SteelWhat is P20 steel and what is it used for? Plastic mold steel
P20 steel is a plastic mold steel. In this guide we explain what P20 steel is, its chemical composition, hardness, how it is heat treated, what it is used for and the sizes we stock.
What is P20 steel?
Chrome-manganese-molybdenum mold tool steel, supplied pre-hardened (quenched and tempered, ~28–32 HRC), ready to machine. Good machinability and polishability, with a homogeneous structure. For plastic injection molds, mold bases and holders.
Chemical composition of P20 steel
This is the typical composition of P20 steel (AISI P20 / EN-DIN 1.2311 standard):
| Element | Contents | What for? |
|---|---|---|
| Carbon (C) | 0.35 – 0.45 % | Hardness and wear resistance |
| Silicon (Si) | 0.20 – 0.40 % | Deoxidizer |
| Manganese (Mn) | 1.30 – 1.60 % | Hardenability |
| Chromium (Cr) | 1.80 – 2.10 % | Hardenability and wear resistance |
| Molybdenum (Mo) | 0.15 – 0.25 % | Hot hardness and hardenability |
| Phosphorus (P) | 0.030 % max. | Impurity, kept low |
| Sulfur (S) | 0.030 % max. | Impurity, kept low |
Hardness and heat treatment of P20 steel
The typical working hardness of P20 is 28 – 32 HRC (pre-hardened). It is supplied pre-hardened (quenched and tempered at the mill), ready to machine. It normally needs no additional heat treatment, which avoids distortion in the already-machined mold. You can see the full overview in our article on heat treatments for steel, and hardness scales in steel hardness.
What is it for? Applications of P20
P20 steel is mainly used in:
- Injection molds
- Plastic molds
- Industrial mold bases
- Mold plates
- Mold cavities
- Mold inserts
- Blow molds
- Extrusion dies
- Casting dies
Forms and sizes we carry
At NAT MAC we stock P20 steel in these forms and sizes:
| Package size | Sizes |
|---|---|
| Round bars | Ø 1/2" – 8" (Ø 13 – 203 mm) |
| Plates | 1/2" – 10" (13 – 254 mm) |
If you need a particular size, tell us which one and we will gladly source it for you.
P20 equivalents and standards
P20 steel is also identified by these standards: AISI P20 / EN-DIN 1.2311. You can see how to read them in our article on steel standards.
In summary
- P20 is a plastic mold steel
- Typical composition: C 0.35 – 0.45 and Cr 1.80 – 2.10, plus alloying elements
- Typical working hardness: 28 – 32 HRC (pre-hardened)
- Ideal for plastic injection molds, ready to machine
- We carry it in round bar (1/2" – 8") and plates (1/2" – 10"), cut to size
Why buy your P20 steel at NAT MAC?
We have more than 54 years of experience as an industrial supplier and ISO 9001 certified quality. We carry a wide range of tool grade steels and help you choose the right one for your tool or mold.
- Quality P20 Steel, backed and traceable
- Material cut to the size you need
- Technical advice on choosing the right grade
- Wide range of tool-grade steels in stock
- On-time deliveries and competitive prices
Tell us what tool or mold you are going to make and in what dimensions, and we will recommend the right grade and form. Request your free quote.
Sources: data sheet from our NAT MAC catalog (composition, sizes and applications) and public industry references for working hardness. Values are for reference and may vary by standard, heat and treatment.
