1 ASTM E28.04 Workshop Len Manning, Dofasco Affect of Proposed Changes on the Mechanical Properties of Low Carbon and HSLA Steels

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ASTM E28.04 Workshop

Len Manning, Dofasco

Affect of Proposed Changes on the Mechanical Properties of Low Carbon and HSLA Steels

2

Dofasco - Study Set Up

Materials Used- Low C steel - 0.02 C, 0.30 Mn, 30ksi Yield

- HSLA steel – 0.06 C, 0.65 Mn, 0.02 Cb, 50 ksi Yield

Sample Prep

– all tensile coupons of each material cut from one sample sheet.

– E8 Sheet type specimens prepared

– all pieces milled by the same operator, on the same milling center, at

the same time.

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Sample Testing– Verification standards run before and after study pieces

– All specimen measurements conducted by one operator

– All tests conducted by one operator on the same day, using

one test frame.

– Testing using the various speeds was conducted in random

order.

4


Testing Speeds

– Three test speed set ups were used

• 0.16”/min. until 5% strain, 1.00”/min. until fracture

• Current lab practice

• 0.03”/min. until 5% strain, 0.9”/min. until fracture

• New E8 – based on minimum parallel length specimen

(2.25”)

• 0.045”/min. until 5% strain, 1.35”/min until fracture

• New E8 – based on 3” parallel length specimen

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Dofasco - Low Carbon Steel

N = 15 Current New E8-3 New E8-2 Diff.

Yield Average 29.34 28.84 28.72 0.62

(ksi) Stdev 0.447 0.477 0.636

Tensile Average 42.35 42.63 42.40 0.28

(ksi) Stdev 0.159 0.146 0.149

Elongation Average 45.31 44.77 45.56 0.79

(%) Stdev 1.120 0.691 1.077

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Dofasco - HSLA Steel

N = 15 Current New E8-3 New E8-2 Diff.

Yield Average 52.17 51.32 51.45 0.85

(ksi) Stdev 0.659 1.040 1.251

Tensile Average 68.87 68.98 68.63 0.35

(ksi) Stdev 0.395 0.430 0.635

Elongation Average 27.65 28.00 28.04 0.39

(%) Stdev 0.370 0.366 0.480

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Dofasco - Low Carbon - Yield Strength - One-way ANOVA

Source DF SS MS F P

Factor 2 3.213 1.606 5.79 0.006

Error 42 11.658 0.278

Total 44 14.871

S = 0.5269 R-Sq = 21.60% R-Sq (adj.) = 17.87%

Individual 95% CI’s For Mean Based on

Pooled StDev

Level N Mean StDev --+---------+---------+---------+-------

YS-CU 15 29.339 0.447 (--------*--------)

YS-E3 15 28.839 0.477 (--------*--------)

YS-E2 15 28.724 0.636 (--------*---------)

--+---------+---------+---------+-------

28.50 28.80 29.10 29.40Pooled StDev = 0.527

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Dofasco - Low Carbon - Tensile Strength - One-way ANOVA

Source DF SS MS F P

Factor 2 0.6534 0.3267 14.14 0.000

Error 42 0.9702 0.0231

Total 44 1.6236

S = 0.1520 R-Sq = 40.25% R-Sq (adj.) = 37.40%


Pooled StDev

Level N Mean StDev -------+---------+---------+---------+--

TS-CU 15 42.353 0.160 (-----*------)

TS-E3 15 42.629 0.146 (-----*------)

TS-E2 15 42.399 0.149 (-----*------)

-------+---------+---------+---------+--

42.36 42.48 42.60 42.72

Pooled StDev = 0.152

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Dofasco - Low Carbon - Elongation - One-way ANOVA

Source DF SS MS F P

Factor 2 4.925 2.462 2.55 0.090

Error 42 40.499 0.964

Total 44 45.424

S = 0.9820 R-Sq = 10.84% R-Sq (adj.) = 6.60%


Pooled StDev

Level N Mean StDev -----+---------+---------+---------+----

EL-CU 15 45.317 1.120 (---------*----------)

EL-E3 15 44.767 0.691 (---------*----------)

EL-E2 15 45.557 1.077 (---------*---------)

-----+---------+---------+---------+----

44.50 45.00 45.50 46.00


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Dofasco - HSLA - Yield Strength - One-way ANOVA

Source DF SS MS F P

Factor 2 5.94 2.97 2.89 0.068

Error 39 40.07 1.03

Total 41 46.00

S = 1.014 R-Sq = 12.91% R-Sq (adj.) = 8.44%


Pooled StDev

Level N Mean StDev -----+---------+---------+---------+----

YS-CU 14 52.174 0.659 (---------*----------)

YS-E3 14 51.321 1.041 (----------*----------)

YS-E2 14 51.446 1.251 (----------*----------)

-----+---------+---------+---------+----

51.00 51.50 52.00 52.50


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Dofasco - HSLA - Tensile Strength - One-way ANOVA

Source DF SS MS F P

Factor 2 0.903 0.451 1.82 0.175

Error 39 9.670 0.248

Total 41 10.573

S = 0.4980 R-Sq = 8.54% R-Sq (adj.) = 3.85%


Pooled StDev

Level N Mean StDev ------+---------+---------+---------+---

TS-CU 14 68.868 0.395 (----------*---------)

TS-E3 14 68.982 0.430 (---------*----------)

TS-E2 14 68.630 0.635 (----------*----------)

------+---------+---------+---------+---

68.50 68.75 69.00 69.25


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Dofasco - HSLA - Elongation - One-way ANOVA

Source DF SS MS F P

Factor 2 1.268 0.634 3.80 0.031

Error 39 6.505 0.167

Total 41 7.772

S = 0.4084 R-Sq = 16.31% R-Sq (adj.) = 12.02%


Pooled StDev

Level N Mean StDev ---+---------+---------+---------+------

Elong-CU 14 27.653 0.370 (--------*--------)

Elong-E3 14 27.996 0.366 (--------*--------)

Elong-E2 14 28.042 0.480 (--------*--------)

---+---------+---------+---------+------

27.50 27.75 28.00 28.25


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Dofasco - Practical Implications for Production Test Labs

Lab Throughput, turn around time, equipment needs

Product Specification Conformance checking

Manufacturing Design capability

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Dofasco - Average Values Against Initial Testing Speed

Low Carbon Steel

25

30

35

40

45

50

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Testing Speed (in/min)

ksi / %

elo

ng

atio

n

Elong

Tensile

Yield

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Dofasco - Average Values Against Final Testing Speed

Low Carbon steel

20

25

30

35

40

45

50

55

0.8 0.9 1 1.1 1.2 1.3 1.4

Final Testing Speed (in/min)

ksi / %

elo

ng

atio

n

Elong

Tensile

Yield

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Dofasco - Average Values Against Initial Testing Speed

HSLA Steel

0

10

20

30

40

50

60

70

80

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Initial Test Speed (in/min)

ks

i/%

str

ain

Yield

Tensile

Elong

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Dofasco - Average Values Against Final Testing Speed

HSLA Steel

0

10

20

30

40

50

60

70

80

0.8 0.9 1 1.1 1.2 1.3 1.4

Final Test Speed (in/min)

ksi/%

str

ain

Yield

Tensile

Elong

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Dofasco - Summary

Some statistical differences

Little practical difference for production type labs

May be a significant difference based on specific situations – i.e. – Research

Significant affect on test time

Documents

1 ASTM E28.04 Workshop Len Manning, Dofasco Affect of Proposed Changes on the Mechanical Properties of Low Carbon and HSLA Steels