Tag: Inconel fasteners for high temperature corrosion resistance

Inconel 625 vs Nitronic 60

Q: Can you explain to me the difference between Inconel 625 and Nitronic 60 in terms of high temperatures?  Both seem to be able to handle temps up to 1800F but which is better?
A: Well that depends on what you are using them for. Inconel 625 bolts are a nickel-chrome based alloy and not only offers high temperature capabilities but it also has excellent corrosion resistance. Inconel 625 bolts provide very good resistance to corrosive chemicals like hydrochloric and sulfuric acid, and are almost completely resistant to salts. Furthermore Inconel 625 fasteners have a typical tensile strength of 144ksi and will maintain its strength to about 1200F before starting to drop and maxes out around 1800F.
 
On the other hand, Nitronic 60 fasteners are stainless steel based and cannot offer the robust level of corrosion resistance or high temperature strength as Inconel. Nitronic 60 bolts are known for good resistance to wear, fretting, galling and oxidation resistance even at elevated temperature and have a typical tensile strength of 95ksi. Nitronic 60 will max out at about 1800F as well.

Inconel vs 310 Stainless Steel Bolts

Q:  I have a high temperature application that can reach close to 1800F that requires not just corrosion resistance from low levels of acid and salt contamination, but I also need good strength. Would Alloy 310 bolts work?
A: Alloy 310 bolts could be a possibility, depending on the strength you need. They have a yield of 30 ksi, which isn’t that high. They are however known for high temperature resistance which can reach 2000F, especially in thermal cycling conditions. If you do in fact require a high strength, corrosion resistant bolt that can work close to 2000F, I would suggest Inconel 625 fasteners. Inconel bolts offer a yield strength of 84ksi (over twice 310SS), plus they are extremely corrosion resistant and can be used to 1800F. I feel Inconel will give you the complete package – where 310SS bolts really are for high temperatures alone.