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X3CrNiMo13-4

13/4 supermartensitic stainless — Rm 830-1000 MPa. Excellent toughness at high strength. Standard for hydraulic turbine runners, pump impellers and offshore valve bodies.

Stainless Steels Martensitic Stainless Steel ENX3CrNiMo13-4 / 1.4313 DIN1.4313 ASTMA743 Grade CA-6NM (cast equiv) UNSS41500 +4
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Description

X3CrNiMo13-4 (EN 1.4313) per EN 10088. Low-carbon Ni-Mo martensitic stainless. Rm 830-1000 MPa with outstanding toughness (KV >100 J at -40 C) — significantly better than standard 410/431. Excellent resistance to cavitation erosion. Standard material for hydraulic turbine runners (Francis, Pelton), large pump impellers and offshore valve bodies requiring both corrosion resistance and high toughness.

Key Properties — Q+T (standard)
Rm (Tensile Strength)
830 – 1,000
MPa
Re / Rp0.2 (Yield)
620 – 800
MPa
A₅ (Elongation)
≥ 14.0
%
Hardness
— – 290
HB
E (Young's Modulus)
200
GPa
Density
7.75
g/cm³
Main Designations (8)
Standard BodyDesignationCountry / RegionNote
EN X3CrNiMo13-4 / 1.4313 EU
DIN 1.4313 Germany
ASTM A743 Grade CA-6NM (cast equiv) USA
UNS S41500 USA (UNS)
BS EN 1.4313 UK
JIS SUS403 (nearest) Japan
IEC IEC 60193 (hydraulic turbines) International
JUS C.4185 Yugoslavia Martensitic stainless for turbines; JUS C.B2.090
Standards (8)
#Standard BodyDesignationCountry / RegionNote
1 EN X3CrNiMo13-4 / 1.4313 EU —
2 DIN 1.4313 Germany —
3 ASTM A743 Grade CA-6NM (cast equiv) USA —
4 UNS S41500 USA (UNS) —
5 BS EN 1.4313 UK —
6 JIS SUS403 (nearest) Japan —
7 IEC IEC 60193 (hydraulic turbines) International —
8 JUS C.4185 Yugoslavia Martensitic stainless for turbines; JUS C.B2.090
All values in wt.%
C
Carbon
≤ 0.0500
Si
Silicon
≤ 0.7000
Mn
Manganese
≤ 1.5000
Cr
Chromium
12.0000 – 14.0000
Ni
Nickel
3.5000 – 4.5000
Mo
Molybdenum
0.3000 – 0.7000
ElementSymbolMin %Max %Typical %
Carbon C — 0.0500 0.0300
Silicon Si — 0.7000 0.4000
Manganese Mn — 1.5000 0.7000
Chromium Cr 12.0000 14.0000 13.0000
Nickel Ni 3.5000 4.5000 4.0000
Molybdenum Mo 0.3000 0.7000 0.5000
Mechanical Properties
ConditionCode Rm min
MPa		Rm max
MPa		 Re min
MPa		Re max
MPa		 A₅ min
%		 Z
%		 KV
J		 HB minHB max HRC minHRC max E
GPa
Q+T (standard) +QT 830 1,000 620 800 14.0 65.0 80.0 — 290 26.0 34.0 200.0
Q+T (high toughness) +QT-T 790 960 590 760 15.0 70.0 120.0 — 270 24.0 32.0 200.0
Physical Properties
Density
7.750
g/cm³
Melting Point
1400–1460
°C
Young's Modulus
200.0
GPa
Poisson's Ratio
0.280
—
Thermal Conductivity
24.0
W/m·K
Thermal Expansion
10.30
×10⁻⁶ /K
Specific Heat
462
J/kg·K
Electrical Resistivity
0.7000
µΩ·m
Magnetic
Yes
 
Heat Treatment
Solution Anneal (normalising)
Temperature:950°C – 1050°C
Medium:Air cool or oil
Duration:20-40 min
Cooling:Air cool
Hardness After:HRC 30-38
Softens martensitic structure.
Tempering
Temperature:580°C – 650°C
Medium:Furnace
Duration:2h min
Cooling:Air cool
Hardness After:HRC 24-34
Single temper. Double temper for large sections.
Sub-zero treatment (optional)
Temperature:-70°C
Medium:Dry ice bath
Duration:2h
Cooling:Air warm-up
Hardness After:Converts retained austenite
-70 C treatment for highest toughness in cryogenic service.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
50.0%
Difficult
Turning Speed (HSS)
28
m/min
Turning Speed (Carbide)
140
m/min
Feed Rate (Turning)
0.160
mm/rev
Drilling Speed (HSS)
22
m/min
Milling Speed (Carbide)
145
m/min
CoolantSoluble oil 8-10%
Chip FormationMedium-short chips
Tool MaterialCarbide M10/P20 TiAlN
Surface FinishRa 0.4-1.6 um
Machine in annealed. After Q+T: finish machining and grinding only.
Applications
Hydraulic Turbines
Francis, Pelton and Kaplan turbine runners, stay rings and guide vanes.
Pumps
Large pump impellers, diffusers and casings for water and slurry service.
Oil & Gas
Wellhead valve bodies, christmas tree components and choke bodies.
Technical Notes
✅
vs 410/431
X3CrNiMo13-4 has 3-4x higher impact toughness than standard 410/431 at same strength. Mandatory for cavitation-resistant turbine runners and any application requiring both high strength and low-temperature toughness.
💡
Cavitation Resistance
13/4 is the standard material for hydraulic turbine runners worldwide due to its combination of hardness (HRC 28-34) and toughness — key for resisting cavitation erosion.