Grain Structure in Spring Wire

Hi Cool

I know the problem well, and in Australia we refer to it, as hydrogen embrittlement. I'm told that the heating process allows the entrapped hydrogen (from the zinc) to pass through the grain structure. We used a 0.2mm spring clip and would leave it in a paint oven at approximately 200°C for 24 hours.

Tony

Hi Tony,

I didn't realy know the zinc was playing a part in my problem.

I was only refering to the graining of the steel.(which is a form of work hardening and causes premature fractures in the wire).

Do you have any referance to what problems the hydrogen is causing beyond the graining issue?

Hi Cool

I only speak from experience and discussions with spring makers. I first noticed this phenomenon when we used zinc coated tie wire, which we would cut and press down. If we did this immediately then it would bend easily, if left for a couple of days in damp conditions a high number of ties would snap. I found this reference, from which I learnt a bit more. They say that the heating process should be done within 4 hours of plating.

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

Tony

normalizing the high carbon steel will happends at much higher temperature. I suppose to say you are looking for the annealing or normalizing temperature of the galvanized zinc material in the outer coatings. otherwise define you question again in detail. thanks

Once i took back my springs to my springs manufacturer because its constant was 20%up or down(i don't remember) (it was for a Cummins governor)At first he apologize because the quality of his wire may be not the same than imported ones so he asked me make a test:he just burn with a simple lighter.Back to the lab was not found any diference with originals.So if those are not great commitment try do the same and comment here please.-