Grade Selection: Cast and Wrought Stainless Steel Compared
The choice between cast and wrought stainless steel determines the corrosion resistance, weldability and pressure class suitability of a stainless steel ball valve. Fergo stocks four austenitic stainless steel grades. The following table compares the technically relevant properties for project specification.
| Criterion | 1.4408 (CF8M) Cast | 1.4404 (316L) Wrought | 1.4401 (316) Wrought | Duplex 1.4462 |
|---|---|---|---|---|
| Carbon (C max.) | 0.07 % | 0.030 % | 0.07 % | 0.030 % |
| Molybdenum (Mo) | 2.0–3.0 % | 2.0–3.0 % | 2.0–2.5 % | 2.5–3.5 % |
| PRE (Pitting Resistance) | ≈ 24–28 | ≈ 24–28 | ≈ 23–26 | ≈ 35–40 |
| IGC resistance after welding | Good (cast structure) | Very good (low carbon) | Limited | Very good |
| Temperature range | −40 °C to +200 °C | −40 °C to +200 °C | −40 °C to +200 °C | −40 °C to +250 °C |
| Max. pressure class | PN100 / ANSI 300 | PN40 | PN40 | On request |
| Post-weld service | Body not weldable | Ready without annealing | Solution annealing recommended | Ready without annealing |
| Typical application | Chemical, pharma, seawater, food | Weld-end, pharma, high-purity media | General chemical industry | Chloride seawater, offshore |
Selection guidance: Grade 1.4408 suits most standard industrial applications and covers the widest DN range. Where the ball valve enters a welded pipeline and post-weld heat treatment must be avoided, grade 1.4404 (low carbon) is the preferred choice. For seawater desalination, offshore platforms and chloride-bearing media above 50 °C, duplex 1.4462 delivers the highest PRE value. Fergo custom solutions cover all duplex and special-alloy executions.










