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AISI H21
Category Steel
Class Tool steel
Type Tungsten hot work steel
Designations  France: AFNOR Z 30 WCV 9
Germany: DIN 1.2581
Italy: UNI X 28 W O9 KU
Japan: JIS SKD5
United Kingdom: B.S. BH 21
United States: ASTM A681 , FED QQ-T-570 , SAE J437 , SAE J438 , UNS T20821

Composition
ElementWeight %
C  0.26-036 
Mn  0.15-0.40 
Si  0.15-0.50 
Cr  3.00-3.75 
Ni  0.3 
W  8.50-10.00 
V  0.30-0.60 
Cu  0.25 
P  0.03 
S  0.03 

Mechanical Properties
Properties Conditions 
T (°C)Treatment
Density (×1000 kg/m3) 8.28 25  
Poisson's Ratio 0.27-0.30 25  
Elastic Modulus (GPa) 190-210 25  

Thermal Properties
Properties Conditions 
T (°C)Treatment
Thermal Expansion (10-6/ºC) 12.4  20-100 more  
Thermal Conductivity (W/m-K) 27  100 more  
Glossary