saej126v001

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Copyright 1986 Society of Automotive Engineers, Inc.2.References

2.1Applicable Publications—The following publications form a part of the specification to the extent specified

herein. Unless otherwise indicated the latest revision of SAE publications shall apply.

2.1.1ASTM P UBLICATIONS—Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.

ASTM A109—Steel, Carbon, Cold Rolled Strip.

ASTM A569—Steel, Carbon (0.15 maximum percent), Hot Rolled Sheet, Commercial Quality (HRCQ).

ASTM A621—Steel, Sheet, Carbon, Hot Rolled, Drawing Quality (HRDQ).

ASTM A622—Steel, Sheet, Carbon, Hot Rolled, Drawing Quality, Special Killed (HRDQSK).

ASTM A568—Steel, Carbon and High-Strength Low-Alloy Hot Rolled Sheet, and Cold Rolled Sheet, General Requirements.

ASTM A366—Steel, Carbon, Cold Rolled Sheet, Commercial Quality (CRCQ).

ASTM A619—Steel, Sheet, Carbon, Cold Rolled, Drawing Quality (CRDQ).

ASTM A620—Steel, Sheet, Carbon, Cold Rolled, Drawing Quality, Special Killed (CRDQSK).

ASTM A749M—Steel, Carbon and High-Strength Low-Alloy, Hot Rolled Strip, General Requirements.

ASTM A635—Steel Sheet and Strip, Carbon, Hot Rolled Commercial Quality, Heavy Thickness Coils.

(Metric ASTM documents are designated by suffix M)

3.Procedure—Evaluate the part to determine the requirements for characteristics A-F, as follows:

3.1 A - Hot or Cold Rolled Product—Normally the finish or thickness of the metal required for a part will

determine whether hot-rolled or cold-rolled product should be specified. (See Table 1A, T able 1B, and Table 4.)

3.2 B - Sheet or Strip—Principal factors to consider in determining whether sheet or strip should be specified are:

Size of part, or more specifically, size of flat steel required to develop part.

Thickness of metal required for the part.

Hot or cold rolled steel.

Selection and specification of temper for cold rolled strip. (See Table 3A, Table 3B.)

Equipment on which the metal will be handled and fabricated.

Steel industry product classification by size. (See Table 1A, Table 1B.)

3.3 C - Selection of Sheet Steel for Formability—For Cold Rolled Carbon Sheet and Hot Rolled Carbon Sheet

and Strip, three levels of formability or drawability (called quality in the steel industry) are available as indicated in the Scope. They are commonly referred to as CQ, DQ, and DQSK.

The following procedure is based on a Forming Severity Index (FSI) which has been developed through experience in production forming of sheet metal stampings. The procedure is recommended for determining the quality needed for a specific part and fabrication operation.

1.Form a sample or prototype part from a specimen of known quality of steel using the gridding

procedure outlined in SAE J863. (For the most accurate description of the quality of steel used for the

gridded blank, the mechanical properties of a sample taken from material adjacent to the blank used

for the gridded part should be known. This can be from the same blank, or the sheet preceding or

following the sheet to be gridded.) If the specimen fractures, form another sample from the next better

quality of steel.

2.Measure the e1 and e2 strains as described in SAE J86

3. (This should be done on a sample part

which has not fractured during forming.)

3.Calculate the Forming Severity Index (FSI), for the critical area or areas of the sample part, using the

following formulae:

NOTE—The e 2 strain is the associated strain (minor) measured perpendicular to the major strain, e 1.

When the e 2 strain as measured on the grid in the maximum stretch area is 0 to +30%.

(Eq. 1)

When the e 2 strain is 0 to −30% (biaxial tension compression forming).

(Eq. 2)where:t = thickness of gridded panel in inches.

e 1 = major strain expressed as a percent (not a decimal value).

e 2 = minor strain expressed as a percent (not a decimal value).

The sign of e 2 is disregarded (an e 2 of −30 is expressed as 30 in the formula).

