H11 Tool Steel

H-11 steel is an air hardening steel, also said as 5% chromium hot work tool steel. In comparison to H13 tool steel ,it is tougher and reduces temper resistance and wear resistance due to less vanadium content. The tools produced from H11 can be cooled using water without any damage as they have low carbon and alloy contents.

CHARACTERISTICS

excellent impact toughness
hot rigidity
abrasion resistant
high strength
high durability
good thermal conductivity
can hold a cutting edge
resistance to deformation at elevated temperature.
good resistance towards thermal fatigue cracking (while heat checking)
excellent resistance for thermal shock when water is cooled in service,good thermal physical phenomena

APPLICATIONS

extrusion process
hot work punches
liner holders
press forging(forging dies)
tool holders
die casting dies
shrink work chucks
hot gripper dies
bridge kind tools
aircraft landing gear
hot shear blades

TYPICAL ANALYSIS

Element	Content (%)
Carbon, C	0.33-0.43
Manganese, Mn	0.20-0.50
Silicon, Si	0.80-1.20
Chromium, Cr	4.75-5.50
Nickel, Ni	0.3
Molybdenum, Mo	1.10-1.60
Vanadium, V	0.30-0.60
Copper, Cu	0.25
Phosphorous, P	0.03
Sulphur, S	0.03
Iron, Fe	Balance

PHYSICAL PROPERTIES

Properties	Metric	Imperial
Density	7.81 g/cm³	0.282 lb/in³
Melting point	1427°C	2600°F

Coeficient of thermal expansionat °C	20-100	20-200	20-300	20-400	20-500	20-600	20-700
10^-6 m/(m*K)	11.7	12.3	12.5	12.7	12.75	12.9	12.9

ThermalConductivity °C	20	350	700
*W/(mK)Annealed**	29.8	30.0	33.5
*W/(mK)Quenched & Tempered**	26.7	27.4	30.4

Mechanical Properties

Longitudinal Tensile Properties

Property	Value
Tensile Strength	260 ksi
Yield Strength at 0.2% Offset	215 ksi
Elongation in 4D	8%
Reduction of Area	30%

Transverse Tensile Properties

Property	Value
Tensile Strength	260 ksi
Yield Strength at 0.2% Offset	215 ksi
Reduction of Area
Individual Value	6%
Average Value	15%

Thermal Properties

Properties	Metric	Imperial
Thermal expansion (@20-100ºC/68-212ºF)	11.9 x 10^-6/ºC	6.63 µin/in°F
Thermal conductivity (@100ºC/212ºF)	42.2 W/mK	292.9 in/hr.ft².°F

Heat Treatment

Soft annealing °C	Cooling	Hardness HB
750 – 800	Furnace	max. 230

Stress-relief annealing °C	Cooling
approx. 600 – 650	Furnace

Hardening °C	Quenching	Hardness after quenching HRC
1000 – 1030	Air ,oil or saltbath, 500 – 550 °C	54

T Tempering °C	100	200	300	400	500	550	600	650	700
HR HRC	52	52	52	52	54	53	48	37	31

Forming

It is done using conventional methods,i.e.,machining and forging.

Welding

It is done by conventional methods.

Heat Treatment

H11 tools are to be preheated to 816°C (1500°F) and then heated by increasing the temperature to 1010°C (1850°F) ,holding it for 15 -40 mins. Air-quenching is performed after heating.

Forging

Forging is done at 1121°C (2050°F).Forging below 899°C (1650°F) is not preferable.

Cold Working

Can be done using conventional methods.

Annealing

Annealing is done at 871°C (1600°F) and slowly cooled down in the furnace at 4°C (40°F) .

Tempering

Tempering is done between 538 to 649°C (1000 to 1200°F) for obtaining Rockwell C hardness of 54 – 38. Double tempering can be done also ,every one hour at preferred tempering temperature.

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