Fatigue corrosion or stress corrosion in car chassis
Fatigue corrosion or stress corrosion in car chassis
(OP)
Hello to all, thinking about car chassis, when it is used we should not always have corrosion due to fatigue at the welding points since they are points of high stress that often do not have a fatigue limit? shouldn't they show micro cracks that will corrode in a short time? I think the coating will not protect from this type of corrosion. what's the difference with stress corrosion? Will stress corrosion also occur for static loads at room temperature?
if anyone could explain these things to me I would be grateful
if instead a car is kept still but it already has some micro fractures in the welding points that are however protected by the paint, these will corrode even with only a static weight
if anyone could explain these things to me I would be grateful
if instead a car is kept still but it already has some micro fractures in the welding points that are however protected by the paint, these will corrode even with only a static weight
RE: Fatigue corrosion or stress corrosion in car chassis
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: Fatigue corrosion or stress corrosion in car chassis
RE: Fatigue corrosion or stress corrosion in car chassis
There is no cyclic loading in induce fatigue.
And as long as it is dry it will not suffer any corrosion.
Why would you think that sitting unused would lead to any derogation?
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Fatigue corrosion or stress corrosion in car chassis
RE: Fatigue corrosion or stress corrosion in car chassis
"The page describes static fatigue definition is limited to ceramics literature which involves a time dependant reduction of material properties whereas the more widely accepted definition of fatigue needs cyclic loading to occur (see Fatigue (material) and Fatigue of Materials by Suresh 2004)"
https://en.m.wikipedia.org/wiki/Static_fatigue
I would give some guideline to underatand better for you.
1. Check if the weldmenet is exposed under out of elastic area by stress. If yes, you have to find a solution from stress and strain curve , not from corrosion
2. Based on chemical corrosion model, generally metal shall contact with corrosive "fluid". If the metal contacts with dry air, corrosion is not a main concern as dry air is non-corrosive.
Lee SiHyoung,
RE: Fatigue corrosion or stress corrosion in car chassis
I mean, i don’t understand how they can design a car with infinite life fatigue, but having welds which cannot be set at a fatigue limit
RE: Fatigue corrosion or stress corrosion in car chassis
In cubic structure metals (Fe, Ni based mostly) you have fatigue curves that actually flatten out with increasing cycles.
That is, if you are below a critical stress level they will have infinite fatigue life.
This is why stainless steel aircraft hydraulic tubing will last longer than the airframe.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube