Stainless Steel 416

Stainless Steel 416 is a martensitic, free-machining stainless steel. It is known for having the highest machinability of any stainless steel (approx. 85%), making it the most cost-effective choice for high-volume manufacturing. Unlike the 300 series (austenitic), 416 is magnetic and can be hardened through heat treatment to increase strength and wear resistance. However, the addition of sulfur to improve machining lowers its corrosion resistance. At Jucheng Precision, we utilize 416 primarily for manufacturing motor shafts, gears, and valve components that require high strength, magnetic permeability, and precision grinding capability.

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Stainless Steel 416

SS 416 Machining Capabilities

Capability Technical Description Jucheng Advantage
Ultra-High Speed Turning 416 has the highest machinability of all stainless steels (85%). We run it at speeds comparable to carbon steel. Perfect for high-volume production of shafts and fasteners, offering significant cost savings over 304/316.
Heat Treatment Unlike 300 series, 416 can be hardened by quenching and tempering to achieve 35-40 HRC. We machine parts slightly oversize, heat treat them for strength, and then finish grind them to precision tolerances.
Precision Grinding 416 responds beautifully to grinding, achieving a high-gloss finish and tight concentricity. Essential for electric motor shafts and pump components requiring low friction and perfect roundness.
Gear Hobbing The material’s brittleness allows for clean chip breaking, making it ideal for cutting gear teeth without burrs. We produce durable, corrosion-resistant gears for industrial actuators and pumps.

Fabrication Guidelines for Stainless 416

Corrosion Warning:
416 has the lowest corrosion resistance of standard stainless steels due to sulfur and lack of nickel. Tip: Do not use in marine or chloride environments. It will rust if exposed to water without oil/grease protection.

Weldability:
Poor. The high sulfur content causes hot cracking. 416 is not designed to be welded.

Magnetic:
416 is strongly magnetic in all conditions. Tip: This is an advantage for magnetic sensors or solenoids, but a disadvantage if non-magnetic properties are required (use 316 instead).

Primary Applications

Electric Motors
The standard material for motor shafts due to high machinability, magnetic properties, and hardenability.

Pumps & Valves
Valve stems, pump shafts, and internal components that need hardness to resist wear but only moderate corrosion resistance.

Fasteners
Machine screws, bolts, and nuts where higher strength than 303 is needed (via heat treat) at a low cost.

Gears
Small precision gears for washing machines, power tools, and industrial automation.

Properties

Density 7.75 g/cm³
Tensile Strength 517 - 1200+ MPa
Yield Strength 275 - 1000+ MPa
Hardness 35 - 40 HRC
Elongation at Break 15 - 30%
Thermal Conductivity 24.9 W/m-K
Electrical Conductivity 2.9% IACS
Machinability Rating 85%
Weldability Poor
Corrosion Resistance Fair
Magnetic Yes
Max Part Size 2000 x 800 x 600 mm