X20Cr13 (420)

Martensitic stainless steel hardenable to HRC 48-52. Used for cutlery, surgical instruments, turbine blades and pump shafts.

Stainless Steels Martensitic Stainless Steel ENX20Cr13 DIN1.4021 AISI/SAE420 ASTMA276 Type 420 +12
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Description

X20Cr13 (EN 1.4021 / AISI 420) per EN 10088. Can be hardened to HRC 48-52 by oil quenching from 1000-1050 C. Unique combination of moderate corrosion resistance and high hardness. Used for cutlery, surgical blades, pump shafts and valve stems.

Key Properties — Annealed
Rm (Tensile Strength)
700 – 900
MPa
Re / Rp0.2 (Yield)
500 – 700
MPa
A₅ (Elongation)
≥ 15.0
%
Hardness
— – 248
HB
E (Young's Modulus)
215
GPa
Density
7.73
g/cm³
Main Designations (16)
Standard BodyDesignationCountry / RegionNote
EN X20Cr13 European Union
DIN 1.4021 Germany
AISI/SAE 420 USA
ASTM A276 Type 420 USA
BS EN 420S29 UK
JIS SUS420J1 Japan
GOST 20X13 (20Kh13) Russia / CIS
UNI X20Cr13 Italy
NF Z20C13 France
SS 2303 Sweden
PN 2H13 Poland
CSN 17021 Czech Republic
UNS S42000 USA (UNS)
GB 20Cr13 China
JUS C.4172 Yugoslavia / Serbia Martensitic Cr stainless, hardenable; JUS C.B2.070
ISO X20Cr13 International
Standards (16)
#Standard BodyDesignationCountry / RegionNote
1 EN X20Cr13 European Union
2 DIN 1.4021 Germany
3 AISI/SAE 420 USA
4 ASTM A276 Type 420 USA
5 BS EN 420S29 UK
6 JIS SUS420J1 Japan
7 GOST 20X13 (20Kh13) Russia / CIS
8 UNI X20Cr13 Italy
9 NF Z20C13 France
10 SS 2303 Sweden
11 PN 2H13 Poland
12 CSN 17021 Czech Republic
13 UNS S42000 USA (UNS)
14 GB 20Cr13 China
15 JUS C.4172 Yugoslavia / Serbia Martensitic Cr stainless, hardenable; JUS C.B2.070
16 ISO X20Cr13 International
All values in wt.%
C
Carbon
0.1600 – 0.2500
Si
Silicon
≤ 1.0000
Mn
Manganese
≤ 1.5000
Cr
Chromium
12.0000 – 14.0000
ElementSymbolMin %Max %Typical %
Carbon C 0.1600 0.2500 0.2000
Silicon Si 1.0000 0.5000
Manganese Mn 1.5000 0.6000
Chromium Cr 12.0000 14.0000 13.0000
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
Annealed +A 700 900 500 700 15.0 40.0 248 215.0
Hardened (oil quench) H 48.0 52.0 215.0
Q+T 600 C (engineering) +QT600 700 900 550 750 16.0 50.0 220 265 215.0
Physical Properties
Density
7.730
g/cm³
Melting Point
1460–1510
°C
Young's Modulus
215.0
GPa
Poisson's Ratio
0.280
Thermal Conductivity
29.0
W/m·K
Thermal Expansion
10.50
×10⁻⁶ /K
Specific Heat
460
J/kg·K
Electrical Resistivity
0.6500
µΩ·m
Magnetic
Yes
 
Heat Treatment
Annealing
Temperature:800°C – 850°C
Medium:Furnace
Duration:3-5 h
Cooling:<=30 C/h
Hardness After:<=HB 248
For best machinability.
Austenitizing
Temperature:1000°C – 1050°C
Medium:Oil (preferred) or air
Duration:20-30 min
Cooling:Rapid quench
Hardness After:HRC 48-52
Pre-heat to 750 C first.
Tempering (cutlery)
Temperature:150°C – 250°C
Medium:Air or oil
Duration:1-2 h
Cooling:Air cool
Hardness After:HRC 46-52
High hardness for cutting edge retention.
Tempering (engineering)
Temperature:580°C – 650°C
Medium:Air
Duration:2 h
Cooling:Air cool
Hardness After:HB 220-270
Balances hardness with corrosion resistance.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
52.0%
Difficult
Turning Speed (HSS)
32
m/min
Turning Speed (Carbide)
155
m/min
Feed Rate (Turning)
0.180
mm/rev
Drilling Speed (HSS)
22
m/min
Milling Speed (Carbide)
160
m/min
CoolantSoluble oil 8-10%
Chip FormationShort-medium chips
Tool MaterialCarbide M10/P20
Surface FinishRa 0.4-1.6 um
Machine in annealed condition. Easier than austenitics.
Applications
Cutlery & Blades
Kitchen knives, cutlery, surgical scalpels and industrial cutting blades.
Pumps & Valves
Pump shafts, valve stems and piston rods.
Turbines
Steam turbine blading (low-pressure stages) and compressor components.
Technical Notes
💧
Corrosion Resistance
Significantly less than 304/316 in hardened condition. NOT suitable for seawater.
420 vs 440C
440C gives HRC 56-60 with better edge retention but less toughness and harder to grind vs 420.