Extrusion & Welding Processes for Magnesium Tubing
Magnesium Tubes
Whether you are a small frame builder or a high-end bike shop, magnesium tubing is a key component to making a durable and efficient bicycle. The materials used for these frames have to be able to stand up under fatigue, and the design of the tubes must be suited to the material.
Extrusion & welding are important in the production of these tubes. The type of process you use to extrude the magnesium will determine what kind of tube you end up with.
When extruded, the billet of magnesium is forced through a die that shapes a two-dimensional cross-section. These extruded tubes come in both porthole and seamless forms.
The former is used in O&G applications where a hole down the center of the tube is desired. The latter is used in a variety of aerospace, military and commercial applications.
Seamless extrusions are also used to create hollow internal sections. These are often required in aerospace and other applications where the OD of the tube needs to be a specific size or shape, such as a circular tube.
A number of processes have been developed to fabricate medical tubes from magnesium alloys. First, soft-metal mandrel drawing was tried, but this method was not suitable for magnesium alloy because of its brittleness.
The problem was resolved with a newly-developed fluid-mandrel drawing process. During this process, a forming mandrel is inserted into the billet of magnesium from the rear and pushed through until it's very close to the opening in the die.
