plating, anodizing, & finishing Q&As since 1989
Aluminium Wire Rod Surface Problem
Q. I work in an Aluminium smelter in Eastern India. We have an aluminium hot rolling mill supplied by Properzi. In some of the coils, a hard & black layer is getting formed. The black layer is not on the full coil but in patches. This is creating difficulty in wire drawing process. The drawing dies are getting prematurely damaged due to this. The black layer is getting generated during storage. The problem is more common during the rainy season.Manasa Mishra
- Nagar, Orissa, India
A. Have you tried to characterize the black coating as to organic or inorganic? Does it burn?, does it leave a residue upon ignition? What is its melting point? Have you charted the occurrence of the black coating along a time line for a year? with * for date the aluminum was poured, and # for date the coil was drawn.
or something like that. This might be helpful even if you can get a sample of the wire to a university for analysis.
Falls Township, Pennsylvania
A. It's due to oxidation, long exposure to moisture.
1) Check your machine after quenching: water should not get carried with rod.
2) Don't pack hot coil
3) Check your storage area
Student - India
May 8, 2023
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