AISI 316 stainless steel

Physical properties

Laser processing

Marking on clean metal does not generate significant toxic fumes. Any protective surface oils must be removed before processing to avoid irritating vapors.

CO₂: Like 304, reflects the CO2 beam. Cutting is not feasible at maker level. Surface engraving is only possible with chemical marking sprays (Cermark/Thermark) that absorb the beam and create a permanent mark by annealing.

Diode: Cannot be marked or cut directly with standard diode lasers due to high reflectance at typical wavelengths (450–850nm).

Fiber: Excellent. The fiber laser (1064nm) is effectively absorbed by steel. Allows high-definition annealing marking and industrial cutting of thin sheets.

CNC / milling processing

Even more difficult than 304 due to the greater work-hardening tendency imparted by Molybdenum. Requires solid carbide cutters, low cutting speeds (30–50 m/min), constant feed rates never below the minimum chipload. Abundant cooling is essential. Machines with rigid structure and minimal mechanical play.

Post-processing

Sanding: Sanding similar to 304: requires zirconia or ceramic abrasives. Always wet sand to prevent localized overheating. Always finish along the existing grain direction to avoid cross-grain marks.

Primer: mandatory. Painting requires two-component epoxy primers or chromate priming. Chemical passivation (nitric acid or citric acid) restores the protective chromium oxide layer after any mechanical processing.

Gluing: Bondable only for non-structural applications with two-component epoxy adhesives or structural methyl methacrylate (MMA), after sandblasting or plasma treatment of the surface.

Over time: Superior to 304 in chloride-rich environments (seawater, swimming pools, chemical and food industry) thanks to the presence of Molybdenum (2–3%), which stabilizes the passive layer and prevents pitting corrosion.

Common defects

• Work hardening even faster than 304 — maintaining constant feed rate during milling is even more critical
• Intergranular corrosion in heat-affected zones after welding if post-weld annealing is not performed

Safety

Recommended PPE: eye_protection, gloves_leather, mask_p3

Machining chips are sharp and cutting. Wear thick leather gloves. When welding 316, hexavalent chromium and nickel fumes are carcinogenic: P3 mask with metal-specific filter mandatory.

Availability and formats

Commercial formats: sheets 1–12mm, round and square bars, tubes and fittings, welding wire

Related materials

Sources

• ASTM A240/A240M — Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
• EN 10088-2 — Stainless steels: Technical delivery conditions for sheet/plate and strip
• MatWeb — AISI 316 Stainless Steel Datasheet