J2340 MAR2017

SURFACE VEHICLE
RECOMMENDED PRACTICE Issued 1999-10
Stabilized 2017-03

Superseding J2340 OCT1999

Categorization and Properties of Dent Resistant, High Strength, and Ultra

High Strength Automotive Sheet Steel

RATIONALE

This document has been determined to contain basic and stable technology which is not dynamic in nature.

STABILIZED NOTICE

This document has been declared "Stabilized" by the SAE Sheet and Strip Steel Committee and will no longer be subjected

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to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical
requirements. Newer technology may exist.

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Foreword—The primary reason higher strength steels are used is because their yield and tensile strengths are
higher than those of low-carbon sheet steel, which are described in SAE J2329. Higher strength steels are
desirable for dent resistance, increased load bearing capability, better crash energy management, or for part mass
reduction through a decrease in sheet metal thickness.

An increase in strength generally leads to reduced ductility or formability. Care must be taken in designing parts,
tooling, and fabrication processes to obtain the greatest benefit from the higher strength sheet steels.
Consultation in grade selection between user and steel producer is recommended to insure compatibility of the
strength and forming characteristics.

Strength in these steels is achieved through chemical composition (alloying) and special processing. Special
processing includes mechanical rolling techniques, temperature control in hot rolling, and time/temperature control
in annealing of cold-reduced steel. Further or additional thermal treatment may modify the original mechanical
properties.

1. Scope—This SAE Recommended Practice defines and establishes mechanical property ranges for seven
grades of continuously cast high strength automotive sheet steels that can be formed, welded, assembled,

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and painted in automotive manufacturing processes. The grade of steel specified for an identified part should
be based on part requirements (configuration and strength) as well as formability. Material selection should

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also take into consideration the amount of strain induced by forming and the impact strain has on the strength
achieved in the finished part. These steels can be specified as hot-rolled sheet, cold-reduced sheet,

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uncoated, or coated by hot dipping, electroplating, or vapor deposition of zinc, aluminum, and organic
compounds normally applied by coil coating. The grades and strength levels are achieved through chemical
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composition and special processing. Not all combinations of strength and coating types may be commercially
available. Consult your steel supplier for details.
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2. References

2.1 Applicable Publications—The following publications form a part of this specification to the extent specified
herein. Unless otherwise indicated, the latest issue of SAE and ASTM publications shall apply.

2.1.1 SAE PUBLICATIONS—Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.

SAE J1058—Standard Sheet Thickness’ and Tolerances

SAE J1562—Selection of Zinc and Zinc-Alloy (Hot Dipped and Electrodeposited) Coated Steel Sheet
SAE J2329—Categorization and Properties of Low Carbon Automotive Sheet Steels

2.1.2 ASTM PUBLICATIONS—Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

ASTM A 370—Standard Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A 980—Standard Specification for Steel Sheet, Carbon, Ultra High Strength Cold Rolled

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ASTM E 8M—Standard Test Methods of Tension of Metallic Materials
ASTM E 517—Standard Test Method for Plastic Strain Ratio r for Sheet Metal
ASTM E 646—Standard Test Method for Tensile Strain-Hardening Exponents (n value) of Metallic Sheet

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Materials

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2.1.3 ANSI/AWS/SAE PUBLICATION—Available from ANSI, 11 West 42nd Street, New York, NY 10036-8002.

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ANSI/AWS/SAE D8.8-97—A Specification for Automotive and Light Truck Component Weld Quality - Arc
Welding
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2.1.4 OTHER PUBLICATION

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AZ-017-02-295 1.0C RI—Weld Quality Test Method Manual; Standardized Welding Test Method Task
Force, Auto/Steel Partnership (A/SP)
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2.2 Related Publications—The following publications are provided for information purposes only and are not a
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required part of this document.

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2.2.1 SAE PUBLICATIONS—Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.
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SAE J416—Tensile Test Specimens

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SAE J810—Classifications of Common Imperfections in Sheet Steel

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SAE J1392—Steel, High Strength, Hot Rolled Sheet and Strip, Cold Rolled Sheet, and Coated Sheet
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SAE J2328—Selection and Specification of Steel Sheet, Hot Rolled, Cold Rolled, and Coated for
Automotive Applications.

2.2.2 ASTM PUBLICATIONS—Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

ASTM A 463—Standard Specification for Cold Rolled Aluminum Coated Type 1 & Type 2 Steel Sheet
ASTM A 568—General Requirements for Carbon and High Strength, Low Alloy Steel Sheet.
ASTM A 653—Steel Sheet, Zinc Coated (Galvanized) or Zinc-Iron Alloy Coated (Galvanneal) by the Hot-
Dip Process.
ASTM A 751—Standard Test Methods for Determining Chemical Composition of Steel Products
ASTM A 924—General Requirements for Steel Sheet Metallic Coated by the Hot Dip Process

2.2.3 ISO PUBLICATION—Available from ANSI, 11 West 42nd Street, New York, NY 10036-8002.

ISO 13887—Cold Reduced Steel Sheet of Higher Strength with Improved Formability

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2.2.4 OTHER PUBLICATION

Steel Products Manual, Sheet Steel; Iron and Steel Society Publication, January 1988

3. General Information—This document defines seven grades of higher strength steel based on material type
and processing. These strength grades are shown in Table 1.

