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C80W1 (Tool / Spring)

C80 / C80W1 — highest-carbon unalloyed steel. Water-hardening (W1). For hand tools, chisels, saw blades and flat springs with HRC 60-65.

Carbon Steels High Carbon Spring/Tool Steel EN ISO 4957C80W1 / 1.1525 DINC80W1 / 1.1525 AISI/SAEW1 (water-hardening) ASTMA686 Grade W1-0.80C +6
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Description

C80W1 per EN ISO 4957 / DIN (1.1525). Water-hardening tool steel with 0.75-0.85% C. Low cost, simple heat treatment. Excellent hardness (HRC 62-66) but very limited hardenability — only thin sections harden through. Standard for hand tools, chisels, wood-cutting tools, files and agricultural blades. Per EN ISO 4957.

Key Properties — Annealed
Hardness
— – 229
HB
E (Young's Modulus)
210
GPa
Density
7.83
g/cm³
Main Designations (10)
Standard BodyDesignationCountry / RegionNote
EN ISO 4957 C80W1 / 1.1525 EU
DIN C80W1 / 1.1525 Germany
AISI/SAE W1 (water-hardening) USA
ASTM A686 Grade W1-0.80C USA
BS BW1A UK
JIS SK5 Japan
GOST U8A (U8A) Russia
UNS T72301 USA (UNS)
GB T8A China
JUS C.7010 Yugoslavia Unalloyed tool steel; JUS C.B5.010
Standards (10)
#Standard BodyDesignationCountry / RegionNote
1 EN ISO 4957 C80W1 / 1.1525 EU —
2 DIN C80W1 / 1.1525 Germany —
3 AISI/SAE W1 (water-hardening) USA —
4 ASTM A686 Grade W1-0.80C USA —
5 BS BW1A UK —
6 JIS SK5 Japan —
7 GOST U8A (U8A) Russia —
8 UNS T72301 USA (UNS) —
9 GB T8A China —
10 JUS C.7010 Yugoslavia Unalloyed tool steel; JUS C.B5.010
All values in wt.%
C
Carbon
0.7500 – 0.8500
Si
Silicon
0.1000 – 0.3500
Mn
Manganese
0.1000 – 0.4000
P
Phosphorus
≤ 0.0250
ElementSymbolMin %Max %Typical %
Carbon C 0.7500 0.8500 0.8000
Silicon Si 0.1000 0.3500 0.2000
Manganese Mn 0.1000 0.4000 0.2500
Phosphorus P — 0.0250 —
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 — — — — — — — — 229 — — 210.0
H+T 150 C H+T — — — — — — — — — 62.0 66.0 210.0
Physical Properties
Density
7.830
g/cm³
Melting Point
1410–1450
°C
Young's Modulus
210.0
GPa
Poisson's Ratio
0.295
—
Thermal Conductivity
48.0
W/m·K
Thermal Expansion
11.00
×10⁻⁶ /K
Specific Heat
460
J/kg·K
Electrical Resistivity
0.1850
µΩ·m
Magnetic
Yes
 
Heat Treatment
Spheroidising Anneal
Temperature:680°C – 710°C
Medium:Furnace
Duration:4-6 h
Cooling:<=15 C/h
Hardness After:<=HB 220
Before machining.
Austenitizing
Temperature:780°C – 820°C
Medium:Water (1-3% NaCl brine) for thin / Oil for thick
Duration:10-20 min
Cooling:Water or oil quench
Hardness After:HRC 62-66 (before temper)
Harden only sections <25 mm through. Water quench — extreme cracking risk on complex shapes.
Tempering
Temperature:150°C – 200°C
Medium:Air oven
Duration:2x2h
Cooling:Air cool
Hardness After:HRC 60-64
Double temper.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
35.0%
Very Difficult
Turning Speed (HSS)
15
m/min
Turning Speed (Carbide)
80
m/min
Feed Rate (Turning)
0.100
mm/rev
Drilling Speed (HSS)
8
m/min
Milling Speed (Carbide)
85
m/min
CoolantSoluble oil 8-12%
Chip FormationShort brittle chips
Tool MaterialCarbide K10/K20
Surface FinishRa 0.4-0.8 um
Machine in spheroidised condition. Very hard after hardening — grinding only.
Applications
Hand Tools
Chisels, punches, screwdrivers, cold chisels and mason chisels.
Cutting Tools
Wood saws, hacksaw blades and garden tool blades.
Agriculture
Hoe blades, spade tips and agricultural cultivator tools.
Technical Notes
⚠️
Water Quench Cracking
C80W1 MUST be water quenched for maximum hardness. Extreme cracking risk on all but simplest shapes. Always temper IMMEDIATELY after quench.
✅
Low Cost
C80W1 is one of the cheapest tool steels. Use for high-volume disposable tools. For anything requiring resharpening or complex shape: use O1 (90MnCrV8) instead.