316L is 304 with molybdenum added, which is what makes it survive chlorides, salt water and many acids. It is the default for marine hardware, medical instruments and chemical equipment. It machines slightly worse than 304 — more prone to galling and work hardening — and costs more, so it is chosen for the environment rather than the workshop.
| Tensile strength | 485 MPa |
|---|---|
| Yield strength | 170 MPa |
| Hardness | 95 HRB |
| Density | 8.00 g/cm³ |
| Elongation | 40% |
| Thermal conductivity | 16.3 W/m·K |
| Series | Austenitic (molybdenum-bearing) |
Typical values for the standard condition (Stainless Steel 316 / 316L). Heat treatment, temper and product form move these numbers — confirm against the mill certificate for your order.
Substantially better chloride and acid resistance than 304
The standard grade for marine and chemical service
Low-carbon "L" version resists sensitization during welding
Widely accepted in medical and pharmaceutical equipment
Starting parameters for carbide tooling. These are the shop's working numbers, not brochure values — adjust for machine rigidity, tool geometry and workholding.
| Surface speed | 50–100 m/min |
|---|---|
| Feed per tooth | 0.05–0.12 mm/tooth |
| Tooling | AlTiN coated carbide, 4–5 flute |
| Coolant | High-pressure flood with good lubricity |
Harder to machine than 304 and more prone to work-hardening and galling. Sharp tooling and a rigid setup matter more than parameter tweaks. Threads and fine features are where galling shows up first.
Material costs more than 304 (the molybdenum is expensive) and machining is slightly slower. The premium is justified by service environment, not by machinability.
For the full cost structure — material, programming, setup, cycle time, finishing and inspection — see CNC machining cost per hour, and for how price changes with quantity see machining by production volume.
Whenever the part sees chlorides — salt water, salt spray, cleaning agents containing hypochlorite, or chemical process streams. 304 pits in these environments while 316L holds up. For indoor atmospheric exposure and food service, 304 is usually adequate and cheaper.
Austenitic stainless has a strong tendency to pressure-weld to itself, and threading concentrates the contact pressure. Use sharp tooling, a lubricating cutting fluid rather than plain coolant, and consider thread milling for critical threads instead of tapping.
It is widely used for surgical instruments, orthopaedic hardware and pharmaceutical equipment, and is accepted by most standards for those applications. Implant-grade applications typically require specific grades and certifications — confirm the applicable standard with your regulatory team.
Low carbon (0.03% maximum versus 0.08% for standard 316). The lower carbon reduces chromium carbide precipitation during welding, which would otherwise deplete chromium near the weld and create a corrosion path. For machined parts that will not be welded, 316 and 316L behave similarly.
Tell us the grade and temper, the quantity and what the part has to do. You get a line-item quote within 24 hours, with DFM feedback on anything that is raising the cost.