Hydrogen embrittlement on 12.9 bolts
Hydrogen embrittlement on 12.9 bolts
(OP)
I have always been of the presumption that to eliminate hydrogen embrittlement in hardened bolts that have been zinc plated it is necessary to bake them after plating. I am being told by our QC guy that it is not recommended to plate the bolt at all as complications can still result even if they have been baked. Any opinions on this mater would be appreciated, I suspect that fastener load is crucial because of the nature of its application.
Thanks
Doug
Thanks
Doug





RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts
However, there is an argument that says avoid anodic coatings on high-strength steel altogether to prevent hydrogen generation during exposure to a corrosive environment. This is common in the structural fastener market, e.g. ASTM A 490 prohibits metallic coatings on fasteners.
Some good information on this subject is available in Specification for Structural Joints Using ASTM A325 or A490 Bolts from the Research Council on Structural Connections (free download):
http
Recently, work was done to qualify Dacromet for ASTM A 490 fasteners. Dacromet is one of several non-electrolytic zinc multilayer coatings that provide high corrosion resistance with improved resistance to hydrogen embrittlement. A review of this work is in the latest edition of Fastener Technology International, available for free here:
http://www.fastenertech.com
RE: Hydrogen embrittlement on 12.9 bolts
The sad part about this is the only good way that I have found to not have problems with hydrogen embrittlement is just a good vendor.
Chris
"In this house, we obey the laws of thermodynamics." Homer Simpson
RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts
Chris
"In this house, we obey the laws of thermodynamics." Homer Simpson
RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts
A decade or 2 ago I worked in a shop that did specialist engine machine work.
A set of Chrysler 426 Hemi rods were rebuilt with new Direct Connection (Chrysler factory high performance division) bolts. The finish machined rods were set on the bench in the balance section. The next day several bolt heads had popped off. Not slight intended against Chrysler then or now, but I believe there is surely some science to making bolts.
RE: Hydrogen embrittlement on 12.9 bolts
There is considerable science to making bolts, however much of it has been discovered in the last 2 decades, which was not able to help you and Chrysler in the past.
RE: Hydrogen embrittlement on 12.9 bolts
RE: Hydrogen embrittlement on 12.9 bolts