NOTE:

a.The thickness t in the above formulae is only a correction factor for calculation of the FSI. Material

formability may not be dependent on the sheet metal thickness.

b.If t is expressed in millimeters, the multiplier will be 13.8 instead of 350.

c.The reliability of the equations for stock over 0.125 in or 3 mm has not been establishe

d.

d.The constant 15 in the above formulae can be modified by mutual consent of the supplier and user

to provide the desired degree of risk of breakage. A constant of 15 approximates a safety factor of

ten percentage of strain points for die, lubricant, press, and material variance of e 1 strain (major

strain). A constant of 20 gives a safety factor of 5, and a constant of 10 gives a safety factor of 15.

4.Select the quality of steel sheet needed for the part from Table 2. When a change in material is

indicated by Table 2, the selection should be verified using the new quality of sheet metal to form

another sample part.

5.After a sufficient production history has been obtained through the use of the SAE Recommended

Practice J424, Determination of Breakage Allowance for Steel Sheets, the quality of steel being used

should be reviewed. For a given part an unusually high scrap rate indicates either a tool, lubricant, or

material quality selection problem. If material quality is found to be the problem, upgrading should be

considered. Conversely, an unusually low scrap rate indicates a less expensive quality should be

considered. SAE Recommended Practice J863 should be followed to determine the most beneficial

material change.

EXAMPLE—In the case of 0.080 in or 2.00 mm thick sheet steel with e 1 strain of 33% and e 2 strain of +10%,

the Forming Severity Index (FSI) would be:

(Eq. 3)

(Eq. 4)

FSI 0.6e 215350t ++()e 1

–=FSI 1.5e 215350t ++()e 1–=FSI 0.610()in ()153500.080()+

+33FSI 16=–=FSI 0.610()mm ()1513.82.0()+

+33FSI 16=–=

If the gridded panel was CRCQ steel, the FSI indicates the selection of a lower quality steel such as

HRDQ (A621). Note that in cases such as this where the FSI is greater than +6 there are other factors

than material which should be investigated to obtain the most economical production.

If the gridded panel was HRDQ, the indicated selection would be HRCQ (A569).

In the case of 0.036 in or 0.9 mm thick stock with an e 1 strain of 55% and an e 2 strain of −15%, the FSI

would be:

(Eq. 5)

(Eq. 6)

If the gridded panel was CRCQ and trouble was being encountered in forming production parts, the

indicated selection would be to upgrade to CRDQ (A619). If the gridded panel was CRDQ, the

indicated selection would be to upgrade to CRDQSK (A620) and if the panel was CRDQSK some

other changes may be required in the forming operations or in the design of the part (comments in

Table 2).

3.4 D - Surface Condition (Finish, etc.)—Consider any surface conditions required for the part. Consult Table 4

for a description of surfaces applicable to the product selected in A, B, and C above. Designate surface, finish,coating, etc. by symbol shown.

3.5 E - Edge Condition—Consider any necessary edge conditions required for the part. Consult Table 5 for a description of edges applicable to the product selected in A, B, and C above. Designate the required edge condition by the symbol shown.

3.6

F - Dimensions—Consider all dimensions required for the part.

Refer to ASTM A568 for thickness tolerance tables.

Designate dimensions in the following order: thickness, width, and length. (Note: Use the symbol C for length of material purchased in coil form.) When the measuring unit is inches, all fractions thereof shall be expressed as decimals and not as common fractions (for example, 1.25 in, not 1-1/4 in). State the thickness to three decimal places and width and length to two decimal places.

When metric units are used for dimensions, the thickness, width, and length should be expressed in millimeters. State thickness to one decimal place and width and length in whole numbers.

EXAMPLE—

For cut length: 0.035 x 36.25 x 84.75 (in) 0.9 x 900 x 2153 (mm)

For coil length:0.047 x 47.37 x C (in) 1.2 x 1200 x C(mm)

(These units are not intended to indicate conversion of inch to metric units.)FSI 1.515()in ()

153500.036()++55FSI 5

–=–=FSI 1.515()mm ()

1513.80.09()++55FSI 5

–=–=

AISI Steel Customer Communication Handbooks are recommended.

