AISI 4145

Low alloy 4145: ASTM A29 (VO1.05)

General scope

AISI 4145 low alloy steel containing 0.20% Molybdenum is widely used particularly throughout oil patch applications. Similar to 4140 which has a lower carbon level it has improved hardenability and is more is commonly used in the higher strength ?110 KSI 0.2% PS condition.

Larger diameters are often supplied with higher Molybdenum level, 0.35% max and may be referred to as a "Drill Collar" analysis.

The hardenability limitations of this grade (depth to which it will harden / obtain the specified mechanical properties after heat treatment) must always be taken into account when designing and selecting equipment.

Chemical composition

C Si Mn P S Cr Mo Fe
Min 0.43 0.15 0.75 0.80 0.15 0.00
Max 0.48 0.35 1.00 0.035 0.040 1.10 0.25 0.00

Mechanical properties

Condition: Hardened and Tempered to 22 HRC max

U.T.S 100 KSI Min (689 N/mm2)
0.2% Proof Stress 80 KSI Min (551 N/mm2)
Elongation 20 %
Red of Area 40 %

Condition: Hardened and Tempered to 30-36 HRC max

NACE MR0175 limits the supply hardness to 22HRC max.
U.T.S 130 KSI Min (896 N/mm2)
0.2% Proof Stress 110 KSI Min (758 N/mm2)
Elongation 13 %
Red of Area 30 %
Size range: 1”∅ - 14”∅

Primarily manufactured in:

  • Dubai, UAE
  • Edmonton, Canada
  • Houston, Texas
  • Sheffield, England
  • Singapore