Conventional aluminum coil production process

A complete description of our conventional aluminum coil production process is as follows:

1. Continuous casting and rolling: 7-8 mm aluminum billets are rolled into coils and then cold rolled to a specified thickness.
2. Combined casting and rolling process: 15-20 mm aluminum billets are heated and hot rolled to 1-2 mm on a three-stand hot rolling mill, and then finish rolled or further cold rolled into thinner materials.
3. Hot finish rolling to 3-4 mm, coiling and cooling, and then cold rolled to a specific thickness, for example, it can become a blank for producing products such as aluminum foil.

Surface quality: continuous casting and rolling > hot rolling > combined casting and rolling.

Mechanical properties: hot rolling > combined casting and rolling > continuous casting and rolling.

The cold-rolled products have a finer surface, more precise dimensions, and significantly improved tensile strength and elongation, which is critical for applications that require larger subsequent deformations.

This article provides a detailed analysis of continuous cast-rolling, continuous casting & rolling, hot rolling, and cold rolling, highlighting their differences, advantages, and applications.

Continuous Cast-Rolling vs. Continuous Casting & Rolling

(1) Continuous Cast-Rolling

• Also called “ingot-free rolling” or “liquid rolling.”
• Directly pours molten aluminum into rolling rolls for crystallization.
• The process results in larger grain structures but a smooth surface with no oxidation skin.

(2) Continuous Casting & Rolling

• Forms cast slabs before reheating and rolling them into thin sheets.
• The heating stage improves ductility, making it suitable for applications requiring high deformation.

Here is the table of alloy types and application areas that can be produced in continuous casting and rolling lines：

Hot Rolling vs. Cold Rolling

(1) Hot Rolling

• Performed above 400°C to improve the mechanical properties of aluminum.
• Used for high-strength aluminum plates, but may produce oxidation skin.

(2) Cold Rolling

• Rolled at room temperature, resulting in high precision and a superior surface finish.
• Suitable for precision aluminum foils and deep-drawing applications.

Comparison of Rolling Methods

By understanding these rolling methods, manufacturers can optimize production decisions and enhance product quality.

Extension:

The proportion of scrap aluminum in the furnace stage for different alloy grades:

• 1070 and above pure aluminum: Cannot add scrap aluminum; only pure aluminum ingots can be used.
• 3104/3105 alloy: Scrap aluminum proportion reaches 70%-80%.
• 1xxx series pure aluminum: Only 1xxx series scrap aluminum can be added.
• 3/4/5/6/8 series: Scrap aluminum proportion reaches 40%.