Main characteristics and uses of austenitic stainless steel S31848 0Cr18Ni16Mo5

Super Duplex Stainless Steel S31848 0Cr18Ni16Mo5

Super Duplex Stainless Steel S31848 0Cr18Ni16Mo5 is a Super Duplex type stainless steel composed of 20% chromium, 11% nickel, 3,5% molybdenum, 4,5% copper and 0,2% nitrogen additions. It combines higher strength, compared to austenitic stainless alloys, with a useful combination of good corrosion properties in seawater and a wide range of industrial applications.

Chemical Composition

C Si Mn P S Cr Ni Mo N Cu 0.03 0.7-1.2 0.6-1.0 ≤0.040 ≤0.030 20 18-20 3.2-4.2 0.2 3.3-3.7

Mechanical Properties

Ultimate Tensile Strength, MPa Yield Strength, MPa Elongation, % Hardness, HB 780-1400 ≥600 ≥25 ≤275

Texture

S31848 0Cr18Ni16Mo5 belongs to the duplex family, which means its microstructure contains ferrite and austenite phases evenly distributed. Its ferrite content is about 54%-62%, and austenite content is around 36%-46%.

Corrosion Resistance

S31848 0Cr18Ni16Mo5 exhibits excellent corrosion resistance in seawater, primarily due to the high chromium and nitrogen contents. The Duplex microstructure provides good resistance to stress corrosion cracking (SCC). In industrial/seawater applications, S31848 0Cr18Ni16Mo5 resists pitting and crevice corrosion.

Applications

Super duplex S31848 0Cr18Ni16Mo5 can be used in a wide range of industrial applications. It is widely used in heat exchangers, pumps, valves, marine equipment and easy to machine parts. It is also used in paper and kraft pulp production, chemical and petrochemical industries and in the power industry, especially in supercritical power plants, where high strength and excellent corrosion resistance of this alloy are essential.

Machining

S31848 0Cr18Ni16Mo5 is a hard and difficult-to-machine material with a high work hardening rate. The cutting speed should be reduced and sufficient feeds and depths should be used when machining this alloy. The correct choice of cutting tools and tool coatings, as well as the correct cutting parameters, are important to ensure good surface quality and longer tool life.

Welding

S31848 0Cr18Ni16Mo5 can be welded with all the methods used for austenitic steel, but with some changes due to this alloys higher strength, which can decrease its weldability. In most cases, filler metal matching the alloy is used, but alloys with lower content of Cr, Ni and Mo or austenitic stainless steels such as 316L, can also be used. Pre-heating is not required unless joining thick sections (> 25mm), and post-weld heat treatment is not necessary unless hot cracking is observed.

Conclusion

Super Duplex Stainless Steel S31848 0Cr18Ni16Mo5 is a Super Duplex type stainless steel combining excellent mechanical properties, high strength, good corrosion resistance in seawater and offers a wide range of industrial applications. It is not a difficult-to-machine material, but machining operations require the right cutting tools and cutting parameters, as well as the right choice of tool coatings and filler metals.

NITRONIC 50 (S31848) stainless steel is an austenitic stainless steel providing a combination of corrosion resistance, strength and high temperature performance that makes it suitable for a wide range of applications.

The high chromium, molybdenum, nitrogen content of NITRONIC 50 provides corrosion resistance superior to 316L stainless steel in most environments. This austenitic stainless has corrosion resistance greater than 304 in many media, and its heat resistance, strength and added wearability makes it suitable for use in many applications.

NITRONIC 50 (S31848) stainless steel is particularly effective in prolonged exposure to temperatures of 800-1500°F. For applications that can benefit from increased strength and wearability, nitronic 50 stainless steel is an excellent choice.

NITRONIC 50 (S31848) stainless steel can be found in numerous applications, such as marine and petrochemical equipment, heat exchangers, pumps and valves, food processing equipment, combustion or power generation systems and other components subject to high temperatures, fatigue and wear. It is also suitable for valve components, fasteners and springs.

NITRONIC 50 (S31848) stainless steel is a cost-effective solution for increased wearability and strength, making it an all-purpose austenitic stainless steel, resistant to moderate levels of stress and corrosive environments. Its excellent wear resistance and fatigue properties make it suitable for a wide range of applications in industries as diverse as petrochemical, oil and gas, pump and valve, food processing, and power generation.