Metal composite plate manufacturing: direct rolling method

The direct rolling method is the most prevalent method for producing metal composite plates; it is further subdivided into the hot rolling composite method, the cold rolling composite method, the asynchronous rolling composite method, and the vacuum rolling composite method. The direct rolling process can manufacture metal composite plates in four ways:

1. Composite hot rolling method

The hot-rolled composite method involves welding the compound material and the base material together while hot-rolling the compound material and the base material. The contact surface between the two metals is extremely similar to a viscous fluid, with higher fluid qualities when shear deformation forces are applied. They produce adhesive friction behavior, which is conducive to the contact surface, the solidification of the metal, with the solidification point as the basis (or core), and the formation of stable thermal diffusion under high-temperature heat activation conditions to achieve a welded bond between the metals once the nascent metal surface is formed.

2. Cold rolling composite technique

The cold-rolled composite method is commonly referred to as having the same roll diameter and roll speed as the cold-rolled composite method. The United States was the first to investigate and propose a three-step production process of "surface treatment + cold-rolled composite + diffusion annealing.". When compared to the hot-rolled composite method, the cold-rolled composite method achieves 60% to 70%, or even higher, when the first deformation is greater. Cold-rolled composite by applying a lot of pressure, the cold-rolled overlap of two or more layers of metal to produce atomic bonding or tongue and groove embedding, and then diffusion annealing to strengthen.

3. Method of asynchronous rolling compounding

Asynchronous rolling is a sheet-rolling production process that first appeared in the 1960s. It rolls the metal by varying the upper and lower roll speeds such that the roll line speed is variable. Many countries, including China, have committed significant efforts to basic research and industrialization since the 1970s. Asynchronous rolling is utilized for the fabrication of composite plates, known as the asynchronous rolling composite method. In general, the asynchronous rolling composite approach pairs the harder metal with fast roll correspondence and the softer metal with slow roll correspondence.

The relative sliding in the "rolling zone" is fully utilized in asynchronous rolling compounding. On the one hand, relative sliding of the interface friction heat provides energy for interface bonding; on the other hand, relative sliding promotes contact surface contamination layer and oxide film breakup and extrusion, thereby promoting the production of fresh surfaces. As a result, relative sliding promotes improved interfacial bonding strength and lower average rolling pressure.

4.  Method of vacuum rolling compound

Typically, in the atmosphere, the metal surface is covered with an oxide film, an absorbent layer, and the surface has a convexity that hampers metal bonding. Given these circumstances, the former Soviet Union initiated the vacuum rolling test in 1953, followed by the United States, China, and Japan. There are two types of vacuum-rolling composite methods: hot rolling and cold rolling in a vacuum. The most important feature of hot rolling in a vacuum is that, because an oxidizing atmosphere is not present, the metal surface does not form oxides or nitrides, making oxidation in the atmosphere and the difficult processing of the metal easier to process. The original characteristics can be brought into full play through the plastic processing of the new surface of the metal generated by the original characteristics, and because the vacuum helps degas, you can get a clean finish metal surface.