Tool Steel P20

AISI P20 is the industry standard pre-hardened tool steel designed specifically for the plastic injection mold industry. Delivered in a quenched and tempered state (typically 28-32 HRC), it allows for immediate CNC machining to final dimensions without the risk of heat-treat distortion or cracking. It offers a superior combination of excellent machinability, uniform hardness through large sections, and good polishability. At Jucheng Precision, we utilize P20 for manufacturing large-scale mold bases, structural frames, and die holders. It is the most economical and reliable choice for medium-run production tooling where dimensional stability and speed-to-market are critical.

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Tool Steel P20 Machining Capabilities

Capability	Technical Description	Jucheng Advantage
Pre-Hardened Machining	P20 is supplied pre-hardened (28-32 HRC). We utilize high-performance carbide tools to machine final shapes directly without further heat treatment.	Eliminates the risk of heat-treat distortion or cracking, significantly reducing lead times for large mold projects.
Large Mold Base Milling	Using heavy-duty CNC gantry mills to process large P20 blocks for automotive and appliance mold bases.	Our rigid setups ensure excellent flatness and parallelism (+/- 0.05mm) across parts up to 2 meters in length.
Precision Boring	Machining deep, accurate guide pin and ejector pin holes with high positional accuracy.	Ensures perfect alignment of mold halves for millions of injection cycles without binding or wear.
High-Quality Surface Prep	P20 offers excellent polishability. We machine surfaces to Ra 0.8μm to reduce manual finishing labor.	Consistent material quality ensures that your mold surfaces are free of voids or hard spots, delivering superior plastic part aesthetics.

Fabrication Guidelines for Tool Steel P20

Ready to Use:
The greatest advantage of P20 is that it is typically used in the condition it is received (Pre-hardened). Tip: This is the most cost-effective choice for medium-production plastic injection molds.

Machinability:
Despite being pre-hardened, P20 machines very well (approx. 65% of 1212). Tip: We use rigid tool holders and constant chip loads to maximize tool life and prevent surface work-hardening.

Welding & Repair:
P20 is weldable, which is critical for mold changes or repairs. Tip: Pre-heating to 300-400°C is required to prevent cracking in the heat-affected zone.

Nitridability:
If higher surface wear resistance is needed, P20 can be nitrided to achieve 50+ HRC surface hardness. This is excellent for abrasive glass-filled plastics.

Primary Applications

Plastic Injection Molds
Large mold cavities and cores for automotive dashboards, appliance housings, and consumer electronic cases.

Mold Bases & Frames
Structural holders for high-precision mold inserts (like 420 or H13) where stability is required.

Die Casting Die Holders
Used as the backing or holder block for high-temperature die-casting inserts.

Zinc Die Casting Dies
P20 is durable enough to act as the primary cavity material for low-melting-point zinc casting.

Properties

Density	7.85 g/cm³
Tensile Strength	830 - 1000 MPa
Yield Strength	700 - 850 MPa
Hardness	28 - 32 HRC (280 - 320 HB)
Elongation at Break	15 - 20%
Thermal Conductivity	29.0 W/m-K
Machinability Rating	65%
Weldability	Good
Surface Finish	SPI B-1 to A-3
Max Part Size	2000 x 800 x 600 mm