4140/4142

Alloy AISI/SAE 4140/ 4142
(UNS G 41400/G 41442)
Chromium-Molybdenum Alloy Machinery Steel
Typical Analysis
4140
C Mn P S Si Cr Mo
.40 .85 .020 .025 .25 .90 .20
4142
C Mn P S Si Cr Mo
.42 .85 .006 .005 .28 1.02 .22
Characteristics
  • These chromium-molybdenum alloys are among the most widely used and versatile machinery steels. The chromium content provides good hardness penetration and the molybdenum imparts uniformity of hardness and strength. They respond readily to heat treatment and tensile strengths in order of 170,000 psi (1172 N/mm2) for small sections and 140,000 psi (965 N/mm2) for larger sections are attainable, all combined with good ductility and resistance to shock. They may be used in both high and low temperature applications and also in sour gas environments with appropriate heat treatments.
  • In the hardened and tempered condition these steels possess good wear resistance which may be considerably increased by flame or induction hardening. Alternatively, they may be nitrided. In the annealed condition, bars are supplied to a hardness of HB 207 approximately. Some sizes may be calcium treated. The 4140 Product is also available in a precision ground surface finish (25RMS Max).
Typical Applications
  • Shafts, gears, bolts, studs, connecting rods, spindles, tool holders. A wide variety of "oil patch" applications, drill collars, Kelly bars, tool joints, subs, couplings etc.
Typical Heat Treatment
  • Forging
    • Commence 1200℃ max.
    • Finish 950℃
  • Annealing
    • 815℃/ 850℃ Cool slowly in furnace
  • Normalizing
    • 870℃/ 900℃ Cool in air
  • Hardened & Tempered: 820℃/ 870℃ Oil quench; Tempering Not usually below 430℃ and up to 700℃ according to the properties required.
Mechanical Properties
  • Annealed:
  • Tensile Strength (min) - 100,000 psi
  • Elongation (min) - 18%
  • Reduction of Area (min) - 50%
  • Hardness: 22RC max
  • Charpy V-Notch at -50˚F – 20 FT LBS average- Minimum15 FT LB
  • Reduction Ratio – Minimum 4:1
Alloy AISI/SAE 4140/ 4142
(UNS G 41400/G 41442)
Mechanical Properties
  • Heat treated to HRC 22 maximum for sour gas service. Minimum tempering temp 1150˚ F. Conforms to NACE Standard MR01-75. Also meets the tensile requirements of L80 as below
  • Heat Treated and Stress Relieved to requirements of ASTMA434CLBC/ BD ≥3" To 9 1/2" Dia, minimum values
Size - inches 3 ¾" Dia 5 ¾" Dia 9.5" Dia
Spec
BC BD
BC BD
BC BD
Tensile Strength, psi
115K 140K
110K 135K
105K 130K
Yield Strength, psi
95K 110K
85K 105K
80K 100K
Elongation (%)
16 14
16 14
15 14
Reduction of Area (%)
45 35
45 35
40 35
Alloy AISI/SAE 4140/ 4142
(UNS G 41400/G 41442)
Mechanical Properties
  • Annealed - Typical
Size - inches 1" Dia 2" Dia 4" Dia 8" Dia
Tensile Strength, psi 98,000 102,000 101,000 100,000
Yield Strength, psi 61,000 62,000 57,000 58,500
Elongation (%) 23 26 25 21
Reduction of Area (%) 54 55 56 59
HB 197 212 202 197
Machinability 66 66 66 66
Alloy AISI/SAE 4140/ 4142
(UNS G 41400/G 41442)
Mechanical Properties
  • Heat treated to requirements of ASTM A.193 Grade B7 – Up to 2.5" Diameter, Minimum Values
Size - inches Up to 2 ½" Dia 2 ½" to 4"
Tensile Strength, psi 125,000 115,000
Yield Strength, psi 105,000 95,000
Elongation (%) 16 16
Reduction of Area (%) 50 50
HB (Max) 321 115,000

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