Tube stainless steel Sanmac® 316/316L

Sanmac® 316/316L is a molybdenum-alloyed austenitic chromium-nickel steel with improved machinability, supplied primarily as hollow bar for industrial applications requiring higher corrosion resistance than steels of type 304/304L.

Standards

• ASTM: MT 316, MT 316L
• UNS: S31600, S31603
• EN Number: 1.4401, 1.4404
• EN Name: X 5 CrNiMo 17-12-2, X 2 CrNiMo 17-12-2
• JIS: SUS316TKA

Product standards

• EN 10216-5* (leakage test deferred to finished component), EN 10297-2, EN 10294-2
• ASTM A511
• JIS G3446

Chemical composition (nominal), %

• C: ≤ 0.030
• Si: ≤ 0.75
• Mn: ≤ 2.00
• P: ≤ 0.040
• S: ≤ 0.030
• Cr: 16.5
• Ni: 11
• Mo: 2.1

Applications

• Machined parts for tube and pipe fittings
• Components for valves, pumps, heat exchangers and vessels
• Tubular shafts and components for chemical, petrochemical, fertilizer, pulp & paper and power industries, and for production of pharmaceuticals, foods and beverages

Corrosion resistance
General corrosion

• Good resistance to organic acids at high concentrations and temperatures (except formic acid and acids with corrosive contaminants)
• Good resistance to inorganic acids (e.g. phosphoric acid) at moderate concentrations/temperatures; sulfuric acid below 20% at moderate temperatures; can be used in sulfuric acid >90% at low temperature
• Resistant to sulfates, sulfides and sulfites
• Resistant in caustic environments

Intergranular corrosion

• Low carbon content gives good resistance to intergranular corrosion

Stress corrosion cracking

• Austenitic steels may be susceptible above ~60°C (140°F) in tensile-stressed conditions, particularly in chloride-containing solutions; for higher resistance consider austenitic-ferritic grades (e.g. SAF 2304, Alleima 10RE51 or Sanmac® 2205)

Pitting and crevice corrosion

• Improved resistance due to molybdenum content; Sanmac® 316/316L has substantially higher resistance than AISI 304/304L

Gas corrosion

• Usable in air up to 850°C (1560°F)
• Usable in steam up to 750°C (1380°F)
• Corrosion resistance in flue gases containing sulfur reduced; usable up to 600–750°C depending on service conditions and impurities

Forms of supply

• Hollow bar: stocked in many sizes up to 250 mm outside diameter in solution-annealed and white-pickled condition (component sizes guaranteed after machining)
• Dimensions: outside diameter tolerance +2 / -0% (min +1 / -0 mm), inside diameter tolerance +0 / -2% (min +0 / -1 mm), straightness ±1.5 mm/m. Other tolerances available on special order.
• Also available in bar with improved machinability (Sanmac trademark)

Heat treatment (recommended after processing)

• Stress relieving: 850–950°C (1560–1740°F), cool in air
• Solution annealing: 1000–1100°C (1830–2010°F), rapid cooling in air or water

Mechanical properties (typical)
At 20°C (68°F) — Metric

• Proof strength Rp0.2 (a): ≥ 220 MPa
• Proof strength Rp1.0 (a): ≥ 250 MPa
• Tensile strength Rm: 515–690 MPa
• Elongation A (b): ≥ 45%
• Elongation A2: ≥ 35%
• Hardness: ≤ 90 HRB

At 20°C (68°F) — Imperial

• Proof strength Rp0.2 (a): ≥ 32 ksi
• Proof strength Rp1.0 (a): ≥ 36 ksi
• Tensile strength: 75–100 ksi
• Elongation: ≥ 45% (A) and ≥ 35% (A2)
• Hardness: ≤ 90 HRB

Proof strength at elevated temperatures (metric, MPa)

• 50°C: Rp0.2 ≥ 210, Rp1.0 ≥ 240
• 100°C: Rp0.2 ≥ 180, Rp1.0 ≥ 215
• 150°C: Rp0.2 ≥ 165, Rp1.0 ≥ 195
• 200°C: Rp0.2 ≥ 150, Rp1.0 ≥ 180
• 250°C: Rp0.2 ≥ 140, Rp1.0 ≥ 170
• 300°C: Rp0.2 ≥ 135, Rp1.0 ≥ 160
• 350°C: Rp0.2 ≥ 130, Rp1.0 ≥ 155
• 400°C: Rp0.2 ≥ 125, Rp1.0 ≥ 150
• 450°C: Rp0.2 ≥ 123, Rp1.0 ≥ 148
• 500°C: Rp0.2 ≥ 120, Rp1.0 ≥ 145
• 550°C: Rp0.2 ≥ 115, Rp1.0 ≥ 140
• 600°C: Rp0.2 ≥ 110, Rp1.0 ≥ 135

