Sheet cobalt alloy 188™

for the aerospace industry

The ATI 188™ alloy is a cobalt-based, solid-solution strengthened alloy that has excellent high temperature strength, excellent oxidation resistance up to 2000°F (1093°C), and good sulfidation resistance. This alloy also has good forming and welding characteristics, which make it useful in fabricating gas turbine components such as combustion cans and transition ducts. The alloy has a face-centered cubic structure. High tungsten content provides solid solution strengthening, while the precipitation of M6C and M23C6 carbides further increases the strength. High chromium content and the addition of lanthanum promote oxidation resistance through formation of a tenacious oxide. FORMS AND CONDITIONS AVAILABLE The ATI 188™ alloy is available in sheet and strip product forms. The alloy is generally supplied in the solution annealed condition. The ATI 188™ alloy (UNS R30188) is covered by the AMS 5608 specification. Limiting Chemical Composition of ATI 188™ Alloy (AMS 5608 Specification Limits for UNS R30188) Element Weight Percent Carbon 0.05 – 0.15 Manganese 1.25 max Silicon 0.20 – 0.50 Phosphorus 0.020 max Sulfur 0.015 max Chromium 20.00 - 24.00 Nickel 20.00 - 24.00 Tungsten 13.00 – 16.00 Lanthanum 0.02 – 0.12 Boron 0.015 max Iron 3.00 max Cobalt Remainder