TABLE 1—STEELS AND STRENGTH GRADES

Steel Description Grade Type Available Strength Grade - MPa
Dent Resistant Non-Bake-Hardenable A 180, 210, 250, 280
Dent Resistant Bake-Hardenable B 180, 210, 250, 280
High Strength Solution Strengthened S 300, 340
High Strength Low Alloy X&Y 300, 340, 380, 420, 490, 550
High Strength Recovery Annealed R 490, 550, 700, 830
Ultra High Strength Dual Phase DH & DL 500, 600, 700, 800, 950, 1000

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Ultra High Strength Low Carbon Martensite M 800, 900, 1000, 1100, 1200, 1300, 1400, 1500

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4. Condition—Several conditions of hot-rolled and cold-reduced uncoated and coated sheet steels are used by
the automotive stamping and assembly operations. The conditions of sheet steel are referred to by letter code

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that follows the class designation.

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Cold-Reduced Uncoated and Metallic Coated Sheet Steel—Three conditions of sheet steel surface
characteristics are produced.
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4.1.1 Exposed (E) is intended for the most critical exposed applications where painted surface appearance is of
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primary importance. This surface condition of sheet steel will meet requirements for controlled surface
texture, surface quality, and flatness.
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4.1.2 Unexposed (U) is intended for unexposed applications and may also have special use where improved
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ductility over a temper rolled product is desired. Unexposed can be produced without temper rolling; this
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surface condition of sheet steel may be susceptible to exhibit coil breaks, fluting, and stretcher straining.
Standard tolerances for flatness and surface texture are not applicable. In addition, surface imperfections
can be more prevalent and severe than with exposed.
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4.1.3 Semi Exposed (Z) is intended for non-critical exposed applications. This is typically a hot-dip galvanized
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temper-rolled product, see SAE J1562 for full explanation. Acceptability of surface characteristics or
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discontinuities shall be negotiated between user and supplier.

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4.2 Hot-Rolled Uncoated and Metallic Coated Sheet Steel—Four conditions of hot-rolled sheet steel are
available.

4.2.1 Condition P is an as hot-rolled coiled product, typically known as hot roll black band, which has not been
pickled, oiled, temper rolled, side trimmed, rewound, or cut back to established thickness and width
tolerances.

4.2.2 Condition W has been processed and is available in coils or cut lengths. This material may be susceptible to
coil breaks and aging. Yield strength range classes apply only to material that has been cut back to
established thickness and width tolerances. Processed coils may receive any or all of the processing steps
listed in 4.2.1.

4.2.3 Condition N has been processed and is available in coils or cut lengths. This material possesses mechanical
properties that do not deteriorate at room temperature, however, condition N material is susceptible to coil
breaks.

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4.2.4 Condition V has been processed and is available in coils or cut lengths. This material is free from coil breaks
and its mechanical properties do not deteriorate at room temperature.

Some of the product characteristics available for each type of hot-rolled steel are listed in Table 2.

TABLE 2—PRODUCT CHARACTERISTICS OF HOT-ROLLED SAE J2340 STEEL

Freedom
From Coil Non Pickle Cut Special
Condition Breaks Aging and Oil(1)(2) Edge(1)(2) Surface(1)(2)
P No No n n n
W No No a a n
N No Yes a a n
V Yes Yes a a a
1. a = available but not required
2. n = not available

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5. Steels and Strength Grades

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5.1 Dent Resistant Cold-Reduced Sheet Steels—There are two types of dent-resistant steel; non-bake-

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hardenable and bake-hardenable. Both are available in grades with minimum yield strengths from 180 MPa
and higher. Both are available uncoated or coated.

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Non-bake-hardenable, dent resistant steels achieve their final strength in the part through a combination of
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their initial yield strength and the work hardening imparted during forming. Bake-hardenable steels exhibit an
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additional increase in strength due to age hardening after forming which is accelerated by subsequent paint
baking.
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Although dent-resistant steels are not specified by chemistry, the following is provided for information purposes
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only. Both non-bake-hardenable and bake-hardenable dent resistant steels can be based on conventional low
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carbon steel (0.02 to 0.08% C), steel vacuum-degassed to very low carbon levels (<0.02% C), or interstitial-
free (IF) steel. IF steel is vacuum degassed to ultra-low carbon levels (<0.01% C) and then any carbon
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remaining in solution is removed by adding titanium, niobium (columbium), or vanadium to form carbide
precipitates. Solid solution strengthening elements such as phosphorous, manganese, or silicon may also be
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added to increase the as-received strength while not significantly reducing the material's work hardenability. A
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material's bake hardenability depends upon the amount of carbon remaining in solution, which is controlled
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through the steel chemistry and thermomechanical processing.

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In this document, classification is based on minimum yield strength of the steel sheet and the strengthening
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that occurs during forming and paint baking. Classification of dent resistant steel is not based on chemistry.

5.1.1 TYPES AND MECHANICAL PROPERTY REQUIREMENTS—Mechanical property requirements of dent resistant
cold-reduced uncoated and coated sheet steel grades are based on the minimum values of the following: As
received yield strength (180, 210, 250, and 280 MPa), n value, tensile strength and the yield strength after
strain (for non-bake-hardenable grades) or strain and bake (for bake-hardenable grades). These are the
only mechanical requirements of this document for dent resistant cold-reduced uncoated and coated sheet
steel grades (see Table 3). Typical mechanical properties of dent resistant cold-reduced uncoated and
coated sheet steel grades are shown in Table A1 (“A” designates the Appendix).

