Can Hydrogen Affect Mechanical Properties?
(57 votes)Welding Inspection
The influence of hydrogen can be observed in mechanical testing; however, its effects on the test results are limited. A high hydrogen content in a tensile specimen can produce “fisheyes” on the fracture surface as seen in Figure 1.
Additionally, the presence of hydrogen can reduce ductility (as expressed by elongation and reduction in area). Hydrogen, however, does not typically influence the impact toughness, ultimate tensile strength or yield strength results. It is only in severe cases that it can influence the ultimate tensile strength.
Since low hydrogen SMAW electrodes like E7018 are also required to have a minimum specified level of Charpy Vnotch (CVN) impact energy, low hydrogen is sometimes equated with a minimum CVN level. This has led some people to specify low hydrogen when the real desire is for notchtoughness. The better approach is to specify notch toughness requirements since there is no automatic link between low diffusible hydrogen content in the weld and CVN values.
Actually, some deposits with high hydrogen levels can deliver relatively high levels of notch toughness. For example, the E6010 classification (non-low hydrogen, 30-50 mL/100g) has a minimum CVN requirement of 20 ft-lbs at minus 20°F.
by R. Scott Funderburk
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http://www.lincolnelectric.com/knowledge/articles/content/fillermetals.asp
Hydrogen Properties
hydrogen pair has a field associated with it that can be visu This heat can complicate low. temperature hydrogen processes, particularly liquefaction.
http://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm01r0.pdf
RITA | Composite Pipe (14.6)
For hydrogen applications, composite pipe materials must be adequate to prevent or Pertinent data include hydrogen-affected mechanical properties (yield, tensile strength,
http://www.rita.dot.gov/publications/hydrogen_infrastructure_safety_analysis/html/section_14_06.html
Aluminum and Aluminum Alloys Casting Problems :: KEY to
lead, nickel. Key to Metals includes more than 1 million properties records for metals also profoundly affects tear resistance and mechanical properties in coarse-grain
http://www.keytometals.com/Article83.htm
PRACTICAL WELDING LETTER, Issue #008 — Ultrasonic Welding
Ultrasonic Welding is a process whereby mechanical energy, developed through the transformation of high in atomic form, hydrogen can diffuse in the Heat Affected Zone.
http://www.welding-advisers.com/PRACTICAL_WELDING_LETTER-PracticalWeldingLetterNo08_C.html
Hydrogen-Related Degradation of Mechanical Properties of
Hydrogen can have a pronounced effect on the mechanical properties of titanium (Ti) and Ti alloys, such as deformation, fracture, and fatigue life.
http://www.astm.org/DIGITAL_LIBRARY/STP/PAGES/STP48994S.htm
Properties of UDMA and Bis-GMA based Composites ” Esstech
It is well appreciated that hydrogen bonding affects a variety of monomer and polymer properties. photopolymerization reaction kinetics, and polymer mechanical properties.
http://www.esstechinc.com/blog/properties-of-udma-and-bis-gma-based-composites/
