What AMS 5842 Covers
The specification's scope is short: it covers a high-strength, corrosion- and heat-resistant cobalt-nickel-chromium alloy in the form of bars. The title adds the details that matter to anyone handling the material:
- Alloy: nominal 19% chromium, 36% cobalt, 25% nickel, 7.0% molybdenum, 0.50% niobium, 2.9% titanium, 0.20% aluminium and 9.0% iron.
- Melting: vacuum induction melting plus vacuum consumable electrode remelting.
- Condition: solution heat treated and work strengthened (cold worked).
- Form: bars.
SAE first issued AMS 5842 in March 1977; the revision listed by SAE is dated August 2006. This page summarises the title and scope in our own words and does not reproduce the specification.
MP159: The Alloy Behind AMS 5842
The chemistry in the AMS 5842 title is the alloy SPS Technologies developed and sells as MP159. ASM's Alloy Digest describes it as a cobalt-nickel multiphase alloy with a combination of ultra-high strength, good ductility and toughness, and excellent corrosion resistance, developed as a fastener alloy for the higher operating temperatures of turbine engines and usable up to about 593°C (1100°F).
| Element | Nominal wt% (AMS 5842 title) |
|---|---|
| Cobalt | 36 |
| Nickel | 25 |
| Chromium | 19 |
| Iron | 9.0 |
| Molybdenum | 7.0 |
| Titanium | 2.9 |
| Niobium | 0.50 |
| Aluminium | 0.20 |
Upmet lists the same material as Alloy 159 cobalt bar to AMS 5842 and names applications including aerospace fasteners, landing gear and bolt material, actuation hardware, springs and hot-section turbine parts.
How MP159 Relates to Other Alloys on This Site
MP159 is neither a conventional cobalt alloy nor a nickel alloy: cobalt is the largest element at about 36%, but nickel and chromium together make up nearly as much. It is often compared with MP35N, another multiphase cobalt-nickel fastener alloy. Among the grades we list, it sits closest to the cobalt alloys and the Udimet and Waspaloy fastener and disc alloys in value terms, because all of them carry substantial cobalt.
What AMS 5842 Means for Scrap
MP159 scrap comes from fastener makers (bar ends, rejected bolts, header and thread-rolling scrap) and from aerospace overhaul (retired fasteners). It is valuable because it combines about 36% cobalt, 25% nickel and 7% molybdenum, but only when it is kept apart: a lot mixed with steel or nickel-alloy fasteners loses most of that value.
| Check | What it shows |
|---|---|
| Cobalt about 36% with nickel about 25% | MP159 chemistry |
| Iron about 9% and titanium about 3% | Part of the MP159 analysis; certificates confirm it against other cobalt-nickel fastener alloys |
| Bar tags and certificates naming AMS 5842 | The quickest proof for bar ends |
| Plating or coatings on fasteners | Note them; they lower the value slightly |
- Keep bar ends with their tags and certificates.
- Bag rejected fasteners by alloy; never mix with steel bolts.
- Cobalt is the largest element, so the scrap is normally declared under heading 8105.30, cobalt waste and scrap. Confirm the line with your customs broker.
To sell or buy MP159 scrap, send an enquiry with the form, weight and any certificates.
AMS 5842 FAQ
What is AMS 5842?
An SAE aerospace material specification for bars of a high-strength, corrosion- and heat-resistant cobalt-nickel-chromium alloy, nominally 19Cr-36Co-25Ni-7Mo-0.5Nb-2.9Ti-0.2Al-9Fe, vacuum melted, solution heat treated and work strengthened.
Which alloy is AMS 5842?
The chemistry in the AMS 5842 title is the alloy known as MP159, developed by SPS Technologies as a high-temperature fastener alloy.
What is MP159 used for?
Mainly aerospace fasteners for turbine engines, with other uses including landing gear and bolt material, actuation hardware, springs and hot-section parts.
Is MP159 the same as MP35N?
No. Both are multiphase cobalt-nickel fastener alloys, but they are separate alloys with different chemistry. MP159 was developed for the higher operating temperatures of turbine engines.
Which HS code applies to MP159 scrap?
Cobalt is the largest element, so heading 8105.30, cobalt waste and scrap, normally applies.
Sources and Review
Figures are quoted as published in these sources; any value we could not confirm has been left out.
- SAE International, AMS 5842 listings (AMS5842 and AMS5842E): title, scope, nominal composition and issue history.
- ASM Alloy Digest Co-138, SPS Technologies MP159 (abstract): description, temperature capability and development as a fastener alloy.
- Upmet, Alloy 159 (MP159) cobalt bar AMS 5842 product page: applications and density.
Reviewed by Mitesh Shah, Proprietor, Mipra Steel · Published by Mipra Steel, Khetwadi, Mumbai · Last updated