654SMo Super Austenitic Stainless Steel Plate

654SMo is a premium-grade super austenitic stainless steel containing high levels of chromium (Cr), nickel (Ni), molybdenum (Mo), and nitrogen (N). It offers exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) in aggressive environments, including seawater, acidic, and chloride-rich conditions. Key features include:

Chemical Composition (wt%)

Element	Content (%)	Role
C	≤0.02	Low carbon to avoid intergranular corrosion
Si	≤0.5	Enhances oxidation resistance^^4^^
Mn	≤2.0	Stabilizes austenite structure
P	≤0.03	Minimizes brittleness
S	≤0.01	Reduces hot cracking risk
Cr	24.0–26.0	Forms passive oxide layer for corrosion resistance
Ni	21.0–23.0	Stabilizes austenite, improves toughness
Mo	6.0–7.0	Resists pitting/crevice corrosion
N	0.4–0.6	Enhances strength and corrosion resistance
Cu	0.5–1.5	Improves sulfuric acid resistance

I. Performance characteristics of 654SMo stainless steel plate

1. Extreme corrosion resistance

(1) High chromium (24-26%), high molybdenum (7-8%) and rich nitrogen (0.45-0.55%) are designed to make its PREN value (pitting equivalent) exceed 50, which can resist the corrosion of high concentration chloride ions (such as seawater, hydrochloric acid) and oxidizing acid media, and its pitting and crevice corrosion performance is better than 254SMO and 904L.

(2) The synergistic effect of nickel (21-23%) and nitrogen significantly improves the resistance to stress corrosion cracking, and is suitable for high temperature, high pressure and chloride-containing environments.

2. Excellent mechanical properties

(1) Tensile strength ≥750 MPa, yield strength ≥430 MPa, elongation ≥40%, with both high strength and high toughness.

(2) Brinell hardness ≤250 HB, good hot and cold processing performance, and the recommended hot processing temperature is 980-1150℃.

3. Stable processing and weldability

(1) Low carbon (≤0.02%) design avoids intergranular corrosion, no heat treatment is required after welding, and the structure is highly stable.

(2) Suitable for conventional welding processes such as TIG/MIG, and the recommended welding material is ERNiCrMo-3 nickel-based welding wire.

II. Main application areas

1. Marine engineering

Seawater desalination equipment evaporators, submarine pipelines and offshore platform components, to resist corrosion in high-salt environments.

2. Chemical and energy

Strong acid reactors (hydrochloric acid, sulfuric acid), flue gas desulfurization systems and nuclear power plant cooling pipes, resistant to high-temperature oxidation and hydrogen sulfide corrosion.

3. Environmental protection and petrochemicals

High-temperature components of waste incineration plants, sulfur-containing oil and gas pipelines, replacing nickel-based alloys to reduce costs.

4. Special equipment

Reverse osmosis high-pressure systems, fire-fighting equipment, taking into account both strength and corrosion resistance requirements.

Summary

654SMo, through its high-molybdenum, nitrogen-rich, and high-chromium alloy design, achieves an excellent balance of corrosion resistance, mechanical properties, and processability, making it a strategic material for extreme working conditions. Its application areas continue to expand, with significant potential in replacing high-cost nickel-based alloys.