The Mass-Reduction Potential of Tailored Steel Products for Automobiles Peter R. Mould Tailored Steel Product Alliance (TSPA)
OUTLINE Definition of tailored steel products Description of TSPA Automotive Requirements Purpose of this study Potential (quantification) for mass reduction Overview of concepts/approaches Total mass savings Impact on costs Summary
DEFINITION OF TSP s Pre-welded structures for subsequent forming (i.e. stamping, hydro-forming, etc.) - Laser welded blanks or tubes - Mash seam welded blanks - Patch welded structures - Tailor rolled structures Allow use of different: - Steels (Mild Steel, HSS & AHSS) - Thicknesses Provide engineering flexibility for locating high strengths at critical locations - Cost effective - Minimize mass
DESCRIPTION OF TSPA Alliance: Tailored Steel Blank Manufacturers, Equipment Suppliers, North American Steel Companies. Purpose: To promote the use of tailored steel products in automotive applications.
TSPA MEMBERS Tailored Blank Manufacturers Noble International Nova-Hyfo Powerlasers ProCoil Company, LLC Shiloh Industries, Inc. TWB Company, LLC Equipment Suppliers Soutec Soudronic TRUMPF VIL/Wayne Trail Technologies North American Steel Companies AK Steel Corporation ArcelorMittal Nucor Corporation Severstal North America, Inc. United States Steel Corporation
TSPA TYPICAL PROJECTS Market Analysis Applications Materials Communications Benefits Development Programs Cost Model Applications Database
AUTOMOTIVE REQUIREMENTS Cost Minimization Materials Manufacturing Increased Engineering Performance Crash Stiffness / Ride Durability Environmental Requirements Mass Reduction How can TSPs help reduce mass?
INTRODUCTION Purpose Scope Review conceptual & actual approaches in using Tailored Steel Products (TSPs) Primary focus: Secondary focus: MASS SAVINGS Cost Source of information for concepts Members studies and prior proposals/ideas Examples from actual vehicles Organizational studies (AISI-ULSAB, A/SP, etc.)
METHODOLOGY Method Select specific areas of the vehicle most likely to offer mass reduction opportunities from TSPs: Body Side Structure Body Side Inner Body Side Outer B-pillar Reinforcement Rails Front/rear Connections to pans Floor Structure Floor/Rear Pans Wheelhouse Inner Motor Compartment Shock Tower Roof Structure Bumper Systems Bumper Beam Crush Box Closures Door Inners Side Impact Beam Life-gate Sub-frames Engine Cradle Rear Sub Frame Others Wheels Lower Control Arm Axle Mount Identify: Mass reduction ranges specific parts Sum the primary mass savings full vehicle Estimate secondary / total mass savings from BIW
OVERVIEW OF CONCEPTS Body-Side Structure Rails Sub-frames Other areas (not reviewed here) Front-end structures Motor compartment Roof structure Bumper systems Wheels Lower control areas Axle mounts
BODY SIDE STRUCTURE Body Side Inner Illustrative Example BSI and Reinforcement Ring (Member company concept) Part reduction: 17 to 7 Multiple steel grades Mass reduction 13 to 15# Improved roof crush and side impact performance Lower variable cost and investment cost Manageable press loads compared with a single LWB inner
BODY SIDE STRUCTURE Body Side Outer (Exposed) Generic Example: 4-piece single LWB Exposed Quality Laser Welding Typical Body Side Outer & Reinforcements Future Body Side Outer Exposed Quality DP500 Steel Exposed Laser Welds Mass savings 20-30 pounds/vehicle
BODY SIDE STRUCTURE Body Side Outer Other Options: Ford F-150 Door Opening Panel FORD F-150 DOP 1.1mm EG coating & 2mm HD coating Class 2 exposed BENEFITS Eliminated 8 reinforcements, 20 stampings and 88 stamping dies Improved stiffness Improved material utilization Mass savings Part reduction Mass savings/ vehicle = 59 pounds Reduced cost Good surface appearance of weld seam in semiexposed door location
BODY SIDE STRUCTURE B-Pillar Reinforcement Illustrative Example Hot stamped LWB of HSLA and Boron Steel (2-piece Audi A5) Boron steel HSLA 350 Mass savings = 4 pounds/vehicle
BODY SIDE STRUCTURE B-Pillar Reinforcement (continued) Illustrative Example Hot stamped LWB of HSLA and Boron Steel (2-piece Renault Laguna III Euro Car Body Conference 2007) Mass Saving /vehicle 3.5 kg 7.7 pounds
BODY SIDE STRUCTURE B-Pillar Reinforcement (continued) Other Options: Hot formed multi diameter tubular structure (member concept) Mass Saving /vehicle 1.6 pounds
RAILS Front Rails Illustrative Example: A/SP Light Weight Front End Structure (LWFES) study (Baseline: GM 2004 Malibu)
