410 vs 416 Stainless
410 and 416 are the same basic alloy: a martensitic stainless with about 12-13% chromium and a little carbon that hardens by quenching and tempering. 416 adds at least 0.15% sulfur, which forms manganese sulfide inclusions that break chips short. That makes 416 the most machinable stainless steel, at roughly 85-90% of B1112 against about 55% for 410.
The sulfides cost something everywhere else. 416 cannot be welded reliably, cracks in tight bends and cold heading, has lower transverse toughness, and pits sooner because each sulfide is a starting point for corrosion. Choose 416 for turned and milled parts that are not welded or formed and live in mild environments. Choose 410 when the part is welded, formed, polished or exposed to moisture.
| Property | 410 | 416 |
|---|---|---|
| Type | Martensitic | Martensitic, free-machining |
| UNS | S41000 | S41600 |
| Chromium | 11.5-13.5% | 12.0-14.0% |
| Carbon / sulfur | 0.08-0.15% / 0.030% max | 0.15% max / 0.15% min |
| Tensile / yield, annealed | ~515 / 275 MPa (75 / 40 ksi) | ~515 / 275 MPa (75 / 40 ksi) |
| Hardness, hardened and tempered at 205 °C (400 °F) | ~38-43 HRC | ~38-42 HRC |
| Machinability (B1112 = 100%) | ~55% | ~85-90% |
| Density | 7.75 g/cm³ | 7.75 g/cm³ |
| Magnetic | Yes | Yes |
| Typical uses | Valve and pump parts, cutlery, turbine blades, fasteners, petrochemical trays | Screw-machine parts, valve trim, motor and pump shafts, fasteners, gears |
Typical values for the stated conditions. Confirm against the mill certificate and your spec.
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Decision matrix
A check marks the side with the edge on that dimension.
| Dimension | 410 | 416 |
|---|---|---|
| Machining | Fair; about 55% of B1112, stringy chips | ✓ Excellent; the most machinable stainless, short chips |
| Welding | ✓ Fair; preheat about 200-300 °C and temper after | Poor; sulfur causes hot cracking, avoid welding |
| Forming | ✓ Fair annealed; bends and cold heads | Poor; sulfide stringers crack in bends and heading |
| Strength | ✓ ~1000 MPa yield hardened; better transverse toughness | Similar strength; lower transverse ductility and impact |
| Corrosion resistance | ✓ Fair; mild atmospheres, fresh water, steam | Fair to poor; sulfides start pits sooner |
| Finishing | ✓ Polishes and passivates well | Passivate with care to avoid flash attack; polishes to a lesser finish |
| Material cost | About the same per pound; slower machining | ✓ About the same per pound; the cheapest hardenable stainless part |
| Availability | ✓ Bar, sheet, plate and strip | Bar, often pre-hardened; few flat products |
Choose 410 when
- Welded assemblies and parts that will be bent, formed or cold headed
- Moisture, steam or mild chemical exposure, where 416 would pit sooner
- Polished, cosmetic or cutlery surfaces
- Sheet, plate or strip, which 416 rarely comes in
- Impact- or fatigue-loaded parts that need transverse toughness
Choose 416 when
- High-volume turned and milled parts where cycle time sets the price
- Shafts, valve trim, fasteners and gears in mild, dry or oiled environments
- Hardenable stainless parts that will never be welded or formed
- Pre-hardened bar machined to size with no heat treat afterward
Frequently asked questions
- What is the difference between 410 and 416 stainless?
- Sulfur. 416 is essentially 410 chemistry with at least 0.15% sulfur added to make it free-machining. Both are martensitic, magnetic and hardenable to about 40 HRC. 416 machines far faster but welds, forms and resists corrosion worse.
- Can 416 stainless be welded?
- Not reliably. The sulfur causes hot cracking and porosity in the weld. If welding is unavoidable, treat it as a low-strength, non-structural joint and qualify the procedure first. Specify 410 for anything that must be welded.
- Is 416 stainless magnetic?
- Yes. Like 410, 416 is martensitic and magnetic in both the annealed and the hardened condition. Neither is a substitute for 304 or 316 where a non-magnetic part is required.
- Does 416 stainless rust?
- It can. With about 13% chromium and sulfide inclusions it is among the least corrosion-resistant stainless steels: fine indoors, in oil and in mild atmospheres, but it shows rust spots in wet, humid or salty service. Passivating after machining helps. For real exposure use 410 if the part must be hardened, or 304 or 316 if it need not be.