TABLE 1A—STEEL SHEET OR STRIP PRODUCT CLASSIFICATION BY SIZE, METRIC UNITS Product Thickness, mm Width, mm Other Limitations Specification Symbol

(ASTM No.) Hot Rolled Sheet 1.2–6.0Over 300 thru 1200Coils and Cut Lengths A 569M, A 621M, or A 622M

1.2–4.5Over 1200

6.0–12.5Over 300 thru 1200Coils Only A 635M

4.5–12.5Over 1200 thru 1800

Hot Rolled Strip 1.2–5.0Thru 200Coils and Cut Lengths A 569M, A 621M, or A 622M

1.2–6.0Over 200 thru 300

6.0–12.5Over 200 thru 300Coils Only A 635M

Cold Rolled Sheet 0.35–2.0Over 50 thru 300See Note 1 A 366M, A 619M, or A 620M

0.35 and Over Over 300See Note 2

Cold Rolled Strip Thru 6.0Over 12 thru 600See Note 3 A 109M

NOTE 1—Cold rolled sheet, coils, and cut lengths, slit from wider coils with cut edge (only), thicknesses 0.35–2.0 mm and carbon of 0.25% max by cast analysis.

NOTE 2—When no special edge or finish (other than matte, commercial bright, or luster) is required and/or single strand rolling of widths under 600 mm is not required.

NOTE 3—Widths 50–300 mm with thicknesses of 0.35–2.0 mm are classified as "sheet" when slit from wider coils, have a cut edge only, and carbon of 0.25% max by cast analysis.

TABLE 1B—STEEL SHEET OR STRIP PRODUCT CLASSIFICATION BY SIZE, INCH-POUND UNITS

Product Thickness, in Width, in Other Limitations Specification Symbol (ASTM

No.) Hot Rolled Sheet0.045 thru 0.230Over 12 thru 48Coils and Cut Lengths A 569, A 621, or A 622

0.045 thru 0.180Over 48

0.230 thru 0.500Over 12 thru 48Coils Only A 635

0.180 thru 0.500Over 48 thru 72

Hot Rolled Strip0.045 thru 0.203Thru 6Coils and Cut Lengths A 569, A 621, or A 622

0.045 thru 0.229Over 6 thru 12

0.230 thru 0.500Over 8 thru 12Coils Only A 635

Cold Rolled Sheet0.014 thru 0.082Over 2 thru 12See Note 1 A 366, A 619, or A 620

Over 0.014Over 12See Note 2

Cold Rolled Strip Thru 0.250Over 0.50 thru 23.9See Note 3 A 109

NOTE 1—Cold rolled sheet, coils, and cut lengths, slit from wider coils with cut edge (only), thicknesses 0.014–0.082 in and carbon of 0.25% max by cast analysis.

NOTE 2—When no special edge or finish (other than matte, commercial bright, or luster) is required and/or single strand rolling of widths under 24 in is not required.

NOTE 3—Widths 2–12 in with thicknesses of 0.014–0.082 in are classified as "sheet" when slit from wider coils, have a cut edge only, and carbon of 0.25% max by cast analysis.

TABLE 2—SELECTION OF QUALITY OF STEEL SHEET AND STRIP

BASED ON THE FORMING SEVERITY INDEX (FSI)

Quality of Steel Used

for the Gridded

Sample Panel

Quality Suggested When the Forming Severity Index is Within the Range Given Below −20 to −11−10 to −10 to +5+6 and Greater DQSK

DQSK (1) (2)1.This indicates too much is being expected of the sheet metal, a part redesign or breakdown into separate components may be necessary in addition to the factors below.

2.This represents a part which is difficult to form, other factors, such as tools, design, drawing compound application, blank development, etc., should be considered to provide an adequate Forming Severity Index because further upgrading is not possible. (Premium quality grades of steel with a high plastic strain ratio (r m ) values may be necessary if the above factors cannot be modified to produce a more favorable Forming Severity Index.)

DQSK 2DQSK DQ DQ

DQSK 2DQSK DQ CQ CQ DQSK

DQ CQ CQ (3)3.The part should have no forming problems and if further economics are desired, factors other than material quality should be investigated, such as, thickness reduction, drawing compound change, or simplified tooling. In the appropriate thickness range HR should be considered in place of CR.