5.1.1.1 Type A—This is a non-bake-hardenable dent resistant steel in which increase in yield strength due to work
hardening results from strain imparted during forming. For the purpose of this document, a non-bake-
hardenable dent resistant steel shall gain at least 35 MPa in yield strength (longitudinal direction) after a
2% tensile prestrain that represents the forming strain. This is considered the “strain hardening index”
(SHI).

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TABLE 3—REQUIRED MINIMUM MECHANICAL PROPERTIES(1) OF DENT RESISTANT SHEET STEEL

SAE J2340 As Received As Received Yield Strength Yield Strength
Grade Designation Yield Strength(2) Tensile Strength As Received After 2% After Strain and
and Type MPa MPa n Value(3) Strain MPa Bake MPa(4)
180 A 180 310 0.20 215
180 B 180 300 0.19 245
210 A 210 330 0.19 245
210 B 210 320 0.17 275
250 A 250 355 0.18 285
250 B 250 345 0.16 315
280 A 280 375 0.16 315
280 B 280 365 0.15 345
1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be per-
formed per Section 10.

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2. Yield Strength is 0.2% offset or, in the presence of yield point elongation, lower yield point.
3. n value shall be calculated, per ASTM E 646, from 10 to 20% strain or to the end of uniform elongation when uniform elongation is
less than 20%.

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4. 2% tensile prestrain and baking at 175 °C for 30 min at temperature. The upper yield point is used for determination of yield
strength. WIth lower yield point, requirement is 5 MPa lower.

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5.1.1.2 Type B—This is a bake-hardenable dent resistant steel in which increase in yield strength due to work
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hardening results from strain imparted during forming and an additional strengthening increment that
occurs during the paint-baking process. For the purposes of this document, bake-hardenable dent
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resistant steels are defined as those products which possess a “bake hardening index” (BHI) (as shown in
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Figure A1). This is an increase in yield strength of at least 30 MPa in upper yield strength or 25 MPa
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based on lower yield point (longitudinal direction) after a 2% tensile strain and baking at 175 °C for 30 min
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(representing the paint-baking process). The total hardening response is the sum of the SHI and the BHI.
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In order to help visualize the concept of the SHI and BHI, Figure A1 in the Appendix shows a portion of a
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stress strain curve and how these two characteristics are determined.
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In practice, the magnitudes of the forming strain and the paint-baking temperature may be different than
those designated for the purposes of this specification. Figures A2 and A3 in the Appendix describe their
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typical effects on the strain hardening and bake hardening increments.

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5.1.2 SUB TYPE T—Sub Type T may be specified to denote an interstitial free dent resistant steel (Type A grades
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only). When interstitial free steel is used the tensile strength shall be 30 MPa higher than a non-interstitial
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free steel. Sub Type T steels shall be specified by the “T” designator (e.g., SAE J2340 - 180AT).

5.1.3 BASE METAL—Dent resistant steel furnished to this document shall be cold-reduced low carbon deoxidized
steel made by basic oxygen, electric furnace, or other process which will produce a material which satisfies
the requirements for the specific grade. This steel shall be continuously cast. The chemical composition
shall be capable of achieving the desired mechanical and formability properties for the specified grade and
type. For grades 180 and 210 using an interstitial free (IF) base metal having a carbon content less than
0.010, an effective boron addition of <0.001% may be required to minimize secondary work embrittlement
(SWE) and to control grain growth during welding. The steel supplier shall define the chemical composition
range that will be furnished on a production basis. The steel supplier shall not change the product/process
without complying with the purchaser’s supplier quality assurance requirements.

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5.2 High Strength Solution Strengthened and High Strength Low Alloy (HSLA) Hot-Rolled and Cold-
Reduced Sheet Steels and High Strength Recovery Annealed Cold-Reduced Sheet Steels—High strength,
HSLA, and high strength recovery annealed categories include steel grades with minimum yield strengths in the
range of 300 to 830 MPa. These sheet steels can be ordered and supplied as uncoated or coated.

Several different types of high strength steel based on chemistry can fall under this category. Solution
strengthened high strength steels are those that contain additions of phosphorus, manganese, or silicon to
conventional low carbon (e.g., 0.02 to 0.13% carbon) steels. HSLA steels have additions of carbide formers,
such as, titanium, niobium (columbium), or vanadium made to conventional low carbon (0.02 to 0.13% carbon)
steel. High strength recovery annealed steels have chemistries similar to the previous varieties of steels, but
special annealing practices prevent recrystallization in the cold-rolled steel.

5.2.1 TYPES AND MECHANICAL PROPERTY REQUIREMENTS—Mechanical properties of these high strength sheet
steels shall be measured in longitudinal direction unless otherwise specified and shall conform to the
requirements for the grades specified in Tables 4 and 5. Classification is based on the minimum yield

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strength: 300 to 830 MPa. Several categories at each strength level are defined as follows:

5.2.1.1 Type S—High strength solution strengthened steels use carbon and manganese in combination with

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phosphorus or silicon (as solution strengtheners) to meet the minimum strength requirements. Carbon
content is restricted to 0.13% maximum for improved formability and weldability. Phosphorus is restricted

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to a maximum of 0.100%. Sulfur is restricted to a maximum of 0.020%.

5.2.1.2 EC
Type X—Typically referred to as HSLA steels, these high strength steels are alloyed with carbide and
nitride forming elements, commonly niobium (columbium), titanium, and vanadium either singularly or in
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combination. These elements are used with carbon, manganese, phosphorus, and silicon to achieve the
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specified minimum yield strength. Carbon content is restricted to 0.13% maximum for improved formability
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and weldability. Phosphorus is restricted to a maximum of 0.060%. The specified minimum for niobium
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(columbium), titanium, or vanadium is 0.005%. Sulfur is restricted to a maximum of 0.015%. A spread of

70 MPa is specified between the required minima of the yield and tensile strengths.
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5.2.1.3 Type Y—Same as Type X, except that a 100 MPa spread is specified between the required minima of the
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yield and tensile strengths.

