Click here to make tpub.com your Home Page

Page Title: Stress Corrosion Embrittlement Factors
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 




img
MIL-S-85419 (AS)
3.5.1.3.5 Stress Corrosion Embrittlement Factors.  To prevent
premature failures caused by stress corrosion or hydrogen
embrittlement,  the design and method of manufacture of parts of
titanium and steel heat-treated to tensile strengths above
220,000 psi or of bare high strength aluminum alloys and the
techniques by which they are assembled and installed shall be
such that sustained or residual surface tensile stresses and
stress concentrations are minimized.  Practices, such as:  the
use of press or shrink fits; taper pins, clevis joints in which
tightening of the bolt imposes a bending load on the female lugs;
and straightening or assembly operations; which result in
sustained or residual surface tensile stresses shall be avoided.
In cases where such practices cannot be avoided, corrective
practices such as stress relief heat treatment, optimum grain
flow orientation, peening (shot or rotary flat) or similar
surface working shall be used to minimize the hazard of stress
corrosion or hydrogen embrittlement damage.  In no case shall
sustained or residual surface tensile stresses in these materials
exceed 50% of the material specification minimum yield strength
in the longitudinal grain flow direction, 35% of the minimum
yield strength in the long transverse direction and 15% of the
minimum yield strength in the short transverse direction, except
that for materials of demonstrated high resistance to stress
corrosion cracking, such as 7075-T73 aluminum alloy, such
stresses may be as high as 75% of the minimum yield strength in
any grain flow direction.  These limits for stresses represent
the algebraic sum of all the continuous tension and compression
surface stresses resulting from any source such as quenching,
forming and assembly.  The use of cadmium in contact with or
plated on titanium shall not be permitted.
3.5.1.3.6 Fatigue Factors.  To prevent premature failures caused
by repeated loads, the design and method of manufacture,
including consideration of the damaging effect of decarburization
and certain metallic coatings, of all critical parts and the
techniques by which they are assembled and installed shall be
such that sustained or residual tensile stresses and stress
concentrations are minimized.  Practices such as cold
straightening, cold forming, and the assembly of mismatched
surfaces, which result in sustained or residual surface tensile
In cases where such practices cannot
stresses shall be avoided.
be avoided, corrective practices such as stress relief heat
treatment, optimum grain flow orientation, peening (shot or
rotary flat) or similar surface working shall be used to minimize
premature fatigue failure.
In no case shall parts of nonuniform
section be cold formed unless the contractor can demonstrate with
test results that required fatigue resistance is obtained.
Surface roughness (as defined in ANSI B46.1-1962) and the
incidence,  location and size of allowable flaws in metallic parts
9

Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business