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Ted Mooney, P.E. RET
Pine Beach, NJ
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Poor cleaning of 301 grade extra hard
Q. We found brown colour contamination on the strip after reducing the thickness (70% reduction at Sendzimir mill) and after degreasing.
It is appearing on 301 grade SS and the reduction is 70% or more.
We use hot alkaline 70 degree C,and rinse twice at two different tanks.
Can anybody help me to fix this problem?
In charge of Production - Jakarta, Indonesia
July 15, 2010
A. Dear Mohamed Abdul Jaleel
Perhaps a bit late, this reaction, but could it be that your brown discolouration comes from the presence of the Mn in the SS 301? Maybe it forms a film of oxide (the oxide is known as a very strong, brown dye.)
In that case, a treatment in sulfuric of hydrochloric acid after the cleaning should remove the brownish discolouration.
Best regards,
Harry van der Zanden
consultant - Tilburg, Netherlands
August 18, 2010
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