TABLE 3A—(INCH-POUND UNITS)--SELECTION AND SPECIFICATION OF THE AMOUNT OF TEMPER

(COLD WORK) (APPLICABLE TO COLD ROLLED STEEL STRIP ONLY)

Requirement of Part (Relative to Hardness and Maximum Severity

of Bend Involved in Forming the Part)

Stock Thickness

in Rockwell Hardness

Bend Test Requirements

Temper of Strip Normally Required

Max (Approx.)Over Thru Min 0.070 --B84 --No bending in any direction.

No. 1 (Hard)

0.0400.070B90 --0.0250.04030T76.0 -- --0.02515T90.0 --0.040 --B70B85(1)1.Rockwell hardness values apply to special killed steels and also rimmed or semi-killed steels at time of shipment only. Aging of these latter steels may result in slightly higher values when tested at a later date.

Bend 90 deg across rolling direction around a radius equal to that of the metal thickness.(2)

2.T o bend across the rolling direction means that the crease formed by the bend shall be at right angles to the length of the strip. T o bend along the rolling direction means that the crease formed by the bend shall be parallel with the length of the strip.No. 2 (Half-Hard)

0.0250.04030T63.530T73.5 --0.02515T83.515T88.50.040 --B60B75(1)Bend 180 deg across rolling direction over one thickness of the strip and 90 deg in the

direction of rolling around a radius equal to the thickness.

No. 3 (Quarter-Hard)(2)

0.0250.04030T56.530T67.0 --0.025

15T80.0

15T85.00.040 -- --B65(1)Bend flat upon itself in any direction.

No. 4 (Skin Rolled)(3)

3.

Number 4 and 5 tempers may sometimes be ordered with a carbon range of 0.15–0.25%. In each instance the maximum hardness requirement is established by agreement.

0.0250.040 --30T60.0 --0.025--15T82.00.040 ----B55(1)Bend flat upon itself in any direction.

No. 5 (Dead Soft)(3)

0.0250.040 --30T53.0 --0.025

--

15T78.5

TABLE 3B—(METRIC UNITS)—SELECTION AND SPECIFICATION OF THE AMOUNT OF TEMPER

(COLD WORK) (APPLICABLE TO COLD ROLLED STEEL STRIP ONLY)

Stock Thickness

mm Rockwell Hardness

Bend Test Requirements

Temper of Strip Normally Required

Max (Approx.)Over Under Min 1.8 --B84 --No bending in any direction.

No. 1 (Hard)

1.0 1.8B90 --0.6 1.030T76.0 -- --0.615T90.0 --1.0 --B70B85(1)1.Rockwell hardness values apply to special killed steels and also rimmed or semi-killed steels at time of shipment only. Aging of these latter steels may result in slightly higher values when tested at a later date.

Bend 90 deg across rolling direction around a radius equal to that of the metal thickness.(2)

2.T o bend across the rolling direction means that the crease bend shall be at right angles to the length of the strip. To bend along the rolling direction means that the crease formed by the bend shall be parallel with the length of the strip.

No. 2 (Half-Hard)

0.6 1.030T63.530T73.5 --0.615T83.515T88.51.0 --B60B75(1)Bend 180 deg across rolling direction over one thickness of the strip and 90 deg in the direction of rolling around a radius equal to the thickness.(2)

No. 3 (Quarter-Hard)(2)

0.6 1.030T56.530T67.0 --0.6

15T80.0

15T85.01.0 ----B65(1)Bend flat upon itself in any direction.

No. 4 (Skin Rolled)(3)

3.

Number 4 and 5 tempers may sometimes be ordered with a carbon range of 0.15-0.25%. In each instance the maximum hardness requirement is established by agreement.

0.6 1.0--30T60.0 --0.6--15T82.01.0 ----B55(1)Bend flat upon itself in any direction.

No. 5 (Dead Soft)(3)

0.6 1.0--30T53.0 --0.6

--

15T78.5

Description of Surface Surface Described

Applicable To

Specification

Symbol

Surface finish as normally used for unexposed automotive parts. Matte

(dull) appearance. Normally annealed last.

Cold rolled sheet U a

Surface finish as normally used for exposed automotive parts which require

a good painted surface. Free from strain markings and fluting. Matte (dull)

appearance. Temper rolled.

