steel - Nouvelle page 1 - Free
steel - Nouvelle page 1 - Free
steel - Nouvelle page 1 - Free
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MMPDS-01<br />
31 January 2003<br />
Figure 2.3.1.3.8(b). Best-fit S/N curves for notched, K t<br />
= 3.3, AISI 4340 alloy <strong>steel</strong> bar,<br />
F tu<br />
= 125 ksi, longitudinal direction.<br />
Correlative Information for Figure 2.3.1.3.8(b)<br />
Product Form: Rolled bar, 1.125 inch diameter,<br />
air melted<br />
Properties:<br />
TUS, ksi TYS, ksi Temp., EF<br />
125 — RT<br />
(unnotched)<br />
150 — RT<br />
(notched)<br />
Specimen Details: Notched, V-Groove, K t =3.3<br />
0.450 inch gross diameter<br />
0.400 inch net diameter<br />
0.010 inch root radius, r<br />
60E flank angle, ω<br />
Surface Condition: Lathe turned to RMS 10<br />
Test Parameters:<br />
Loading - Axial<br />
Frequency - 2000 to 2500 cpm<br />
Temperature - RT<br />
Atmosphere - Air<br />
No. of Heat/Lots: 1<br />
Equivalent Stress Equation:<br />
Log N f = 9.75-3.08 log (S eq -20.0)<br />
S eq = S max (1-R) 0.84<br />
Std. Error of Estimate, Log (Life) = 0.40<br />
Standard Deviation, Log (Life) = 0.90<br />
R 2 = 80%<br />
Sample Size = 11<br />
Reference:<br />
2.3.1.3.8(a)<br />
[Caution: The equivalent stress model may<br />
provide unrealistic life predictions for stress<br />
ratios beyond those represented above.]<br />
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