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5140 41Cr4 SCr440 alloy structural steel

41Cr4 alloy structural steel offers good hardenability, high tensile strength, and excellent wear resistance. With good toughness and fatigue strength, ideal for automotive shafts, gears, bolts, and other medium-load structural components.

Standard: AISI 5140, DIN 41Cr4(1.7035), JIS SCr440, GB 40Cr
Technique: EAF + LF + VD, forged or hot-rolled, multi-directional forging ratio ≥4, quenched and tempered as required
Shape: Round, Flat, Plates, Blocks
Heat treatment: Supplied in quenched and tempered (QT) condition with hardness 22–30 HRC typical; annealed or normalized condition available on request
Surface Treatment: Turned, milled / ground, sawn ends. Black (hot-rolled / forged surface) available for large sections
Tolerance: flat bars & plates thickness: +0.5/-0.0 mm (turned); forged blocks: ±0.2 mm
MOQ: 1 Ton

We supply DIN 41Cr4 in various custom sizes

Chemical Composition (%)

Grade	C	Si	Mn	P (≤)	S (≤)	Cr
5140	0.38–0.43	0.15–0.35	0.70–0.90	0.035	0.040	0.70–0.90
41Cr4 (1.7035)	0.38–0.45	0.15–0.35	0.50–0.80	0.035	0.035	0.90–1.20
SCr440	0.38–0.43	0.15–0.35	0.60–0.85	0.030	0.030	0.90–1.20
40Cr	0.37–0.44	0.17–0.37	0.50–0.80	0.030	0.030	0.80–1.10

Main characteristics of 41Cr4 Alloy Steel

Good hardenability – ensures uniform properties throughout section
High tensile strength – reliable under heavy mechanical loads
Excellent wear resistance – extends service life of components
Good fatigue strength – durable under cyclic stress conditions

5140 | 41Cr4| SCr440 Alloy Steel applications

41Cr4 steel for Automotive Transmission Gear

Good hardenability and high wear resistance ensure precise, long-lasting gear engagement under medium-duty torque loads.

41Cr4 steel for Steering Knuckle & Suspension Component

Excellent toughness and fatigue strength withstand repeated shock and bending stresses, guaranteeing structural safety and reliability.

41Cr4 steel for Medium-Duty Drive Shaft

Balanced strength and torsional fatigue resistance deliver consistent power transmission in industrial and agricultural drive systems.

Our Production Technology For 41Cr4 (1.7035 / AISI 5140 / SCr440) Engineering Alloy Steel

EAF
LF
VD
ESR
Forged or Hot Rolled
Annealed / Normalized / Quenched and Tempered
Machined surface / Peeled / Black finish

Ultrasonic testing (UT) 100% as per ASTM A388 or SEP 1921 (upon request)
Micro Cleanliness as per ASTM E45 or DIN 50602 (upon agreement)
Grain size ≥ 5.0 per ASTM E112 for critical applications
Delivery condition options:
Soft annealed (+A): max. 241 HB
Cold shearable (+S): max. 255 HB
Quenched and tempered (+QT): 800–1200 MPa tensile strength (depending on diameter)
Mechanical properties as per EN 10083-3 or ASTM A29
Manufacturing route: Steelmaking → Hot forging/rolling → Heat treatment → Cold working (as required)

mechanical properties & heat treatment of 41Cr4 steel

Heat temperature	Start forging temperature	Finish forging temperature	Cooling method
1050 – 1080 °C	1050 – 1000 °C	≥ 850 °C	Pit, sand, or furnace cooling

Annealing

Annealing temperature: 680 – 720°C
Hold at temperature for sufficient time (minimum 2 minutes per mm of section thickness, or 2–5 hours depending on section size)
Cool slowly in the furnace to room temperature
Hardness after annealing: max. 241 HB
Annealing in a protective atmosphere is recommended to reduce decarburization and surface scaling

Hardening

41Cr4 steel for quenching and tempering can be hardened in oil, water, or polymer. Proper preheating and austenitizing are critical to achieve the desired hardness without cracking. It through hardens in oil up to approx. 40 mm diameter
Pre-heating (recommended): Preheat to 600 – 650°C to reduce thermal shock during austenitizing
Austenitizing temperature: 820 – 860°C.
Lower range (820–850°C): water quench
Upper range (830–860°C): oil quench
Holding time: At least 30 minutes at austenitizing temperature (or 30 min per 25mm of section thickness
Quenching media (select based on section and geometry) :
Oil (most common — provides good hardness with moderate distortion)
Water (faster quench — for smaller sections, but increases distortion and crack risk)
Hardness after quenching: Surface hardness approx. 52–54 HRC (induction surface hardening achieves min. 52–53 HRC)

Stress relieving

Perform after rough machining, heavy stock removal or welding to reduce residual stresses and reduce distortion risk during final hardening
Heat carefully to approx. 650°C
Hold at temperature for 1 hour per 25mm of section thickness (minimum 2 hours)
Slow cool in the furnace to 200°C, then air cool to room temperature (or after holding, air cool)
This operation reduces the risk of distortion during final heat treatment and improves dimensional stability

Tempering

Temper immediately after the workpiece cools to handwarm temperature (approx. 50–70°C). Delayed tempering may cause cracking
Number of tempers: Minimum 1 time for standard applications; 2 times recommended for critical components requiring maximum toughness and property stability
Holding time: 1 hour per 25mm of section thickness (minimum 2 hours)
Cooling method: Air cool after each tempering cycle
Tempering temperature range: 540 – 680°C, depending on final hardness requirement

Why Choose NSPM as Your 41Cr4 Alloy Steel Supplier

Source Direct

Direct mill cooperation ensures stable supply, competitive pricing, and consistent quality. Global resource integration and strong supply chain management guarantee reliable material sourcing and long-term availability.

Stock Ready

50,000+ tons inventory across 11 warehouses enables fast delivery. Flexible cutting, short lead times, and ready stock support urgent demands and improve customers’ production efficiency.

Expert Team

600+ professionals, including R&D specialists and technical engineers, provide application-driven support. Fast response and deep tooling knowledge ensure accurate solutions for diverse industrial needs.

Fully Inspected

Strict quality control system with full traceability, UT testing, and heat treatment records. Certified standards (ISO, CE) ensure every material meets high-performance and reliability requirements.

Full-Chain Machining

From steel supply to precision machining, heat treatment, and equipment manufacturing, NSPM offers integrated solutions that enhance accuracy, efficiency, and overall tooling performance.