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5.2.1.4 Type R—High strength recovery annealed or stress-relief annealed steels achieve strengthening primarily
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through the presence of cold work. Alloying elements mentioned under Types S and X may also be
added. Carbon is restricted to 0.13% maximum for improved formability and weldability. Phosphorus is
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restricted to a maximum of 0.100%. Sulfur is restricted to a maximum of 0.015%. These steels are best
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suited for bending and roll-forming applications since the mechanical properties are highly directional and
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ductility and formability are limited.

5.2.2 SUB TYPE F—Sub Type F may be specified to denote sulfide inclusion controlled. These steels are specified
for forming applications and are generally used in unexposed applications only. Special steel making
practice is used to control the shape or the volume fraction of manganese sulfide inclusions to improve edge
stretching or bending in some applications. It is recommended that the producer and purchaser consult to
determine the specific forming requirements prior to specifying Sub Type F. Sub Type F steels may be
specified by the “F” designator (e.g., SAE J2340 - 340XF).

5.2.3 BASE METAL—High strength steel furnished to this document shall be a low carbon deoxidized steel made by
basic oxygen, electric furnace, or other process which will produce a material which satisfies the
requirements for the specific grade. This steel shall be continuously cast. The chemical composition shall
be capable of achieving the desired mechanical and formability properties for the specified grade and type.
The steel supplier shall define the chemical composition range that will be furnished on a production basis.
The steel supplier shall not change the product/process without complying with the purchaser’s supplier
quality assurance requirements.

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TABLE 4—REQUIRED MECHANICAL PROPERTIES(1) OF HIGH STRENGTH AND HSLA HOT-ROLLED

AND COLD-REDUCED UNCOATED AND COATED SHEET STEEL(2)
SAE J2340 Yield Strength(3) Yield Strength(3) Tensile % Total Elongation % Total Elongation
Grade Designation MPa MPa Strength MPa Min Min
and Type Minimum Maximum Minimum Cold-Reduced Hot-Rolled(4)
300 S 300 400 390 24 26
300 X 300 400 370 24 28
300 Y 300 400 400 21 25
340 S 340 440 440 22 24
340 X 340 440 410 22 25
340 Y 340 440 440 20 24
380 X 380 480 450 20 23
380 Y 380 480 480 18 22

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420 X 420 520 490 18 22
420 Y 420 520 520 16 19
490 X 490 590 560 14 20

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490 Y 490 590 590 12 19
550 X 550 680 620 12 18

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550 Y 550 680 650 12 18

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1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be performed
per Section 10.
2. Consultation between user and producer is recommended regarding the selection of specific steel grade and welding process optimiza-
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tion.
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3. Yield strength is 0.2% offset or, in the presence of yield point elongation, lower yield point.
4. For thickness less than 2.5 mm, minimum percent elongation is permitted to be 2% less than the value shown.
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TABLE 5—REQUIRED MECHANICAL PROPERTIES(1) OF HIGH STRENGTH RECOVERY ANNEALED

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COLD-REDUCED SHEET STEEL(2)

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SAEJ2340 Yield Strength(3) Yield Strength(2) Tensile % Total

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Grade Designation MPa MPa Strength MPa Elongation

and Type Minimum Maximum Minimum Minimum
A

490 R 490 590 500 13

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550 R 550 650 560 10

700 R 700 800 710 8
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830 R 830 960 860 2

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1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be per-
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formed per Section 10.

2. Consultation between user and producer is recommended regarding the selection of specific steel grade and welding process
optimization.
3. Yield strength is 0.2% offset or, in the presence of yield point elongation, lower yield point.

5.3 Ultra High Strength Cold-Rolled Steels; Dual Phase and Low Carbon Martensite—The Ultra High Strength
Dual Phase and Low Carbon Martensite (LCM) categories include steel grades with minimum tensile strengths
in the range of 500 to 1500 MPa. These sheet steels may be ordered and supplied as uncoated or coated.
Contact your steel supplier to determine coating availability.

Special heat treating practices that involve quenching and tempering treatments are used to generate a
martensite phase in the steel microstructure. The volume fraction and carbon content of the martensite phase
determines the strength level. These steels are primarily alloyed with carbon and manganese. Boron may be
added in some cases.

Specification of chemical limits for low carbon martensitic grades may be found in ASTM A 980.

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5.3.1 TYPES AND MECHANICAL PROPERTY REQUIREMENTS—The mechanical property requirements of ultra high
strength sheet steels are specified in Tables 6 and 7. Classification is based on the minimum tensile
strength of the sheet steel: 500 to 1500 MPa. Typical mechanical properties of ultra high strength sheet
steels are shown in Tables A2 and A3.

The formability and weldability characteristics of these ultra high strength steels shall be agreed upon
between purchaser and supplier.

