STEEL SHEETS AND STRIPS MICROALLOYED, HOT ROLLED, CLOSE TEMPERATURE CONTROL, HIGH YIELD STRENGTH
MATERIALS STANDARD
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Supervisor: Supervisor :
FEDERICI Claudio
D.I.P. D.I.P. – Central Laboratories Laboratories Tel. 011.6835758 011.6835758
Manager: Manager :
BOTTAZZI Mauro
D.I.P. – Central Laboratories Tel. 011.6833070 011.6833070
SCOPE To define the characteristics for microalloyed low carbon, close temperature control hot rolled, high yield strengt h steel sheets and strips, for medium and light drawing and cold bending
Reference GM GMW3032 M – ST – S High Strength Sheet Steel (180 MPa – 550 MPa Yield Strengths)
This Standard consist s of 10 pages
––
Oct. 84
3rd Edition – Fully revised .
(AS)
––
Jan. 02
4th Edition – Completely revised to comply to GM Standard GMW3032 M–ST–S.
(AD AD))
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| § ‘‘A’’ : TEST EQUIPMENT The equipment required for the tests is indicated in the Standards listed in para. “B”.
| § ‘‘B’’ REFERENCES
|50020
| Material data processing coding TMD
|50108
| General test – Rockwell hardness test. TMD
|50113
| Tension testing – general purpose tests. TMD
|50116
| Tests on metals – Determination of formability indices. TMD
|50125
| General test – Bend test. TMD
|50240
| Requirements for ferrous metals – Pipes, sheets, wide strips, flat strips and sections – Test procedures and preparat ion of specimens. TMD
|52120
| Chemical composition variations on steel products. TMD
|54406
| Hot rolled steel sheet and strips – Dimensions and tolerances. F2
|9.01102
| Quality of FIAT AUTO S.p.A. supplies CFO
|9.50240
| Steel sheets and strips – Technical supply requirements. CMD
|3244–UNI
| Microscopic inspection of ferrous materials – Assessment of non metallic inclusions in steels by means of standard images.
|3245–UNI
| Microscopic examination of ferrous materials. Determination of the size of austenit ic or ferritic grain in the steel.
| 000–EN.78.0 | Authorizat ion to use products that vary from the technical specificat ions. (D.P: Dept – Industrial Methodo logy Development)
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1 GENERAL 1.1 Material Low carbon steel sheet with a thickness betwee n 1 and 16 mm, microalloyed, anti–ag ing, not for heat treat ment , suppl ied as close tempera tur e contr ol hot–r olled in sheet s or coils for medium and light drawing and cold bending applications in order to avoid altering mechani cal properties. 1.2 Application Highly stressed structural parts. 2 EXAMPLE OF INDICATION ON DRAWING, N OF DATA PROCESSING CODE AND CORRESPONDING FIAT AND G.M. CODES.
Example of indication on drawing and number of data processing code
MAJOR Steel sheets and strips not to be used in NEW DESIGNS started after 01/01/2002.
INDICATION ON DRAWING
Code Number Data processing (As per Standard 50020)
FE E 275
20165
FE E 355
20153
FE E 420
20112
FE E 490
20154
This identifica tion of the semi–finished product is to be completed with the associated symbol regarding appearance and surface finish as per Procurement Specification 9.50240. The general supply conditions are indicated in Procurement Specification 9.50240.
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Example of indication on drawing, n of data processing code and correspondence to GMW
MAJOR Steel sheets and strips to be used in NEW DESIGNS started after 01/01/2002.
INDI CATION ON DRAWING
Code Number Data processing (As per Standard 50020)
CORRISPONDENCE TO GM W
FEE 270
20186
GMW 3032 M – ST – S HR 270
FEE 300
20187
GMW 3032 M – ST – S HR 300
FEE 340
20188
GMW 3032 M – ST – S HR 340
FEE 380
20189
GMW 3032 M – ST – S HR 380
FEE 420
20190
GMW 3032 M – ST – S HR 420
FEE 500
20191
GMW 3032 M – ST – S HR 500
This identification of the semi – f inished product is to be completed with the associate d symbol regarding appearance and surface finish as per Procurem ent Specification 9.50240. The general suppl y condit ions are indicat ed in Procur eme nt Speci fic atio n9.50240.
3 CLASSIFICATION AND CHARACTERISTICS TO BE CHECKED 3.1 General applications Unless otherwise specified when ordering, the tables indicated in items 5 and 6 are to be compli ed to .
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Designs started before 01/01/2002
CHARACTERIS TICS TO BE CHECKED (X) MATERIAL
APPLICATIONS (GENERAL)
Chemic al composition
Tension hardness and bending
St ru ct ur e
R es il ie nce
FE E 275
Parts with deep drawings
(X)
(X)
(X)
(X)
FE E 355
Parts with medium bending and drawing
(X)
(X)
(X)
(X)
FE E 420
Very stressed parts with medium and light bending and drawing
(X)
(X)
(X)
(X)
FE E 490
Very stresse d part s with light bending and drawing
(X)
(X)
(X)
(X)
New designs started after 01/01/2002
CHARACTERIS TICS TO BE CHECKED (X) MATERIAL
APPLICATIONS ( GENERAL)
Chemical composition
Tension and bending
Formability index
Structure
FEE 270
Parts with difficult bending and drawing
(X)
(X)
(X)
(X)
FEE 300
Parts with medium a nd difficult bending and drawing
(X)
(X)
(X)
(X)
FEE 340
Parts with medium bending and drawing
(X)
(X)
(X)
(X)
FEE 380
Very stressed parts with medium and light bending and drawing
(X)
(X)
(X)
(X)
FEE 420
Very stresse d part s with light bending and drawing
(X)
(X)
(X)
(X)
FEE 500
Very stresse d part s with bending and forming
(X)
(X)
(X)
(X)
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3.2 Special applications For very demanding applications and only for exceptional cases, the order is to have attached the “Rolled product data sheet” appropriately prepared by the “Product Definition Services”. An example of this form is illustrat ed in Procurem ent Specification 9.50240. The material identific ation is to be slightly changed with the addition of
“KP” in high case
preceded by a dash. Example:
For old designs:
FE E 355 F – KP.
