4145H MOD Alloy Steel

4145H MOD Alloy Steel Drill Collars 4145h mod 4145H MOD Alloy Steel 4145H MOD Alloy Steel Drill Collars

4145H MOD Alloy Steel Drill Collars

4145H MOD Alloy Steel forged bar 4145h mod 4145H MOD Alloy Steel 4145H MOD Alloy Steel forged bar

4145H MOD Alloy Steel forged bar

4145H MOD Alloy Steel stabilizer 4145h mod 4145H MOD Alloy Steel 4145H MOD Alloy Steel stabilizer

4145H MOD Alloy Steel stabilizer


AISI 4145H MOD is a chromium molybdenum quality alloy steel specification. As a high tensile steel grade AISI 4145H MOD is primarily supplied in the hardened and tempered condition to 30-36HRc range to AISI 4145H MOD. With a slightly higher carbon content AISI 4145H MOD is similar to AISI 4140 in that it offers good ductility, shock resisting characteristics combined with resistance to wear.


AISI 4145H MOD Steel is commonly used for a variety of applications in the oil and gas sector. Used often for the manufacture of down hole drilling tools such as drill collars. Other applications include gears, shafts for hydraulic presses, rolls for paper mills, pump shafts and tool holders.

Quality Standard

ASTM A29 Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General
API 7 Specification for Rotary Drill Stem Elements.

Chemical Composition(%)

C Mn Si P S Cr Ni Mo
0.43-0.49 0.85-1.10 0.10-0.35 0.035 max 0.040 max 0.80-1.10 0.25 max 0.15-0.25


Produced by electric arc furnace, metallurgically treated in ladle furnace and vacuum degassed.


Grain Size: The austenitic grain size shall be 6-9 as defined in ASTM E-112.

Mechanical Property Requirements

Tensile Strength Rm (KSI) Yield Strength R2 (KSI) Elongation(%) Reduction Ration (%) Hardness (HRC)
140 min 120 min 14 min 40 min 30-36


Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of eachAISI 4145H MOD Steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of AISI 4145H MOD Steel.
Annealing: Heat the steel slowly to 800-850°C and allow enough time for the steel to be thoroughly heated. Cool slowly in the furnace to 480°C followed by air cooling.
Stress Relieving: When parts are heavily machined, ground or otherwise subject to cold work, stress relieving will be beneficial prior to hardening.
Hardening: AISI 4145H MOD Steel is usually supplied ready heat treated to 30-36HRc. If further heat treatment is required annealed AISI 4145H MOD Steel should be heated slowly to 840-875°C and after adequate soaking at this temperature quench in oil. Temper as soon as the tools reach room temperature.
Tempering: Heat carefully to a suitable temperature selected by reference to a tempering chart or table (usually between 550-700°C, soak at the temperature for 2 hours per 25mm of ruling section, then allow to cool in air. Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact values of this steel.


Preheat the steel carefully, then raise the temperature to 1150-1200°C for forging. Do not forge below 850°C. AISI 4145H MOD Steel has good forging characteristics but care must be taken when cooling the steel due to its susceptibility to cracking.

Mill′s test certificate

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.

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