Q: It says that Alloy 330 is carburization resistant. What does that mean exactly?

A: Carburization is when heat hardens a metal. Carburizing is sometimes used in alloy aging processes when your goal is to harden the alloy. On the other hand unwanted carburization can occur at extreme temperatures which causes the metal to unwantedly harden and become brittle – which inturn can cause breakage. Alloy 330 bolts minimize this even at extreme temperatures to 2100°F.

Q: I’m running a high temperature ethylene process that will reach 750-850C. I need a fastener that is carburization and creep resistance. Also moderate corrosion can be an issue. Any suggestions on materials?

A: This process is ideal for Incoloy 800H or 800HT bolting. These materials are designed for long-term high temperature use. These specialty alloy fasteners are typically used in temperatures above 1500°F where creep and stress rupture protection required. Incoloy bolts also offer moderate corrosion resistance to seawater, brine, sour gas, chlorides and sulfur containing atmospheres as well as oxidation and carburization. However depending on the size you need Incoloy fasteners may have limited availability so Inconel 600 bolts would be a safe bet as well.