The Next Generation of Advanced High Strength Steels – Computation, Product Design and Performance First-Year Progress Update on the DOE ICME 3GAHSS Project Louis G. Hector, Jr., Technical Fellow General Motors R&D, Warren, MI 48316 Ron Krupitzer, Vice President Steel Market Development Institute 2000 Town Center, Suite 320 Southfield, MI 48075-1123

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New ICME Project on Third Generation Advanced High Strength Steels (3GAHSS) Award to USAMP through Sec. Chu’s Office (DOE): February, 2013 • http://energy.gov/articles/energy-department-investments-develop-lighter-strongermaterials-greater-vehicle-fuel

DOE Funding: $8,571,253 ($6,000,000 DOE funding (70%), $2,571,253 industry funding) Duration: Four Years (February 1, 2013 – January 31, 2017) Approach: Integrated Computational Materials Engineering + 3GAHSS Alloy Development

Recipients, Sub-recipients, and Key Contractors • USAMP: Chrysler, Ford, General Motors • A/SP and SMDI: AK Steel, ArcelorMittal, Nucor Steel, Severstal North America, and US Steel Corporation • Universities: Brown University, Clemson University, Colorado School of Mines, Michigan State University, University of Illinois • National Lab: PNNL • Engineering Companies: EDAG, LSTC

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Candidate Automotive Components for ICME 3GAHSS Project Current Materials

Elongation (%)

Gen 3 Steel Targets DOE Steel Targets

Weight Reduction (Gage and/or Geometry)

Rails

Tensile Strength (MPa) www.autosteel.org

ICME Constitutive Model Development for 3GAHSS (a) …use computers (with minimal experimental inputs) to “design” multi-phase steel microstructures that achieve desired strength and ductility targets (for example).

(d) …predict formability and failure limits.

(b) …generate constitutive models that accurately account for the multi-scale physical phenomena in an advanced steel under an arbitrary strain path.

(c) …pass models onto metal forming and CAE engineers for formability and performance predictions in commercial FE codes.

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Task 2 - ICME Constitutive Model Development Path for 3GAHSS ST 2.3 Computational : Atomistics for Defects/Strengthening/ Hardening (years 1-4)

UIUC

ST 2.1 Experimental: Nanometric to Grain Scale Mechanical Tests/Texture (EBSD) (years 1-4)

Brown

ST 2.4 Computational: Crystal Plasticity For Mechanical Properties of Phases in Microstructure (years 1-4)

ST 2.5 Evolutionary Yield Function (years 1-4)

Michigan State

Michigan State

ST 2.2 Experimental: Coupon-Level Tests for Flow Behavior, Formability, Failure Fracture (years 1-4)

Clemson

ST 2.6 Computational: Microstructure-Based Finite Element Approach for Bulk Sheet YS, UTS, TE, UE and Formability (years 1-4)

PNNL

LP Start with QP980

ST 2.7 Computational: Failure/Fracture Models (years 3-4)

Brown ST 2.8 Computational: Microstructural Design and Analysis of 3GAHSS CSM (years 1-2)

ST 2.10 Computational: Development and Validation of Macroscopic Constitutive Models for Deformation and Fracture -PamStamp,\LS-DYNA, ABAQUS (years2-4)

PNNL + A/SP ST 2.9 Experimental Design and Manufacture of 3GAHSS (years 1-4)

A/SP

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Phase II Integration, design, cost analysis, and model and property database with 3GAHSS

Experimental: Nanometric to Grain Scale Mechanical Tests/Texture (EBSD) • Brown University, School of Engineering – – – –

Prof. Sharvan Kumar Prof. Allan Bower Dr. Hassan Ghassemi-Armaki Dr. Hyokyung Sung

•

Purpose: – Measure flow properties of individual steel phases with state-of-the-art micropillar compression – Measure texture information with Electron Backscatter Diffraction (EBSD); measure austenite transformation kinetics.

•

Integration: – Provide experimental data for inputs to atomistic and crystal plasticity (microstructural) simulations and model validation.

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ST 2.1 Experimental: Nanometric to Grain Scale Mechanical Tests/Texture

Experimental: Nanometric to Grain Scale Mechanical Tests/Texture (EBSD) As Received

As Received

As Received

Martensite Evolution with Strain in 201LN

100 mm 10 % strain

1000

Interrupted tests

Stress (MPa)

800

Austenite Martensit e

201LN

600 5%

400

10% 20% 30%

200

40% 50% Fracture

0 0.0

0.1

0.2

0.3

0.4

0.5

Strain

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Neutron diffraction estimated values AK steel corp.

