Aluminum clad steel

Can somebody tell me why the diameter of our cladded material is getting smaller in diameter during the cladding process?
We are cladding high carbon steel with 1350 aluminum.

Hello Brian,

Wow, this is very interesting.

I presume this has confirmed by you by direct and precise measurement.

In order to shrink pre-stressed steel, you require lots of heat. This apparently happens during the cladding process (No information at all!) and we have no information on the the steel you are using.

We certainly have a serious lack of information.

Please provide us with all the rest of your information

We are not actually shrinking the steel, rather the aluminum coating is getting smaller. We are cladding using a continuous extrusion method. We are noticing the reduced diameter after a few reels of production, usually we see an increase in diameter do to the wear of the extrusion die. We are using 1060c steel wire and coating it with 1350 aluminum.

Hello again Brian,

Ok and as I understand it now,

- The 1060 steel wire and the molten 1350 Aluminum cladding are brought together on a continuous casting line and then rolled/ drawn to a final diameter before quenching.
- After spooling, and after the first few reels of production, the diameter of the composite conductor reduces by a measurable amount
- By microscopic measurement, it has been learned that the aluminum alloy cladding has been reduced but that the steel wire diameter has remained unchanged.

If you are absolutely sure that this is really happening then:

1 - There may be a very high level of inbred stress in the weaker aluminum alloy when compared to the level of stress in the steel and thus the aluminum alloy is relieving this inbred stress on the take-up spool. This might be reducing the thickness of the cladding material. We note that, after running for a period of time, the composite wire on the take up reel could be warmer and thus stress relief of the aluminum alloy could happen at a faster rate.

2 - At the microscopic level, we wonder if the damaged aluminum alloy cladding is regrowing its crystal structure to eliminate huge number of molecular grain discontinuities and grain fractures. This might be reducing the thickness of the cladding material although we find this to be a far less likely phenomenon Moreover we note that, after running for a period of time, the composite wire on the take up reel could be warmer and thus crystal regrowth of the aluminum alloy could happen at a faster rate.

We suggest you contact the metallurgical engineering faculty at your nearest engineering campus. Once you have an appointment, meet with a metallurgist and show him both your typical samples showing the shrinkage that has occurred. Likewise he must understand your full process. Don't forget to bring samples!

Note - Because we cannot see your production line, we not sure of exactly what is occurring.