De-embrittlement after nickel plating
Are there any requirements into the max time allowed between nickel plating and heat treatment for de-embrittlement. We try to complete this within a few hours, but sometimes this is difficult due to production volumes, I'm sure the longer you leave it the more hydrogen impregnates the base material, but what are the safe guidelines and where is this documented.Lee Franckeiss
Component repair - Southampton, Hants, England
Some specifications will give time limits. It depends! How hard is the parts that are plated. For practical purposes, the higher the hardness, the quicker it needs to get into the oven. Production volume is a poor excuse for not doing what is right. If you are plating Rc55 4340, you better get it into the oven ASAP. If you are going to fudge times, you probably should run daily notch bar tests with whatever batch will take the longest time between plate and bake. We used 15 mins from dry off to oven and never had a failure in several years of nickel plating and used notch bars with a tensile strength of nearly double what we were routinely plating.James Watts
- Navarre, Florida
Post plating heat treatment information is given in BS ISO 9588. There is a lot of other info on-line and in text books, etc.
Basically though, the previous answer is correct, the requirement for de-embrittlement is highly dependent on tensile strength and therefore hardness, any strength <1000 N/mm2 being not normally necessary. The treatment is time and temperature dependent, and should be carried out preferably within one hour of plating.
Best of Luck.Martin Rich
DML - Ship Repair - Plymouth, England
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