PlasticMoldSteels
P-20 family and 420 stainless steels for injection and blow molding
Prehardened and stainless steels for injection and blow molds, offering good machinability, polishability, uniform hardness and corrosion resistance.
Introduction
Few processes demand as much from a tool steel as plastics molding. Machinability, polishability, thermal conductivity, uniform hardness in large blocks and corrosion resistance must coexist in the same material.
The P-20 family covers most injection molds in the prehardened condition (approximately 30–34 HRC), eliminating heat treatment after machining and shortening manufacturing lead time. Nickel-alloyed variants maintain uniform hardness even in large-section blocks.
For corrosive polymers, high-gloss molds and optical applications, 420-series stainless steels—especially ESR versions—provide superior metallurgical cleanliness, mirror polishability and chemical resistance.
MainMaterials
P-20 Standard — DIN 1.2311
Prehardened 30–34 HRC, good machinability
Small and medium injection molds
P-20 High-Machinability — DIN 1.2312
Sulfur addition for faster machining
Mold bases and cavities without high-polish requirements
P-20 + Ni — DIN 1.2738
Nickel alloying for uniform hardness in large sections
Large molds and thick-section blocks
Modified P-20 + Ni
Adjusted composition for greater homogeneity
Large molds with demanding dimensional requirements
P-20 HH — High Hardness
Supplied at higher hardness
Molds with higher wear demands
P-20 ESR / Premium
Electroslag remelting (ESR) for superior metallurgical cleanliness
High-gloss, textured and critical surfaces
DIN 1.2083
420 martensitic stainless steel, hardenable and corrosion-resistant
Molds for corrosive plastics and high-gloss finishes
1.2083 ESR
Remelted version for mirror polishing
Optical molds and lenses
DIN 1.2316
Prehardened stainless steel with good corrosion resistance
PVC and plastics that release aggressive gases
1.2316 ESR
Greater cleanliness and polishability
Molds for corrosive applications with demanding finish requirements
DIN 1.2085
Easy-machining prehardened stainless steel
Mold bases and components for wet environments
Modified 420 / Prehardened
Stainless steel supplied ready to use
General-purpose molds requiring corrosion resistance
BestChoiceFor
P-20 Family
- Small and medium molds → 1.2311
- High machinability → 1.2312
- Large molds → 1.2738
- High-gloss and textured finishes → P-20 ESR
Stainless Steels for Molds
- PVC and corrosive plastics → 1.2316
- Optical molds → 1.2083 ESR
- Wet environments → 1.2085
Why ESR
- Electroslag remelting (ESR)
- Greater metallurgical cleanliness
- Superior polishing with reduced pitting
- Homogeneity in large blocks
Applications
- Thermoplastic injection molds
- Blow molds
- Mold bases and plates
- Cavities and cores
- Textured and high-gloss molds
- Molds for reinforced and corrosive plastics
KeyAdvantages
Polishability
ESR versions, with superior metallurgical cleanliness, enable mirror polishing and uniform texturing.
Hardness Homogeneity
Nickel-alloyed grades maintain uniform hardness from core to surface in large-section blocks.
Corrosion Resistance
420-series stainless steels for PVC, POM and polymers that release aggressive gases.
Ready to Machine
Prehardened materials eliminate heat treatment after machining and shorten lead times.
RequestTechnicalSupport
Tell us what you need and our technical team will respond with the best recommendation.