4140 Steel Machining

Steel 4140

Steel alloy 4140 cold roll is a popular general-purpose alloy, ideal for parts that require high tensile strength and toughness. It has considerable atmospheric corrosion and wear resistance, and will not become brittle.

4140 has a machining cost factor of 2.9 when compared to steel 12L14. It is not ideal for welding due to its lead content. It is often used for forging, responds very well to heat treatment, and can be annealed.

Industries & Applications

  • Gears
  • Shafts
  • Bolts and nuts
  • Pins
  • Pump and valve components

Steel Parts Gallery

Steel 4140 Characteristics

TEMPER Yield Strength (ksi) Ultimate Tensile Strength (ksi) Modulus of Elasticity (ksi) Brinell Hardness (500km/10mm)

Annealed

96

130

30,000

200

Quenched and Tempered

140

160

30,000

310

Normalized

96

150

30,000

300

 

Steel Cost Comparison

Type General Characteristics Alloy Common Applications Tolerances for a 1/2" Dia. Bar Material Cost Factor Machining Cost Factor
Steel
Popular general-purpose alloy. Direct hardening
4140 or 4142
Gears, shafts, pins, bolts and nuts, pump and valve components
Cold drawn
0
1.1 2.9

Common Material Cost Comparison

Type General Characteristics Alloy Common Applications Tolerances for a 1/2" Dia. Bar Material Cost Factor Machining Cost Factor
Steel
Designed for excellent machinability. Case hard only
12L14
Endless commercial products; probably more pounds used in turned products than any other bar stock
Cold drawn
0
1 1
Stainless Steel
Designed for machining, non-magnetic
303
Electronic hardware, automotive, aerospace, medical instruments, and many applications requiring corrosion resistance
Cold finished
+/- .002
1.9 2.7
Brass
Strength, corrosion and wear resistance, and excellent machinability
C35300
Well suited for parts with knurling or threading
+0015 3.5 .07
Aluminum
Designed for machining
2011
Electronic hardware, endless commercial products
Cold finish
+/-.0015
3.8 .6
Titanium
High strength, light weight, good bio-compatibility
Ti-6Al-4VEli
Medical implants
Ground & polished
+/-.002
30.2 6

To review our Machining Materials Guide, please click here.

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