ASTM A194 43

Ideal for low temperature applications which require large diameter bolting.

ASTM A194 Grade 43 nuts are carbon steel high tensile nuts used in low temperature applications predominantly in the oil, gas, and petrochemical industries, used in conjunction with ASTM A320 L43 Studs or headed fasteners. 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 Fasteners Europe hold various options of ASTM A194 43 Grade nuts offering a standard product with the supplementary requirements of ASTM A194 or bespoke manufactured to the additional requirements of API 20E BSL 2 or 3.

ASTM A194 43: Forms

  LoneStar Manufacture 
Imperial Nuts – Heavy and Normal Series – Including ANSI B18.2.2
Metric Nuts – Regular and High types – Including DIN 934 H=D, ISO
Available with locking features

ASTM A194 43: Sizes and Threads

  LoneStar Manufacture 
Metric Coarse
Metric Fine
Imperial UNC
Imperial 8UN
Imperial UNF
Metric sizes available Up to M100 Up to M100
Imperial sizes available Up to 4.00″ Up to 4.00″

ASTM A194 43: Chemical Composition

Carbon 0.38 – 0.43
Manganese 0.60 – 0.85
Phosphorus 0.035 % Max
Sulphur 0.04 % Max
Silicon 0.15 – 0.35 %
Chromium 0.70 – 0.90 %
Nickel 1.65 – 2.00 %
Molybdenum 0.20 – 0.30 %

Mechanical Properties


Proof Load Hardness Hardness
Up to 4” Inc. ASTM A194 Table
3 + 4
248-327 HB 24-35 HRC

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