1.4404 vs 1.4571 Stainless Steel: What’s the Difference?

What material is 1.4401 ?

1.4404 is an ultra-low carbon austenitic stainless steel (C ≤ 0.03%) with 2-2.5% molybdenum. It offers excellent resistance to chloride ion pitting and is five times more resistant to pitting than 304 stainless steel. It is resistant to common corrosive environments such as seawater, diluted hydrochloric acid, and other corrosive media. It is ideal for welding applications (e.g., storage tanks, pipelines) without requiring post-weld heat treatment.

What Standard is Equivalent to 1.4404?

🔹ASTM (USA): 316L (UNS S31603)

🔹GB (China): 022Cr17Ni12Mo2

🔹JIS (Japan): SUS316L

 

What type of material is 1.4571?

1.4571 is an austenitic stainless steel (equivalent to 316Ti), containing 2-3% molybdenum and a slightly higher nickel content (11-14%) compared to 1.4404, which enhances austenite stability. Titanium (Ti ≥ 5×C%) is added for stabilization, significantly improving resistance to intergranular corrosion at high temperatures. This grade is suitable for high-temperature applications (e.g., power plant heat exchangers, catalytic cracking units).

What is 1.4571 Steel Equivalent to?

🔹ASTM (USA): 316Ti (UNS S31635)

🔹GB (China): 0Cr18Ni12Mo3Ti (old grade, now classified as 316Ti)

🔹DIN (Germany): X6CrNiMoTi17-12-2

Performance Comparison: Welding, High Temperature, and Corrosion Resistance

1.4404 vs 1.4571 Stainless Steel Corrosion Resistance

Intergranular Corrosion:

🔹1.4404: Designed with ultra-low carbon content, making it resistant to intergranular corrosion after welding without requiring post-weld heat treatment. It is ideal for one-time welded structures such as flanges and brackets.

🔹1.4571: The titanium content stabilizes carbon, which ensures low risk of intergranular corrosion even at sensitized temperatures (400-800°C) for long-term use, such as in boiler pipelines.

1.4404 vs 1.4571 Stainless Steel High-Temperature Performance

🔹1.4404: Maximum service temperature of about 650°C, with gradual strength degradation at high temperatures. It is suitable for general chemical equipment heating sections.

🔹1.4571: Maximum service temperature of 800°C, with titanium addition improving oxidation resistance, making it ideal for long-term use in the 500-700°C range, such as in heat exchangers and catalytic cracking units.

1.4404 vs 1.4571 Stainless Steel Welding and Processing

🔹1.4404:

Excellent weldability, no preheating required, and suitable for on-site welding (e.g., steel structure installation).

It can be cold-formed easily (e.g., flat bars, angle bars) and polished (Ra ≤ 0.8μm).

No post-weld heat treatment needed for most applications.

🔹1.4571:

Welding requires careful control of heat input to prevent titanium loss. It is recommended to use titanium-containing electrodes (e.g., E316Ti-16).

Ideal for complex welded structures (e.g., multi-layer welds in pipelines).

Cutting performance is slightly inferior to 1.4404, requiring hard alloy tools and a 10% reduction in cutting speed.