What is 1.4104 Stainless Steel?

1.4104 stainless steel, commonly known as 416 or UNS S41600, is a free-machining martensitic stainless steel. It is modified with sulfur or selenium to improve machinability, making it one of the most machinable stainless steels. While it offers moderate corrosion resistance, it is primarily chosen for applications requiring high-speed machining, such as screws, bolts, gears, and other precision components.

 

This free-machining grade is standardized under key international systems.

Standard	Equivalent Grade
EN (Europe)	1.4104
ASTM/AISI (USA)	416, UNS S41600
JIS (Japan)	SUS416
KS (Korea)	STS416

Sulfur or selenium additions are key to its improved machinability.

Element	C	Si	Mn	P	S	Cr	Se (optional)
Content (%)	≤ 0.15	≤ 1.0	≤ 1.25	≤ 0.06	≥ 0.15	12.0 - 14.0	≤ 0.15

It can be heat treated to achieve moderate strength and hardness.

Condition	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HRC)
Annealed	~ 275 MPa	~ 515 MPa	~ 20%	~ 20 HRC
Hardened & Tempered	≥ 690 MPa	≥ 860 MPa	≥ 12%	30 - 40 HRC

 

Key Characteristics and Applications of 1.4104 / 416

Excellent Machinability: One of the most machinable stainless steels due to sulfur/seelenium additions, allowing for high-speed machining with good surface finish.

Moderate Corrosion Resistance: Provides reasonable resistance to atmospheric conditions and mild chemicals, but is not suitable for severe corrosive environments.

Magnetic and Hardenable: Strongly magnetic and can be heat treated to improve strength and hardness.

 

Primary Applications:

Fasteners and Fittings: Screws, bolts, nuts, and washers produced via machining.

Precision Components: Gears, shafts, valve parts, and pump components.

Firearms and Defense: Small parts requiring good machinability and moderate corrosion resistance.

General Engineering: Components where machinability is prioritized over corrosion resistance.

 

What is the main advantage of using 416 (1.4104) over 420 (1.4021)?
The primary advantage is machinability. 416 is specifically designed for free machining, allowing for faster cutting speeds, longer tool life, and better surface finishes compared to 420. However, 420 generally offers better corrosion resistance and can achieve higher hardness after heat treatment. 416 is chosen for high-volume machined parts, while 420 is preferred for applications requiring higher wear resistance or edge retention.

 

How does the sulfur content affect the corrosion resistance of 416 stainless steel?
The high sulfur content (≥0.15%) that improves machinability also forms manganese sulfide inclusions, which can act as initiation sites for pitting corrosion. This reduces the overall corrosion resistance compared to low-sulfur martensitic grades like 410 or 420. Therefore, 416 is not recommended for highly corrosive environments or applications where surface finish integrity is critical.

Looking for a Reliable Supplier of 1.4104 / 416 Stainless Steel?
GNEE Steel supplies free-machining 416 (1.4104) stainless steel in bar, wire, and rod forms, ideal for high-volume machining applications. We provide material certification and processing support. If you have any requirements, please feel free to contact us.