Oxide coating for enhancing metal formability

Abstract

This invention discloses a metal product that is suitable for a forming process. By anodizing an oxide layer onto at least one surface of the metal product, the total amount of lubricant that is applied onto the metal product prior to being formed is reduced or eliminated. This invention also discloses a method of generating such an oxide layer onto the metal product.

Description

FIELD OF THE INVENTION [0001] This invention relates generally to metal forming. More specifically, this invention discloses a method in which an enhanced oxide layer is generated on an aluminum alloy to reduce or eliminate the total amount of lubricant that is applied to the aluminum alloy prior to the metal forming process. BACKGROUND OF THE INVENTION [0002] Metal forming, in most instances, is performed with the aid of lubricants in order to control the friction that is generated between the forming tool and the surface of the metal workpiece during the forming process, and to limit or eliminate the transfer of metal from the metal workpiece to the tooling surface. Most metals, including aluminum and its alloys, which are used in a forming process have a natural oxide layer that is present on the surface of the metal. The natural oxide layer's formation is due to a reaction between the metal's surface and the oxygen, water, and other oxidizing species in the environment. Under dr...

AI Technical Summary

Benefits of technology

"This patent describes a method for preparing a metal product for forming without the need for lubricants. The method involves anodically generating an oxide layer on the surface of the metal product and then using a forming process to create the desired shape. This method reduces costs associated with metal forming by eliminating the need for lubricants and also eliminates the need to remove excess lubricant after forming. Additionally, the method results in a protective surface film that prevents corrosion and scratching."

Problems solved by technology

Metal transfer tends to occur when the contact conditions during a forming process are severe enough to substantially disrupt the naturally formed oxide layer that is present on the surface of the metal workpiece.

As metal deformation and temperature increase, however, the ability of the lubricant to perform these functions is significantly inhibited.

Even solid lubricants, such as graphite or boron nitride, also suffer from a number of problems despite their high thermal stability.

For instance, solid lubricants are difficult to apply uniformly onto the metal product, may adhere poorly once applied, and may not spread readily to provide lubrication to newly formed surfaces.

The utilization of solid lubricants in a forming process can also lead to frequent manufacturing line interruptions because of lubricant accumulation on the forming tool.

Additionally, solid lubricant residue can interfere with downstream processing and finishing.

Furthermore, some solid lubricants can promote corrosion of the surface of the metal product onto which they are applied.

Finally, in an industrial environment, solid lubricants not only present inhalation risks but they can also present challenges to safety and housekeeping by being difficult to clean from the work environment.

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