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Advanced High Strength Steels: an economical solution for Automotive Lightweight Structures

Advanced High Strength Steels: an economical solution for Automotive Lightweight Structures. Advanced High Strength Steels: inside an extended steel grade offer for Automotive. Automotive Steel Families. Advanced High Strength Steels: Massive and Growing use in the Automotive Industry.

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Advanced High Strength Steels: an economical solution for Automotive Lightweight Structures

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  1. Advanced High Strength Steels: an economical solution for Automotive Lightweight Structures

  2. Advanced High Strength Steels: inside an extended steel grade offer for Automotive

  3. Automotive Steel Families

  4. Advanced High Strength Steels: Massive and Growing use in the Automotive Industry

  5. Advanced High Strength SteelsEstimated Market needs • AHSS usage will grow • from 7% in 2006 to 11% in 2010, mainly at HSS expenses • A long term potential of • 35% of AHSS in a BIW • has been estimated through a model study > 1 Mt in Europe > 3 Mt in Europe

  6. Car Example 32% AHSS 46% AHSS Eu 4x4 – new model Eu 4x4 – previous model Source: Eurocarbody Source EuroCarBody 2007

  7. Advanced High Strength Steels WHY?

  8. AHSS are dedicated to Structural parts A-frame reinf. Bumper Beam Roof bow B-pillar reinforcement Front side members Floor side reinf. - sill inner Rear side member WHY DOES THE NEED OF AHSS INCREASE ? • Reduce CO2 emissions • Reduce fuel consumption • Safety requirements • Equipment & Comfort • Downgauging • compensate by higher crash performances of steel • Cost effective Car structure mass reduction AHSS

  9. Example in Brazil Euroncap test as illustration FRONTAL Crash regulation in 2010 => would increase need of AHSS

  10. Car crash situations Situation where need is to control absorbed energy Situation where need is to control intrusion (displacement)

  11. AM test for:Energy absorption under compressive load Closed-Top-Hat test conditions Sample Final specimen observation Records

  12. Energy Absorption Average crushing force for 1.5mm thickness H260 DP980LCE DP450 DP500 DP600 DP780 MP800 MS1200 TRIP980 MP1000 TRIP590 TRIP690 TRIP780 HSLA500 DP1180HY ArcelorMittal 04 • Increased energy absorption with higher UTS • Ranking made at iso-part geometry

  13. AM test for:Maximal Load under 3P bending. Sample test conditions: 3 point bending records 45 Impactor f 50 Maximum force (ulitmate failure stress) Yield force f 200 Force (kN) 50 Support 700 Displacement (mm) 100 75 300 480 30 140 Impact speed: 8 m/s Kinetic energy : 10 kJ Final specimen observation

  14. H260 DP980LCE DP450 DP500 DP600 DP780 MP800 MS1200 TRIP980 MP1000 TRIP590 TRIP690 TRIP780 HSLA500 DP1180HY ArcelorMittal 04 Usibor 1500 • Increased anti-intrusion with higher UTS • Ranking made at iso-part geometry max crushing force for 1.5mm thickness

  15. Strategic Interest in Advanced High Strength Steels (AHSS) for Automotive business is no more a question • Because it is the most economically efficient solution to reach: • Lightweighting goals in structural areas of the car • Safety goals in the safety-critical parts • Reduce complexity of stamped parts

  16. Example of weight saving potential

  17. Example of Weight saving in Automotive parts: AM generic steel solution catalogue for Bodyside Reference : 5 doors European vehicle “Bodyside” Scope

  18. In the “solutions” catalogue: 1 very efficient proposal for weight saving ROOF RAIL INNER : DP980HY 0.7mm A-PILLAR Upper INNER : Trip 780 1.25mm ROOF RAIL R/F DP780 0.6mm A-PILLAR Upper R/F : Usibor 0.9mm Reference A-PILLAR Lower INNER DP600 0.8mm B-PILLAR TWB INNER : DP980 HY 1.0 (up) ARC04 0.7 (low) B-PILLAR R/F TWB Usibor 2mm (up) Ductibor 1.6mm (low) This solution A-PILLAR R/F Usibor 0.9mm Cost : +10% Weight saving : -25% ROCKER INNER DP980HY 0.85mm ROCKER R/F RR + ROCKER R/F FR : DP980 HY 0.85mm

  19. What kind of steels are AHSS?

  20. AHSS = MULTIPHASE STEELS Strengthening by quenching generated hard phases: martensite, bainite, retained austenite Conventional = ferritic Martensitic DP TRIP 1000 : 1 Le Pera 20 µm MP or CP Ferrite Bainite

  21. AHSS = produced by conventional process Run out table Cooling and coiling Continous casting Slabs 25 t Steelmaking 230 t Hot Rolling mill Coils, 25t, length 1000 m Hot Dip Galvaninzing line Hot Dip galvaninzing product (coils, length 2000 m) Cold rolling mill

  22. Metallurgy of ArcelorMittalAHSS MULTIPHASE structure  Manage phase transformation Coupled key factors: PROCESS and CHEMICAL COMPOSITION PROCESS = control the structure at high temperature + the continuous cooling strip temperature « Conventional » steels TRIP steels CGL or CAL DP steels time (s) Area of ferrite formation during cooling Adjusted by chemical composition and processing Area of Bainite formation during cooling Area of Martensite formation during cooling

