Sorry do not exist MAYBE in science. If who wrote this it is 3 (triple) Nobel Price in 1. metallurgy, 2. Physics of materials and 3. Molecular Physics and Chemistry, I will accept. This theorems do not exist. This it is just a science-fiction of someone.
First, the cladding is say cold because the materials are not heat enough to reach theirs half temperature from the melting point. The rolls are in general at 100 deg. C and due to the 8 to 12 tones rolling apply, the core will develop mere energy which is transformed in heat (thermal energy) and the Cu molecules from the Ni-Cu alloy can mixt with the Cu molecules of the core. The core rolls are polish after are rolled. So no strides or maybe some Micronics ones..
Outside rolls of the cladding develop strides due to the high friction, heat and strength of the material if are not well oiled.
So you have here or the rolling strides, or the Die polishing strides.
Sorry for this long explanation, but I has to take an extra high blood pressure pill of this cause post.