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Hot Rolled (Also available in DCF)
This medium carbon alloy grade is widely used for many general purpose parts requiring high tensile strength and toughness. 4140 contains chromium and molybdenum as alloying elements and may be heat treated over a wide range to give the combined advantages of proper hardness, strength and ductility. In conditions where localized hardness may be required, this steel is readily flame or induction hardened.
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TYPICAL ANALYSIS |
AISI 4140 |
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Carbon (C) |
,38/.43 |
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Manganese (Mn) |
.75/1.00 |
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Silicon (Si) |
.15/.30 |
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Tungsten (W) |
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Molybdenum (Mo) |
.15/.25 |
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Chromium (Cr) |
.80/1.10 |
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Phosphorus (P) |
.035 MAX |
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Sulphur (S) |
.040 MAX |
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FORGING (a)
Start forging at
Do not forae below |
2000-2200° F
(1100-1200° C)
1800° F(980°C) |
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NORMALIZING (b)
(871 -899° C) |
1600-1650° F |
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ANNEALING (c)
Temperature
Rate of cooling, max. per hour
Typical annealed hardness, Brinell |
1500-1550° F
(816-843° C)
212 |
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HARDENING
Rate of heating
Preheat temperature
Hardening temperature
Time at temperature, minutes
Quenching medium |
Slowly
1500-1550° F
(816-843° C)
0(l) |
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WEAR RESISTANCE |
Medium |
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TOUGHNESS |
Very High |
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RESISTANCE TO SOFTENING EFFECT OF ELEVATED
TEMPERATURE |
Low |
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DEPTH OF HARDENING |
Medium |
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MACHINABILITY |
Medium |
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GRINDABILITY |
High |
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DISTORTION IN HEAT TREATING |
Medium |
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SAFETY IN HARDENING |
Low |
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RESISTANCE TO DECARBURIZATION |
Medium |
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