TABLE 6—REQUIRED MECHANICAL PROPERTIES(1) OF ULTRA HIGH STRENGTH DUAL PHASE

HOT-ROLLED AND COLD-REDUCED SHEET STEEL(2)
SAE J2340 Yield Strength MPa Tensile Strength % Total Elongation
Grade Designation and Type Minimum (3) MPa Minimum in 50 mm Minimum
500 DL 300 500 22
600 DH 500 600 14
600 DL1 350 600 16

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600 DL2 280 600 20
700 DH 550 700 12

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800 DL 500 800 8
950 DL 550 950 8

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1000 DL 700 1000 5
1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be
performed per Section 10.
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2. Consultation between user and producer is recommended regarding the selection of specific steel grade and welding pro-
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cess optimization.
3. Minimum yield strength can be waived upon agreement between user and supplier.
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TABLE 7—REQUIRED MECHANICAL PROPERTIES(1) OF LOW CARBON

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MARTINSITE HOT-ROLLED AND COLD-REDUCED SHEET STEEL(2)(3)

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SAE J2340 Yield Strength Tensile Strength

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Grade Designation and Type MPa Minimum(4) MPa Minimum

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800M 600 800

900 M 750 900
1000 M 750 1000
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1100 M 900 1100

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1200 M 950 1200

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1300 M 1050 1300

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1400 M 1150 1400

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1500 M 1200 1500

1. The mechanical property requirements shall be determined in longitudinal direction
unless otherwise specified and shall be performed per Section 10.
2. Consultation between user and producer is recommended regarding the selection of
specific steel grade and welding process optimization.
3. Minimum total elongation for all grades is 2%.
4. Minimum yield strength can be waived upon agreement between user and supplier.

5.3.1.1 Type DH/DL—The ultra high strength dual phase steel microstructure is comprised of ferrite and
martensite, (dual phase), with the volume fraction of low-carbon martensite primarily determining the
strength level. Two types of dual phase steels are available; a) a high yield ratio (ratio of YS/TS) product
designated as DH in Table 6; and b) a low yield ratio product designated as DL in Table 6. For the purpose
of this specification, products with yield ratios of 0.7 or lower are designated as DL and products with yield
ratios greater than 0.7 are designated as DH.

5.3.1.2 Type M—In these fully martensitic ultra high strength sheet steels, carbon content determines the strength
level. These steels have limited ductility.

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5.3.2 BASE METAL—High strength steel furnished to this document shall be a low carbon deoxidized steel made by
basic oxygen, electric furnace, or other process which will produce a material which satisfies the
requirements for the specific grade. This steel shall be continuously cast. The chemical composition shall
be capable of achieving the desired mechanical and formability properties for the specified grade and type.
The steel supplier shall define the chemical composition range that will be furnished on a production basis.
The steel supplier shall not change the product/process without complying with the purchaser’s supplier
quality assurance requirements.

6. Weldability—When the steel is used in welded applications, welding procedures shall be suitable for the steel
chemistry and intended service. Unspecified chemical elements may be present. Limits on chemistry shall be
as stated in Table 8. The sum Cu, Ni, Cr, and Mo shall not exceed 0.50% on heat analysis. When one or more
of these elements are specified, the sum does not apply; in which case, only the individual limits on the
remaining unspecified elements will apply.

TABLE 8—CHEMICAL LIMITS ON UNSPECIFIED ELEMENTS

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Maximum Weight Maximum Weight Maximum Weight Maximum Weight
Percent Allowed Percent Allowed Percent Allowed Percent Allowed

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Element Type A, B, and R Type S Type X and Y Type D and M
P 0.100(1) 0.100 0.060 0.020

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S 0.015 0.020 0.015 0.015
Cu 0.200 0.200 0.200 0.200

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Ni 0.200 0.200 0.200 0.200
Cr 0.150 0.150 0.150 0.150
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Mo 0.060 0.060 0.060 0.060
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1. Maximum phosphorus shall be less than 0.050 on grades 180A and 180B.
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6.1 High Strength Steel—In welding high strength steels it is important to consider several factors usually not
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considered in welding lower strength steels; for example, welding process, welding parameters and, of course,
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material combinations. Integration of these types of considerations can result in a successful system of
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welding for HSS. Various welding methods (arc welding, resistance welding, laser welding and high frequency
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welding) all have unique advantages in welding specific sheet steel combinations. Considerations for
production rate, heat input, weld metal dilution, weld location access, etc., may make one system more
weldable than another system. For instance, an HSS that is problematic for spot welding may not exhibit the
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same difficulty in arc or high frequency welding. In fact, a low heat input resistance seam welding method has
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been successfully employed for commercial production of bumper beams with a 1300M grade. Considerations
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with respect to material combinations are important for those welding processes that solidify from a molten
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pool, or that are constrained by thickness ratio. In general, caution should be exercised in spot welding an
HSS to itself because of possible weld metal interfacial fracture tendencies, but even a problematic HSS can
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be spot welded to a low carbon mild steel.

The resistance spot weldability requirements for low strength steels evaluate the operational robustness of the
candidate steel. This often embodies measurements of current range and electrode wear (for galvanized
coatings). The resistance spot weldability requirements for HSS may be similar to those of low strength steels
with the added requirement for mechanical performance. The evaluation of mechanical performance alone
may also be sufficient to assess weldability. End use requirements will determine required spot weld
performance. These requirements may limit the current range and/or electrode life based on individual
company weld quality specifications. For instance, fast quenching of the weld may damage the weld metal
integrity causing interfacial fracture, or excessive weld heat input may cause metallurgical changes that soften
the heat affected zone. Both of these conditions could result in a loss of joint strength. Incorporation of
appropriate weld and temper cycles or modification of weld chemistry through selective dilution of the joint can
lead to acceptable weld strength and thus ensure the retention of advantages to using HSS for weight
reduction in automotive components.

