416 Free-Machining Stainless Steel (UNS S41600)
410 with sulfur added — the most machinable of all stainless steels, heat treatable to 190 ksi bolts, for turned pins, shafts, fittings and set screws.
What 416 Stainless is.
Type 416 is the free-machining version of 410: 12 to 14 percent chromium, a little above 410's 11.5 to 13.5, and the same hardenable carbon, plus a minimum of 0.15 percent sulfur that breaks chips and lets the alloy be turned at the highest rates of any stainless. It hardens and tempers like 410, so a complex part can be machined soft and hardened afterwards. The sulfides reduce corrosion resistance and ductility, so it suits machined parts in mild service rather than pressure bolting.
We run 416 on the Swiss and CNC lathes for pins, shafts, fittings, set screws and small fasteners, from certified A582 bar, and heat treat to Condition T or H or the F593 Group 5 conditions.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | — | 0.15 |
| Manganese | Mn | — | 1.25 |
| Phosphorus | P | — | 0.06 |
| Sulfur | S | 0.15 | — |
| Silicon | Si | — | 1.00 |
| Chromium | Cr | 12.0 | 14.0 |
Values per ASTM A582/A582M-22 Tables 1 and 3 (verified against the specification); free-machining grades are covered by A582, not A276. Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and nominal diameter (in.) | Tensile strength, min (ksi) | Yield strength 0.2% offset, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| Condition A (annealed) — all | — | — | — | — | 262 HBW max |
| Condition T (intermediate temper) — all | — | — | — | — | 248 to 302 HBW |
| Condition H (hard temper) — all | — | — | — | — | 293 to 352 HBW |
Values per ASTM A582/A582M-22 Tables 1 and 3 (verified against the specification); free-machining grades are covered by A582, not A276. Confirm the edition called out on your purchase order with our estimating team. ASTM A582 controls free-machining bar by hardness; bolt strengths are per F593 below.
| F593 condition · marking | Nominal diameter (in.) | Tensile strength (ksi) | Yield strength, min (ksi) | Rockwell hardness |
|---|---|---|---|---|
| H (hardened, tempered ≥1050 °F) · F593P | ¼ to 1½ | 110 to 140 | 90 | C20 to C30 |
| HT (hardened, tempered ≥525 °F) · F593R | ¼ to 1½ | 160 to 190 | 120 | C34 to C45 |
Values per ASTM F593-24 Table 2, full-size tests (verified against the specification). Yield is 0.2 % offset; hardness is Rockwell. Machined-specimen limits differ slightly.
Specifications that apply.
How 416 Stainless ships from Houston.
- Hex and heavy hex bolts and cap screws
- Full-thread studs and threaded rod
- Socket head cap and set screws
- Hex, jam and lock nuts
- Washers and spacers
- Machined components from certified bar
416 Stainless fasteners we make.
Every item is manufactured to your drawing or standard in 416 Stainless, imperial or metric, with an EN 10204 3.1 certificate.
What is 416 stainless steel?
416 is 410 with sulfur added for machinability. Manganese sulfide inclusions act as chip breakers, so the alloy turns, drills and taps faster than any other stainless, and because it is still a hardenable martensitic grade it can be finished soft and then quenched and tempered to the strength required. The same sulfides lower corrosion resistance and transverse toughness, which keeps 416 out of chloride service and pressure bolting.
Where 416 belongs
- Complex turned parts made in quantity: pins, shafts, valve stems, fittings, gun and instrument parts.
- Hardened wear parts that need moderate corrosion resistance.
- Set screws and small fasteners for mild environments.
- Not for welding, seawater or pressure-boundary bolting; use 410 or an austenitic grade there.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or marking symbol F593P or F593R and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
- PMI verification on request
410 Stainless Steel (UNS S41000)
The basic hardenable stainless: 12 percent chromium, heat treatable to 120 ksi and beyond, magnetic, and corrosion resistant in mild atmospheres — for valve trim, pump parts and high-strength stainless bolts.
ASTM A582 bar · ASTM F593 bolts303 Free-Machining Stainless Steel (UNS S30300)
304 with sulfur added for fast, clean machining — the grade for complex turned fasteners and fittings where corrosion resistance can give a little.
ASTM A276 bar · ASTM F593 bolts431 Stainless Steel (UNS S43100)
The strongest and most corrosion resistant of the common martensitic grades: 16 percent chromium with nickel, heat treatable to 220 ksi bolts, for marine shafts, pump parts and high-strength stainless fasteners.