Experimental: Nanometric to Grain Scale Mechanical Tests/Texture (EBSD) Micropillar Deformation in As-Rec. Austenitic 201LN 1200

Single Slip System

1000

124

800

436

600

316

400

436 316 124

200 0 0.00

0.01

0.02

0.03

0.04

Stress (MPa)

Stress (MPa)

1000

1200

Multiple Slip Systems

115

800

113 600

003

400

003 033 113 115

200

0.05

0 0.00

0.01

0.02

Strain

0.03

Strain

003 115 316 124

033

436 033

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113 225

0.04

0.05

Experimental: Coupon-level Tests for Flow Behavior, Formability, Failure/Fracture • Clemson University, - Prof. Fadi Abu-Farha •

Purpose: – Perform macro-scale measurements, including: • • • • • • • •

Uniaxial tensile testing Hydraulic bulge test (balanced biaxial) Controlled biaxial testing (cruciform) Austenite-to-martensite transformation at different conditions Shear testing Formability testing -Nakajima/Marciniak Tension-compression testing Edge fracture (hole expansion test, center hole specimen tension test) • Other (draw bend / stretch bending test, springback, etc.)

•

Integration: – Provide experimental data for input to and crystal plasticity (microstructural) simulations and homogenized constitutive model validation.

ST 2.1 Experimental: Coupon-Level Tests for Flow Behavior, Formability, Failure Fracture

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Digital Image Correlation Simple Tension of Q&P980 (@45o, 23oC) Stationary color bands appear on the tensile bar surface.

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Digital Image Correlation Formability test of Q&P 980 steel stretching with a cylindrical punch @ 23oC.

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Computational: Atomistics for Defects/Strengthening/Hardening •

University of Illinois – Prof. Dallas Trinkle – Dr. Michael Fellinger

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Purpose: – Using electronic structure methods, compute material properties, elastic constants, hardening parameters of 3GAHSS phases/chemistry. – Compute dislocation core structures, then energetics of core/solute interactions for e.g. Critical Resolve Shear Stress (CRSS), and (possibly) other hardening parameters.

•

Integration: – Provide computed inputs to crystal plasticity modeling effort to reduce number of experimental inputs; reduce dependencies upon data fitting.

ST 2.1 Computational: Atomistics for Defects / Strengthening / Hardening

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Computational: Atomistics for Defects/Strengthening/Hardening

Stacking-fault energy surfaces: bcc {110} and {112}, and fcc {111}

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Computational: Atomistics for Defects/Strengthening/Hardening

Bain transformation from fcc to bcc FCC

Energy (eV)

Volume

Bain path calculations including C are in progress

BCC

Screw dislocations in bcc Fe: Initial geometry and force-constant calculations www.autosteel.org

Computational: Crystal Plasticity for Mechanical Properties of Phases in Microstructure • Michigan State University – Prof. Farhang Pourboghrat

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Purpose: – Generate and then mesh a realistic 3D RVE of 3GAHSS for use in crystal plasticity simulations. – Develop evolutionary yield function for FE simulations.

•

Integration: – Apply Brown-measured data to facilitate crystal plasticity simulations.

ST 2.1 Computational: Crystal Plasticity for Mechanical Properties of Phases in Microstructure

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Computational: Crystal Plasticity for Mechanical Properties of Phases in Microstructure

Using Brown University Generated Microstructural Data to Generate a 3D Representative Volume Element (RVE)

or

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Computational: Crystal Plasticity for Mechanical Properties of Phases in Microstructure

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Computational: Microstructural Design and Analysis of 3GAHSS • Colorado School of Mines – Professor David Matlock – Professor John Speer

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Purpose: – Develop recipes for 3GAHSS that meet DOE targets for mechanical properties, mass and cost savings.

•

Integration: – Provide recipes to make 3GAHSS coupons.

ST 2.8 Computational: Microstructural Design and Analysis of 3GAHSS

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Computational: Microstructural Design and Analysis of 3GAHSS Exceptional Strength Targets - High Ductility 1500 MPa/25% TE • Steel Type: Quenching and partitioning (Q&P) steel • Processing: • Austenite: 820 °C, 2 min. • Quench: 180 °C • Partition: 400 °C, 100 s Under development

Example: SEM of Q&P steel 0.3C–3Mn–1.6Si sample austenitized at 820°C for 120 s, quenched to 200°C, and partitioned at 400°C for 30 s. E. De Moor, J.G. Speer, D.K. Matlock, J.H. Kwak, and S.B. Lee, “Effect of Carbon and Manganese on the Quenching and Partitioning Response of CMnSi Steels,” ISIJ Intl. Vol. 51, no. 1, 2011, pp.137-144.

