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Stainless steel · wrought
1.4401

X5CrNiMo17-12-2

STANDARDEN 10088-2 / -3FORMPlate, bar, forgingASTM A240 / A182316 · F316UNSS31600JISSUS 316

Molybdenum-bearing austenitic stainless steel. With 2–2.5% Mo it resists pitting in chloride environments markedly better than 304. The most widely used stainless grade for bodies, discs and stems of process valves.

Rp0.2 · MPa
≥ 220
Rm · MPa
520–670
TEMPERATURE
−196 … +538 °C
COST
Representative sample of 1.4401: machined top face and rolled side
REPRESENTATIVE IMAGE

Chemical composition

C≤ 0.07
Si≤ 1.00
Mn≤ 2.00
P≤ 0.045
S≤ 0.015
N≤ 0.10
Cr16.5–18.5
Mo2.00–2.50
Ni10.0–13.0

Cast analysis, %. In bar, controlled S 0.015–0.030 is permitted for machinability.

Mechanical properties

STANDARD · CONDITIONRp0.2 MPaRp1.0 MPaRm MPaA %KV J
EN 10088-2 · hot-rolled plate (P), t ≤ 75 mm220260520–6704560 (transverse)
EN 10088-3 · bar, t ≤ 160 mm200235500–70040100
ASTM A240 · 316 plate205—≥ 51540—

Room temperature, solution annealed (+AT). Transverse specimen in plate.

Minimum Rp0.2 at elevated temperature

EN · TEMPERATURE20 °C100 °C200 °C400 °C
Rp0.2 MPa220177147115

EN 10028-7 / EN 10088 values; the minimum proof strength used in pressure equipment design.

ASME B16.34 pressure-temperature ratings

CLASS · bar−29 … 38 °C100 °C200 °C300 °C400 °C500 °C
Class 15019.016.213.710.26.52.8
Class 30049.642.235.731.629.428.2
Class 60099.384.471.363.258.956.5
Class 900148.9126.6107.094.988.384.7
Class 1500248.2211.0178.3158.1147.2140.9
Class 2500413.7351.6297.2263.5245.3235.0

Standard class, bar. Material group: F316. Greyed values are outside the material's service range (−196 … +538 °C). Flanged-end ratings end at 538 °C.

Service temperature

This is the limit of the material itself. A valve's service temperature is usually set by the seal and seat materials; product pages give it for each seal option.

Physical properties and heat treatment

DENSITY
8.0 kg/dm³
MODULUS OF ELASTICITY (20 °C)
200 GPa
THERMAL EXPANSION (20–100 °C)
16.0 × 10⁻⁶ /K
THERMAL CONDUCTIVITY (20 °C)
15 W/m·K
SPECIFIC HEAT (20 °C)
500 J/kg·K
ELECTRICAL RESISTIVITY
0.75 µΩ·m
MAGNETISM
non-magnetic (solution annealed)
CRITICAL PITTING TEMPERATURE, CPT (TYPICAL)
20 ± 2 °C
HEAT TREATMENT
Solution annealing 1030–1110 °C (Outokumpu: 1070 ± 40 °C), water or air cooling.

Media suitability GENERAL TREND

Fresh water
Seawater
Steam
Hydrocarbons, oil
Dilute acid
Caustic
Air, gas
Low temperature

Emsal assessment. The final choice is made from corrosion tables, taking concentration, temperature, chloride content and flow velocity into account.

Strengths and weaknesses

Strengths

  • Markedly better pitting resistance than 304 in chloride environments
  • Retains toughness at cryogenic temperatures
  • Good weldability, no preheating required
  • Plate, bar, pipe, forging: readily available in every form

Weaknesses

  • Pitting and crevice corrosion remain a risk in warm seawater and high chlorides (PREN ≈ 24)
  • Stress corrosion cracking in chloride environments above 60 °C
  • Work-hardens during machining; machines more slowly than carbon steel
  • High thermal expansion, low thermal conductivity: distortion in welding

Manufacturing and use

ECONOMY
Medium. Depending on nickel and molybdenum prices, about 20–30% more expensive than 304; several times the price of carbon steel.
MANUFACTURING METHODS
Machining from hot-rolled plate (Emsal wafer check valve body) · Turning from bar: stem, disc, pin · Forged body and flange (ASTM A182 F316)
TYPICAL VALVE PARTS
Body · Disc · Stem · Bolts, nuts (A4) · Spring

Used in 61 Emsal products

Source: EN 10088-2 / -3. Values compiled and verified by Emsal Vana; for binding values, refer to the current edition of the standard and the material certificate.