What is the European equivalent of AISI 4140?

AISI 4140 has a European equivalent under DIN/EN standards with Werkstoff number 1.7225. It is also equivalent to BS 709M40 (UK) and JIS SCM440 (Japan). Please refer to our related grades section for equivalent grades we stock separately.

What condition is AISI 4140 normally supplied in?

Nifty Alloys supplies AISI 4140 in the quenched and tempered condition (Condition T) with tensile strength 850–1000 MPa and hardness approximately 28–34 HRC.

Is AISI 4140 suitable for welding?

Yes, with precautions. Preheat to 200–300°C and use low hydrogen electrodes. Post-weld stress relief at 600–650°C is strongly recommended to prevent cold cracking.

Can AISI 4140 be surface hardened?

Yes. Pre-hardened 4140 can be further surface hardened by flame or induction hardening, achieving case hardness in excess of HRC 50.

Alloy Steel dealers in UAE

AISI 4140

Chromium-molybdenum low-alloy steel offering high tensile strength, toughness, and fatigue resistance — one of the most widely used engineering steels globally.

Industries Served

Oil & Gas

Manufacturing

Automotive

Aerospace & Defense

Mining

Heavy Engineering

Power Generation

Applications

Axle shafts, drive shafts, and transmission components
Gears, sprockets, and pinions for heavy machinery
Crankshafts and connecting rods for engines
Hydraulic cylinder shafts, piston rods, and rams
Drill collars, stabilisers, and downhole oil field components
Mould bases, tool holders, and ejector pins
Guide rods, spindles, and pump shafts
High-strength bolts, studs, and structural fasteners
Mining equipment components and conveyor pins
Chuck bodies, collets, and lathe spindles

Chemical Composition

0.4 %

Carbon

0.38 – 0.43 %

0.25 %

Silicon

0.15 – 0.35 %

0.88 %

Manganese

0.75 – 1 %

0.95 %

Chromium

0.8 – 1.1 %

0.2 %

Molybdenum

0.15 – 0.25 %

Phosphorus

≤ 0.035 %

Sulfur

≤ 0.04 %

Typical value Range (min–max) Minimum (≥) Maximum (≤) Hover / tap for notes

Standard

A29/A29M — 2023

Available Forms

Round Bar

Solid circular cross-section. Most common supply form for 4140

Flat Bar

Rectangular cross-section, width significantly greater than thickness.

Hexagonal Bar

Six-sided bar. Used for fastener manufacture.

Plate

Flat product, thickness typically >6mm.

Forging

Open or closed die forged product. For large or custom section sizes.

Designations & Equivalents

Standard	Designation	Notes
AISI / SAE	4140	Primary designation
UNS	G41400	Unified Numbering System
EN / Werkstoff	1.7225	European material number
DIN	42CrMo4	German standard designation
BS	709M40	British Standard
JIS	SCM440	Japanese Industrial Standard
ISO	42CrMo4	ISO designation — same as DIN
ASTM	A29 / A322 / A331	Multiple ASTM product standards

Compliance & Certification

Standard	Status	Notes
EN 10204 3.1	Suitable	Provided as standard with all supply. Confirms chemistry and properties to ASTM A29.
EN 10204 3.2	Conditional	Available on request. Third-party inspection required — specify at order stage.
NACE MR0175 / ISO 15156	Requires Confirmation	4140 may comply in annealed condition at ≤22 HRC. Q&T condition typically exceeds NACE hardness limits. Confirm with project NACE document.
NACE MR0103	Requires Confirmation	Hardness limit compliance must be confirmed at time of order.

Specifications

Mechanical Properties

Values are minimums unless noted; hardness is a maximum.

Property	AISI 4140 — ASTM A29 — Quenched & TemperedDefault
Tensile Strength (UTS)range	850–1000 MPaTypical: 930 MPaCondition: Room temperature, longitudinalNotes: Condition T range — section ≤150mm.
Yield Strength (0.2% Proof Stress)min	655 MPaTypical: 735 MPaCondition: Room temperature, longitudinalNotes: Minimum per ASTM A29 Q&T.
Elongationmin	13 %Typical: 17 %Condition: 50mm gauge lengthNotes: Minimum per ASTM.
Reduction of Areamin	45 %Typical: 57 %Condition: LongitudinalNotes: Minimum per ASTM.
Hardnessrange	28–34 HRCTypical: 31 HRCCondition: Surface, Rockwell C scaleNotes: Typical Q&T hardness range.
Impact Energy (Charpy V-notch)min	27 JTypical: 47 JCondition: Room temp (+20°C), V-notchNotes: Typical — not always mandatory in ASTM A29.

Physical Properties

Property	AISI 4140 — ASTM A29 — Quenched & TemperedDefault
Density20°C	7.85 g/cm³
Modulus of Elasticity25°C	205 GPa
Thermal Conductivity100°C	42.6 W/m·K
Coefficient of Thermal Expansion20–100°C range	12.3 µm/m·°C
Specific Heat CapacityRoom temperature	473 J/kg·K
Melting Point	1416 °C

ENGINEERING NOTES

Weldability

Fair

AISI 4140 can be welded using low hydrogen electrodes. Preheat to 200–300°C before welding, particularly for sections over 25mm. Post-weld heat treatment (stress relief at 600–650°C, 1 hour per 25mm section) is strongly recommended to avoid cold cracking and hydrogen embrittlement. Do not weld in the fully hardened condition.

Machinability

Good

Machines well in the annealed or pre-hardened condition (18–22 HRC). In the Q&T condition (28–34 HRC), carbide tooling is required with reduced cutting speeds. Improved machinability variant (4140HM) is available for high-volume machining operations.

High-Strength Chromium-Molybdenum Engineering Steel

AISI 4140 is a chromium-molybdenum (CrMo) low-alloy steel renowned for its excellent combination of high tensile strength, toughness, fatigue resistance, and wear resistance. With a chromium content of 0.80–1.10% and molybdenum of 0.15–0.25%, the alloy achieves outstanding hardenability and responds exceptionally well to a wide range of heat treatment processes — from annealing through to quenching and tempering. In its standard quenched and tempered condition, AISI 4140 delivers tensile strengths in the range of 850–1000 MPa, making it one of the most versatile and cost-effective high-tensile engineering steels available.

Certified Stock Availability and Technical Support

Nifty Alloys maintains a consistent stock of AISI 4140 in round bar, flat bar, square bar, and plate across a wide range of sizes, available for immediate supply across the UAE and GCC region. All material is supplied with EN 10204 3.1 Mill Test Certificates as standard, with EN 10204 3.2 third-party inspection available on request. Our team provides expert guidance on grade selection, heat treatment options, and equivalent standards — ensuring you receive the right specification for your application without delay. Whether you are sourcing for oil field tooling, general engineering, or precision machined components, Nifty Alloys delivers certified, traceable material with the technical support your project demands.

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AISI 4140 is used for shafts, gears, axles, crankshafts, drill collars, hydraulic components, and high-strength fasteners across oil & gas, automotive, aerospace, and general engineering.

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