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Can anodizing change aluminum temper?
We are having a problem with inconsistency of the temper of an aluminum extrusion. The alloy is specified as 6063-T5. The extrusion is tubular and approximately 5/8" diameter. Some of the material received is so soft that a three foot length can be bent over your knee with very little effort. It seems like the temper is T0 instead of T5.
The extruder thinks it the anodizing process that is "changing" the temper. Is it possible for the anodizing process to change the temper?
INDUSTRIALIST - Santa Rosa, California, USA
March 21, 2011
Anodizing will not change the temper of the aluminum.The maximum temperature in the bath is 55 to 60 °C in the etching tank. The temper will change if the temperature reaches to more then 100 °C and above.
Hanif HamzahPress Metal - Klang, Selangor, Malaysia
May 16, 2011
When someone with an issue baselessly accuses my firm of such a silly thing, it raises my 'temper' and I'm tempted to scream. As anodizers and platers are often the last to touch parts prior to a problem manifesting itself, we're often put on the defense to explain why passivated parts dissolved or EN pitted or anodized parts exhibit pits. While our chemical processing reveals upstream issues in the base material and as a result of heat treated or grinding, we're seldom the cause. However, I've never been blamed for changing the temper during anodize - this simply can't happen as the previous responder replied.
Milt Stevenson, Jr.
Syracuse, New York
May 19, 2011
No, anodizing cannot change the temper of 6063-T5 extrusion. You have to check the hardness of extrusion in mill finish to see whether it conforms to T-5 temper, before delivery to anodising plant.
Insufficient hardness after aging may be a result of improper alloy composition, extrusion temperature & quenching, and aging heat treatment conditions. (Lower temperature, insufficient holding time or malfunctioning aging furnace).
- Istanbul, Turkey
July 27, 2011
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