RAILS Front Rails (continued) Illustrative Example: A/SP LWFES study: Stamping and Tubular options yield substantial mass reduction and some cost reduction. Mass savings (incl. bumper) = 24-30 pounds/vehicle
RAIL INTEGRATIONS Rail to Floor Pan Illustrative Example: Redesign to allow integration with floor pan new Honda Accord Mass Saving /vehicle 6-7 pounds Euro. Car Body Conference 2007
SUB-FRAMES Engine Cradle Illustrative Example: Stamped Approach: plasma arc welded LWB (Yorosu/Nissan 2006 MY Metalforming Magazine April 2007) 8 pieces 1 to 2.9 mm thickness Mass savings = 10-15 pounds
SUB-FRAMES Engine Cradle (continued) Other Option: Tubular Approach: HSS replacing Al die casting (Mercedes C-Class Euro. Car Body Conference 2007)
IMPACT ON MASS/VEHICLE Category Parts Estimated Mass Savings (pounds) Body in White Body Side Inner 13-15 Body Side Structure Body Side Outer 13-30 B-Pillar 3-8 29-53 Rails Front rails (incl. bumper beam) 24-30 Rear rails 12-16 Rail/Pan Connection 6-7 42-53 Floor/End Structures Floor/Rear pans 6-10 Wheelhouse inner 4-7 Dash panel 1-2 11-19 Motor Compartment Shock Tower 2-4 2-4 BIW = 89-139 Roof Structure Sunroof 5-10 5-10 Bumper Systems Bumper beam (1-4) Crash Box 3-5 3-5 Bumpers = 3-5 Closures Door inners (4 doors) 4 8 Side Impact Beam (4 doors) 3 4 Lift gate 3 4 10-16 Closures 10-16 Sub-Frames Engine cradle 10 15 Rear sub-frame 8-12 18 27 Sub-frames 18-27 Others Wheels 12 16 Lower Control Arm 4 6 Axle Mount 2 4 Others 18-26 TOTAL 138-213
MASS SAVINGS BIW and CLOSURES For BIW and Closures: survey has identified: 99-155 pounds of Primary Mass Savings Additional Secondary Mass Savings No Resizing of Power Train Resizing of Power Train 0.5x Primary* 1.5x Primary* *Recent study by Auto / Steel Partnership - Future Generation Passenger Compartment Team
TOTAL MASS SAVINGS Est. Pounds/vehicle Estimated BIW & Closures mass savings 99 155 Total estimated primary mass savings 99 155 Additional secondary mass savings No Power Train Resizing (0.5 x Primary) * With Power Train Resizing (1.5 x Primary) * 50 78 149 233 Total mass savings 149 233 248-388 *Based on a recent study by the A/SP Future Generation Passenger Compartment Team
IMPACT OF TSP s ON COST TSPA has developed a cost model to compare the application costs of TSP s with conventional processes: Process-based Cost Methodology (MIT) Excel spreadsheet format User friendly 3 Case studies evaluated Door inner Body side inner Front rails All showed: - Lower cost for TSP s - Lower mass
TSPA COST MODEL DOOR INNER CASE STUDY 11 (279) Baseline LWB 22.8 (579) 22.8 (579) Mirror Support Gauge = 0.047 (1.2) 31.5 (800) 50.5 (1283) 31.5 (800) 39.6 (1007) 50.5 (1283) 11 (279) Hinge Reinforcement Gauge = 0.047 (1.2) 55 (1410) Inner Gauge = 0.026 (0.7) (Dimensions in parentheses in mm) 14 (356) 41.5 (1054) 55 (1410) Inner Gauge = 0.063 (1.5) - Left 0.026 (0.7) - Right
DOOR INNER DESIGN CONTENT Baseline LWB # of Parts Weight (kg) Stampings 6 14.12 # of Parts Weight (kg) -- -- Tailored Blanks -- -- 2 13.12 TOTAL 6 14.12 2 13.12 # of Spot Welds 50 0 Includes left and right assemblies Same materials in both designs (mild steel).
UNIT COST (275K VEHICLES / YEAR) Total Unit Cost $, (L & R assemblies) Door Inners 30.00 Base LWB 25.00 20.00 27 7.97 2.81 23 2.35 1.58 Total Cost: 26.65 23.24 Other 7.97 2.35 Labor & Equipment 5.25 1.55 Variable & Fixed* 2.72 0.80 15.00 19.31 Tooling 2.81 1.58 10.00 5.00-15.87 Base LWB Blank 15.87 19.31 Material 15.71 15.25 Blanking 0.16 0.63 Welding 0.00 3.43 * Variable: Energy, process material costs Fixed: Building, maintenance, overhead
DOOR INNER TOOLING INVESTMENT COSTS Fixed Investment $ millions Baseline LWB 2.93 1.65 LWB saves $1.28 million or 43%
SUMMARY Tailored Steel Products (TSPs) offer the potential for substantial mass savings: Up to 230 pounds (105 kg) without power train resizing Up to 380 pounds (173 kg) with power train resizing
SUMMARY Additional benefits can be realized by using TSPs Optimized performance Increased stiffness Improved safety / crash Selected use of different steels / different thickness The right steel for the right location Reduced cost Improved material utilization Reduced manufacturing / assembly costs Reduced tooling costs TSPs a powerful, cost-effective technology
MORE INFORMATION CONTACT: Peter R. Mould Program Manager TSPA prmould@comcast.net (810) 225-8250 VISIT: www.tailoredsteelproducts.org