Extreme high strength fasteners made from advanced alloys allow industries such as aerospace, mining, and oil & gas to push the limits of what is possible. With requirements of ultimate tensile strengths beyond 200ksi this newsletter reviews these materials, their specific traits and niches.
17-4 PH
Age hardened, 17-4PH fasteners can range from 125 -200ksi, but in the H900 condition they are capable of yield strengths over 4x’s that of 316 stainless steel.
NICHE: Customized strength via several different age hardened conditions.
WASPALOY
Just under 200 ksi in UTI, Waspaloy fasteners maintains one of the highest strengths at elevated temperatures.
NICHE: Strength at extreme temperatures well over 1300F exceeding that of Inconel 718.
INCONEL 718
Inconel 718 bolts offers very high strength at high temperatures as well as excellent resistance to wide range of corrosive media.
NICHE: Unique combination of strength, temperature and corrosion resistance.
MP159
One of the strongest alloys, MP159 fasteners offer slightly less strength capabilities to sister alloy MP35N but can be used at greater temperatures to 1100F.
NICHE: Superior strength with good temperature resistance.
MP35N
MP35N bolts offer ultimate tensile strength up to 294ksi and are usable to 800F. Like MP159 they offer good corrosion resistance to most mineral acids, hydrogen sulfide, and seawater.
NICHE: Strongest fastener material commercially available.
When Strength AND High Temperature are Needed
Often high strength materials are needed in extreme temperature situations. This chart ranks the high temperature capabilities of these alloys.
I’m currently looking to purchase MP35N & Inconel 718 material.
I would like to know if these two materials would cause any type of galling issue to my current parts made out of Nitronic 50 material.
Hello Mario,
One of the best ways to minimize galling is to use dissimilar matting materials especially with regards to composition and hardness. In this case the Nitronic 50 is a iron based alloy, while Inconel 718 is nickel based and MP35N is nickel / cobalt based alloy. Because of these large differences in chemistry as well as Inconel 718 and MP35N being much harder than Nitronic 50, I would think galling will be not much of an issue. If you still have concerns, you could try using a moly-disulfide anti-seize lubricant to further minimize the effects. (https://www.extreme-bolt.com/extreme-anti-seize-lubricant.html)
Dean