Dent Resistant Steels - ArcelorMittal...Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions

Note: Information contained in this document is subject to change. Please contact our sales team whenever you place an order to ensure that your requirements are fully met. Please contact us if you have a specific requirement that is not included in the range of products and services covered by this document. Update: August 2009

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Grade Availability

ArcelorMittal offers the automotive industry a spectrum of Dent Resistant Steels which include products for exposed quality automotive outer-body-panels. These grades are available as both non-bake-hardening and bake-hardening types at various strength levels ranging from 180 to 300 MPa. The non-bake hardening grades are part of ArcelorMittal's HI FORM (HF) family of steels. The bake-hardening grades are part of ArcelorMittal's MINDENT® family of steels.

Dent Resistant Non Bake Hardening Grades

Hot Rolled Cold Rolled Strength Levels

Uncoated Uncoated EG HDGI HDGA

180 MPa YS or 340 MPa TS

- Yes Yes Yes Yes

210 MPa YS - Yes Yes Yes -

Dent Resistant Bake Hardening Grades

Hot Rolled Cold Rolled Strength Levels


180 MPa YS - Yes Yes Yes Dev

210, 220 MPa YS or 340 MPa TS - Yes Yes Yes Yes

250, 260 MPa YS - Yes Yes Yes -

280 MPa YS - Yes Yes - -

300 MPa YS - Yes - Yes Dev

YS: Yield Strength TS: Tensile Strength EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed Yes: Products commercially available Dev: Products under development or in limited production Please inquire about status and availability of the se products

Automotive Worldwide Product Offer for US

Dent ResistantDent ResistantDent ResistantDent Resistant Steels Steels Steels Steels


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Product Characteristics

Dent resistant steels are designed to improve dent resistance for automotive outer body panels. Using a combination of work hardening and bake hardening, the steels offer additional strength in the final panels for improved dent resistance. 'Non-bake-hardenable' steels achieve their final part strength by work hardening alone. ‘Bake-hardenable’ steels are those where the final part strength is achieved by a combination of work hardening (during forming) and bake hardening (during paint baking). Most dent resistant grades are low carbon grades, with several having ultra-low carbon compositions. Non-bake-hardenable grades are non-aging and their properties do not degrade over time. In contrast, bake-hardening grades have carbon/nitrogen in solution to develop the bake-hardening response. The aging phenomenon in bake-hardening grades is controlled through a combination of composition and processing.

Application

Dent resistant steels are widely used in the automotive industry. Exposed quality exterior automotive body panels such as doors, hoods, deck lids, fenders that require high dent resistance are commonly manufactured using these grades. Selection between non-bake-hardenable and bake-hardenable grades depends on formability and final part performance (dent resistance) requirements. Depending upon the amount of strain induced in the part during stamping, non-bake-hardenable grades can achieve similar final part strength as compared to corresponding bake-hardenable grades. Designing and manufacturing of parts should utilize the unique properties of individual grades.

In addition to outer body-panels, all dent resistant steels can also be used for structural applications. In fact, the higher strength (280 and 300 MPa grades) can be used to replace micro-alloyed HSLA 300 and 350 type products, respectively.

Representative Stress-Strain Curves of some Dent Resistant Steels


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Dent Resistant, Non Bake Hardening 180 MPa YS or 34 0 MPa TS Steels

Grade Availability – ArcelorMittal Products

Hot Rolled Cold Rolled


- - - HFY 180 PLUS -

- HFT 340 HFT 340 - -

- - - - HFT 340 PLUS

EG: Electrogalvanized HDGI: Hot-Dip-Galvanalized HDGA: Hot-Dip-Galvannealed ArcelorMittal offers various cold rolled dent resistant, non-bake-hardening grades at the 180 MPa yield strength and 340 MPa tensile strength levels with different coating conditions. These grades are part of ArcelorMittal's HI FORM (HF) family of steels. The 'PLUS' grades offer enhanced formability at the strength level. Application These products are used for exposed quality automotive outer-body panels, which require dent resistance.


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Chemistry

Product Chemistry

HFT 340 Low carbon grade, containing Mn and P

HFT 340 PLUS

HFY 180 PLUS Vacuum degassed ultra-low carbon steel containing Mn, P, Ti and Nb

Processing

Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced product is then further processed using batch annealing or continuously annealing technologies. HFT 340 grade is batch annealed and is available as uncoated (bare) or electrogalvainized (EG). HFT 340 PLUS and HFY 180 PLUS grades are continuously annealed and are available as hot-dip-galvanized (HDGI) and hot-dip-galvannealed (HDGA), respectively.

