Dear Atik Islam

it is well known that the twisting process imposes large strain deformation in the material, resulting a considerable refinement of microstructure and enhancement of mechanical properties and corrosion resistance. My concern is with the twisted structure heterogeneity that may leading to reveal an uneven surface corrosion susceptibility. However, this point is not so critical as you can be optimized.

Best regards

Dear Sir

Assalamualikum, Thank you for your reply. but this is very difficult for me to

understand.

You mean that there is no corrosion effect on twisting zone.

Dear Dr. Atik Islam ,

I suggest you to have a look at the following, interesting document:

CORROSION OF ALUMINUM-FIN, COPPER-TUBE HEAT EXCHANGE COILS JAY E. FIELD, PH.D. TRANE RESIDENTIAL SYSTEMS TYLER, TX (2002)

available at:

https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/4580/ESL-HH-02-05-30.pdf?sequence=5

Enjoy reading and my best regards, Pierluigi Traverso.