As we all know , When the specific pressure in service is very high or there is a risk to damage the chromium plated surface by shocks or abrasions, it is advisable to use the induction hardened AISI 4140 chrome bars. In this case the chromium overlay receives a better support by the hardened base material and is, therefore, less delicate.
Why Induction Hardening?
Our controlled induction hardening process ensures:
Targeted Hardening: Only the working surface is hardened (HRC 58-62), preserving core ductility.
Uniform Case Depth: Precise electromagnetic induction achieves consistent case depth (0.8–1.2 mm), mitigating distortion risks.
Thermal Efficiency: Faster than traditional furnaces, with minimal decarburization.
The Technical of AISI 4140 Chrome bars
Material Composition & Performance. 4140 Alloy Steel: A chromium-molybdenum steel (0.75–1.00% Cr, 0.15–0.30% Mo) offering exceptional tensile strength (≥980 MPa) and torsional rigidity.
Chrome Plating: A 50-100 µm thick chromium layer (HRC 60+) enhances surface hardness, corrosion resistance, and reduces friction in hydraulic cylinders, pistons, or valve components.
Our Production Process Of The Induction Hardening Of aisi 4140 Chrome bars
Step 1: Material Selection: Sourced from certified mills (ASTM A29 compliant) with full chemical traceability. Strict incoming inspection for grain size (≤ASTM 7) and cleanliness (oxygen ≤15 ppm).
Step 2: Chrome Plating
Electroplating Parameters: Current density: 3–5 A/dm². pH: 1.8–2.2 . Temperature: 50–60°C .Post-plating bake (180°C, 4 hours) to eliminate hydrogen embrittlement.
Step 3: Induction Hardening
Equipment: IGBT-based induction heaters with ±5°C temperature control.
Process: Preheating: 800°C → Quenching (water/ polymer-based medium) → Tempering (200°C). Real-time monitoring via pyrometers to ensure accuracy.
Step 4: Quality Assurance
Testing: Hardness: (HRC 58-62 verified with microhardness testing). Case Depth: Metallographic cross-section analysis per ASTM E1077. Surface Roughness: Ra ≤0.8 µm post-polishing.
Certifications: ISO 9001:2015, Nadcap for heat treatment.
