LABELLE® SILICON #2
(AISI S5)
LaBelle Silicon #2 is a shock resisting tool steel capable of maximum toughness at relatively high hardness. It has excellent resistance to impact and battering, with good edge retention.
Typical Chemistry
Carbon 0.60%
Manganese 0.85%
Silicon 1.90%
Chromium 0.25%
Molybdenum 0.30%
Vanadium 0.20%
Typical Applications
Heading Tools Punches
Chisels Shear Blades
Rivet Sets Concrete Breakers
Stamps Hammers
Hand Tools
Hardening

Note: Full hardness will only be attained in sections less than a few inches thick.
Critical Temperature: 1410F(765C).
Preheat: 1250/1400F(675/760C)
High Heat: 1550/1650F(845/900C), hold 10/20 minutes at temperature. The low end of the temperature range is normally used for water-quenching; the high end of the range is normally used for oil quenching.
Quench: Quench in water or oil to hand warm, 150F(65C). For minimum distortion, parts may be removed from water or oil once they are below about 400F(205C), and air-cooled to hand warm.
Temper: 350/900F(175/480C); hold one hour per inch of thickness, two hours minimum, four hours preferred.
Typical Properties
Hardness and Impact Toughness Data
Oil quenched from 1650F(900C).
Tempering
Temperature
Hardness
HRC
Toughness,
Charpy C-Notch
°F
°C
ft-lbs
Joules
As Quenched 60-61 –
300 150 60-61 49 66
400 205 58-60 138 187
500 260 58-59 146 198
600 315 57-58 142 193
700 370 56-57 156 212
800 425 51-52 –
900 480 47-48 –
1000 540 44-45 –
Water quenched from 1600F(870C).
Tempered
Hardness
HRC
°F
°C
As Quenched 64-65
300 150 60-61
400 205 59-60
500 260 59-60
600 315 57-58
700 370 56-57
800 425 51-52
900 480 48-49
1000 540 44-45
Surface Treatments
LaBelle Silicon #2 can be given standard surface treatments such as hard chrome plating if desired. Nitriding is not generally practical due to a substantial loss of core hardness.

Annealing
A. Heat to 1425/1450F(775/790C), hold two hours, cool slowly, 50F(30C) per hour maximum, to below 1100F(540C), then air cool.
OR
B. Heat to 1425/1450F(775/790C), hold two hours, cool to 1250/1300F(675/705C), hold 4 hours, then air cool.

Typical annealed hardness: 187/235 BHN

Stress Relieving
Annealed Material: 1100/1300F(595/740C), hold 2 hours, cool in still air.
Hardened Material: 50F(30C) below last tempering temperature, hold two hour, cool in still air.

Welding
Use shock resisting (S2, S5, S7) tool steel filler material.
Annealed material: Preheat to 400/600F(205/315C). Maintain over 400F(205C) during welding. Allow to cool to hand warm (150F(65C) after welding. Reanneal, or temper 1250/1300F(675/705C) for 4 hours.
Hardened material: Preheat to 50F(30 C) below tempering temperature (300F(150C) minimum). Maintain over 300F(150C) during welding. Allow to cool to hand warm (150F(65C)) after welding. Retemper at 25/50F(15/30) below original tempering temperature.

Physical Properties
Modulus of Elasticity ...................................................................30 psi x 106 (207 GPa)
Density .......................................................................................0.280 lb/in3 (7760 kg/m3)
Specific gravity ..............................................................................................................7.76
Thermal Conductivity ....(Approximate).... 19 BTU/hr/ft/°F(200F) .... 33 W/m°K(95C)
Thermal Expansion
Temperature
Range
Coefficient of Thermal
Expansion
°F
°C
in/in/°Fx10-6
mm/mm/°Cx10-6
RT/800
RT/425
7.0
12.6
RT/1000
RT/540
7.4
13.3
RT/1200
RT/650
7.6
13.7
Return to top of page