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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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The electroless nickel plater smoked my tool steel extrusion head
Q. Hi I need some help to understand what went wrong. I had a extrusion head made of tool steel which has been plated approx. 10 times. The last time I tried to have it plated the company called me and said the head had been destroyed during the stripping process. A 2" thick by 3" wide piece of tool steel turned into a 1" piece of charcoal. can anyone explain how this would happen?
Thanks
I have parts plated 4 times a year - Minneapolis, Minnesota, United States
2007
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A. They forgot and left your die in nitric acid (perhaps overnight, maybe over weekend!). If they value your business and their prestige, they must pay for another die. If you want to be indulgent and keep them as suppliers, give them more jobs to let them get even. If you also want to be helpful, tell them there are proprietary strippers (like the ones that advertise here) that prevent such accidents. Monterrey, NL, Mexico 2007 A. Much as tool steel is different than say 1018 steel, all electroless nickels (EN)are not alike. There are high phos, low phos and phos levels in between. On top of that there is EN co-deposited with PTFE, cubic boron nitride and / or silicon carbide. Subsequently hardened EN via precipitation hardening heat treatment once again changes the mechanical and chemical properties of the deposit. If a plater believes that a plated die or mold is high phos, they'er used to parts being in a strip for up to a week in some cases. One way to kick off the stripping of these coatings is to start off in nitric acid. If one tries this and it turns out to be another type of EN, the coating can be readily stripped in minutes and then the nitric would attack the tool steel. It's impossible to tell; what did your plater say? Is he the same plater that has successfully stripped and re-plated it in the past? It's an interesting story but parts that have been stripped and re-plated several times over don't just all of a sudden become dissolved IF THE SAME PROCESS IS USED.  Milt Stevenson, Jr. Syracuse, New York 2007 |
Q. Thanks for giving me some insight on this.
This company has done all the stripping and plating on this tooling,I called them late last week to ask about there process. the stripping process they use nitric acid they said it usually takes about 5 hrs. to strip and after checking the bath about 1.5 hrs. later they noticed some bubbling going on so they pulled up the basket and saw my parts destroyed.now I took in 9 parts altogether and 4 parts where wrecked.
Thanks,
- Minneapolis, MN, U.S.A.
2007
EASY TO EXPLAIN
Stripping Solution was adulterated. Most probably they added HF by accident or increase strongly the temperature (the less probably. I usually conduct stripping analysis to our parts and the process is stable for a "X" system at a fixed T.
- Minneapolis, Minnesota, USA
2007
adv.
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