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P20+Ni 1.2738 PDS5S plastic mold steels

1.2738 tool steel offers excellent hardness uniformity, superior toughness, and outstanding polishability. Pre-hardened for direct use, ideal for large complex plastic molds and high-gloss components.

Standard: AISI P20+Ni, DIN 1.2738(H,HH), JIS PDS5S, GB 3Cr2NiMo
Technique: EAF + LF + VD or ESR, forged, multi-directional forging ratio ≥4, quenched and tempered (pre-hardened)
Shape: Round, Flat, Plates, Blocks
Heat treatment: Supplied in pre-hardened condition. Typical hardness: 1.2738 28–32 HRC, 1.2738H 33–35 HRC, 1.2738HH 36–40 HRC; custom hardness upon 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 1.2738 in various custom sizes

Chemical Composition (%)

Grade	C	Si	Mn	P (≤)	S (≤)	Cr	Mo	Ni
1.2738 (40CrMnNiMo8-6-4)	0.35–0.45	0.20–0.40	1.30–1.60	0.030	0.030	1.80–2.10	0.15–0.25	0.90–1.20
1.2738H	0.35–0.45	0.20–0.40	1.30–1.60	0.030	0.030	1.80–2.10	0.15–0.25	0.90–1.20
1.2738HH	0.23–0.29	0.20–0.40	1.40–1.70	0.030	0.030	1.20–1.80	0.30–0.70	0.90–1.20
P20+Ni	0.28–0.40	0.20–0.50	0.60–1.00	0.030	0.030	1.40–2.00	0.30–0.55	0.80–1.20
PDS5S	0.30–0.38	0.20–0.40	1.00–1.30	0.025	≤0.010	1.50–1.80	0.30–0.45	0.80–1.10
3Cr2NiMo	0.30–0.38	0.20–0.40	0.80–1.20	0.030	0.030	1.80–2.20	0.30–0.50	0.80–1.20

Main characteristics of 1.2738 tool steel

P20+Ni | 1.2738 tool | PDS5S steel applications

1.2738 steel for AUTOMOTIVE MOLDS

Pre-hardened 1.2311 provides uniform hardness and excellent machinability, enabling fast, stable production of large automotive interior and exterior trim moulds.

1.2738 steel for HIGH-GLOSS & STRUCTURAL

Superior polishability and consistent hardness ensure high-gloss surface finish and precise dimensional stability for structural components.

1.2738 steel for HOME APPLIANCE MOLDS

Balanced strength and wear resistance make 1.2311 the reliable choice for long-lasting home appliance housing moulds requiring efficient machinability.

Our Production Technology For 1.2738 (P20+Ni / 3Cr2NiMo) Prehardened Plastic Mold Steel

Ultrasonic testing (UT) 100% as per EN 10228-3 Class 4, SEP 1921 Class E/e, or ASTM A388 (upon request)
Micro Cleanliness as per ASTM E45 Method A: A sulfides ≤ 1.5, B oxides ≤ 2, C silicates ≤ 2, D oxides ≤ 2; or DIN 50602-K4 ≤ 20
Spheroidized microstructure as per relevant tool steel standards
Delivery condition:
1.2738 Standard: Quenched and tempered (prehardened), hardness 280 – 330 HB (29 – 35 HRC), typical 300 HB / 32 HRC
1.2738 HH (Higher Hardness): Quenched and tempered, hardness 330 – 370 HB (35 – 39 HRC), typical 340 HB / 36 HRC

mechanical properties & heat treatment of 1.2738 steel

Heat temperature	Start forging temperature	Finish forging temperature	Cooling method
1050 – 1150 °C	1050 – 1100 °C	≥ 850 °C	Pit, sand, or furnace cooling

Annealing

Heat slowly and uniformly to 680 – 740°C (710–740°C typical)
Hold at temperature for sufficient time to ensure uniform heating (minimum 2 minutes per mm of section thickness, or 2–4 hours depending on section thickness)
Cool slowly in the furnace to room temperature
Hardness after annealing: max. 235 HB (approx. 22 HRC)
Annealing in a protective atmosphere is recommended to reduce decarburization and surface scaling

Hardening

1.2738 is typically used in the prehardened delivery condition and does not require additional heat treatment. Rehardening is only required when:
The steel has been annealed after forging and requires restoration to prehardened condition
A higher hardness level (e.g., 1.2738 HH) is needed for specific applications after annealing
The mold requires maximum wear resistance and the standard prehardened hardness is insufficient
Pre-heating (required): Preheat to 600 – 650°C and hold for sufficient time (typically 30 minutes) to ensure uniform temperature distribution and reduce thermal shock
Austenitizing temperature: 840 – 880°C (850–880°C per some sources).
Lower range (840–860°C): For minimizing distortion, suitable for complex shapes.
Upper range (860–880°C): For higher hardness and improved wear resistance
Holding time: After temperature equalization, hold for at least 1 minute per mm of section thickness (minimum 30 minutes, typically 30–45 minutes depending on thickness)
Quenching media:
Oil (preferred for most sections) — quench immediately after holding
Polymer — also suitable, providing better distortion control
Air — for minimizing distortion, suitable for smaller sections and less critical applications
Hot bath at 180 – 220°C (martempering) — as an alternative for complex shapes requiring minimum distortion
Hardness after quenching: approx. 52 HRC (approx. 500 HB).

Stress relieving

Perform after rough machining or heavy stock removal, especially for tools with complex shapes or unbalanced crosssections, to reduce the risk of distortion during subsequent processing
For quenched and tempered (prehardened) material: heat carefully to 500 – 600°C (550°C typical; max. 30°C below the final tempering temperature used for the prehardened condition)
For soft annealed material: heat carefully to 600 – 650°C
Hold at temperature for sufficient time (minimum 2 minutes per mm of section thickness, or 1–2 hours depending on size)
Air cool or furnace cool after holding
This operation is recommended to eliminate residual stresses induced by mechanical working and to reduce distortion during final processing

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 recommended to improve toughness and ensure complete transformation of retained austenite. After each tempering cycle, cool to room temperature before the next tempering
Holding time: Soak for at least 3 minutes per mm of section thickness (minimum 2 hours per cycle)
Cooling method: Air cool after each tempering cycle

Why Choose NSPM as Your 1.2738 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.