steel - Nouvelle page 1 - Free

MMPDS-01
31 January 2003
2.1.2.1.4 Stress-Strain Relationships — The stress-strain relationships presented in this chapter
are prepared as described in Section 9.3.2.
2.1.2.1.5 Fatigue — Axial-load fatigue data on unnotched and notched specimens of various steels
at room temperature and at other temperatures are shown as S/N curves in the appropriate section. Surface
finish, surface finishing procedures, metallurgical effects from heat treatment, environment and other factors
influence fatigue behavior. Specific details on these conditions are presented as correlative information for
the S/N curve.
2.1.2.2 Physical Properties — The physical properties (ω, C, K, and α) of steels may be considered
to apply to all forms and heat treatments unless otherwise indicated.
2.1.3 ENVIRONMENTAL CONSIDERATIONS — The effects of exposure to environments such as
stress, temperature, atmosphere, and corrosive media are reported for various steels. Fracture toughness of
high-strength steels and the growth of cracks by fatigue may be detrimentally influenced by humid air and
by the presence of water or saline solutions. Some alleviation may be achieved by heat treatment and all
high-strength steels are not similarly affected.
In general, these comments apply to steels in their usual finished surface condition, without surface
protection. It should be noted that there are available a number of heat-resistant paints, platings, and other
surface coatings that are employed either to improve oxidation resistance at elevated temperature or to afford
protection against corrosion by specific media. In employing electrolytic platings, special consideration
should be given to the removal of hydrogen by suitable baking. Failure to do so may result in lowered
fracture toughness or embrittlement.
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