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NSPM8418 4Cr5Mo2V hot work tool steel

8418 tool steel combines excellent isotropic toughness, high thermal-fatigue resistance, and strong tempering resistance, making it suitable for die-casting molds, hot-forging dies, and extrusion tooling.

Standard: Ningshing NSPM8418, GB 4Cr5Mo2V, ASSAB Dievar
Technique: Vacuum refining + Electroslag remelting (ESR) + Special forging process + Ultrafine treatment
Shape: Round , Blocks
Heat treatment: Annealing: 840–860 °C, air cool below 500 °C, hardness ≤ 235 HB Quenching: 1010–1030 °C, oil or air cooling, media temp. 20–60 °C, cool to room temperature, hardness 53–57 HRC Tempering: 560–620 °C, air furnace, air cooling, hardness 45–50 HRC
Surface Treatment: Delivered in annealed condition (asforged / black scale or machined finish as per actual supply)
Tolerance: According to Ningshing’s standard supply specification
MOQ: 1 Ton

We supply NSPM 8418 in various custom sizes

Chemical Composition (%)

钢种	C	Si	Mn	Cr	Mo	V	P	S
NSPM8418 (Ningshing)	0.35	0.30	0.50	5.10	2.40	0.55	≤0.015	≤0.002
4Cr5Mo2V (GB/T)	0.35~0.42	0.25~0.50	0.40~0.60	5.00~5.50	2.30~2.60	0.60~0.80	≤0.020	≤0.008
Dievar (ASSAB)	0.35	0.20	0.50	5.00	2.30	0.60	—	—

Main characteristics of 8418 tool steel

Excellent Isotropic Toughness – Resists crack propagation under severe thermal and mechanical loads
High Thermal-Fatigue Resistance – Helps reduce heat checking and thermal cracking
Strong Temper Resistance – Retains hardness and strength during prolonged high-temperature exposure
Good Dimensional Stability – Maintains dimensional accuracy after heat treatment and surface coating

8418 tool steel applications

8418 steel for Die-Casting Molds

Excellent thermal fatigue resistance and high-temperature strength enable NSPM8418 to withstand extreme thermal cycling in aluminum and magnesium die casting, significantly extending die life.

8418 steel for Hot-Forging Die Inserts

Superior temper resistance and high toughness ensure dimensional stability and crack resistance under heavy mechanical and thermal shock in hot forging.

8418 steel for Extrusion Tooling

High hot hardness and wear resistance deliver stable profile accuracy and long service life in high-temperature extrusion of light alloys and copper.

Our Production Technology For NSPM8418 (4Cr5Mo2V / Dievar) Premium Hot Work Tool Steel

EAF
LF
VD
ESR
Special Forging Process
Ultra-Fine Grain Treatment
Spheroidizing Annealed
Machined surface / Peeled

Quality Control:
Ultrasonic testing (UT) as per SEP 1921 or ASTM A388 (upon request)
Micro Cleanliness as per ASTM E45 — ultra-low inclusion levels (P ≤ 0.015%, S ≤ 0.002%)
Grain size ultra-fine, homogeneous structure
Delivery condition: Soft annealed, hardness ≤ 235 HB
Product forms:
Forged blocks: 60 – 500 × 300 – 1200 mm
Round bars: Φ60 – 600 mm

mechanical properties & heat treatment of 8418 steel

Heat temperature	Start forging temperature	Finish forging temperature	Cooling method
1100 – 1150 °C	1100 – 1050 °C	≥ 900 °C	Pit, sand, or furnace cooling

Spheroidizing Annealing

Spheroidizing annealing is performed to produce a fine, uniform spheroidized carbide microstructure for optimum machinability and to prepare the steel for final hardening
Annealing temperature 840 – 860°C
Holding time Sufficient for uniform heating (typically 4–6 hours depending on section thickness)
Cooling method Furnace cool to below 500°C, then air cool to room temperature
Hardness after annealing ≤ 235 HB

Hardening

NSPM8418 is a premium hot work tool steel with excellent hardenability. Proper preheating and austenitizing are critical to achieve the desired hardness without cracking. The steel can be quenched in oil or air, providing flexibility for distortion control
Pre-heating (recommended) 600 – 850°C (two-stage preheat recommended to reduce thermal stress)
Austenitizing temperature 1010 – 1030°C
Holding time 15 – 30 minutes after temperature equalization
Quenching media Oil (preferred) or Air
Cooling medium temperature 20 – 60°C
Cool to Room temperature
Hardness after quenching 53 – 57 HRC

Stress relieving

Perform after rough machining, heavy stock removal, or EDM to reduce residual stresses
Heat carefully to 600 – 650°C
Hold at temperature for 1 – 2 hours (minimum)
Air cool after holding
This operation reduces the risk of distortion during final hardening 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 2 times. Double tempering is mandatory for this grade to ensure complete transformation of retained austenite and optimal property stability
Holding time: 2 hours minimum per cycle (or 1 hour per 20mm of section thickness)
Cooling method: Air cool after each tempering cycle
Tempering temperature range: 560 – 620°C
Avoid the range 425 – 550°C to prevent temper embrittlement

Why Choose NSPM as Your 8418 Tool 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.