For new designs:
FEE 340 F – KP.
3.3 Variances If material is used that has character istics different to those indicated below, the Variance Authoriz ation Request Procedure 000–EN.78.0 and Procurement Specification 9.01102 are to be applied.
4 SURFACE APPEARANCE 4.1 Appearance and finish
For definition of appearanc e ratings MH, MG or MF see procurement Specificat ion 9.50240.
Visual inspection The rolled product s are to be free of defects tha t could adversely affect norm al use. The surface s are to be technically clean , free of rust and foreign matter. Flaws that could cause failures duri ng service, damage to equipment, welding or brazing problems or paint or protect ive coating adhesion difficult ies are not allowed. According to the spec ificatio ns of the order, the rolled sheets may be supplied with as–rolled or trimm ed edges. Edge condition shall not jeopardize semi finished product applicatio n.
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% LADLE ANALYSIS Rare earth elements may be added (TR) to reduce the transverse effect. Maximum allowed variatio ns are indicated in Standard 52120. Design s started before 01/01/2 002
MATERIAL
C Max.
Mn Max.
Si Max.
P Max.
S Max.
Al min.
FE E 275
Nb min. 0.015
0.10
0.60
FE E 355
0.020 0.40
0.025
0.025
0.020
FE E 420
0.11
1.00
0.030
FE E 490
0.12
1.60
0.040
No other microalloy elements are allowed, unless otherwise agreed upon when ordering.
New designs started after 01/01/2002
MATERIAL
C Max.
Mn Max.
FE E 270
1.00
FE E 300
1.30
FE E 340
1.50 0.12
FE E 380
1.50
FE E 420
1.60
FE E 500
1.70
P Max.
S Max.
Al min.
Si Max.
0.030
0.030
0.015
0.50
Microalloy elements: Nb 0.015 to 0.040 Nb + Ti + V 0. 2
CHARACTERISTICS: Mechanical properties (Designs started before 01/01/2002) Resilience test on specimen longitudinal in direction of rolling
Tension test (Standard 50113) Min elongation %
Load unit Failure R
Designation of semi–finished product
N/mm 2
Load unit yield Rs min.
at o of yield – break
N/mm2
Rs/R max..
Hardness t est (Rockwell)
Test f or bending
sp per tan-dard 50108)
sp per tan-dard 50125)
Specimen longitudinal in direction of rolling
Index of formability (As per Standard 50116)
(As per Standard 50130)
A80 s<3
(A) s 3
mm
mm
D/a = 180
HRB max..
Work hardening
KV min. J
n min.
t – 20 C
FE E 275
350 470
275
0,89
23
29
82
0
0,17
40
FE E 355
415 530
355
0,89
21
26
87
0
0,16
40
FE E 420
470 590
420
0,89
19
24
91
0,5
––
40
FE E 490
540 690
490
0,89
15
20
95
1,0
––
40
For test specimen cutting see Standard 50240. For reject purposes valid rated values are R, Rs, A %, r and n obtained as average of 3 determinations. Test not decisive for rejectio n purposes. Results of tensile test and st ructural inspection shall prevai l in disputed cases. Only when requested and for thicknesses to be agreed upon, and in any case 5 mm.
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Mechanical properties (New designs started after 01/01/2002)
Tension test (Standard 50113) (longitudinal direction)
Design ation of semi–finished product
Load unit Failure R
Load unit yield Rs
Minimum elongation A80 %
mm2
Index of formability (As p per Standard 50116)
mm 2 r min.
Test for bending (As per Standard 50125
D/ a α = 180
n min.
FEE 270
330
270 350
27
0.15
0
FEE 300
370
300 380
25
0.14
0
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Mechanical properties (New designs started after 01/01/2002)
Tension test (Standard 50113) (longitudinal direction)
Design ation of semi–finished product
Load unit Failure R
Load unit yield Rs
Minimum elongation A80 %
mm2
Index of formability (As p per Standard 50116)
mm 2 r min.
Test for bending (As per Standard 50125
D/ a α = 180
n min.
FEE 270
330
270 350
27
0.15
0
FEE 300
370
300 380
25
0.14
0
FEE 340
410
340 420
23
0.13
0.5
0.12
0.5
n er study
FEE 380
450
380 460
21
FEE 420
480
420 520
20
0.11
1. 0
FEE 500
560
500 600
18
0.09
1. 5
For test specim en cutting see Standard 50240. For reject purpos es valid rated values are R, Rs, A %, r and n obtained as average of 3 determ inations. Evaluated by 6 % at the end of even elongat ion. Test not decisive for rejection purposes. Results of tensile test and structu ral inspection shall prevail in disputed cases.
Weldability Weldability is guaranteed for normal processes and normal welding applications. Special procedur es and applications are to be agreed upon at the time of ordering. The zone affected by casting heat undergoe s a certain reduction in mechanical strengt h but no embrittlement.
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Structure Struct ure shall be ferritic with evenly distributed fine grains. The grains shall not have preferent ial orie ntat ion. The size of the grains , determi ned as per Stand ard UNI 3245, is to be 10 or fine r. Size 9 grains are allowed only in percenta ges less than 10 %. Type A inclusions are not to exceed grade 3 of the JK scale (UNI 3244). The struct ure inspection is to be made at 1/3 of the rolled product width. Dimensions and tolerances See Standard 54406.
