31CrMoV9 / 31CrMoV9 / 1.8509 Round Steel For Construction & Machinery

Products Specification

Standard Size of our Steel Round Bar In Stock

38CrMoAlA/1.8509 Nitriding Alloy Steel Round Bar

Grade Compliance: DIN 1.8509 / GB 38CrMoAlA / UNS – (Custom Equivalent)

Material Highlights

38CrMoAlA/1.8509 is a premium nitriding steel optimized for applications demanding extreme surface hardness and core toughness. Its unique aluminum-chromium-molybdenum composition enables deep nitrogen diffusion during nitriding, producing components resistant to wear, corrosion, and thermal fatigue.

Key Advantages

• Ultra-Hard Surface Layer: Achieves 900-1100 HV after nitriding, ideal for abrasive environments.

• Stable Core Properties: Maintains high tensile strength (≥980 MPa) and ductility even under cyclic loads.

• Precision Machinability: Pre-hardened state allows efficient machining prior to final nitriding.

• Dimensional Stability: Minimal distortion during heat treatment for tight-tolerance applications.

Technical Specifications

Chemical Composition (% Weight)

• C: 0.35–0.42 | Cr: 1.35–1.65 | Mo: 0.15–0.25

• Al: 0.70–1.10 | Mn: 0.30–0.60 | Si: 0.20–0.45

• Impurities (max): P: 0.025 | S: 0.025

Physical Properties

• Density: 7.85 g/cm³

• Thermal Conductivity: 42 W/m·K (at 20°C)

• Coefficient of Thermal Expansion: 11.5 ×10⁻⁶/K (20–300°C)

Processing Guidelines

1. Forging: Heat to 1150–1200°C; finish forging above 850°C.

2. Annealing: 680–720°C slow cooling to ≤200 HB for improved machinability.

3. Final Heat Treatment:

   • Quenching: 930–950°C oil cooling.

   • Tempering: 550–650°C (adjust for target hardness).

4. Nitriding: Gas/plasma nitriding at 480–530°C for 20–100h (case depth: 0.2–0.8mm).

Targeted Applications

• High-Precision Components: Camshafts, gear synchronizers, bearing races.

• Tooling & Dies: Extrusion dies, injection molding cores with anti-galling surfaces.

• Oil & Gas: Valve stems, pump shafts exposed to corrosive media.

• Automotive: Turbocharger parts, fuel injection systems.

Product Offerings

• Sizes: Ø10mm – Ø350mm (cold-drawn or hot-rolled).

• Surface Finish: Peeled, ground, or black oxide-coated.

• Certifications: RoHS compliant, ISO 9001:2015, batch-specific chemical/mechanical reports.

• Custom Services: Pre-cut blanks, stress-relieved stock, partial nitriding masking.

Quality & Compliance

• Testing Protocols:

  • Hardness gradient analysis (core vs. case).

  • Microstructure inspection for nitride layer uniformity.

  • Fatigue testing per ISO 12107.

• Traceability: Full material history (heat number, mill origin).

Why Choose Our 38CrMoAlA/1.8509?

• Consistent Performance: Vacuum degassed steel for low inclusion ratings.

• Global Logistics: Stocked in EU, Asia, and Americas warehouses.

• Technical Support: Free nitriding parameter optimization guides.

Contact Us: For specialized requirements (e.g., cryogenic treatment, PVD coating compatibility).