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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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Manganese iron Phosphating of 2-1/4% Chrome F22 material
Q. Is it possible to successfully Manganese-Iron Phosphate material with 2 1/4% Chrome content, i.e., F22 material?
We are experiencing patchy/sooty deposits when processing this material. Is this common?
Does anyone know the limit of Chrome content of a carbon steel material which can be successfully phosphated.
Plating Shop Supervisor - Leeds, West Yorkshire, England
January 28, 2011
A. It may depend on the particularly phosphating chemicals that are being used to some degree, but as a rule of thumb the steel needs to be 98%+ iron for the phosphating to be successful. I don't have any direct experience with F22, but I would expect it to phosphate blotchy. If you must phosphate, you'll need to use a steel that has more iron.
Jon Barrows, MSF, EHSSC
GOAD Company
Independence, Missouri
February 2, 2011
Adhesion problem in manganese phosphating steel with 2.75% chromium
Q. I am testing a new Mn Phosphating setup and I was coating coupons (100 x 50 x 3 mm samples). I was having adhesion problem when coating a >2.75% Cr sample, while there is no problem with <1.5% Cr ones.
The bath was relatively new as it had not started production, and we use blasting and conditioning. However, the tank underwent prolonged heating without load/work due to heater testing etc; and we dried up the tank once, stored the solution in drums and returned it into the tank after a long weekend (3 days).
I tested a mini setup with a brand new solution in a 1,000 ml container, and the process was a success.
* What is the cause of this problem? Is there any way to "rectify" the solution in my tank?
* Our phosphating tank is 316SS, can we just leave the solution in the tank when there is no load for few days, or should I store it in plastic drums?
* Based on the mini setup, can I expect that if I replace the solution with a brand new one, that it would give a satisfactory result?
- Batam, Indonesia
March 3, 2014
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