A nickel-iron-chromium grade, RA330® offers an exceptional combination of strength and resistance to carburization, oxidation and thermal shock.

RA330® was created to service the needs of the thermal process industries with a reliable source of a wrought product that could handle high temperature carburizing and nitriding conditions with repeated quenching. RA330® has excellent oxidation resistance up to 1148°C.

  • UNS Number: N08330
  • Werkstoff Number: 1.4886
  • ASTM: B511, B512, B535, B536, B546, B710, B739, 5716, B829, B726
  • AMS: 5592

Product availability

Expanded Metal
Pipe (Seamless)
Pipe Fittings
Round Bar
Welding Electrode
Welding Wire

Chemical analysis



  • Muffles and retorts
  • Quenching fixtures
  • Furnace, fans and shafts
  • Hot pressing platens
  • Bar baskets
  • Radiant tubes
  • Salt pots – both neutral and cyanite
  • Tube hangers for crude oil heaters and steam boilers

About RA330®

The chemical composition of RA330® has changed over the years to allow for improved performance in the thermal process industry.

RA330® is the workhorse of the heat resistant alloys with good strength and oxidising resistance up to 1148°C. In addition, the alloy is excellent in carburizing and nitriding environments.

The properties of RA330® are enhanced by a nominal 1.25% silicon addition. It has been designed to withstand thermal shock induced by liquid quenching.

RA330® finds wide applications in high temperature environments where good resistance to the combined effect of carburization and thermal cycling conditions are the prime requisite.

RA330® remains fully austenitic at all temperatures so it is not subject to sigma embrittlement. It is highly resistant to chloride-induced stress corrosion cracking and thus an alloy of choice where common stainless grades have failed by stress corrosion cracking.

RA330® can be fabricated and machined using procedures used for stainless steels or nickel-chromium alloys. Heat treatment is not necessary after most forming and welding operations. When required, the recommended full anneal is 1038-1371°C, rapid air cool or water quench. RA330® can be readily welded using RA330-04® or other weld fillers of matching conditions.

RA330® is the registered trademark of Rolled Alloys Inc.

  • Density: 7944 g/cm³

Mechanical & Physical Properties

Mechanical & Physical Properties21°C538°C593°C649°C704°C760°C816°C871°C982°C1093°C
Ultimate Tensile Strength /MPa586.1489.5457.8390.9305.4247.5184.8145.571.722.1
0.2% Yield Strength /MPa268.9172.4166.9151.7144.8142.7119.3106.258.613.8
Minimum Creep 0.0001% per hr /MPa-----24.8-14.53.4-
10,000 hr Rupture Strength/MPa----29.6-
Coefficient of Thermal Expansion /µm/m⁰C -----17.46-17.6418-
Thermal Conductivity /kcal/(hr.m.°C) 10.71----20.39-21.1321.87-
Modulus of Elasticity / x105 MPa2----1-11-
Proud members of the British Valve & Actuator AssociationProud members of the British Valve & Actuator Association