What is 1.4520 Stainless Steel?

1.4520 stainless steel, commonly known as 29-4-2 or UNS S44735, is a super ferritic stainless steel with high chromium and molybdenum content. It offers exceptional resistance to chloride-induced pitting, crevice corrosion, and stress corrosion cracking, making it suitable for aggressive environments such as seawater, chemical processing, and desalination plants.

 

This high-performance ferritic grade is standardized under key international designations.

Standard	Equivalent Grade
EN (Europe)	1.4520
ASTM/AISI (USA)	29-4-2, UNS S44735
Common Name	29-4-2

Its high alloy content, particularly chromium and molybdenum, provides outstanding corrosion resistance.

Element	C	Si	Mn	P	S	Cr	Mo	Ni
Content (%)	≤ 0.025	≤ 0.50	≤ 0.50	≤ 0.03	≤ 0.02	28.0 - 30.0	3.5 - 4.5	2.0 - 2.5

It offers moderate strength and good ductility, typical of ferritic stainless steels.

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)
Typical Value	≥ 415 MPa	550 - 700 MPa	≥ 20%	≤ 230

 

Key Characteristics and Applications of 1.4520 / 29-4-2

Exceptional Chloride Resistance: Provides excellent resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-containing environments, including seawater and brine.

Good Thermal Conductivity: Typical of ferritic stainless steels, it offers better thermal conductivity than austenitic grades.

Magnetic and Weldable with Care: Strongly magnetic. Weldability requires controlled procedures to avoid embrittlement.

 

Primary Applications:

Seawater and Desalination: Heat exchanger tubing, condensers, and piping systems.

Chemical Processing: Equipment for handling chloride-containing media.

Pollution Control: Scrubbers and ducting in aggressive environments.

Oil & Gas: Components exposed to sour (H₂S) environments.

 

How does 29-4-2 (1.4520) compare to duplex 2205 (1.4462)?
While both offer high chloride resistance, 29-4-2 is a ferritic stainless steel with higher chromium and molybdenum but lower nickel content compared to duplex 2205. This gives 29-4-2 superior resistance to stress corrosion cracking and better thermal conductivity, but lower toughness and weldability. Duplex 2205 offers higher strength and better overall toughness, making it more versatile for structural applications.

 

What are the welding considerations for 29-4-2 stainless steel?
Welding 29-4-2 requires careful control to avoid excessive grain growth and embrittlement in the heat-affected zone. Low heat input techniques, preheating, and post-weld annealing are often recommended. Use of matching or over-alloyed filler metals may be necessary to maintain corrosion resistance. It is less forgiving to weld than austenitic or duplex grades.

Looking for a Reliable Supplier of 1.4520 / 29-4-2 Stainless Steel?
GNEE Steel supplies high-performance 29-4-2 (1.4520) super ferritic stainless steel in tube, sheet, and plate forms for demanding corrosive applications. We provide full material traceability and certification. If you have any requirements, please feel free to contact us.