HALCOMB® 218
(AISI H11)
Halcomb 218 is a general purpose hot work tool steel, combining good toughness with moderate high-temperature strength and heat check resistance. Because of its high toughness, it is particularly suited for applications where drastic coolants are used, or where gross cracking resistance is a concern.
Typical Chemistry
Carbon 0.40%
Manganese 0.30%
Silicon 0.90%
Chromium 5.00%
Molybdenum 1.30%
Vanadium 0.50%
Typical Applications
Extrusion Tooling Forging Dies
Hot Upset Dies Die Casting Dies
Die Inserts
Hardening

Critical Temperature: 1505F

Preheat: 1100/1200F, equalize, 1400/1500F, equalize.

High Heat: 1800/1875F, hold 30/45 minutes at temperature.

Quench: Air, positive pressure vacuum, salt, or interrupted oil to 125/150F.

Temper: 1000/1200F, hold one hour per inch of thickness (two hours minimum). Temper twice.
Typical Properties
Air cooled from 1850F, triple tempered as shown.
Tempering
Temperature °F
 Hardness
HRC
 CVN
1000 52-54 13
1050 46-48 18
1100 40-43 23
1150 34-36 —
1200 26-28 —
Effect of Temperature on Impact Properties
Air cooled from 1850F, double tempered to original hardness indicated, tested at elevated temperature as shown.
Original RT
HRC
 Charpy V-Notch at (°F)
RT
 500
 1000
 1100F
54 13 18 20 —
48 18 28 31 30
42 23 43 47 —
Surface Treatments
Because of its high tempering temperatures (>1000F), Halcomb 218 may be treated by most surface treating processes, including conventional and ion nitriding, titanium nitriding, and other coatings or treatments. Nitrided surface hardness will be about 60/65 HRC.

Annealing
Heat to 1600F. Hold 2 hours at temperature. Cool slowly (50F per hour maximum) to 1200F, then air cool to room temperature.
or
Heat to 1600F. Hold 2 hours at temperature. Cool to 1400F. Hold 6 hours at temperature, then air cool to room temperature.

Typical annealed hardness: 192/235 BHN.

Stress Relieving
Annealed material: Heat uniformly to 1200/1250F, hold two hours at temperature, cool in still air to room temperature.
Hardened material: Heat uniformly to 25/50F below tempering temperature, hold two hours, cool in still air to room temperature.

Welding
Use H11 or other hot work tool steel filler material.
Annealed material: Preheat to 800/1000F. Maintain above 700F during welding. Reanneal, or temper 1400F 6 hours.
Hardened material: Preheat to 800/1000F. Maintain above 700F during welding. Allow to cool to hand warm (150F) after welding. Retemper at 25/50F below original tempering temperature (1000F minimum).

Physical Properties
Modulus of Elasticity ................................................................30 psi x 106
Density ......................................................................................0.280 lbs/in3
Thermal Conductivity ....................200F.............................15 BTU/hr/ft/°F
                                       .....................600F .............................16 BTU/hr/ft/°F
Thermal Expansion
        RT-200F ......................................................................5.8 x 10-6 in/in/°F
        RT-400F ......................................................................6.3 x 10-6 in/in/°F
        RT-800F ......................................................................6.9 x 10-6 in/in/°F
        RT-1000F ....................................................................7.1 x 10-6 in/in/°F
        RT - 1200F ..................................................................7.3 x 10-6 in/in/°F
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