Nauticalloy 4404 316L | 1.4404

Prior to the introduction of Nauticalloy 4462, Nauticalloy 4404 represented the established industry standard within the marine propeller shaft sector, earning widespread recognition for its reliable performance and proven track record across diverse marine applications. This austenitic stainless steel continues to provide exceptional value where moderate strength requirements are combined with excellent general corrosion resistance.

Whilst Nauticalloy 4404 exhibits lower strength and corrosion resistance compared to the advanced duplex grade Nauticalloy 4462, it delivers significantly superior performance compared to standard austenitic grade 1.4307-304L, making it an optimal choice for marine applications requiring enhanced corrosion resistance without the premium associated with duplex metallurgy.

1.4404

Material equivalents

Marine propeller shafts in Nauticalloy 4404 are equivalent to marine propeller shafts in 1.4404, AISI 316L, UNS S31603, and 316L, which are internationally recognised within various material norms, ensuring global specification compatibility and supply chain reliability across diverse marine markets.

View Nauticalloy 4404 data sheet

Chemical Composition

Element	C	Si	Mn	P	S	Cr	Ni	Mo	N
% min	-	-	-	-	-	16.50	10.00	2.00	-
% max	0.03	1.00	2.00	0.045	0.03	18.50	13.00	2.50	0.11

Chemical composition (% by weight)

Mechanical properties

Property	Rp0.2 (Proof Strength)	UTS (Tensile Strength)	Elongation A4 %	Reduction of Area %	Hardness BHN (max)
Metric (MPa / N/mm²)	>240 MPa	520 - 680 MPa	40	30	<215
Imperial (ksi)	>35 ksi	75 - 100 ksi	40	30	<215

Characteristics

Low-carbon austenitic structure

Nauticalloy 4404 features a low-carbon austenitic microstructure that provides exceptional resistance to carbide precipitation during welding and thermal processing. The reduced carbon content (≤0.03%) significantly enhances intergranular corrosion resistance, making it particularly suitable for marine environments where thermal cycling may occur.

Molybdenum-enhanced corrosion resistance

The addition of 2-3% molybdenum significantly enhances pitting and crevice corrosion resistance compared to standard 304L/1.4307 grade, providing superior performance in chloride-containing marine environments whilst maintaining excellent general corrosion resistance.

Excellent weldability and fabrication

The low-carbon composition ensures excellent weldability without post-weld heat treatment requirements, maintaining corrosion resistance properties in heat-affected zones whilst providing formability and machinability for complex marine component manufacturing.

Marine applications and benefits

Nauticalloy 4404 has established an extensive service history in marine propeller shaft applications, where its combination of moderate strength, excellent corrosion resistance and proven reliability provides dependable performance for leisure craft, commercial vessels and marine equipment applications.

The material finds widespread application in marine pumps, valves, heat exchangers and piping systems where superior corrosion resistance to seawater and marine atmospheres is essential whilst moderate strength requirements are acceptable.

Applications extend to marine structural components, rigging hardware and marine architectural elements where corrosion resistance, fabricability and established performance history provide optimal material selection.

The low-carbon composition and excellent cleanability characteristics make Nauticalloy 4404 particularly suitable for food processing equipment, galley installations and sanitary systems.

Processing Quality Assurance Nauticalloy 4462 Nauticalloy 4542 Nauticalloy 22HS Nauticalloy 4501

For Nauticalloy 4404 technical consultation, contact our specialist technical sales team at +44 (0)1902 409409 or email sales@millstockstainless.com

Nauticalloy 4404