What is the difference between 1.4435 and 1.4439 stainless steel pipe?

1.4435 and 1.4439 are both molybdenum-bearing austenitic stainless steels, commonly used in chemical processing, pharmaceutical, and high-corrosion environments. While they may appear similar, they differ significantly in their chemical composition, corrosion resistance, and mechanical strength, making them suitable for different operating conditions.

What is 1.4435 stainless steel pipe?

1.4435 stainless steel (X2CrNiMo18-14-3) is a low-carbon austenitic stainless steel, similar to 316L but with higher nickel (Ni) and molybdenum (Mo) content. It offers improved corrosion resistance and excellent weldability, making it suitable for pharmaceutical, food processing, and biotech applications.

What is 1.4439 stainless steel pipe?

1.4439 stainless steel (X2CrNiMoN17-13-5) is a nitrogen-enhanced austenitic stainless steel, equivalent to AISI 317LMN. It features high Mo (4.0–5.0%) and added nitrogen, giving it superior resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking-ideal for marine, chemical, and desalination systems.

What is the AISI equivalent of EN 1.4439?

The AISI equivalent of EN 1.4439 is AISI 317LMN, with UNS designation S31726. It is classified as a super austenitic stainless steel due to its high alloy content.

What is the chemical difference between 1.4435 and 1.4439?

Property	1.4435 (316L variant)	1.4439 (317LMN variant)
AISI Equivalent	AISI 316L (modified)	AISI 317LMN
UNS	S31603 (modified)	S31726
Cr (%)	17.0 – 18.5	17.0 – 18.5
Ni (%)	12.5 – 14.5	12.5 – 14.5
Mo (%)	2.5 – 3.0	4.0 – 5.0
N (%)	≤ 0.11	0.10 – 0.16
PREN (pitting index)	~26–28	~38–42

Can 1.4435 be used in marine applications?

Yes, but with limitations. While 1.4435 has good general corrosion resistance, it's not ideal for harsh marine environments with high chlorides. For long-term durability, 1.4439 or duplex stainless steel is preferred.

What is the difference between 316L modified and 317LMN?

316L modified (1.4435) is an enhanced version of standard 316L with slightly higher Ni and Mo for better corrosion resistance.

317LMN (1.4439) includes much higher Mo and added nitrogen, resulting in significantly better performance in aggressive chemical and saline environments.

📦 Looking for EN 1.4435 or 1.4439 Pipes?

We supply high-quality 1.4435 and 1.4439 stainless steel pipes, certified to ASTM A312, EN 10216-5, and other global standards. Contact us for:

Seamless or welded pipe stock

Customized cutting, polishing, and bending

Mill test certificates (3.1/3.2)

Contact now