RA330® Nickel Alloy: A Profile

Also known by the common trade names UNS N08330 and Alloy 330, RA330® is a patented alloy created with the heat treatment industry in mind. It consistently outperforms its often disappointing generic counterparts – RA330® has higher levels of manganese to prevent hot cracking.

While composition has changed over the years, today RA330® is made up of:

• 35% nickel
• 19% chromium
• 1.25% silicon

Other elements include chromium, iron, manganese and carbon. Put together, these elements provide a very strong structure. A nominal 1.25% silicon addition takes oxidation resistance and carburisation to 1148°C.

So, for situations where a quality, heat resistant alloy is needed, RA330® offers a unique blend of strength and resistance to carburisation, thermal shock and oxidation.

What’s more, the product stays completely austenitic whatever the temperature, and does not become brittle due to sigma formation.

To sum up its properties, RA330® Nickel Alloy offers:

• Metallurgical stability
• Great strength at high temperatures
• Thermal shock resistance
• Resistance to nitriding as well as carburisation
• Resistance to oxidation to temperatures of 1148°C

How it’s made

Fabrication is similar to the way conventional austenitic stainless steels are made, and its work hardening rate can be compared to 305 stainless.

RA330® Nickel Alloy is welded with the use of RA330-04 weld fillers of the same make-up. RA330-04 welding wires can be bought in spools for GMA welding, or in straight lines for bare welding.

To get optimum results, do not preheat, ensure that interpass temperatures stay low and make use of strengthened bead contours.

When machining, bear in mind that this kind of chromium-nickel alloy becomes harder more quickly and needs more power to be cut than standard carbon steels. Equally, chips can be stringy, cold-work material with comparatively high ductility.

This alloy is used in a broad range of applications in industrial environments where temperatures are high and a strong resistance is needed to the dual effects of thermal cycling and carburisation.

So this nickel alloy has been used in just about everything from steam boiler and crude oil heater tube hangers to shafts and furnace fans and conveyors, radiant tubes, retorts and muffles among a number of others, including things like corrugated boxes and bar baskets.

As everyone working in the heat treatment sector will appreciate, materials of the best quality are essential. Choose RA330® for a first class alloy that resists corrosion and intense heat. It’s the ideal solution where stainless steels have not withstood manufacturing processes.