Corrosion resistant fasteners – Nickel Alloys
When stainless steel, duplex, superduplex and superaustenitc alloys do not meet the operating conditions, nickel alloy and titanium fasteners are the most suitable corrosion resistant fasteners solutions but also the most expensive. In this document, we will talk about nickel alloy fasteners, the “cheaper” one. Nickel alloys are mainly use for corrosion risistant fastener in particulary for typical chloride cracking resistance property. In the table bellow, is resume a list of the most used nickel alloys, for fastener production, and the relative aqueous corrosion resistance:
| Seawater | Alkalies | Hydrochloridic | Sulfuric | Hydrofluoric | Phosphoric | Nitric | Organic | |
| and Salts | Acid | Acid | Acid | Acid | Acid | Acids | ||
| MONEL® 400 | Excellent | Excellent | Acceptable | Excellent | Excellent | Excellent | Not Suitable | Excellent |
| MONEL® K-500 | Excellent | Excellent | Acceptable | Excellent | Excellent | Excellent | Not Suitable | Excellent |
| INCONEL® 600 | Acceptable | Excellent | Not Suitable | Acceptable | Acceptable | Acceptable | Not Suitable | Excellent |
| ALLOY 20 | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent |
| INCONEL® 625 | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent |
| HASTELLOY® C-276 | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Acceptable | Excellent |
| INCOLOY® 800 | Acceptable | Not Suitable | Not Suitable | Acceptable | Not Suitable | Acceptable | Excellent | Excellent |
| INCOLOY® 825 | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent |
Corrosion resistant fastener guide
MONEL® 400
A Ni-Cu alloy with high strength and excellent resistance to a range of media including seawater, hydrofluoric and sulfuric acids, and alkalies. Used in marine and offshore engineering, salt production and chemical and hydrocarbon processing.
Material Specifications:
- UNS N04400
- W.Nr. 2.4360 – 2.4366
MONEL® K-500
Similar to MONEL alloy 400 but age-hardenable for improved strength and hardness. Used for pump shafts, oil well tools, doctor blades, springs, fasteners and marine propeller shafts.
Material Specifications:
- UNS N05500
- W.Nr. 2.4375
INCONEL® 600
A Ni-Cr-Fe alloy, with good high-temperature strength and oxidation-resistance, and resistance to stress corrosion cracking and caustic corrosion. Used in chemical, petrochemical and thermal processing as well as commercial and military nuclear power plant.
Material Specifications:
- UNS N06600
- W.Nr. 2.4816
ALLOY 20
Alloy 20 is an alloy with resistance to general corrosion, pitting and crevice corrosion in media containing chlorides and sulfuric, phosphoric and nitric acids. Used in chemical and process plants.
Material Specifications:
- UNS N08020
- W.Nr. 2.4660
INCONEL® 625
Is a Ni-Cr-Mo alloy with resistance to severely corrosive environments, particularly to pitting, crevice corrosion and high-temperature oxidation, and with high strength from cryogenic temperatures up to 1500°F (815°C). Used in aerospace engineering, gas
turbines, chemical processing, oil and gas extraction, pollution control, and marine and nuclear plant.
Material Specifications:
- UNS N06625
- W.Nr. 2.4856
HASTELLOY® C-276
An alloy with excellent resistance to reducing and mildly oxidizing environments. Resistant to localized attack and stress-corrosion cracking. Used extensively in pollution control applications and throughout the chemical and process industries.
Material Specifications:
- UNS N10276
- W.Nr. 2.4819
INCOLOY® 800
An alloy with high strength and corrosion-resistance used in chemical, petrochemical and food processing, in nuclear engineering, and for the sheathing of electric heating elements. Applications generally at temperatures below 1200°F (650°C).
Material Specifications:
- UNS N08800
- W.Nr. 1.4876
INCONEL® 825
A Ni-Fe-Cr alloy with excellent resistance to sulfuric and phosphoric acids. Resistant to oxidizing and reducing acids, stress-corrosion cracking, pitting and intergranular corrosion, it is used in chemical and petrochemical processing, oil and gas extraction, pollution control, waste processing and pickling applications.
Material Specifications:
- UNS N08825
- W.Nr. 2.4858