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Weld Quality Test Method Manual (AZ-017-02 295 1.0C RI) or AWS/ANSI/SAE Standard D8.9-97, should be
used as reference documents for further details. Note these standard test methods are intended for strength
levels up to 420 MPa and modifications may be required for higher strength levels. Due to unique properties of
HSS, selection of the weld process parameters should be determined in consultation with the steel supplier. It
is recommended that product validation include production intent weld processes, preferably at the extremes
of expected spot properties as determined by the laboratory studies.

Similar to resistance spot welding, the evaluation of other welding methods should take into account the
appropriate operational robustness measures and the mechanical and/or fracture performance of the resulting
weld quality. Weld performance, not absolute base material chemistry, is the important distinction between low
and high strength steels. Since weldability requirements differ for different weld methods, it is difficult to
summarize these requirements into a unified document. For example, ANSI/AWS/SAE Standard D8.8-97,
may be used as a reference document for further details. Consultation is recommended between user and
steel producer regarding the selection of specific steel grade as well as weld process optimization.

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7. Cold Bending—High strength steels are frequently fabricated by cold bending. There are a multiplicity of
inter-related factors which affect the ability of a given piece of steel to form over any given radius in shop
practice. These factors include thickness, strength level, degree of restraint in bending, relationship to rolling

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direction, chemical composition, and microstructure. Table A4 lists those ratios which should be used as
minimums for 90 degree bends in actual shop practice. It recognizes that “hard way” bending (bend axis

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parallel to rolling direction) is common in production and presupposes that reasonably good forming practices
will be employed. Where design permits, users are encouraged to employ large radii that are shown in Table
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A4 for improved performance. Where the bend axis can be designed across the width (“easy way”) of the
sheet, or bends less than 90 degrees, slightly tighter radii can be employed. As the cold forming becomes
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progressively more difficult, that is, from a straight bend to a curved or offset bend to stretching or drawing, it is
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advisable that the producer and user consult to determine the special material, design, and tooling
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requirements of the application. The fabricator should be aware that steel may crack to some degree when
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bent on a sheared or burned edge. This is not to be considered to be the fault of the steel, but rather a function
of the induced cold work or heat affected zone (HAZ).
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8. Nomenclature and Suggested Ordering Practice

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8.1 Specifying sheet steel on the engineering drawing under this document should include the following
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information to adequately describe the desired material:

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a. Name of material being specified; such as electro-galvanized bake-hardenable steel.

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b. SAE Recommended Practice number (SAE J2340).

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c. Base metal type; hot rolled (HR) or cold reduced (CR).

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d. Grade (four character identification which includes minimum yield strength and sheet steel product
type).
e. Coating type and coating weight, if any. Indicate hot-dip or electro-galvanized zinc coating and coating
weight. See SAE J1562 for detailed nomenclature.
f. Surface condition. Indicate exposed, E, unexposed, U; or semi exposed, Z, matte, or dull finish will be
supplied unless otherwise specified.
g. Part thickness plus the tolerance.
8.2 Suggested ordering practice should include the specification from the engineering drawing plus the following
additional information.

a. Application (show part identification and description).

b. Dimensions (thickness, tolerance, width, and length for cut lengths).
c. Condition (specify pickled if required, specify oiled or not oiled as required, specify chemical treatment
for coated product if required).
d. Edges (must be specified for hot-rolled sheet and strip, that is, mill edge or cut edge).

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e. Coil size and weight requirements (must include inside diameter, outside diameter, and maximum
weight).
f. Cut length weight restrictions, that is, maximum weight of individual bundle.
g. Heat or cast analysis and mechanical property report (if required).

8.3 Typical specification and ordering descriptions are as follows:

a. Hot-dip galvanized dent resistant steel per SAE J2340 CR 180A HD70G70GZ, 1.00 mm min. +0.08
thick. Cold-reduced hot-dip galvanized dent resistant sheet for a semi-exposed application, cut edge,
1625 mm wide x coil.
b. Electro-galvanized bake-hardenable steel per SAE J2340 CR 250B EG70G70GE, 0.80 mm min. +
0.08 thick. Cold-reduced electro-galvanized bake-hardenable sheet for an exposed application, 1500
mm wide X 2540 mm.
c. High strength low alloy steel per SAE J2340 HR 340XU, 2.50 mm min +0.30 thick. Hot-rolled high
strength low alloy sheet steel, pickled and oiled, unexposed surface, 1400 mm wide X coil.
d. Ultra high strength sheet steel per SAE J2340 CR 1300M, 1.20 mm min + 0.10 thick. Cold-reduced

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ultra high strength sheet steel, 1220 mm wide x coil.

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9. Thickness Tolerances—Tolerances for dimensions are shown in SAE J1058.

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10. Tensile Samples

10.1 Method
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10.1.1 Samples should be flat and free of defects such as scores, wrinkles, die marks, etc.
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10.1.2 For standard testing, one longitudinal 0 degree coupon is needed.

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10.1.3 For r-Bar (rm) testing, one longitudinal 0 degree, one diagonal 45 degrees and one transverse 90 degrees
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samples are required. r Bar (rm) is a calculated number from individual r value tests.
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10.1.4 Care should be taken to insure that the samples be cut exactly at 0 degree, 45 degrees, or 90 degrees to the
coil rolling direction.
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10.1.5 Tensile test shall be made with coating on.

