investments– assembly process– logistic costs– floor space required
• Potential savings up to 1 US$/unit exclusive of weight-increasing
Reduction of assembly groups by Tailor Rolled Blanks.
conventional design
TRB – design
Features of TRB
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The technology offers high potentials for different components in the structure and chassis areas. Application criteria for optimum TRB applications have been identified.
Application Examples
connection member
tunnel reinforcementcross member
seat cross member
rear side member
strut tube
roof bow
front side memberrocker panel
Structure & chassis parts
• Load exposed parts with sufficient thickness for local reductions
• Sub-assemblies with reinforcements
• Weight reduction of 20% and above
• Straight parts with high material utilization from blank to part (below 40%)
• Integration of parts to reduce complexity
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Producing structure parts for the DC E-class and the BMW 5-series,we verified volume production capacity.
TRB Series Applications
• Increased torsional stiffness • Weight reduction of 1,2 kg
vs. conventional part
HSLA 300 / 350 TRB Z100flexible rolled 1,9 > 1,05 > 1,9 mm
1,93
1,93
1,050,8
1
1,2
1,4
1,6
1,8
2
0 200 400 600 800 1000
Platinenlänge in mmB
andd
icke
in m
mStrip length in mm
Stri
p th
ickn
ess
in m
m
Rear cross member
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Considering the technology advantages of TRB during the part development process results in maximal weight reduction and low costs.
TRT Series Applications
0,000,200,400,600,801,001,201,401,601,802,00
0 200 400 600 800 1000 1200 1400
Rohrlänge in mm
Wan
dstä
rke
in m
m
HSLA420 TRBflexible rolled
1.0 > 1.6 > 1.8 > 1.6 > 1.0 > 1.4 > 1.0
• 30% weight reduction• Narrowest part tolerances• Cost-effective light weight
construction
Tube length in mm
Strip
thic
knes
s in
mm
Cockpit cross member
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Mubea put the first production line for Tailor Rolled Tubes in stream.
Tailor Rolled Products
Tube Production Line
Layout tube production line • Discontinuous tube production
• High number of profile shapes by means of flexible forming techniques
• Connection by laser beam welding
• Integration of further process stepslike bending and forming
Tube with a constant outer diameter and invisible thickness transition run
Tube with constant inner diameter and visible thickness transition run
Tube with variable diameters and varying thicknesses
Profile shapes
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Tailor Rolled Tube with variable diameters
Development of Tailor Rolled Tubes (TRT)
Manufacturing tubes with variable diameters and sheet metal thicknesses features maximum flexibility in weight optimization and design.
Diameter variation: 52%Thickness variation: 43%Weight reduction: 33%
Diameter variation: 31%Thickness variation: 50%Weight reduction: 35%
• Different diameters along the whole tube
• Different thicknesses over the whole length
of the tube
• Maximum weight savings
• High degree of design flexibility
• Cost efficient manufacturing of complex tube
geometries (compared to hydro forming)
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Combination of Hot Forming and Flexible Rolling
The combination of matched sheet metal thickness and extremely high material strengths allows a maximal weight reduction.
Coil
Presswith
coolingOvenCoil rolling
levelling, profile cut
Hot fromed TRB
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PM49 B-Pillar
BTR 165 TRBflexible rolled 1.0 > 1.9 > 1.6 > 1.3
• 24% weight reduction• Improved crash performance as a
result of integration of componentsand adaptation of thickness
Weight optimized B-pillar design through load adapted thicknesses.
Rp0.2 [N/mm²] Rm [N/mm²] A5 [%]min. 950 min. 1300 min. 6
die hardened
Hot fromed TRB
0.00
0.50
1.00
1.50
2.00
2.50
0 200 400 600 800 1000 1200 1400 1600 1800
length in mm
shee
t met
al th
ickn
ess
in m
m
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Summary
• Flexible Rolling is designed as a continuous rolling process for metal sheets with periodically varying thickness.
• Mubea developed the complete process chain for a steel component made of Flexible Rolled Blanks.
• The adoption of Tailor Rolled Blanks in the automotive industry offers great potential for the optimization of weight, function, cost and complexity.
• The material and forming properties of Tailor Rolled Blanks are comparable to conventionally rolled metal.
• All conventional process steps for the production of metal parts are applicable for Tailor Rolled Blanks.
• The technology offers high potential for different components in the structure and chassis area.
• Mubea has put the first production line for Tailor Rolled Tubes in stream.
• World-wide, Mubea is leading in the production of Tailor Rolled Products.
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THANK YOU VERY MUCHFOR YOUR ATTENTION!!!!