ASTM H12 Tool steel | 1.2605 | X35CrWMoV5 | SKD62 | BH12
AISI h12 Tool steel is a general hot work steel with 4.75~5.5% chromium content. H12 Tool steel contains less vanadium (0.2~0.5%) than H13 hot working Tool steel (0.8~1.2%), which is widely used. ASTM/AISI H12 steel is a deep hardening, air hardening steel with minimal dimensional changes during heat treatment. H12 Tool steel has good resistance to thermal fatigue cracking (hot cracking) and excellent resistance to large cracking and Thermal shock when water-cooled in use. Therefore, it can be said that H-12 Tool steel mainly has the following characteristics:
Excellent wear resistance, high strength at high temperatures.
Good homogeneity and high toughness.
Ultrafine structure without grain boundary carbides.
The shape of inclusions is controllable and the cleanliness is high.
Material number: 1.2605
EN grade: X35CrWMoV5
Executive standard: ENISO4957 Tool steel
H12 Tool Steel Chemical composition:
C0.32-0.4
Si0.8-1.2
Mn0.2-0.5
Pmax0.03
Smax0.02
Cr4.75-5.5
Mo1.25-1.6
W1.1-1.6
V0.2-0.5
Hardness HB: 229
Mechanical properties of hot working Tool steel
Elastic modulus [103 x N/mm2]: 207
Density [g/cm3]: 7.84
Thermal conductivity coefficient [W/mK]: 18.9
Linear thermal expansion coefficient 10-6 oC-1
Heat treatment of Tool steel
annealing
Slowly and evenly heat H-12 steel to 845-900 ℃, and furnace cool it to 540 ℃ at a rate of 10-20 ℃/hr. Hardness HB 229 max
Stress relief
The stress relief of processing stress should be carried out by heating H12 steel to about 650oC, holding it for 1-2 hours, and then air cooling. Perform this operation to reduce deformation during heat treatment.
Hardening
Preheating (1): Heat H-12 steel to approximately 540~650 ℃ and hold for 30 minutes every 25mm.
Preheating (2): Heat H12 Tool steel to about 845~870 ℃, and keep it for 30 minutes every 25 mm.
Austenitization: Heat steel H12 to approximately 1010~1050 ℃ and hold for 30 minutes every 25mm.
Quenching: By oil or air.
tempering
Tempering temperature: 520-700oC, insulation for at least 2 hours, air cooled dual tempering.
Application of AISI H12 Tool steel
AISI H12 hot work Tool steel is typically used for Hot working applications that require maximum resistance to cracking. Typical applications of this type include:
Extrusion industry: Extrusion molds and liners, extrusion tools
Forging industry: forming molds, stamping molds
Die casting industry: hard alloy molds
Tool industry: hot punches, hot scissors, cold rolled direct rolls
