Generation 3 Steels - A Guide to Applications of Gen3 AHSS

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1 United States Steel Automotive Solutions to Light Weighting Generation 3 Steels - A Guide to Applications of Gen3 AHSS August 25, 2016 Michael Davenport Director Product Application Engineering

2 Why are Gen3 Steels Required? The day of the passenger car made primarily of iron and steel is on the wane giving ground to aluminum, magnesium and plastics. 2

3 What is the Automotive Material of Choice? CARS Magazine October 1953 The day of the passenger car made primarily of iron and steel is on the wane giving ground to aluminum, magnesium and plastics. 3

4 Steel Innovation 1970s Body-on-Frame Body-Frame-Integral 1980s Uncoated Galvanized Rust Resistant The day of the passenger car made primarily of iron and steel is on the wane giving ground to aluminum, magnesium and plastics. 1990s Mild Steel High Strength and Bake Hard Steel 2000s Mild & High Strength GEN1 AHSS and PHS Today GEN3 Advanced High Strength Steels 4

5 What is Gen3? 70 Generation 2 Elongation (%) IF Mild BH IF - HS ISO UTS x TE = Generation 1 HSLA MART Tensile Strength (MPa) USS CR 1180 Gen 3 Target 5

6 Data Needed to Turn Coils into Parts Microstructure Characterization Gauge and width capability Mechanical Properties Bake hardening / Aging High strain rate Denise, Janet, Kyle & Stephanie Your case studies and template designs are beautiful and central to this book. Fatigue 1.0 Plane Strain Compatibility with paint system True Major Strain 0.5 Forming Limit Curve True Minor Strain FLD Aisling, Denise, Tyler & Ivan The book wouldn t have Safe happened without your rocking design skills and tenacity. Hole expansion ratio Spot Weld Dynamic Crush Dynamic Bending Hydrogen embrittlement Fracture toughness evaluation 6

7 Mechanical Properties Formability and High Strength 66% Higher Strength 25% Shorter crush distance Engineering Stress [MPa] USS: 590MPa Crush Force (kn) DP590 (1.6mm) 980Gen3 (1.0mm) 200 USS: Gen3 980MPa Engineering Strain (%) Displacement (mm) 980 Gen3 make 37% weight save and better crush performance possible 7

8 Mechanical Properties Formability and High Strength 5% Higher formability with 980 Gen3 Uniform strain distribution with 980 Gen3 70 DP GEN Cup Height at Fracture (mm) DP GEN3 True Thinning Strain DP Gen Distance (mm) 980 Gen3 has 5% higher formability and better strain distribution than DP590 8

9 Welding 980Gen3 - Characterization of Parameters Wide range of welding parameters No softening in HAZ observed A 2.2 kamp D 600 Weld Time, Cycles B C 2.1 kamp 2.2 kamp E F Hardness, HVN Weld Current, kamp Indentation Welding 980Gen3 steels can be achieved with a wide range of welding parameters and uniform hardness behavior. 9

10 Dynamic Crush Critical for Energy Absorption Part Testing Structural Analysis 20 Part correlation Energy absorption (kj) Test 1 5 Test 2 Simulation Displacement (mm) Test/Simulation correlation 10

11 Guide to Applications of Gen3 Material Portfolio Forming Global Formability Functional Objectives Assembly Local Formability Structural Components Impact Crack Resistance 11

12 Material Portfolio Hance Diagram View 12

13 Understand the Components Functional Objectives q Functional Objective Form into complex shapes Minimize Intrusion Absorb Energy q Application Load beam reinforcements B Pillar reinforcements Roof rail inner reinforcements Front Roof Header & Bow roof Panel Body side sill reinforcements Reinforcement Front & Rear rails Reinforcement floor cross members 13

14 Understand Global Formability Result with USS solution: Safe forming with upgrade & downgage Good correlation between CAE and trial 13% weight reduction Minimal springback without any adjustment to production die Splits Splits in 780MPa UTS 980 Gen3 for global formability Safe 14

15 Understand Local Formability Edge Stretch & TFS Result with USS solution: Safe Forming Improved crack resistance 980MPa UTS selected by strength only Splits 980MPa UTS selected by microstructure and TFS Safe 15

16 Local Formability - Bending Under Tension & TFS Determination of minimum die radius Future Paper 16

17 Local Formability - Crack Propagation & TFS Future Paper 17

18 Local Formability - Crack Propagation & TFS Future Paper 18

19 Guide to Applications of Gen3 Material Portfolio Forming Global Formability Functional Objectives Form into complex shapes Minimize Intrusion Absorb Energy Assembly Local Formability Structural Component Impact Crack Resistance 19

20 Full Engineering Solution Provider 20