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Computational: Microstructural Design and Analysis of 3GAHSS High Strength - Exceptional Ductility Targets: 1200 MPa/30% TE • Steel Type: Medium Mn, Duplex TRIP steel • Processing: Intercritical anneal: 600 °C, 96 h Reversion anneal: 640 °C, 16 h

Under development

Example: SEM of Medium Mn (7.1-Mn) steel annealed for 168 hr. at 600 °C followed by water quenching – selected to illustrate features anticipated in10-Mn microstructure P. J. Gibbs: “Design considerations for the third generation advanced high strength steels”, Ph.D Thesis, Colorado School of Mines, 2013

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Design and Manufacture of 3GAHSS Steel Sheets • Auto/Steel Partnership •

To validate length scale material models, 3GAHSS heats are being made and rolled. – AK Steel used CSM recipes to cast two heats which are being processed into sheet. – Mechanical property test results and microstructural analysis will be used to validate the material models • Refined and validated models will eventually be used to predict 3GAHSS chemistry and microstructure with mechanical properties that meet the DOE 3GAHSS targets

AK Steel 3GAHSS Heat

ST 2.9 Design and Manufacture of 3GAHSS Steel Sheets

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Task 3: Forming – Component-Scale Performance Prediction and Validation • Auto/Steel Partnership •

•

Purpose: – To identify applicable forming models and validate these models using componentscale forming trials. Integration: – Integration of forming models with the length scale material models of Task 2 and Task 5 design optimization. – Use of 3GAHSS heats from Sub-Task 2.9 for forming and performance model validation

Hardening

Yield

FLD

Images courtesy of Severstal.

Task 3: Forming – Component-Scale Performance Prediction and Validation

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Task 3: Forming – Component-Scale Performance Prediction and Validation

• •

•

Forming simulations: begin with the BAO QP980 steel and then progress to 3GAHSS from Sub-Task 2.9. Outputs to the forming simulation: to be compared to forming trials with components such as a T-shaped and/or U-bend component. The validated models will be integrated with the length scale material models from Task 2 and the Task 5 Design Optimization

Draw stretch sample

Image courtesy of Severstal. Stretch bend sample Image courtesy of ArcelorMittal R&D East Chicago.

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Task 4 ‘Assembly’ and Task 6 ‘Integration’ • Livermore Software And Technology Corporation • Auto/Steel Partnership •

Purpose: – Task 4: To assemble validated length scale material models sufficient to predict 3GAHSS chemistry and microstructures that can meet the DOE FOA target mechanical properties. – Task 6: To integrate the length scale material models with forming models, performance models, design optimization and technical cost modeling into the ICME model.

Task 4 ‘Assembly’ and Task 6 ‘Integration’

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Status: Task 5 ‘Design Optimization’ and Task 7 ‘Technical Cost Modeling’’ • EDAG Corporation • Auto/Steel Partnership •

Purpose: – Task 5: To optimize a baseline assembly consisting of four or more AHSS components using 3GAHSS mechanical properties – Task 7: To develop a technical cost model that includes material and manufacturing costs.

•

Integration – Design optimization will be coupled with forming and performance simulations from Task 3 • Determine the feasible 3GAHSS gauges and shapes for weight optimized assembly.

Task 5 ‘Design Optimization’ and Task 7 ‘Technical Cost Modeling’’

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Status: Task 5 ‘Design Optimization’ and Task 7 ‘Technical Cost Modeling’’ •

The baseline assembly is the body structure of a four-door, mid-size sedan. – Bill of materials (alloys and grades) - Complete – Component and assembly weights - Complete – Load cases have been defined • • • • • •

•

Body Structure: Baseline Mid-Size sedan

Side barrier impact Pole impact Roof crush Front impact Rear impact Seat belt anchorage strength

– Currently assessing baseline assembly performance against defined load cases – Design optimization with 3GAHSS will begin with the completion of the baseline assembly performance assessment. Preliminary Technical Cost Model - Complete

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“The Endgame”

Task 2.

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Acknowledgement

This material is based upon work supported by the Department of Energy National Energy Technology Laboratory under Award Number No. DEEE0005976. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Such support does not constitute an endorsement by the Department of Energy of the work or the views expressed herein.

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Thank You For Your Attention! Questions? “…one cannot be but impressed by the potentialities of an implement of research so fine-grained that it reveals the mode of association of the atoms themselves.” Edgar Bain, United States Steel Corp. (ca. 1920s)

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North American Light Vehicle Metallic Material Trends

PRESENTATIONS WILL BE AVAILABLE MAY 16 Use your web-enabled device to download the presentations from today’s event Great Designs in Steel is Sponsored by:

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