The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.

The chemical composition is given as % by mass.

¹⁾Elongation according to EN standard:
A₈₀ for thickness below 3 mm.
A for thickness = 3 mm.
Elongation according to ASTM standard A_2” or A₅₀.

Moda 439/4510 has good corrosion resistance in solutions of many halogen-free organic and inorganic compounds over a wide temperature and concentration range. It can withstand many sufficiently diluted organic and mineral acids depending on the temperature and concentration of the solution. Moda 439/4510 may suffer from uniform corrosion in strong organic and mineral acids, as well as in hot concentrated alkaline solutions.

In aqueous solutions containing halogenides, e.g. chlorides or bromides, pitting and crevice corrosion may occur depending on the halogenide concentration, temperature, pH-value, concentration of oxidizing compounds, or crevice geometry, if applicable. For short periods of time, for instance when cooking food in stainless steel dishes, Moda 439/4510 can tolerate even relatively high chloride concentrations. The presence of corrosion inhibiting or accelerating compounds like transition metal ions or organic compounds may influence the corrosion behavior of Moda 439/4510. Due to its ferritic crystal structure, Moda 439/4510 is not prone to chloride-induced stress corrosion cracking.

Moda 439/4510 can be used for indoor applications in rural areas and urban environments where chloride contamination is low. The best material performance is reached usually with the help of adequate design, correct post-weld treatment, and regular cleaning during use (if applicable).

Due to its titanium and/or niobium content, the risk of sensitization for intergranular corrosion is strongly reduced when compared to non-stabilized ferritic grades. Moda 439/4510 can be used in the temperature range in which chromium carbides would precipitate in non-stabilized ferritic grades. Its maximum service temperature in dry air is 800 °C. The presence of other corrosive compounds in the hot environment, like water and sulfur compounds, reduce the maximum service temperature significantly.

For more information on corrosion resistance, please refer to the Outokumpu Corrosion Handbook or contact the Outokumpu corrosion experts.

PRE Pitting Resistant Equivalent calculated using the formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
CPT Corrosion Pitting Temperature as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions).
CCT Critical Crevice Corrosion Temperature is the critical crevice corrosion temperature which is obtained by laboratory tests according to ASTM G 48 Method F

For a more detailed description of their corrosion resistance properties in different environments, see the Outokumpu Corrosion Handbook.

Forming

The formability of Moda 439/4510 is comparable to many high-quality carbon steels. It is well suited for standard cold forming operations like bending, flanging, and drawing. The stabilized product Moda 439/4510 is particularly suitable for deep drawing.

Machining

Moda 439/4510 is relatively easy to machine. Compared to austenitic grades, it has lower tendency to form edges, which gives a larger machining window. Since the machinability is comparable to that of low-alloyed carbon steels, the same recommendations regarding choice of tool, cutting speed, and cutting feed can be used.

Welding

Moda 409/4512 has good weldability and can be welded using common fusion and resistance welding methods. Conventional welding methods like MMA, MIG, MAG, TIG, SAW, LBW, or RSW – except gas welding – are applicable. Austenitic 19 9 L (308L) or ferritic 17 Ti (439) or 18 L Nb (430LNb) filler metals can be used.

Low interstitial levels and added stabilizer have made enormous improvements to the welding characteristics of ferritic grades. Heat input should be minimized to reduce the grain growth in the heat-affected zone (HAZ). Titanium stabilization of Moda 439/4510 improves autogenously welded joints by refining the grain structure in the weld metal. Stabilization prevents chromium carbide precipitation, which could otherwise lead to sensitization embrittlement. Consequently, the stabilized grades are practically immune to intergranular corrosion when welded.

Shielding gases should be Ar/He-based, mixed with a maximum of 2% oxygen to improve the arc stability. Hydrogen and nitrogen additions are forbidden.

More detailed information concerning welding procedures can be obtained from the Outokumpu Welding Handbook, available from our sales offices.