Typical Microstructure

HDGA-HFT 340 PLUS - Fine grained ferrite

Typical Mechanical Properties

Coating Product Yield Strength (MPa)

Tensile Strength (MPa)

Total Elongation

(%) r-bar n 1

Bare HFT 340 224 368 38 1.6 0.20

HDGA HFT 340 PLUS 190 361 40 1.6 0.22

1 The strain range for n-value is 10-20%


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Representative Stress-Strain Curves

Stress-Strain curve data is available upon request.

Formability

Angular Stretch Bend Test Results


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Sheared Edge Stretching Test Results

Product Gauge (mm)

Average Hole Expansion (%)

HDGA-HFT 340 PLUS 0.89 159.2

Fatigue

Strain Life Parameters

Fatigue Strength Coefficient (MPa) 726

Fatigue Ductility Coefficient 0.271

Fatigue Strength Exponent -0.111

Fatigue Ductility Exponent -0.515

Cyclic Strength Coefficient (MPa) 838

Cyclic Strain Hardening Exponent 0.198

Strain Life Curve


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Dent Resistant, Non Bake Hardening 210 MPa YS Steel s

Grade Availability - ArcelorMittal Products



- HFY 210 HFY 210 - -

- - - DEV HFY 210 PLUS -

- ISODENT Y210 ISODENT Y210 - -

EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed DEV: Products are under development or in limited production. Please inquire about the status and availability of these products. ArcelorMittal offers various cold rolled dent resistant non-bake-hardening grades at the 210 MPa yield strength level with different coating conditions. These grades are part of ArcelorMittal's HI FORM (HF) family of steels. Also available, at this strength level, is an isotropic steel (ISODENT) which exhibits uniform mechanical properties in all rolling directions. The 'PLUS' grades offer enhanced formability at the strength level. Application Typical applications of these products are where dent resistant and good drawability is required in the panel. These products are used for outer-body applications such as door-outers, body-side-outers. Chemistry

Product Chemistry

HFY 210 Low carbon steel, containing Mn and P

ISODENT Y210 Low carbon steel containing Mn and Ti

HFY 210 PLUS Vacuum Degassed ultra-low carbon, interstitial free steel, containing Mn, P, Nb and Ti

Processing Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced products is then further processed using batch annealing or continuously annealing technologies. HFY 210 and ISODENT Y210 grades are batch annealed and is available as uncoated (bare) or electrogalvainized (EG). HFY 210 PLUS is in-line continuously annealed and is available as hot-dip-galvanized (HDGI).


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ISODENT Y210 contains ferrite and carbides




Total Elongation

(%) r-bar n 1

Bare HFY 210 234 370 39 1.6 0.20

Bare ISODENT Y210 230 345 41 1.0 0.20



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Stress-Strain curve data is available upon request

Fatigue Behavior Strain Life Parameters








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Strain Life Curve

Dent Resistant, Bake Hardening 180 MPa YS Steels




- MINDENT® BH Y180 MINDENT® BH Y180 DEV MINDENT® BH Y180

-

- - - - DEV

MINDENT® BH Y180 PLUS

EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed 'DEV' products are under development or in limited production. Please inquire about the status and availability of these products.

ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 180 MPa yield strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels. The 'PLUS' grades offer enhanced formability at the strength level. Application These grades are extensively used in automotive outer body panels, where superior dent resistant is achieved by part from the work hardening of the steels during stamping and bake hardening during the paint bake treatment. These grades are, also, used for several unexposed structural applications like reinforcements and brackets.


