- Grade / Alloy
- Alloy 20
- EN / W.Nr.
- 2.4660
- AISI / SAE
- —
- UNS
- N08020
- Family
- Nickel-iron
Chemical composition
Chemical composition
Typical compositionTypical analysis and stated composition ranges for Alloy 20.
| Element | Content (% by mass) |
|---|---|
| CCarbon | ≤ 0.06 |
| PPhosphorus | ≤ 0.035 |
| SiSilicon | ≤ 1 |
| NiNickel | 32.5–35 |
| MnManganese | ≤ 2 |
| SSulfur | ≤ 0.035 |
| CrChromium | 19–21 |
| MoMolybdenum | 2–3 |
| FeIron | Balance |
| CuCopper | 3–4 |
| Nb+TaNiobium + tantalum | 8 × C ≤ Nb+Ta ≤ 1.00 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
What is Alloy 20?
Alloy 20 is a specialised material often discussed between stainless steels and higher-nickel corrosion alloys. It contains iron, nickel and chromium together with molybdenum, copper and niobium, and is designated N08020 and 2.4660.
Its relationship to sulphuric acid
Sulphuric-acid plants are among Alloy 20’s best-known applications. Copper and molybdenum contribute to this performance. Chemical equipment and acid storage and transfer systems value its chemical resistance rather than exceptionally high hardness.
Typical equipment examples
Vessel bodies provide large acid-contact surfaces, while pipes and exchangers carry fluids and transfer heat. Alloy 20 is used across these components as well as fittings and valve parts, rather than serving only one type of machinery.
Difference from 316L and other nickel alloys
Alloy 20 is not another name for 316L, with differences including nickel and copper. It also differs from high-molybdenum grades such as B-2. The number 20 is a designation, not a strength or quality ranking.
Typical application areas
Sulphuric acid equipment, tanks, piping and heat exchangers.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.