254SMo、UNS S31254、W.Nr.1.4547、X1NiCrMoCu20-18-7、CK3MCuN

Overview of 254SMo (S31254, F44, 1.4547) super austenitic stainless steel:

254SMO (S31254, F44, 1.4547) is a super austenitic stainless steel. Because of its high molybdenum content, it has extremely high resistance to pitting and crevice corrosion. This grade of stainless steel was developed and developed for use in halide-containing environments such as seawater. 254SMO also has good resistance to uniform corrosion. Especially in halogen-containing acids, this steel is superior to ordinary stainless steel. Its C content is <0.03%, so it is called pure austenitic stainless steel (<0.01% is also called super austenitic stainless steel).

Super stainless steel is a kind of special stainless steel. It is different from ordinary stainless steel in chemical composition at first. It refers to a high alloy stainless steel containing high nickel, high chromium and high molybdenum. Among them, the more famous is 254SMo containing 6% Mo. This type of steel has very good local corrosion resistance. It has good pitting resistance (PI≥40) under seawater, aeration, gaps, and low-speed erosion conditions. Good stress corrosion resistance, it is a substitute for Ni-based alloys and titanium alloys. Secondly, in terms of high temperature or corrosion resistance, 304 stainless steel is irreplaceable. In addition, from the classification of stainless steel, the metallographic structure of special stainless steel is a stable austenitic metallographic structure.

Because 254SMO (S31254, F44, 1.4547) is a high-alloy material, it is quite complicated in the manufacturing process. Generally, people can only rely on traditional processes to manufacture this special stainless steel, such as pouring, forging, and rolling. It is also possible to make seamless steel pipes by center drilling, cold rolling or cold drawing.

 

Chemical composition of 254SMo (S31254, F44, 1.4547) super austenitic stainless steel:

C≤	Si≤	Mn≤	P≤	S≤	Cr≥	Ni≥	Mo≥	N≤	Cu≤	Fe≤
0.02	0.80	1.00	0.030	0.010	19.5 20.5	17.5 18.5	6.0 6.5	0.18  0.22	0.50 1.00	margin

 

Physical properties of 254SMo (S31254, F44, 1.4547) super austenitic stainless steel:

Density: 8.24g / cm3,

Melting point: 1320-1390 ℃,

Magnetic: None

 

Mechanical properties of 254SMo (S31254, F44, 1.4547) super austenitic stainless steel:

1. Mechanical properties: tensile strength: σb≥650Mpa,

2. Yield strength σb≥310Mpa:

3. Elongation: δ≥40%.

4. Hardness: 182-223 (HB)

 

254SMo (S31254, F44, 1.4547) Super austenitic stainless steel corrosion resistance:

254SMO (S31254, F44, 1.4547) stainless steel is a high corrosion resistant super austenitic stainless steel. It is developed for halide and acid environments. It is widely used in harsh working environments such as high concentration chloride ion media and seawater. In various industrial applications of acidic media, especially in halide-containing acids, 254SMO is far superior to other stainless steels, and in some cases can be comparable to Hastelloy and titanium. The low carbon content and high molybdenum content make it have better resistance to pitting and crevice corrosion, excellent resistance to intergranular corrosion, and is a cost-effective stainless steel. widely used.

 

254SMo (S31254, F44, 1.4547) Supporting consumables for super austenitic stainless steel:

Welding wire: ERNiCrMo-3, electrode: ENiCrMo-3.

 

254SMo (S31254, F44, 1.4547) Application fields of super austenitic stainless steel:

1. Ocean: marine structures in the sea environment, seawater desalination, seawater aquaculture, seawater heat exchange, etc.

2. Environmental protection field: flue gas desulfurization equipment for thermal power generation, wastewater treatment, etc.

3. Energy field: atomic power generation, comprehensive utilization of coal, sea tide power generation, etc.

4. Petrochemical industry: oil refining, chemical and chemical equipment, etc.

5. Food field: salt making, soy sauce brewing, etc.

6. High-concentration chloride ion environment: paper industry, various bleaching devices

 

254SMo (S31254, F44, 1.4547) Corrosion performance of super austenitic stainless steel:

1. A large number of field experiments and extensive use experience show that even at slightly higher temperatures, 254SMO has high crevice corrosion resistance in seawater, and only a few types of stainless steel have this performance.

2. The corrosion resistance of 254SMO in acidic solutions and oxidizing halide solutions such as those required for bleaching in the paper industry can be compared with nickel-based alloys and titanium alloys with the strongest corrosion resistance.

3. Because 254SMO has higher nitrogen content, its mechanical strength is higher than other types of austenitic stainless steel. In addition, 254SMO has high ductility and impact strength and good weldability.

4. The high molybdenum content of 254SMO can make it have a higher oxidation rate during annealing, so that it has a rougher surface than ordinary stainless steel after pickling. However, this has no adverse effect on the corrosion resistance of the steel.