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Titanium Washers |
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Many Titanium alloys have been developed for aerospace applications where mechanical properties are the primary consideration. The main issue with industrial applications is typically corrosion resistance.
Commercially pure industrial grades of titanium are listed by ASTM grade in the table on the right. Titanium Grade 2 represents the vast majority of the titanium used for industrial applications where corrosion resistance is the main concern.
| Industrial grades of titanium | ||||
|---|---|---|---|---|
| ASTM Grade | UNS Designation | Nominal Composition | Yield Strength (PSI) | |
| 1 | R50250 | Commercially Pure | 25,000 | |
| 2 | R50400 | Commercially Pure | 40,000 | |
| 3 | R50550 | Commercially Pure | 55,000 | |
| 4 | R50700 | Commercially Pure | 70,000 | |
The corrosion resistance of titanium is due to a stable, protective, strongly adherent oxide film layer. This film forms instantly when a fresh surface is exposed to air or moisture. A 12-16 angstroms thick oxide film is immediately formed on clean titanium when it is exposed to air. It continues to grow slowly, reaching 50 angstroms after 70 days and 80-90 angstroms after 545 days. The film growth is accelerated under strong oxidizing conditions. This oxide film is very stable and is only attacked by a few substances - most notably hydrofluoric acid. The titanium oxide film is capable of healing itself instantly in the presence of moisture or oxygen.
Anhydrous conditions should be avoided since the protective film may not be regenerated in the absence of oxygen.
| Industrial grades of titanium alloys | |||
|---|---|---|---|
| ASTM Grade | UMS Designation | Nominal Composition | |
| 7 | R52400 | Grade 2 + .15% Pd | |
| 11 | R52250 | Grade 1 + .15% Pd | |
| 16 | R52402 | Grade 2 + .05% Pd | |
| 17 | R52252 | Grade 1 + .05% Pd | |
| 26 | R52404 | Grade 2 + .10% Ru | |
| 27 | R52254 | Grade 1 + .10% Ru | |
Several alloys of titanium have been developed with small amounts of palladium or ruthenium which have significance in industrial applications. Even though titanium has excellent corrosion resistance to a wide variety of corrosive media, it is limited in very hot brine and under acidic or reducing conditions as occur in crevices. The addition of palladium or ruthenium improved the corrosion resistance of the alloy under these conditions and extends the service temperatures of sea water and brine service. The presence of a small amount of these noble metals does not change the mechanical properties of the titanium. Palladium- and ruthenium-stabilized industrial grades of titanium are represented by the following ASTM grades in Table 2.
The availability of lean palladium and ruthenium grades of titanium is still low, but with ASME code approval and increasing potential applications, the supply will increase to meet demand.
TITAN Metal Fabricators
835 Flynn Rd.
Camarillo, CA 93012
Phone: (805) 487-5050
Fax: (805) 487-5047
E-Mail Us at:
titan@titanmf.com