  23. ArcelorMittal WW AHSS offer FB FB DP DP TRIP TRIP XIP DP DP FB FB DP EUR FB PH DP MP NAM DP DP Mart MP FB TRIP DP FB PH PH DP FB MP FB SAM MP FB DP DP : Dual Phase (&CP) MP: MultiPhase (CP) Mart : Martensitic grade EUR: Europe PH: Press Hardening grade NAM: North America FB : Ferrite bainite TRIP : Transformation Induced Plasticity SAM: South America

  24. CommercialUnexposed only CommercialExp. and Unexp. Customer Trials Under Development Hot Rolled Cold Rolled Example of WW offer processus: ArcelorMittal AHSS in Brazil Concept and Know-How are transfered from original region (Eu, US) to Brazil Plant with total technical support => OEM gets locally an equivalent product compared to the original region Generic Y/T EUR & SAM Grade NAM Grade UC EG GI GA AS ZA/AZ DP450 T 450 EUR EUR EUR EUR DP500 T 500 490 EUR NAM EUR NAM EUR NAM NAM DP590 T 600 590-600 EUR NAM SAM EUR EUR DP780HFL T 780HFL T EUR NAM EUR NAM EUR NAM SAM EUR NAM SAM DP590 600 590-600 Dual Phase NAM T DP590 HHE 600 HHE 590R EUR EUR NAM NAM T DP690 HHE HFT690 T NAM NAM EUR NAM SAM SAM EUR NAM SAM DP780 780 780 T DP780 HHE 780 HHE EUR EUR NAM T EUR EUR DP780 LCE 780 LCE 780 LCE FB450 T 450 EUR SAM EUR FB540 T 540 540SF EUR SAM EUR NAM Ferrite-Bainite FB560 T 560 EUR NAM FB590 T 590 EUR SAM T 590SF FB590 HHE 590 HHE EUR NAM SAM MP800 T 800 EUR NAM EUR Multi-Phase HFL: High Fatigue Life, HHE: High Hole Expansion, LCE:Low Carbon Equivalent

  25. Example of WW offer processus: ArcelorMittal AHSS in Brazil Example: Transfer DP600GI from Europe to Brazil (VEGA do Sul)

  26. ArcelorMittal keeps on developing the AHSS family • Because: • OEM needs are already growing for 1000MPa and above grades. • At these levels, Steelmaker and OEM must, together, overcome increasing difficulties in part forming, part welding and other in-use properties.

  27. CR DP 980

  28. Development in Europe and America with Low C/Low CEQ of a new DP980 with low C content & improved drawability : Toward low Ceq ~ 0.28-> ~ 0.23 Increase drawability : min 0.5t Bendability, +30% Hole Expansion, Robust Weldability Excellent Combination of Properties: YS 650 MPa, TS 1020 MPa, TE 12-17% (Gauge dependent) Qualified at Multiple Auto Manufacturers Utilized in Vehicles beginning Model Year 2009 Applications include B-Pillars, Cross-members, Seat Parts DP980LCE DP980LCE DP980 with excellent formability/bending combination + good weldability B-Pillar Cross-members

  29. MP800HY, a HR 800MPa steel with good stretch flangeability

  30. MP800HY, a HR 800MPa steel with good stretch flangeability M800HY Ferrite + Granular bainite

  31. MP800HY, a HR 800MPa steel with good stretch flangeability

  32. initial = 10mm  = 45mm MP800HY, a HR 800MPa steel with good stretch flangeability • Good bendability: • Whatever the thickness is • similar behaviour in rolling and transverse direction • Conical hole expansion : • Around 60% in average • Development of 85% HE • Dome stretching underlines good formability. • Very good weldability Punch diameter : 75mm

  33. AHSS for roll-forming

  34. DP 1180HY Mid-carbon steel YS ~950MPa, TS ~1200MPa, TE ~5% (ISO) Minimum bend radius of 2t Martensite 1100 / 1300 / 1500 Lean alloying (C, 0.5Mn) YS ~1000/1150/1300MPa, TS ~1180/1380/1550MPa, TE >3% Minimum bend radius of 4t Industrial Applications include bumper beams, door beams, rails in multiple vehicle platforms ArcelorMittalAHSS Steels ≥1000 MPa for Roll Forming & bending

  35. Press-Hardened Steel: USIBOR1500P® a special AHSS

  36. Typical hot-stamping lines

  37. Metallurgical structure after hot-stamping USIBOR 1500P 100% martensitic Hardness : 400 to 500 HV1 Homogeneous mechanical properties in any point of the parts : Ys  1100 MPa, Ts  1500 MPa, E (ISO)  6%

  38. AlSi Coating after hot-stamping

  39. Parts in Usibor 1500P

  40. ArcelorMittal has in market an extended and Worldwide Advanced High Strength Steels offer in order to Provide the most effective solution for car structure weight reduction where the OEM select and validate material to imagine new cars. where the OEM builds cars. ArcelorMittal keeps on developing new AHSS with further improvements In lightweighting potential (higher Grades) In manufacturing properties ArcelorMittal AHSS: Conclusion

  41. Thank you for you Attention

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