Issue 37

D. Angelova et alii, Frattura ed Integrità Strutturale, 37 (2016) 249-257; DOI: 10.3221/IGF-ESIS.37.33

(a)

A and B spring steels

1000 1200 1400 1600 1800

-0,1465

 = 6171,8N f

-0,0449

 = 1829,7N f

R 2 = 0,8509

R 2 = 0,9973

0 200 400 600 800

-0,3347

 = 39085N f

Stress range, [MPa]

R 2 = 0,992

EN 10270-1 SH; Air, 11 Hz; rotating-bending BS 250 A53; Air, 5 Hz, fully reversed torsion BS 250 A53; 0.6M NaCl, 5 Hz, fully reversed torsion

1000

10000

100000

1000000

10000000

[cycles]

Number of cycles to failure, N f

(b)

Figure 4 : Wöhler curves: (a) Steel A and characteristic areas with short cracks on the hourglass specimen surfaces, corresponding to given number of cycles. The higher curve shows in-air fatigue, 136 .0 86.9   f N  , and the lower curve - corrosion fatigue, 368 .0 31.73   f N  ; (b) comparison between Wöhler curves of both steels.

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