- Grade / Alloy
- 444
- EN / W.Nr.
- 1.4521X2CrMoTi18-2
- AISI / SAE
- 444
- UNS
- S44400
- Family
- Ferritic
Chemical composition
Chemical composition
Typical compositionTypical composition of the principal alloying elements; not a complete acceptance analysis.
| Element | Content (% by mass) |
|---|---|
| CCarbon | 0.02 |
| CrChromium | 18 |
| MoMolybdenum | 2 |
| NbNiobium | 0.4 |
| TiTitanium | 0.13 |
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 distinguishes 444 stainless steel?
444 is a ferritic stainless steel identified as 1.4521 and X2CrMoTi18-2. Molybdenum is one of the additions distinguishing it from familiar 430 stainless. It contributes to resistance to localised corrosion, particularly in chloride-bearing environments. This helps explain the use of 444 in equipment that contacts water, transfers heat or undergoes regular cleaning. Its ferritic structure also gives it different thermal and magnetic characteristics from austenitic grades such as 304 and 316L.
Hot-water and heat-exchanger applications
In a hot-water tank or heat exchanger, the metal transfers heat while remaining in contact with water. Corrosion resistance is important, but the heat-conduction characteristics of the ferritic structure also contribute to the role of 444. Lower thermal expansion than common austenitic stainless steels means less dimensional change as temperature varies. Hot-water storage, tanks in solar-heating systems and heat-transfer surfaces are examples where these characteristics are useful together.
How 444 differs from 316L
444 and 316L can appear in similar water-handling applications, but they are different materials. 316L is an austenitic chromium-nickel-molybdenum steel, whereas 444 is ferritic and molybdenum bearing. Their magnetic behaviour, heat conduction and thermal expansion differ. Use in water equipment does not make 444 a universal replacement for 316L, nor is 316L automatically a superior choice for every duty. The two grades offer different combinations of properties.
Magnetism and applications
444 is attracted to a magnet. This follows naturally from its ferritic structure and does not mean that the material is not stainless. In food equipment, water tanks and heating systems, its usefulness comes from the combination of molybdenum-supported corrosion resistance, heat conduction and relatively low expansion. Sheet products serve tank bodies and broad equipment surfaces, while tubes are associated with fluid handling and heat transfer.
Typical application areas
Hot-water tanks, heat exchangers and food equipment.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.