4145 Drill Collar Bars

AISI 4145 H MODIFIED HTSR Solid Drill Collars to API Spec 7
Typical Analysis
4" - 6 ¼" dia
C Mn P+S Si Cr Mo
.42/.49 .80/1.10 .025Max .15/.35 .75/1.20 .15/.25
6 ⅜" - 7" Dia
C Mn P+S Si Cr Mo
.42/.49 .85/1.15 .025Max .15/.35 .85/1.15 .25/.35
7 ⅛" - 10" Dia
C Mn P+S Si Cr Mo
.42/.49 .85/1.20 .025Max .15/.35 .85/1.15 .25/.35
10 ⅛" - 11" Dia
C Mn P+S Si Cr Mo
.42/.49 .85/1.30 .025Max .15/.35 1.00/1.30 .25/.35
Characteristics
  • Drill collar bars are usually supplied in lengths of 31'0"/31'6" with a straightness tolerance of 125" in 5 ft. The heat treatment is by water quenching, tempering and stress relieving to the mechanical properties detailed below. Tensile and impact specimens are taken within 3 ft. of the end of the bar and at 1" below the surface. Tensile and impact testing is determined on the basis of one test per 10 bars per heat, per heat treatment lot. Bars are surface hardness tested at both ends, 9 ft. from each end. All bars are individually identified.
AISI 4145 H MODIFIED HTSR Mechanical Properties
  • Typical
Size - inches 4 ¾" Dia 6 ½" Dia
Tensile Strength, psi 156,509 148,884
Yield Strength, psi 137,452 126,020
Elongation (%) 19.6 18.6
Charpy V-Notch Ft/lb/J 52-52-51 ft/lbs 50-51-52 ft/lbs
Hardness HB 311 302
AISI 4145 H MODIFIED HTSR Mechanical Properties
  • Specified
Size - inches Through 6 ⅞" Dia Over 6 ⅞" Dia
Tensile Strength, psi 140,00 135,000
Tensile Strength, N/mm² 965 930
Yield Strength, psi 110,000 100,000
Yield Strength, N/mm² 759 689
Elongation (%) 13 13
Impact values at R.T
Izod ft/lbs/Joules
Charpy V-Notch Ft/lb/J 40/54 Min 40/54 Min
Hardness HB 40/54 Min 40/54 Min
⅛" below surface 285/ 341 285/ 341
1" below surface 285 Min 285 Min

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