When it comes to selecting the right plastic mould, the choice of steel directly impacts mould life, surface finish, and production efficiency. Among the many available grades, 1.2311 steel has earned a strong reputation tool rooms for its reliability, machinability, and consistent performance. In this article, we will explain why 1.2311 steel remains a preferred plastic mould steel across industries.
Introduction to 1.2311 Steel
1.2311steel is a pre-hardened plastic mould steel and it is commonly known as a P20-type steel. It is supplied in a ready-to-use condition, eliminating the need for additional heat treatment in most applications. This makes it ideal for toolmakers who value faster turnaround times and predictable results.
Because of its balanced mechanical properties, 1.2311 steel is widely used for medium to large plastic moulds requiring good polishability and dimensional stability.
Chemical Composition & Mechanical Strength
The chemical composition of 1.2311 steel is carefully balanced to provide strength, toughness, and ease of machining. It typically contains carbon, chromium, manganese, and molybdenum, which together enhance hardness and wear resistance.
Key properties of 1.2311 steel include
Uniform pre-hardened hardness (typically around 28–32 HRC)
Good toughness to resist cracking
Excellent machinability for faster mould manufacturingStable structure that maintains accuracy over long production runs
These characteristics make it dependable for consistent mould performance.
1.2311 steel dominates the plastic mould sector because it offers an ideal balance between performance and cost. Toolmakers prefer it because it machines easily, polishes well, and performs reliably under continuous production cycles.
Its ability to deliver smooth surface finishes makes it suitable for moulds where appearance and dimensional accuracy are critical.
1.2311 Steel vs P20 – Are They the Same?
1.2311 steel is often referred to as a P20-equivalent grade. While both share similar properties, 1.2311 is produced under stricter European standards, offering better consistency in hardness and chemical composition. This consistency is especially valued in precision mould making.
Best Applications in Manufacturing
1.2311 steel is commonly used for:
Plastic injection moulds
Household and consumer plastic products
Packaging and container moulds
Large mould bases and core inserts