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10.2 Preparation of Samples

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10.2.1 Method (ASTM E 8, E 517, E 646)

10.2.1.1 Samples must have all oils, lubricants, or dry films removed prior to measurement.

10.2.1.2 If base metal hardness is a desired value for correlation information, all coating must be removed from
samples prior to testing.

10.2.1.3 Samples should be EDM (electrical discharge machining) cut if possible. If specimens are milled,
preparation must be such that minimal cold work is imparted to the edges of the reduced section.

10.2.2 DIMENSIONS

10.2.2.1 Gage Length—50 mm ± 0.10 mm.

10.2.2.2 Width—12.50 mm ± 0.25 mm.

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10.2.2.3 Parallelism

a. Standard Testing—Reduced section must be parallel to ±0.025 mm.

b. r value Testing—Reduced section must be parallel to ±0.013 mm.

10.2.2.4 Reduced section should be approximately 75 mm.

10.2.2.5 Overall length should be approximately 200 mm.

10.3 Measurements

10.3.1 EQUIPMENT

10.3.1.1 Use a digital measuring device capable of resolving to least 0.013 mm.

10.3.1.2 Measuring device should be verified and documented with a test block or pin daily, before measurements

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are made.

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10.3.1.3 Measuring device should be zeroed after each set of tests. If it does not return to zero, reset the device
and re-measure the previous set of samples.

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10.3.2 MEASUREMENT METHOD

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10.3.2.1 Standard Testing—Measure narrowest width and thickness within the 50 mm gage marks.
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10.3.2.2 r Value Testing—Measure at least three equally spaced width and thickness measurements across the
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50 mm gage length. Average these for the initial dimensions. End gage mark must be at least 25 mm
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from grips.
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10.4 Testing
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10.4.1 TENSILE MACHINE OPERATING PARAMETERS—See Table 9.

TABLE 9—TENSILE MACHINE OPERATING PARAMETERS

A
M

Crosshead Speed Strain Rate

R

Ramp rate 1 (1) 3.0 mm/min 1.5 mm/min

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Ramp rate 2(2) to determine r value 12.5 mm/min 6.2 mm/min

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Ramp rate 2 for all standard tensile tests 25.0 mm/min 12.5 mm/min
1. Ramp rate 1 is prior to and through yield or YPE.
2. Ramp rate 2 is after yield or YPE (yield point elongation). Either crosshead speed control or strain rate control can
be used; the method must be noted in test report results. Speed of testing greatly affects stress values, making uni-
formity critical.

10.4.2 Machine grips should cover at least 2/3 of the gripped section of the sample.

10.4.3 Stopping point for r value test measurement is 17% elongation.

10.4.4 n-value determination range is 10% to 20% elongation, or 10% - ultimate load if uniform elongation is less
than 20%. Minimum 5 data pairs. Calculation per ASTM E 646 Part 10.

10.4.5 Tensile machine repeatability and reproducibility must be performed, and results documented as defined by
the quality control procedures of the testing laboratory.

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10.5 Calculation methods

10.5.1 Elongation can be determined by either the piece-fit method or computer generated through the
extensometer. Whatever method is used must be stated in the lab report, because piece-fit elongation is
generally higher than extensometer elongation. Elongation value is invalid if the specimen breaks within
6 mm of, or outside the gage marks.

10.5.2 Uniform elongation is defined as the elongation value measured at peak stress.

10.5.3 0.2% offset yield strength will be used for all samples without YPE. For samples with YPE, the yield strength
at the lowest point of discontinuous yielding shall be reported, along with the percentage of YPE.

10.5.4 r Bar (rm) Value = (r90° r0° + 2r45°)/4

10.5.5 Earing Tendency (∆r) = (r90° + r0° - 2r45° )/2

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PREPARED BY THE SAE IRON AND STEEL TECHNICAL COMMITTEE
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DIVISION 32—SHEET AND STRIP STEEL

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APPENDIX A

DENT RESISTANT STEELS

DATA ARE SHOWN IN THE APPENDIX FOR INFORMATION ONLY.

A.1 Dent Resistant Steels—See Table A1.

TABLE A1—TYPICAL MECHANICAL PROPERTIES(1) OF DENT RESISTANT COLD-REDUCED SHEET STEEL

As Received As Received As Received
Properties Properties Properties Yield Upper Yield
SAE J2340 Yield Tensile Total As Received As Received Strength Strength After
Grade and Strength(2) Strength Elongation Properties Properties after 2% 2% Strain and
Type MPa MPa % n Value(3) rm Value(4) Strain MPa Bake MPa(5)
180 A 200 350 40 0.22 1.7 235
180 B 200 330 39 0.21 1.6 265

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210 A 230 375 38 0.21 1.7 265
210 B 230 350 37 0.19 1.5 295

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250 A 270 400 36 0.20 1.5 305
250 B 270 370 35 0.18 1.4 335
280 A 300 430 36 0.18 1.4 335

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280 B 300 410 35 0.17 1.1 365

Section 10. EC
1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be performed per

2. Yield Strength is 0.2% offset or, in the presence of yield point elongation, lower yield point.
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3. n value shall be calculated, per ASTM E 646, from 10 to 20% strain or to the end of uniform elongation when uniform elongation is less
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than 20%.
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4. r value shall be calculated, per ASTM E 517, at 17% strain, rm calculation by (r0 + r90 + 2r45)/4. The rm value can be up to 0.2 lower
for thickness greater than 1.4 mm and/or galvanneal products.
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5. 2% tensile prestrain and baking at 175 °C for 30 min at temperature.