Impact strength

• Very good impact strength at room and cryogenic temperatures; fulfils 60 J at -196°C per EN 13445-2 (UFPV-2) and EN 10216-5

Physical properties

• Density: 8.0 g/cm³ (0.29 lb/in³)

Thermal conductivity (W/m·°C / Btu/ft·h·°F)

• 20°C: 14 W/m·°C (68°F: 8 Btu/ft·h·°F)
• 100°C: 15 W/m·°C (200°F: 8.5 Btu/ft·h·°F)
• 200°C: 17 W/m·°C (400°F: 10 Btu/ft·h·°F)
• 300°C: 18 W/m·°C (600°F: 10.5 Btu/ft·h·°F)
• 400°C: 20 W/m·°C (800°F: 11.5 Btu/ft·h·°F)
• 500°C: 21 W/m·°C (1000°F: 12.5 Btu/ft·h·°F)
• 600°C: 23 W/m·°C (1100°F: 13 Btu/ft·h·°F)

Specific heat capacity (J/kg·°C / Btu/lb·°F)

• 20°C: 485 J/kg·°C (68°F: 0.11 Btu/lb·°F)
• 100°C: 500 J/kg·°C (200°F: 0.12 Btu/lb·°F)
• 200°C: 515 J/kg·°C (400°F: 0.12 Btu/lb·°F)
• 300°C: 525 J/kg·°C (600°F: 0.13 Btu/lb·°F)
• 400°C: 540 J/kg·°C (800°F: 0.13 Btu/lb·°F)
• 500°C: 555 J/kg·°C (1000°F: 0.13 Btu/lb·°F)
• 600°C: 575 J/kg·°C (1100°F: 0.14 Btu/lb·°F)

Thermal expansion, mean values (×10⁻⁶ per °C)

• 30–100°C: 16.5
• 30–200°C: 17
• 30–300°C: 17.5
• 30–400°C: 18
• 30–500°C: 18
• 30–600°C: 18.5
• 30–700°C: 18.5

Modulus of elasticity (×10³ MPa)

• 20°C: 200 ×10³ MPa
• 100°C: 194 ×10³ MPa
• 200°C: 186 ×10³ MPa
• 300°C: 179 ×10³ MPa
• 400°C: 172 ×10³ MPa
• 500°C: 165 ×10³ MPa

Welding

• Good weldability. Suitable methods: MMA/SMAW and gas-shielded arc welding; TIG/GTAW is first choice.
• Due to machinability alloying, surface oxides on weld beads may be higher—arc instability possible during TIG without filler; welding with filler behaves similarly to standard 316L.
• Recommended heat input < 2.0 kJ/mm and interpass temperature < 150°C (300°F). Preheat/post-weld heat treatment normally not necessary.
• Recommended filler metals: TIG/GTAW or MIG/GMAW — ISO 14343 S 19 12 3 L / AWS A5.9 ER316L; MMA/SMAW — ISO 3581 E 19 12 3 L R / AWS A5.4 E316L-17

Machining

• Sanmac® is Alleima's trademark for improved machinability without compromising corrosion resistance or mechanical strength.
• Improved machinability achieved by optimized non-metallic inclusions, optimized chemical composition and optimized process/production parameters.
• Detailed cutting data recommendations are provided in brochure S-02909-ENG; a machining diagram (ranges for tool life ≥10 minutes) is supplied for turning, thread cutting, parting/grooving, drilling, milling and sawing.

Caractéristiques / spécifications techniques

• Commercial name: Sanmac® 316/316L
• Manufacturer / brand: Alleima
• Material type: Molybdenum-alloyed austenitic chromium-nickel steel
• EN numbers: 1.4401, 1.4404
• UNS: S31600, S31603
• Typical chemical composition (wt%): C ≤0.030; Si ≤0.75; Mn ≤2.00; P ≤0.040; S ≤0.030; Cr 16.5; Ni 11; Mo 2.1
• Density: 8.0 g/cm³
• Proof strength (20°C): Rp0.2 ≥220 MPa; Rp1.0 ≥250 MPa; Tensile 515–690 MPa; Elongation ≥45%
• Forms of supply: Hollow bar up to Ø250 mm OD (solution-annealed, white-pickled); also available in bar
• Typical tolerances (hollow bar): OD +2 / -0% (min +1 / -0 mm); ID +0 / -2% (min +0 / -1 mm); Straightness ±1.5 mm/m
• Heat treatment recommendations: Stress relieving 850–950°C; Solution annealing 1000–1100°C
• Recommended welding fillers: ER316L / E316L-17 (see welding section)