1.2083 is a premium German standard martensitic stainless tool steel, specified under DIN (Deutsches Institut für Normung) standards. It is primarily valued for its excellent corrosion resistance, superior polishability, and good hardenability, making it a top choice for high-precision plastic moulds, medical devices, and components requiring both aesthetic quality and durability in mild corrosive environments. Below is a detailed overview:
Chemical Composition
The typical chemical composition of 1.2083 stainless steel is carefully balanced to optimise corrosion resistance and polishability:
Element Content Range Role
Carbon (C) 0.30–0.40% Enhances hardness and wear resistance after heat treatment; forms carbides to improve durability.
Chromium (Cr) 13.00–15.00% The core element for corrosion resistance, forming a dense chromium oxide passive layer on the surface.
Silicon (Si) ≤1.00% Aids in deoxidation during manufacturing and improves mechanical stability.
Manganese (Mn) ≤1.00% Enhances hardenability and reduces brittleness.
Phosphorus (P) ≤0.030% Minimised to avoid embrittlement and machining defects.
Sulfur (S) ≤0.015% Strictly controlled to ensure high polishability and surface quality (low sulfur reduces inclusions).
Molybdenum (Mo) ≤0.60% (Optional) Trace additions to further enhance corrosion resistance in specific formulations.
Key Properties
1.2083 stainless steel is engineered to meet the stringent demands of precision and corrosion-resistant applications:
1. Excellent Corrosion Resistance
With 13–15% chromium content, it forms a stable passive oxide film that resists corrosion from mild chemicals, moisture, and non-aggressive plastics (e.g., PP, PE). It performs well in environments where rust resistance is critical, such as medical tools or food-contact components.
2. Superior Polishability
Its low sulfur content and fine, homogeneous microstructure allow it to achieve high-gloss surface finishes (up to mirror polish). This makes it ideal for plastic moulds producing parts requiring strict aesthetic standards (e.g., automotive interiors, electronic casings, cosmetic packaging).
3. Good Hardenability and Hardness
As a martensitic stainless steel, 1.2083 can be hardened via heat treatment to 45–50 HRC, balancing wear resistance and toughness. This ensures longevity in high-volume mould applications or components subject to mechanical stress.
4. Dimensional Stability
Exhibits minimal distortion during heat treatment, ensuring tight tolerances in precision components like moulds or medical instruments where dimensional accuracy is critical.
5. Machinability in Annealed State
In the annealed state (hardness ≤230 HBW), it offers reasonable machinability, allowing for precise machining of complex geometries (e.g., mould cavities, intricate tool details) before final heat treatment.
Physical Properties
Density: ~7.75–7.85 g/cm³
Melting Point: ~1450–1510°C
Thermal Expansion Coefficient: ~10.5×10⁻⁶/K (at 20–100°C)
Thermal Conductivity: ~25 W/(m·K) (at room temperature)
Magnetic Properties: Magnetic (due to its martensitic crystal structure).
Mechanical Properties (After Heat Treatment)
Property Typical Value
Hardness 45–50 HRC (quenched and tempered)
Tensile Strength (Rm) ~1200–1500 MPa
Yield Strength (Rp0.2) ~1000–1300 MPa
Elongation (A) ~10–15%
Impact Toughness (Charpy V-notch) ~15–25 J/cm² (at room temperature)
Heat Treatment Process
Proper heat treatment is essential to unlock 1.2083’s optimal performance, balancing hardness, corrosion resistance, and dimensional stability:
1. Annealing
Purpose: Soften the steel for machining, relieve internal stress, and improve ductility.
Process: Heat to 800–850°C, hold for 2–4 hours, then furnace cool slowly (≤50°C/hour) to below 500°C before air cooling.
Result: Hardness ≤230 HBW, ensuring ease of machining.
2. Quenching
Purpose: Harden the steel by transforming austenite to martensite.
Preheating: Heat to 600–700°C to avoid thermal shock.
Austenitizing: Heat to 1000–1050°C, hold for 30–60 minutes (depending on section thickness) to ensure uniform chromium and carbon diffusion.
Cooling: Quench in oil or air (oil quenching for deeper hardness; air quenching for minimal distortion in complex parts).
3. Tempering
Purpose: Relieve quenching stress, reduce brittleness, and stabilise hardness while preserving corrosion resistance.
Process: Temper at 200–250°C for high hardness (48–50 HRC) or 450–500°C for improved toughness (45–47 HRC). Hold for 1–2 hours per 25mm thickness, then air cool.
Result: Optimised balance of hardness, toughness, and corrosion resistance.
Application Fields
1.2083 stainless steel is widely used in applications demanding corrosion resistance, high polishability, and precision:
Plastic Injection Moulds: Ideal for moulds producing high-gloss plastic parts (e.g., automotive interiors, electronic device casings, cosmetic containers) and moulds processing non-aggressive plastics.
Medical Devices: Used for surgical instruments, medical tooling, and components requiring corrosion resistance and easy sterilisation.
Food-Contact Components: Suitable for moulds or tools in food packaging manufacturing, where hygiene and rust resistance are critical.
Precision Hardware: Applied in high-end valves, shafts, and fittings in mild corrosive environments.
Aesthetic Components: Used for parts requiring mirror-like finishes, such as luxury goods or decorative hardware.
Comparison with Similar Steels
Feature 1.2083 Stainless Steel 1.2316 Stainless Steel (German) SUS420J2 (Japanese)
Corrosion Resistance Excellent Superior (higher chromium + molybdenum) Moderate
Polishability Excellent Excellent Good
Max Hardness (HRC) 45–50 45–50 55–58
Best For High-gloss plastic moulds, medical tools Corrosive plastic moulds (e.g., PVC) High-wear mechanical parts
Summary
1.2083 stainless steel stands out for its exceptional combination of corrosion resistance, polishability, and hardenability, making it a premium choice for high-precision applications. Its ability to achieve mirror finishes and resist mild corrosion ensures long-term performance in plastic moulding, medical, and aesthetic-critical industries. Whether for intricate moulds or medical instruments, 1.2083 delivers reliability and quality in demanding environments.