F44 (UNS S31254 / W.Nr. 1.4547)

F44 (UNS S31254 / W.Nr. 1.4547) an austenitic stainless steel used in seawater and other aggressive chloride- bearing media. This grade has excellent resistance to pitting and crevice corrosion, high resistance to general corrosion and stress corrosion cracking, with a higher strength than conventional austenitic stainless steels, and good weldability.

Equivalent Grades

Trademark	GB	GOST	ASTM	UNS	DIN	W.Nr.	NF	BS	JIS	SS
F44 254 SMO	–	–	F44	S31254	X1CrNiMoCuN20-18-7	1.4547	Z1 CNDU 20.18.06AZ	X1CrNiMoCuN20-18-7	–	–

Chemical Composition, %

Alloy	C	Si	Mn	P	S	Cr	Ni	Mo	N	Fe
254 SMO	≤0.02	≤0.80	≤1.0	≤0.03	≤0.02	19.5-20.5	17.5-18.5	6.0-6.5	0.18-0.25	Bal

Typical Physical and Mechanical Properties (RT, Annealed)

Density, g/cm3	Melting Point, ℃	Tensile Strength, MPa	Yield Strength, MPa	ELongation, %	Hardness, HRB
8.0	1130-1280	655-850	≥313	≥35	/

Available Products and Specifications

Rod, Bar, Wire and Forgings	ASTM A182
Plate, Sheet and Strip	ASTM A312
Pipe and Tube	ASTM A167, 240
Welding Product	–
Others	ASTM A403

Features

The steel combines moderate mechanical strength (typically over 300 MPa yield strength) and high ductility with excellent corrosion resistance in seawater and a variety of industrial environments. Typically the alloy has a PREn (Pitting Resistance Equivalent) of 42-44 which ensures that the resistance to pitting corrosion is high. In addition, the steel provides good resistance to crevice corrosion. Ambient and sub-zero temperature notch ductility is very good. These attributes mean that this high molybdenum stainless steel can be used successfully as an alternative to 300 series austenitic stainless steels (such as type 316) in applications where higher mechanical strength and/or enhanced resistance to pitting and crevice corrosion is required.