Nickel Alloys – What Are They?
The term Nickel Alloys covers a range of materials where nickel is usually a significant proportion of the chemistry (normally 50%+ although we also classify our Alloy 286 / 660 high temperature bolting steel -with its 24-27% nickel content – as a nickel alloy).
Nickel is added to high chromium stainless steel to create a class of corrosion and heat resistant steels where the tendency of nickel to form austenite is responsible for toughness and high strength at both high and low temperatures. Nickel also improves resistance to oxidation and corrosion. It increases toughness at low temperatures when added in smaller amounts to alloy steels.
Nickel and nickel alloys are used for a wide variety of applications, including aircraft gas and steam turbines, medical applications, nuclear power systems, and of most interest to Broder Metals Group, oil, chemical and petrochemical industries.
Nickel is a very versatile alloy material element, and there are many classifications that nickel alloys can be classified into. One of the most common classifications is as follows:
- Commercially Pure/Low Alloy Nickels – Nickel is supplied in powder, pellet, or anode forms. These materials are very high density, offering magnetic and electronic property capabilities. They also offer excellent corrosion resistance along with reasonable thermal transfer characteristics.
- Nickel-Copper alloys – possess excellent corrosion resistance in reducing chemical environments and in sea water, where they deliver excellent service in nuclear submarines and various surface vessels. By changing the various proportions of nickel and copper in the alloy, a whole series of alloys with different electrical resistances can be created. Prime amongst these alloys are Alloy 400 and Alloy K500.
- Nickel-chromium – provide higher strength and resistance to elevated temperatures. Prime alloys are Alloy 600, Nimonic alloys including N80a, Alloy X750. Alloy 718, Alloy 625. Alloy C-22, and Alloy C-276.
- Iron-Nickel-Chromium Alloys – Used in high-temperature petrochemical environments, where sulphur-containing material are cracked into component distillate parts. Prime alloys in this class are Alloy 800 / 800HT. Alloy 825, Alloy 925
- Controlled-expansion alloys – offer high strength and low coefficient of thermal expansion, for example Alloy 902, 903, 907, and 909.
- Nickel-lron Low-Expansion Alloys – developed for the lamp and electronics industries where glass-to-metal seals in sealed environments are important. Prime alloys are Alloy 42 and Alloy 426.
- Soft Magnetic Alloys – these nickel-iron alloys also offer magnetic permeability properties used principally in switchgear and for direct current motors and generators.
- Welding Alloys – additions of aluminium, titanium, magnesium, and other elements are made to the filler metals and welding electrodes to provide better weld effects and to overcome any hot-short cracking and malleability problems.
Broder Metals Group’s core product range (including the major specifications covered and a brief description of their uses) is as follows:
|Alloy 286 / 660||ASTM A 453 / A 453M – 08 Grades D & A||A precipitation hardened austenitic steel – high stress component situations in petrochemical, aerospace and oilfield industries for gas turbines, engines, shafts, pins, bolts, exhaust re-heaters and thrust nozzles.|
|Alloy 625||ASTM B446-03
UNS N06625 GRADE 1
AMS 5666 REV F
BS3076 1989 NA21
|A low-carbon nickel-chromium alloy – resistant to corrosive media, used for structures in contact with seawater and subject to high mechanical stresses|
|Alloy 718||API 6A 718
NACE MR 01 75 (Solution Annealed and Aged to meet maximum Hardness of 40 HRC)
ASTM B637 (Solution Annealed and Aged to meet minimum Hardness of 40 HRC)
AMS 5662 (Solution Annealed (capability to AMS 5663 – test piece))
AMS 5663 (Solution Annealed and Aged fully to achieve minimum hardness of 35.5 HRC)
|A precipitation hardenable nickel alloy – high temperature application nuts, bolts and fasteners.|
|Alloy K500||BS 3076-89 NA18
|A precipitation hardenable, nickel-copper alloy – used widely in marine environments, as Pump Shafts, Fasteners, Propeller Shafts, Rotor Blades, Valve Trim, etc.|
|High temperature bolting material for powergen applications – bolting, rod and pipe supports etc.|
|316 High Tensile||ASTM A193/193M – A4-80
BS EN ISO 3506 – B8M Class 2
|316 stainless cold drawn for higher tensile strength – bolting applications.|
|Brodernab22||ASTM B150: C63200 TQ-50 temper||A nickel aluminium bronze manufactured to a TQ-50 temper for bolts, valve stems etc.|
The full chemical composition and mechanical properties of these core nickel alloy grades is shown on the relevant data sheets on our product pages.
If you would like more information or to discuss which nickel alloy would be most suitable in a particular environment / situation, please call Broder Metals Group on +44 (0) 114 232 9241.