P20|1.2311

Category

Plastic mold steel
Delivery condition

Hot rolled&forged
Supply form

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

Introduction:

1.2311 is a pre-hardened plastic mold steel. It offers a well-balanced combination of toughness, strength, and machinability, making it one of the most widely used steels in the mold industry. With good polishability and uniform hardness across sections, it is suitable for general-purpose plastic molds and tooling.

Chemical composition:

Corresponding international common brands				Hardness	Chemical Composition (%)
CHINA	US	JAPAN	GERMNAY	Hardness	C	Si	Mn	P	S	Cr	Ni	Mo	V
3Cr2Mo	P20	HPM2	1.2311	HRC:28-36	0.3-0.5	0.2-0.4	1.3-1.6	≤0.03	≤0.03	1.8-2.1	-	0.1-0.3	-

Characteristics:

Pre-hardened plastic mold steel (typically 28–36 HRC).
Uniform hardness through large cross-sections due to good hardenability.
Good machinability in the supplied condition.
Good polishing and photo-etching properties.
Toughness and strength suitable for medium-size molds.

Mechanical Properties

Tensile Strength	Yield Strength	Hardness	Elongation	Compressive Strength	Elastic Modulus
965-1030 MPa	827-862 MPa	30 HRC	20%	862 MPa	190-210 GPa

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.