What is 1.4529 Stainless Steel?

1.4529 stainless steel, commonly known as Alloy 28 or UNS N08028, is a high-performance, molybdenum-enhanced austenitic stainless steel designed for extreme corrosion resistance, particularly in sulfuric acid and chloride-containing environments. It is often used in chemical processing, pollution control, and offshore applications where standard grades like 316L or 904L are insufficient.

 

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

Standard	Equivalent Grade
EN (Europe)	1.4529
ASTM/AISI (USA)	Alloy 28, UNS N08028
Common Name	Alloy 28

Its high chromium, nickel, molybdenum, and copper content provide outstanding corrosion resistance.

Element	C	Si	Mn	P	S	Cr	Ni	Mo	Cu
Content (%)	≤ 0.02	≤ 0.7	≤ 2.5	≤ 0.03	≤ 0.01	26.0 - 28.0	29.0 - 32.0	3.0 - 4.0	0.6 - 1.4

It offers good mechanical properties combined with superior corrosion resistance.

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)
Typical Value	≥ 220 MPa	500 - 700 MPa	≥ 35%	≤ 220

 

Key Characteristics and Applications of 1.4529 / Alloy 28

Excellent Acid Resistance: Particularly resistant to sulfuric acid across a wide range of concentrations and temperatures, as well as phosphoric, nitric, and organic acids.

High Chloride Resistance: Offers good resistance to pitting and crevice corrosion in chloride-containing environments, including seawater and brine.

Good Weldability and Formability: Can be welded using common techniques and exhibits good ductility for forming operations.

 

Primary Applications:

Chemical Processing: Reactors, heat exchangers, and piping for sulfuric acid and other aggressive media.

Pollution Control: Scrubbers, ducts, and chimney liners in flue gas desulfurization (FGD) systems.

Oil & Gas: Downhole tubing, wellhead components, and offshore platforms.

Pharmaceutical: Equipment requiring high purity and resistance to corrosive cleaning agents.

 

How does Alloy 28 (1.4529) compare to 904L (1.4539)?
Both are high-alloy austenitic grades, but Alloy 28 contains higher levels of chromium and nickel, and includes copper, giving it superior resistance to sulfuric acid and better overall corrosion performance in mixed acid environments. Alloy 28 is often selected for more severe conditions where 904L may not provide sufficient corrosion resistance, especially in sulfuric acid service.

 

What are the welding considerations for Alloy 28 stainless steel?
Welding Alloy 28 requires matching or over-alloyed filler metals, such as Alloy 625 or a higher-grade austenitic filler, to maintain corrosion resistance in the weld zone. Controlled heat input and proper shielding gas (typically argon-based) are important to avoid excessive grain growth and precipitation of detrimental phases. Post-weld cleaning is recommended to restore corrosion resistance.

 

Looking for a Reliable Supplier of 1.4529 / Alloy 28 Stainless Steel?
GNEE Steel supplies premium Alloy 28 (1.4529) stainless steel in plate, pipe, fitting, and bar forms for the most demanding corrosive applications. We provide full material traceability and certification to ensure optimal performance. If you have any requirements, please feel free to contact us.