ASTM A320 L43

Ideal for large-diameter bolting and low-temperature environments within the oil and gas industry.

ASTM A320 L43 Grade is manufactured from AISI 4340 base material and is supplied in a quenched and tempered condition. It is mainly used for large-diameter bolting, predominantly between 2 ½” and 4” diameter throughout the oil and gas industry in low-temperature environments.

Lonestar can offer this material in a standard condition, or it can be provided with supplementary testing as defined in ASTM A320. This material can also be offered fully in compliance with the additional requirements of API 20E BSL 2 and 3.


ASTM A320 L43: Forms

  LoneStar Manufacture 
Stud Bolts
Hexagon Headed Bolting
Socket Headed Bolting
Double Ended and Waisted Studs
Associated OEM Parts

ASTM A320 L43: Sizes and Threads 

  LoneStar Manufacture 
Metric Coarse
Metric Fine
Imperial UNC
Imperial 8UN
Imperial UNF
Metric sizes available Up to M100
Imperial sizes available Up to 6.00″

ASTM A320 L43: Chemical Composition

Carbon 0.38-0.43
Manganese 0.60-0.85
Phosphorus 0.035 % Max
Sulphur 0.040 % Max
Silicon 0.15-0.35
Chromium 0.70-0.90 %
Nickel 1.65-2.00 %
Molybdenum 0.50-0.30 %

ASTM A320 L43: Mechanical Properties

Over 2.1/2″ to 4″ Over 4”
Tensile Strength Min, Ksi (MPa) 125 (860) 100
Yield Strength  min, 0.2% offset Ksi (MPa) 105 (725) 85
Elongation in min% 16 16
Reduction of Area min% 50 45
Hardness Max 321 HBW 321 HBW
Hardness Max 35 HRC 35 HRC

ASTM A320 L43: Impact Properties

Test Temperature °F (°C) -150 (-101)
Average impact toughness, min, ft-lbf (J) 20 (27)
Average impact toughness, min, ft-lbf (J) 15 (20)

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