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Chemistry

Product Chemistry

MINDENT® BH Y180 Low carbon steels strengthened with Mn and P

MINDENT® BH Y180 PLUS Vacuum degassed ultra-low carbon steels strengthened with Mn, P, Ti and Nb

Processing

Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced product is then further processed using continuously annealing technologies. Typical Mechanical Properties



Total Elongation

(%) r-bar n 1

Bare MINDENT® BH Y180 201 329 44 1.6 0.21

HDGI MINDENT® BH Y180 225 345 41 1.6 0.20

HDGA MINDENT® BH Y180

PLUS 202 309 39 1.8 0.19



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Dent Resistant, Bake Hardening 210, 220 MPa YS or 3 40 MPa TS




- MINDENT® BH Y210 MINDENT® BH Y210 - -

- MINDENT® BH Y210 PLUS

MINDENT® BH Y210 PLUS - MINDENT® BH Y210

PLUS

- MINDENT® BH Y220 MINDENT® BH Y220 DEV

MINDENT® BH Y220 -

- - - - MINDENT® BH T340 PLUS

EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed DEV: Products are under development or in limited production. Please inquire about the status and availability of these products. ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 210 and 220 MPa yield strength and 340 MPa tensile strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels. The 'PLUS' grades offer enhanced formability at the strength level.


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Application

These grades are extensively used in automotive outer body panels, where superior dent resistant is achieved by part from the work hardening of the steels during stamping and bake hardening during the paint bake treatment. These grades are, also, used for several unexposed structural applications like reinforcements and brackets.

Chemistry

Product Chemistry

MINDENT® BH Y210



MINDENT® BH T340 PLUS

Vacuum degassed ultra-low carbon steels strengthened with Mn, P, Ti and Nb

Processing

Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced product is then further processed using continuously annealing technologies. The Bare/EG MINDENT® BH Y210 and Y220 grades are continuously annealed and are available as uncoated or electrogalvanized (EG). The HDGI-MINDENT® BH Y220 and the HDGA-MINDENT® BH Y210 PLUS and T340 PLUS grades are in-line continuously annealed and are available as hot-dip-galvanized (HDGI) or hot-dip-galvannealed (HDGA), respectively.


Bare/EG MINDENT® BH Y210 containing ferrite and pearlite.


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Total Elongation

(%) r-bar n 1

Bare/EG MINDENT® BH Y210 250 370 40 1.5 0.19


HDGI MINDENT® BH Y220 270 360 39 1.1 0.18


PLUS 229 349 40 1.6 0.21





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Fatigue








Strain Life Curve


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Dent Resistant, Bake Hardening 210, 220 MPa YS or 3 40 MPa TS Steels





- MINDENT® BH Y210 PLUS

MINDENT® BH Y210 PLUS - MINDENT® BH Y210

PLUS

- MINDENT® BH Y220 MINDENT® BH Y220 DEV MINDENT® BH Y220 -

- - - - MINDENT® BH T340 PLUS

EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed DEV: Products are under development or in limited production. Please inquire about the status and availability of these products.

ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 210 and 220 MPa yield strength and 340 MPa tensile strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels. The 'PLUS' grades offer enhanced formability at the strength level. Application

These grades are extensively used in automotive outer body panels, where superior dent resistant is achieved by part from the work hardening of the steels during stamping and bake hardening during the paint bake treatment. These grades are, also, used for several unexposed structural applications like reinforcements and brackets. Chemistry

Product Chemistry

MINDENT® BH Y210


MINDENT® BH Y210 PLUS Vacuum degassed ultra-low carbon steels

MINDENT® BH T340 PLUS strengthened with Mn, P, Ti and Nb

Processing

Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced product is then further processed using continuously annealing technologies. The Bare/EG MINDENT® BH Y210 and Y220 grades are continuously annealed and are available as uncoated or electrogalvanized (EG). The HDGI-MINDENT® BH Y220 and the HDGA-MINDENT® BH Y210 PLUS and T340 PLUS grades are in-line continuously annealed and are available as hot-dip-galvanized (HDGI) or hot-dip-galvannealed (HDGA), respectively.



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Bare/EG MINDENT® BH Y210 containing ferrite and pearlite




Total Elongation

(%) R-bar n 1

Bare/EG MINDENT® BH Y210

250 370 40 1.5 0.19


HDGI MINDENT® BH Y220 270 360 39 1.1 0.18


PLUS 229 349 40 1.6 0.21



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Fatigue









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Strain Life Curve

Dent Resistant, Bake Hardening 250 and 260 MPa YS S teels





- - - DEV MINDENT® BH Y260 -

EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed DEV: Products are under development or in limited production. Please inquire about the status and availability of these products. ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 250 and 260 MPa yield strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels.

Application

These grades are used in outer body panels, where superior dent resistant is achieved due the increase in the part strength from the paint bake treatment. These grades can, also, be used for unexposed structural applications.


