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1.8509 SACM645 alloy structural steel

1.8509 alloy structural steel offers excellent nitriding response, high surface hardness, and superior wear resistance. With good tempering stability and core toughness, ideal for nitrided components such as cylinder liners, pump shafts, and high-precision guide rods.

Standard: DIN 1.8509(41CrAlMo7-10), JIS SACM645, GB 38CrMoAl
Technique: EAF + LF + VD, forged or hot-rolled, multidirectional forging ratio ≥4, quenched and tempered for uniform microstructure prior to nitriding
Shape: Round, Flat, Plates, Blocks
Heat treatment: Supplied in quenched and tempered (QT) condition, hardness 26–32 HRC typical; annealed condition available on request
Surface Treatment: Turned, milled / ground, sawn ends. Black (hotrolled / 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 1.8509 in various custom sizes

Chemical Composition (%)

Grade	C	Si	Mn	P (≤)	S (≤)	Cr	Mo	Al
38CrMoAl	0.35–0.42	0.20–0.45	0.30–0.60	0.035	0.035	1.35–1.65	0.15–0.25	0.70–1.10
1.8509 (41CrAlMo7-10)	0.38–0.45	≤0.40	0.50–0.80	0.025	0.035	1.50–1.80	0.25–0.40	0.80–1.20
SACM645	0.40–0.50	0.15–0.50	≤0.60	0.030	0.030	1.30–1.70	0.15–0.30	0.70–1.20

Main characteristics of 1.8509 alloy steel

Excellent nitriding response – forms extremely hard surface layer
High wear resistance – extends service life of components
Good core toughness – withstands impact and mechanical stress
Superior tempering stability – maintains hardness at elevated temperatures

1.8509 | SACM645 alloy steel applications

1.8509 steel for Precision Leadscrew & Spindle

The deep nitrided case provides extreme surface hardness and fatigue resistance, maintaining precise motion and long life in high-precision machine tools.

1.8509 steel for Injection Molding Screw & Barrel

High wear and corrosion resistance of the nitrided layer withstands abrasive engineering plastics and fillers, significantly extending component service intervals.

1.8509 steel for Hydraulic Piston Rod

Surface hardness and anti-galling properties after nitriding prevent scratching and pitting, ensuring reliable sealing in harsh hydraulic environments.

Our Production Technology For 38CrMoAl (SACM645 / 41CrAlMo7) Nitriding alloy steel

EAF
LF
VD
Argon Shielding / Protective Casting — prevents aluminum oxidation during pouring
ESR — optional for premium cleanliness and isotropy
Forged or Hot Rolled
Annealed / Normalized / Quenched and Tempered
Machined surface / Peeled / Black finish

Ultrasonic testing (UT) as per SEP 1921, ASTM A388, or EN 10228-3 (upon request)
Micro Cleanliness as per ASTM E45 or DIN 50602
Delivery condition options:
Annealed or high-temperature tempered: hardness ~229 HB (standard)
Normalized: as specified in contract
Quenched and tempered: mechanical properties per GB/T 3077
Mechanical properties as per GB/T 3077:2015

mechanical properties & heat treatment of 1.8509 steel

Heat temperature	Start forging temperature	Finish forging temperature	Cooling method
1050 – 1100 °C	1050 – 1000 °C	≥ 850 °C	Pit, sand, or furnace cooling

Annealing

Hardening

38CrMoAl is a nitriding steel. Quenching and tempering (hardening and tempering) is performed as a preparatory heat treatment before nitriding to develop the required core strength and toughness. The steel is typically supplied in the annealed condition and requires in-house heat treatment for final properties.
Pre-heating (recommended): Preheat to 600 – 650°C to reduce thermal shock during austenitizing
Austenitizing temperature: 920 – 940°C.
Preferred range: 940°C for optimal property development.
Alternative: 840°C for specific applications requiring lower distortion
Holding time: Minimum 30 minutes at temperature (adjust for section thickness)
Quenching media:
Oil (preferred for most sections — provides good hardness with moderate distortion).
Water (faster quench — for larger sections or when maximum hardness is required).
Selection depends on section size and component complexity
Hardness after quenching: Dependent on section size and quenching medium

Stress relieving

Perform after rough machining, heavy stock removal, or other cold working operations to reduce residual stresses
Heat carefully to 600 – 650°C (below the tempering temperature)
Hold at temperature for 1 hour per 25mm of section thickness (minimum 2 hours)
Air cool after holding
This operation reduces the risk of distortion during final heat treatment and improves dimensional stability

Tempering

Temper immediately after quenching to avoid cracking
Tempering temperature (select based on final hardness requirement):
610°C: For standard nitriding preparation (core hardness ~260 HB).
640°C: For lower hardness and improved toughness.
680 – 700°C: For maximum toughness (HB < 217).
470 – 560°C: For intermediate hardness ranges (HRC 32–52)
Holding time: 1 hour per 25mm of section thickness (minimum 2 hours)
Cooling method: Water or oil cool after tempering

Why Choose NSPM as Your 1.8509 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.