Alloy 330 - UNS N08330 high in nickel and chromium

Alloy 330 (UNS N08330/T. Nr. 1. 4886) is an austenitic nickel-iron-chromium alloy designed for exceptional resistance to carburizing and oxidizing environments at elevated temperatures. With a nickel content ranging from 34 to 37 percent, the alloy offers excellent resistance to both chloride stress corrosion cracking and embrittlement from the precipitation of sigma phase. This makes it a popular choice in applications where resistance to the combination of thermal cycling and carburization is essential.

Alloy 330 provides a high level of corrosion resistance, especially to oxidation, carburization, and nitridation. The chromium content of 330 provides resistance to oxidizing conditions in aqueous environments, while the nickel content enhances resistance to reducing conditions. Additionally, the high nickel content makes it highly resistant to chloride stress corrosion cracking and sigma phase embrittlement.

The alloy is highly resistant to scale formation at temperatures up to 2000°F (1095°C), and any scale that does form is tightly adherent, especially under cyclic conditions of heating and cooling. The 35 percent nickel content and silicon addition contribute greatly to its exceptional resistance to carburization, making it an ideal choice in applications that involve changing carburizing and oxidizing atmospheres. Alloy 330 also exhibits excellent resistance to the "green rot" phenomenon.

Furthermore, Alloy 330 demonstrates good resistance to nitrogen-containing atmospheres with low oxygen content. This makes it a popular choice in parts handling broken ammonia. Overall, Alloy 330 is a highly reliable and durable alloy with excellent resistance to a wide range of corrosive environments at elevated temperatures.