Precision Gears from 1.8519 Nitriding Steel: Wire EDM Machining After Quenching & Tempering for High-Hardness Transmission

We manufactured a batch of precision gears in various sizes and profiles for an industrial power transmission supplier. The gears are machined from 1.8519 (31CrMoV9) nitriding steel, which undergoes quenching and tempering to achieve 52–58 HRC core hardness. Due to the high hardness and complex gear tooth geometry, conventional hobbing or milling is impractical. We used slow wire EDM to cut the gear teeth directly in the hardened state, achieving DIN 5 gear accuracy with no heat-affected zone or post-heat distortion.

Project Overview

Key Technical Highlights

• Hardened-State Gear Cutting: Wire EDM cuts gear teeth after quenching and tempering (52–58 HRC), eliminating the risk of distortion or micro-cracking associated with post-heat treatment grinding.
• DIN 5 Gear Accuracy: Achieved ±0.008mm tooth profile tolerance and ±0.005mm pitch error across all gear sizes, ensuring smooth, quiet, and efficient power transmission.
• Any Gear Profile: Wire EDM handles spur gears, helical gears, internal gears, splines, and custom profiles without requiring special hobs or form cutters — ideal for prototypes and small-to-medium batches.
• No Heat-Affected Zone (HAZ): Unlike laser or plasma cutting, wire EDM produces no metallurgical damage to the gear tooth surface, preserving the nitriding steel's wear resistance and fatigue life.
• 1.8519 Material Benefits: This nitriding steel offers excellent core toughness after Q&T, and subsequent gas nitriding can further increase surface hardness to 800–900 HV for extreme wear applications.

Quality Verification

Every gear undergoes gear measuring center inspection for tooth profile, lead, pitch, and runout (DIN 5 compliance). Hardness is verified with Rockwell tester (52–58 HRC core). Surface finish of tooth flanks measured with profilometer (≤0.4μm Ra). Optional CMM inspection for bore and keyway geometry.

Industry Applications

These 1.8519 wire EDM gears are ideal for:
✓ Industrial gearboxes & reducers
✓ Robotics servo drives
✓ Aerospace actuation systems
✓ Heavy machinery transmissions
✓ Prototype & custom gear replacements

Why Partner With Us?

• Hardened gear cutting via slow wire EDM (no distortion)
• DIN 5 accuracy on gears up to 250mm OD
• Any profile: spur, helical, internal, spline, custom
• Full heat treatment support: Q&T + nitriding
• 25+ years of precision gear manufacturing