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A.1.1 Determination of Strain-Hardening Index and Bake-Hardening Index—Bake-hardening steel strength

shall be determined in specimens that have been prestrained 2% and baked at 175 °C for 30 min. Standard
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test specimens will be taken from unstrained and unbaked material in the longitudinal (rolling) direction per
ASTM A 370. Referring to Figure A1, both the bake-hardening index (BHI) and the strain-hardening index
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(SHI) of the material can be determined as follows in Equation 1:

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BHI = C – B (Eq. A1)

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where:
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B = Flow stress at 2% prestrain

C =Yield strength (either upper or lower yield strength) after baking at 175 °C for 30 min.

SHI = B – A (Eq. A2)

where:

A = Initial 0.2% offset yield strength

B = Flow stress at 2% prestrain

The original specimen area is used in calculation of all engineering strengths in this test (A, B, and C). The
total increase in strength from the test is reported as BHI (BHIU or BHIL) + SHI.

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FIGURE A1—REPRESENTATION OF STRAIN-HARDENING AND BAKE-HARDENING INDEX

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For the purpose of part design, it may be desirable to predict yield strength at various locations on the finished
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part. The yield strength for 180B, 210B, 250B, and 280B shown in Table 3 is attained by straining 2% during
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forming followed by a paint cycle of 30 min at 175 °C. Figure A2 approximates the changes from this yield
strength with varying amounts of prestrain.
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Figure A2—

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The after strain and bake yield strengths given in Table 3 were initially developed with data derived from
samples subjected to 2% strain followed by a 30-min bake at 175 °C. Figure A3 is presented to show the effect
of lower paint bake temperatures following 2% strain on resulting typical yield strength values.

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Figure A3—

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EC
A.2 Ultra High Strength Dual Phase Steels—See Table A2.

TABLE A2—TYPICAL MECHANICAL PROPERTIES(1) OF ULTRA HIGH STRENGTH DUAL PHASE

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HOT-ROLLED AND COLD-REDUCED SHEET STEEL
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SAE J2340 Yield Yield after 2% Tensile % Total

Bend Radii(2)
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Grade Designation and Strength Strain and Bake Strength Elongation

Type MPa MPa MPa in 50 mm r/t
A

500DL 340 480 550 28 .5 L & T

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600DH 550 690 710 20 2L&T

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600DL1 390 560 650 22 .5 L & T

600DL2 340 490 660 27 .5 L & T
700DH 600 720 760 16 2L&T
A

800DL 580 800 860 14 1L&T

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950DL 680 1030 1050 12 4L&T

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1000DL 810 1070 1070 9 3L&T

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1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall
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be performed per Section 10.

2. 90 degrees Bend test shall be conducted per ASTM A 370. Ratio of bend radius to thickness (T = transverse specimen
and L = longitudinal specimen).

Forming limits studies are helpful in predicting the success of forming complex shapes. Roll forming
processes are recommended. Stampings which require draws may be unsuccessful due to the limited flow of
dual phase and martensitic microstructures. Spring back variation is much greater in dual phase and
martensitic steel and should be considered in the part, tool, and weld fixture designs.

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A.3 Ultra High Strength Martensitic Steels—See Table A3.

TABLE A3—TYPICAL MECHANICAL PROPERTIES(1) OF ULTRA HIGH STRENGTH LOW CARBON

MARTENSITE COLD-REDUCED SHEET STEEL
SAE J2340 Yield Tensile % Total Bend
Grade Designation Strength Strength Elongation Radii(2)
and Type MPa MPa in 50 mm r/t
800M N. A.(3) N. A. N. A. N. A.
900M 900 1025 5 4L&T
1000M N. A. N. A. N. A. N. A.
1100M 1030 1180 4 4L&T
1200M 1140 1340 6 4T&L
1300M 1200 1400 5 4L&T
1400M 1260 1480 5 4T&L
1500M 1350 1580 5 4L&T

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1. The mechanical property requirements shall be determined in longitudinal direction unless otherwise specified and shall be
performed per Section 10.

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2. 90 degrees Bend test shall be conducted per ASTM A 370. Ratio of bend radius to thickness (T = transverse specimen and
L = longitudinal specimen).

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3. N. A. - Information not available.

A.4 High Strength Solution Strengthened and HSLA Steels—See Table A4.
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TABLE A4—TYPICAL INSIDE BEND RADII(1)(2)(3) HIGH STRENGTH AND HSLA,
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COLD-REDUCED AND HOT-ROLLED AND HIGH STRENGTH RECOVERY
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ANNEALED COLD-REDUCED UNCOATED AND COATED SHEET STEEL

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SAE J2340 Cold-Reduced Hot-Rolled

Grade Designation Bend Radius/ Bend Radius/
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and Type Thickness Thickness

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300 S, X, & Y 1/2 T 1T

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340 S, X, & Y 1/2 T & L 1T&L

380 X & Y 1T&L 1T&L
A

420 X & Y 1T&L 1T&L

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490 X & Y 2T&L 2T&L

550 X & Y 2T&L 2T&L
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490 R 3T&L N. A.(4)

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550 R 3T&L N. A.
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700 R 4T&L N. A.
830 R 6T&L N. A.
1. 90 degrees Bend test shall be conducted per ASTM A 370. Ratio of bend radius to thickness (T =
transverse specimen and L = longitudinal specimen).
2. The suggested minimum bending radius is based on the nominal rolled thickness, not the minimum
ordered thickness.
3. For thicknesses over 4.50 mm, add 1/2 t to the radius shown in the Table.
4. N. A. - Information not available

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