Titanium

Titanium is the fourth most abundant structural metal and ninth most common element in the earth's crust. Refined from rutile (TiO2) ores mined in the United States, Australia, Africa, China and Russia. Rutile is most commonly recognized as the gold color fibrous crystals in rutilated quartz. Titanium metal weighs 45% less than steel and melts at 3,045°F. Titanium can be TIG and MIG welded inert gas. Fusion welders are used to attach ear posts and other findings. In most applications, rivets, nuts and bolts, and bezels are used for mechanical joining. Titanium cannot be soldered in a studio situation. A smooth inert oxide film is present on the surface of the metal and it resists solders.

Due to its high strength (especially the alloys) and light weight, titanium has many applications in the aerospace industry. Excellent corrosion resistance makes this metal highly desirable for chemical and food processing, also bone replacement and other body implants. This hypo-allergenic metal is safe for sensitive wearers. Titanium is available in some 20 standard grades and alloys. Grade #1, commercially pure (C.P.) titanium is the best suited to jewelry applications. It is ductile and surprisingly slow to work harden. Although the other alloys and less pure grades will color, they are too hard for jewelry work. Titanium needs to be freshly etched to produce its most vivid colors.

Titanium may be either hot or cold forged. At approximately 1640°F titanium goes through a structural phase change and becomes very ductile. As it drops below this temperature it will suddenly harden. The main disadvantage to hot work is the build up of very tough surface oxides. These are dark and may extend deep into the metal surface. They must be ground off and the surface finished before coloring. Cold forging can be a very rewarding technique. Grade #1 metal will feel very firm under the hammer but it will continue to move over a very long range. Often a simple design can be completed in a single forging without need to stop, anneal, and clean. Annealing requires inert gases or hard vacuum.

Author: Bill Seeley
ArtMetal Editor/Curator: enrique