Background: Aluminum rolled sheet is one of the most highly efficient, cost effective and recyclable materials. Everyday, it is used in the manufacture of products worldwide - from versatile packaging, to advanced automotive and aerospace applications, to durable and aesthetically pleasing architectural uses.
Producers of aluminum sheet satisfy customer demand for specific performance characteristics by blending aluminum with small quantities of other elements such as copper, manganese, silicon, iron or magnesium that impart the required properties to the metal. The final aluminum alloy is cast into an “ingot” -- a dense block of metal weighing several thousand pounds. Ingots are fed into a rolling mill where they are subjected to extreme pressure and rolled into sheet and foil products of various thicknesses, depending upon customer requirements.
Sometimes, customers of rolled aluminum products desire product performance that is difficult or impossible to satisfy due to the molecular behavior of the alloys. For instance, because magnesium adds strength to aluminum, “high-mag” alloys are popular in a variety of applications where strength and light-weight are highly valued, such as architectural applications. But magnesium also is a highly reactive metal and therefore promotes oxidation resulting in diminished surface quality. With such single-alloy sheet products, customers must make trade-offs between strength, formability, surface appearance and corrosion-resistance.
Traditional Aluminum Cladding: To date, rolled aluminum suppliers have addressed such difficulties with a process called “ingot cladding” – whereby a separately cast metal layer is welded to the top and/or both sides of the core ingot before feeding this “sandwich” into the rolling mill. In this way, the properties of two alloys can be combined in the finished sheet. A low-corrosion layer can be clad to a high-mag core, for instance, providing the customer a very strong finished sheet that maintains superior surface characteristics. Cladding is, however, a low-tech, high-cost, labor-intensive and problem-prone solution. Clads can slip from the core in rolling, oxidation between layers causes product imperfections and the choices of clad-to-core alloy combinations are extremely limited. Still, cladding has been an industry standard for more than 60 years.
What’s New: Novelis FusionTM technology is a breakthrough process that simultaneously casts multiple alloy layers into a single aluminum rolling ingot. This marks the first time that any company has achieved the commercial production of multi-alloy aluminum ingots. Engineers have tried for decades to cast multi-alloy ingots in a commercial environment. Novelis has succeeded, and has been producing Novelis Fusion ingots and delivering product to customers since March of 2006. Multi-alloy ingots are rolled into sheet products with different properties on the outside than on the inside, allowing previously unattainable performance for flat rolled products.
Why it’s Important: The new Novelis technology produces a perfect metallurgical bond between the alloy layers at the molten metal stage. It not only exceeds the efficiency and performance of conventional ingot cladding, but it also permits alloy combinations never before possible in aluminum rolling. This opens the door to new, premium applications for aluminum.
Impact: The market potential for Novelis Fusion technology is with customers in the automotive, architectural, building and construction, durable goods, electronics and transportation industries. Examples of potential applications include:
- Automotive sheet with both strength and improved formability to enable new design options.
- Architectural applications with a superior surface finish and enhanced strength.
- Household appliances with a variety of attractive finishes and better dent resistance.
- Underground pipes with maximum corrosion resistance combined with high strength.
- Rail cars with high load-carrying capacity and better wear resistance.
- Electronics cases that are highly durable and feature a high-tech appearance.
- Boat hulls with enhanced corrosion resistance without compromising strength.
Novelis Fusion is a proprietary technology of Novelis Inc. and is covered by patent applications in numerous countries worldwide.