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Chemistry

Product Chemistry

MINDENT® BH Y250

MINDENT® BH Y260 Low carbon grade strengthened with Mn and P

Processing

These Dent Resistant Steels are produced regular low-carbon compositions. Steels are cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced product is then further processed using continuously annealing technology. Typical Mechanical Properties



Total Elongation

(%) r-bar n 1

Bare MINDENT® BH Y250

276 381 39 1.19 0.18

HDGI MINDENT® BH Y260

286 380 36 1.2 0.17





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EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed

ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 280 MPa yield strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels.

Application

These can be used in automotive outer body panels, where superior dent resistant is achieved due the increase in the part strength from the paint bake treatment. Product has been successfully used for Hood-Outer applications. This grade can also be used in structural parts, replacing conventional HSLA 300 products. Chemistry

Product Chemistry


Processing

Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced products is then further processed using continuously annealing technology. The Bare/EG MINDENT® BH Y280 grades are continuously annealed and are available as uncoated or electrogalvanized (EG). Typical Mechanical Properties

Coating Product Yield Strength

(MPa)


Total Elongation

(%) r-bar n 1


314 417 36 1.17 0.18



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Formability

Angular Stretch Bend Test Results


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Sheared Edge Stretching Test Results

Product Gauge (mm)

Average Hole Expansion (%)

EG-MINDENT® BH Y280 0.71 98.9





- MINDENT® BH Y300 MINDENT® BH Y300 MINDENT® BH Y300 -

- - - - DEV


EG: Electrogalvanized HDGI: Hot-Dip-Galvanized HDGA: Hot-Dip-Galvannealed DEV: Products are under development or in limited production. Please inquire about the status and availability of these products. ArcelorMittal offers various cold rolled dent resistant bake-hardening grades at the 300 MPa yield strength level with different coating conditions. These grades are part of ArcelorMittal's MINDENT® family of steels. The 'PLUS' grades offer enhanced formability at the strength level.

Application

These grades are commonly used for unexposed structural applications. After strain and baking, these steels can provide equivalent part strength, as compared with HSLA 350 type products.

Chemistry of MINDENT ® BH Y300

Product Chemistry

MINDENT® BH Y300 Low carbon grade, strengthened with Mn and P

MINDENT® BH Y300 PLUS Vacuum degassed ultra-low carbon steels strengthened with Mn, P, Ti and Nb

Processing

Depending on the application, these Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions. Steels are then cast into slabs and hot rolled. Hot rolled coils are further processed and cold reduced into lighter gauges. The cold reduced products is then further processed using continuously annealing technologies. The Bare/EG MINDENT® BH Y180 grades are continuously annealed and are available as uncoated or electrogalvanized (EG). The HDGI-MIDENT BH Y300 and the HDGA-MINDENT® BH Y300 PLUS are in-line continuously annealed and are available as hot-dip-galvanized (HDGI) or hot-dip-galvannealed (HDGA), respectively.


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Bare MINDENT® BH Y300 containing ferrite and carbide.

HDGI MINDENT® BH Y300 containing ferrite and carbide.


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HDGI MINDENT® BH Y300 containing ferrite and carbide

HDGA MINDENT BH Y300 containing ferrite.

Typical Mechanical Properties of MINDENT ® BH Y300



Total Elongation

(%) R-bar n 1


319 446 35 1.1 0.17

HDGI MINDENT® BH Y300 325 429 33 1.0 0.16


PLUS 333 423 28 1.0 0.13



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Post Baking Properties of MINDENT® BH Y300

Typical Yield Strengths after 0% and 2% Prestrain and Baking (170°C for 30min)

Coating Product Yield Strength (MPa) 0% Prestrain

Yield Strength (MPa) 2% Prestrain

Bare/EG MINDENT® BH Y300 350 412

HDGI MINDENT® BH Y300 348 412

HDGA MINDENT® BH Y300 PLUS 380 410


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Fatigue Behavior





Fatigue Ductility Exponent -.614



Endurance Limit, 5 x 106 cycles (MPa) 193


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Strain Life Curve

Documents

Dent Resistant Steels - ArcelorMittal...Depending on the application, Dent Resistant Steels are produced using vacuum degassed ultra-low-carbon or regular low-carbon compositions