PSI - Issue 5

Przemyslaw Strzelecki et al. / Procedia Structural Integrity 5 (2017) 832–839 Przemyslaw Strzelecki et al. / Structural Integrity Procedia 00 (2017) 000 – 000

838

7

Material

C45+C

42CrMo4

S355J2+C

1.4301

Model

I

II

III

I

II

III

I

II

III

I

II

III

m A

7.8

9.5

5

7.6

9.1

5

9.5

9.4

5

24.6 63.4

8.6

5

25.7

30

-

26.2

30.2

-

30.3

30.1

-

25.5

-

1.7∙10

6.7∙10 4

8.7∙10 4

8.4∙10 5

6.7∙ 10 4 427

2∙10 5

N 0

10 6

-

10 6

10 6

-

10 6

6

S e [MPa]

310

332

394

- - - -

440

523

359

359

- - - -

189 16.1 511 441

250

m'

- - -

-

-

-

-

- - -

-

-

-

S u from HB S y from HB

830 696

789

1130

1047

904 753

853

500

-

924

-

-

-

Table 4. Values estimated for tested materials.

Material

S235JR

AW-6063 T6

C45+C Kt=1.99

42CrMo4 Kt=1.99

Model

I

II

III

I

II

III

I

II

III

I

II

III

m A

8.2

10.1 28.7

5

7.1

9.6

5

4.2

4.9

5

6.1

4.8

5

23.9

-

19.9

24.2

-

15.1

27.2 10 6 167

-

20.3

17.2 10 6 221

-

6∙10 5

3.1∙10 8

6.7∙10 4

N 0

- - - - -

10

- - - - -

10 6

- - - - -

- - - - -

8.7·10 4

6

S e [MPa]

172

204

79 24

100

198

263

m'

-

-

-

-

-

-

-

S u from HB S y from HB

413 360

408

198 176

200

830 696

789

1130

1047

-

-

-

924

-

Table 5. Values estimated for material from literature.

Material

1045 from Aviles et al. (2013)

SUS630 from Mohd et al. (2015)

2024 T351 from Mayer et al. (2013)

Model

I

II

III

I

II

III

I

II

III

m A

8.1

9.3

5

8.8

15.3 49.5 10 6 693

5

9.2

9.6

5

26.5

30.2 10 6 393

-

30.8

-

27.2

27.2 10 6 165 18.2 413 360

-

1.1∙10

7.1∙10 4

1.1∙10 6

1.4∙10 5

9.5∙10 7

6∙10 5

N 0

6

S e [MPa]

352

468

651

629

120 25.3

204

m'

- - -

-

-

- - -

-

-

-

S u from HB S y from HB

998 825

935

1385 1110

1258

- -

408

-

-

-

4. Summary and conclusions

From the analysis presented it may be deduced that it is possible to exactly evaluate fatigue strength using model II. The use of model III should be deemed as not recommended. The reason for this fact may be assuming fixed value of m slope in model III. The assumed value 5 is significantly lower than the experimental values; only for the notched elements was this value close to the experimental value. Moreover, in model III, the dependency determining the base number of cycles N k estimated this value to be much below the experimental value. With model II, estimating life for three materials (1.4301, AW-6063 T6, 2024T351) was unsatisfactory. Estimating the tensile strength and yield strength from the hardness measurement may be deemed as satisfactory - except for the materials for which the S y to S u relationship assumes extreme values. These materials may be deemed as plastic (for low S y / S u values), or brittle (for high S y / S u values), which suggests that the relationships (1), (2) and (3) are good approximations for elastic-plastic materials. The above observation may be found in the PN-H 04357 (1993),