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Stainless Steel

416 Stainless

416 is the free-machining martensitic stainless: sulfur added for chip control, plus the ability to harden by heat treatment. It machines at 4/5, the best of any stainless here, and unlike austenitics it's magnetic and hardenable. Corrosion resistance is moderate (3/5), the price paid for the sulfur and lower chromium.

How 416 Stainless machines

At 4/5 it's the easiest stainless to cut, behaving more like a free-machining carbon steel than an austenitic. Sulfide inclusions break chips cleanly and give excellent finishes at high speeds. It doesn't work-harden like 303/316, so screw-machine production is straightforward with standard carbide tooling.

Manufacturing & processing

CNC machining is the home process. Being martensitic, 416 hardens by quench-and-temper to raise strength and wear resistance, typically machined soft then heat-treated. Welding is not recommended, the sulfur and air-hardening nature promote cracking. Magnetic in all conditions. Passivate after machining, and expect slightly reduced corrosion versus 410 due to the sulfur.

Typical applications

Machined shafts, valve stems and components, pump parts, gears, studs, fasteners, and motor shafts. Common where a hardenable, magnetic stainless must be turned in volume, such as solenoid and relay parts that exploit its ferromagnetism, plus firearm and instrument components.

When to choose it

Choose 416 when you need a stainless that machines fast and can be heat-treated for hardness and wear, and moderate corrosion resistance is acceptable. If the part must be welded or face chlorides, avoid it, use 304/316. If you need higher strength with better corrosion resistance, step to 17-4 PH.

Suitable surface finishes

Common finishes for 416 Stainless: passivation, electropolishing, bead blasting, brushed. Use the finish selector →

FAQ

Is 416 stainless magnetic?
Yes. 416 is martensitic, so it's ferromagnetic in both annealed and hardened conditions, unlike austenitic 303/304/316 which are essentially non-magnetic. That magnetism makes 416 useful for solenoid cores, relay armatures, and other parts that must respond to a magnetic field while resisting some corrosion.
Can 416 be hardened?
Yes. As a martensitic grade it hardens by quench-and-temper heat treatment, which 303 and 316 cannot do. Parts are usually machined in the annealed state, then hardened and tempered for strength and wear resistance. The sulfur that aids machining slightly limits maximum attainable toughness.
How does 416 corrosion resistance compare to 304?
It's notably lower, 3/5 versus 304's 4.5. The lower chromium content and sulfur inclusions reduce passive-film integrity, so 416 suits mild indoor and dry environments but not marine or chemical service. Always passivate after machining, and choose 304/316 when corrosion is the priority.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.