hastelloy C-276——General corrosion

The uniform corrosion resistance of hastelloy C-4 alloy is basically the same as that of hastelloy C alloy in various media. The most important feature of this alloy is that the C, Si and Fe contents are controlled at a low level, so the carbide and intermetallic phase precipitates are less, which makes the uniform corrosion resistance better than hastelloy C and Hastelloy C-276 alloy, especially welding. The corrosion resistance of the post- or aged alloy remains substantially at the solid solution level (Tables 8-40). Figure 8-31 and Figure 8-32 show the isocorrosion of this alloy in H2SCV and HN03. In strong reducing media (such as hydrochloric acid), its corrosion resistance is not as good as hastelloy C-276 alloy, but it is worse than hastelloy C-276 alloy in strong oxidative corrosion medium.

Table 8-40 Corrosion resistance of hastelloy C-4 alloy in some acid media