P20+Ni|1.2738

Category

Plastic mold steel
Delivery condition

Hot rolled&forged
Supply form

Flat bar, Square bar, Plate/Block ,Round bar

Introduction:

1.2738 is a nickel-alloyed variant of 1.231, engineered to provide improved toughness, hardness uniformity, and excellent polishability across large cross-sections. Supplied pre-hardened in the range of 33-38 HRC, it maintains consistent mechanical properties even in thick sections. Its high surface finish capability makes it especially suitable for molds used in transparent or high-gloss plastic products.

Chemical composition:

Corresponding international common brands				Hardness	Chemical Composition (%)
CHINA	US	JAPAN	GERMNAY	Hardness	C	Si	Mn	P	S	Cr	Ni	Mo	V
3Cr2MnNIMo	P20+Ni	HPM7/PX5	1.2738	HRC:33-38	0.35-0.45	0.2-0.5	1.2-1.6	-	-	1.8-2.1	-	0.15-0.25	-

Characteristics:

Modified version of 1.2311 with added nickel (~0.9—1.2%).
Provides improved toughness and hardness uniformity in large cross-sections.
Pre-hardened to 33-38 HRC.
Excellent polishability and good suitability for surface treatments (nitriding, chrome plating).
Better wear resistance compared to 1.2311/1.2312.

Applications:

Large and complex plastic injection molds.
Mold tools for transparent plastics requiring high surface finish (optical parts, lenses, light covers).
Automotive exterior and interior moldings.
Suitable for plastic molds where long tool life and high toughness are needed.

Mechanical Properties

Tensile Strength	Yield Strength	Hardness	Elongation	Impact Toughness	Modulusof Elasticity
850-1100 MPa	770-980 MPa	32-36 HRC	13-16%	20 J/cm2-42J/cm2	205×10³N/mm2

Physical Properties

The physical properties can vary slightly depending on the specific composition and heat treatment of the P20+Ni /DIN 2738 /AISI P20+Ni steel. It's always recommended to refer to the manufacturer’s specifications for precise information.

Coefficient of thermal expansionat °C	20-100	20-200	20-300	20-400	20-500	20-600	20-700
10-6m/(m*K)	11.2	12.8	13.5	13.7	14.3	14.7	14.9

Thermal Conductivity at °C	20	350	700
W/(m*K)	35	34	33

Heat Treatment & Processes

01
Hardening

Heat the steel evenly to 820–840°C until the whole section reaches temperature. Then quench in oil to cool.
02
Normalizing

Heat the steel uniformly to about 900°C to achieve a normalized structure.
03
Annealing

Heat P20 steel to 770–790°C, hold it well at temperature, and then let it cool slowly inside the furnace.
04
Tempering

Heat the steel evenly and hold it for at least 1 hour per 25 mm of thickness at the chosen tempering temperature. Allow it to cool in still air.