Cold rolled sheet E b Same as above, except commercial bright appearance.Cold rolled sheet B Same as above, except luster appearance.Cold rolled sheet L

No. 1 or dull finish (no luster). Especially suitable for lacquer or paint

adhesion. Facilitates drawing by reducing the contact friction between

the die and the metal.

Cold rolled Strip1

No. 2 or regular bright finish (moderately smooth). Suitable for many

applications, but not generally applicable for parts to be plated, unless

polished and buffed.

Cold rolled strip2

No. 3 or best bright finish (relatively high luster). Particularly suitable for

parts to be plated.

Cold rolled strip3 As rolled or black (oxide or scale not removed).Hot rolled sheet and strip A Pickled (scale removed), not oiled.Hot rolled sheet and strip P

Same as above, except oiled.Hot rolled sheet and strip O

a U - unexposed is presently also designated as Class 2, Cold Rolled Sheet.

b E - exposed is presently also designated as Class 1, Cold Rolled Sheet.TABLE 5—SELECTION AND SPECIFICATION OF EDGE CONDITION OF STEEL SHEET AND STRIP

Description of Edge Edge Described

Applicable To Specification Symbol

Cut Edge.Cold rolled sheet None required

No. 1 Edge is a prepared edge of a specified contour (round, square, or

beveled) supplied when a very accurate width is required, or where the

finish of the edge is required to be suitable for electroplating, or both.

Cold rolled strip1

No. 2 Edge is a natural mill edge carried through the cold rolling from the

hot rolled strip without additional processing of the edge.

Cold rolled strip2

No. 3 Edge is an approximately square edge produced by slitting, on which

the burr is not eliminated.

Cold rolled strip3

No. 4 Edge is a rounded edge produced by edge rolling the natural edge of

hot rolled strip or slit-edge strip. This edge is produced when the width

tolerance and edge condition are not as exacting as for No. 1 Edge.

Cold rolled strip4

No. 5 Edge is an approximately square edge produced by rolling or filing of

a slit-edge to remove burr only.

Cold rolled strip5

No. 6 Edge is a square edge produced by edge rolling the natural edge of

hot rolled strip or slit-edge strip, where the width tolerance and finish

required are not as exacting as for No. 1 Edge.

Cold rolled strip6

Mill Edge.Hot rolled sheet and strip M

Cut Edge.Hot rolled sheet and strip C

Square Edge (square and smooth, corners slightly rounded). Produced by

rolling through vertical edging rolls during the hot rolling operation.

Hot rolled strip S

Rationale—Not applicable.

Relationship of SAE Standard to ISO Standard—Not applicable.

Application—This SAE Recommended Practice outlines a procedure for selecting the proper specification for carbon steel sheet and strip which are purchased to make an identified part.

Reference Section

ASTM A109—Steel, Carbon, Cold Rolled Strip

ASTM A569—Steel, Carbon (0.15 maximum percent), Hot Rolled Sheet, Commercial Quality (HRCQ) ASTM A621—Steel, Sheet, Carbon, Hot Rolled, Drawing Quality (HRDQ)

ASTM A622—Steel, Sheet, Carbon, Hot Rolled, Drawing Quality, Special Killed (HRDQSK)

ASTM A568—Steel, Carbon and High-Strength Low-Alloy Hot Rolled Sheet, and Cold Rolled Sheet, General Requirements

ASTM A366—Steel, Carbon, Cold Rolled Sheet, Commercial Quality (CRCQ)

ASTM A619—Steel, Sheet, Carbon, Cold Rolled, Drawing Quality (CRDQ)

ASTM A620—Steel, Sheet, Carbon, Cold Rolled, Drawing Quality, Special Killed (CRDQSK)

ASTM A749M—Steel, Carbon and High-Strength Low-Alloy, Hot Rolled Strip, General Requirements

ASTM A635—Steel Sheet and Strip, Carbon, Hot Rolled Commercial Quality, Heavy Thickness Coils Developed by the SAE Division 32 Sheet and Strip Steel

Sponsored by the Iron and Steel Technical Committee