The authoritative public forum
  for Metal Finishing since 1989
-----

Hydrogen Embrittlement relief bake for zinc-nickel

I have 52100 steel parts to be zinc-nickel plated.
Is there a major problem with hydrogen embrittlement if I were to bake the parts at 300 F for 8 hrs approx. 1 hour after plating? I have consulted ASTM 850 and it sates that the parts have to be baked for an excess of 22 hrs at 190-220 C. Most plating vendors state that the bake time is extremly excessive and charge a huge price for the extra time. Can I get by with that bake time? Will the reduction in tensile strength be excessive if I don't go to the ASTM suggested bake time?

Joe Malinski
Product Engineer - Lansing, Illinois, USA
2005

---

Hydrogen embrittlement relief is a dangerous phenomenon in the catastrophic failure cases. Hence do not take any chance to minimise the duration.

The baking time does not reduce or increase the tensile strength of your part at 200°C It is to do with diffusing out the hydrogen using the potential difference of hydrogen between the atmosphere and the product. Since the volume and depth of hydrogen is more in product the duration of baking is defined high for complete diffusion.

V. G. Rajendran
- Trichy, Tamilnadu, India
2005

Hydrogen bake at 200C will reduce hardness on hardened steel by about one Rc if the anneal temp was near the 200C.

James Watts
- Navarre, Florida
2005