Tensile strength; Y ield strength [M P a]
1000
900
800
700
600
500
400
300
200
100
0
DC04 DD14 DC01 DD11
H240 LA
H280 LA
S315 MC
H320 LA
S355 MC
H360 LA
H400 LA
S420 MC
S460 MC
14
Strengthening mechanism
15
HSLA steel
16
Grades of HSLA steel in EU
17
Application of HSLA steel
18
Dual phase (DP) steel
19
EU steel grades
Comparison European steel grades (Mild steel, HSLA, Dual-Phase)
10
Strain rate sensitivity
Strain rate Strain rate sensitivity exponent
Strain rate sensitivity has a crucial influence on the research of crash resistance and high-speed stamping formability.
11
Worldwide steel grades
12
Worldwide steel grades
13
Common steel types and evolving AHSS types
▪ Interstitial free (IF) steels ▪ Mild steels ▪ Bake hardenable (BH) steels ▪ Isotropic (IS) steels ▪ Carbon-manganese (CM) steels ▪ High-strength low-alloy (HSLA) steels ▪ Dual phase (DP) steels ▪ Transformation induced plasticity (TRIP) steels ▪ Complex phase (CP) steels ▪ Martensitic (Mart) steels
Elongation Reduction of area
6
True stress-strain curve
True stress
True strain
7
Working hardening (strain hardening)
Strain hardening exponent (n-value)
8
3
Engineering stress-strain curve
4
Engineering stress-strain curve
5
Strength and Ductility
Strength parameters
Engineering stress Engineering strain
Ductility
钢材种类和变形的基础知识
Introduction to elasticity and plasticity
1. 固体材料受外力作用产生变形，从变形开始到破坏一般要经历 两个阶段：弹性变形(elastic deformation)和塑性变形(plastic deformation)。
2. 外力卸载后，弹性变形能够完全消失，而塑性变形不能消失。 3. 弹性变形和塑性变形的机理：材料原子之间的作用力平衡。 4. 位错(dislocation)理论。 5. 强化机制(work hardening mechanism)。
(only acc. my information; must be checked and confirmed by Purchasing department)
S AE J2340 HR 550 X H S LA 550
Influence of strain-hardening exponent
n3
n2
n1

9
Anisotropy (R-value)
Width strain: εw=ln(w/w0) Thickness strain: εt=ln(t/t0) R= εw/εt
Planar anisotropy ratio Normal plastic anisotropy ratio
Dislocation movement
2
Uniaxial tensile test
Typical tensile test piece
GB/T228 金属材料室温拉伸试验方法 EN10002-1 Metallic materials - Tensile test - Part 1 : test
method (in ambient temperature)
S500 MC
S550 MC
DP59 0/
DP60
DP78 0/
DP80
Rm max 350 400 410 440 450 480 510 530 550 600 620 620 650 700 760 700 900
Rm min. 270 270 270 270 340 370 390 400 430 430 460 480 510 550 600 600 780
Re min. 140 140 140 170 240 280 315 320 355 360 400 420 460 500 550 320 450
Re max. 210 330 280 360 310 360
410
460 500
400 550
Legend: Cold Rolled Hot Rolled Dual Phase cold rolled (values from ARCELOR)
Not for new products
!: Availibility to be clarified
From Claus Unruh 20
Dimension availability
Availability check materials Europe versus US – update Nov 2006