SMLS PIPE AISI 4145H For Drill Pipe

AISI 4145H is a chromium-molybdenum medium-carbon alloy steel. The "H" suffix stands for Hardenability, indicating that the steel is manufactured to meet specific Jominy hardenability band requirements. This ensures that the material achieves uniform hardness and strength even across large cross-sections.

In the drilling industry, AISI 4145H is the industry standard for manufacturing Drill Collars, Heavy Weight Drill Pipes (HWDP), and Tool Joints. Its high fatigue strength and impact toughness allow it to withstand extreme torque, high tensile loads, and harsh downhole vibrations.

Ensure your drill string's integrity with API 7-1 certified AISI 4145H seamless pipes. Request a full compliance and mill test report today.

Specification: SMLS PIPE AISI 4145H

Chemical Composition of AISI 4145H

Mechanical Properties of AISI 4145H

Measured in the Quenched & Tempered (Q+T) condition for sections ≤ 5" thickness.

Tolerance for Seamless Tubing

Based on ASTM A519 and API 7-1 standards, the typical tolerances for AISI 4145H seamless tubes are:

Outer Diameter (OD):

OD ≤ 2.5": ±0.015" (0.38mm)

OD 2.5" - 6": ±0.030" (0.76mm)

OD > 6": ±0.05% to ±1% of nominal OD

Wall Thickness:

Typically ±10% of nominal thickness or +12.5% / -10%.

Straightness:

For drill collars and pipe, strict straightness is required, usually not exceeding 1.6mm per 1000mm (0.019 in/ft).

Comparison With Similar Materials

Applications: SMLS PIPE AISI 4145H

Due to its high strength and superior fatigue resistance, this material is primarily used for:

Drill Collars: Providing weight-on-bit (WOB) and maintaining the direction of the drill bit.

Heavy Weight Drill Pipe (HWDP): Serving as a transition between thin-walled drill pipe and heavy drill collars.

Tool Joints: The threaded ends of drill pipe that must withstand high-frequency make-and-break cycles.

Stabilizers and Reamers: Downhole tools used to stabilize the drill string and maintain wellbore diameter.

Fishing Tools: High-strength recovery tools used to retrieve lost equipment from the wellbore.

AISI 4145H Drill Pipe Processing 

AISI 4145H Drill Pipe certificate

FAQ

What is aisi 4145H equivalent to?

AISI 4145H does not have a "perfect" 1:1 match in all international systems because of its specific carbon range (0.43-0.48%), but the following are the closest functional equivalents:

European Standard (EN/DIN): 42CrMo4 (Material No: 1.7225) - Note: This is the most common commercial equivalent.

Chinese Standard (GB): 42CrMo or 45CrMo.

Japanese Standard (JIS): SCM445 (or SCM445H).

British Standard (BS): 708M40 (closely related to the old EN19).

What is the difference between AISI 4145 and 4145H?

The main difference is the "H", which stands for Hardenability.

AISI 4145: Only specifies the chemical composition (the ingredients). There is no guarantee of how deep or consistently the steel will harden during heat treatment.

AISI 4145H: Specifies both the chemical composition and guaranteed hardenability. It must pass a Jominy end-quench test to prove that it will reach a specific hardness at a certain depth.

Is AISI 4145H Steel Corrosion Resistant?

No. AISI 4145H is a low-alloy steel, not a corrosion-resistant (stainless) steel.

Rusts easily: It will rust and corrode when exposed to moisture, oxygen, or salt water.

Low Chromium: It contains only about 1% Chromium, whereas true "corrosion-resistant" stainless steels require at least 10.5% Chromium.

Protection needed: In oilfield applications, it must be protected by specialized coatings, corrosion inhibitors, or specific heat treatments (for "Sour Service") to survive in harsh environments.

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