Empowering European Gear Manufacturing through Vacuum Carburizing

Lakshmi Vacuum Technologies delivered a fully integrated Low Pressure Vacuum Carburizing Furnace (LPCF series) with 15-bar gas quenching to a leading Bulgarian gear manufacturer, enabling cleaner, distortion-free heat treatment for high-performance gears.

Client Background

Based in Bulgaria, the client supplies critical transmission gears to Tier-1 automotive and industrial OEMs in the EU. They needed to replace atmosphere carburizing and oil quenching with a modern, green, distortion-controlled heat treatment process.

Surface hardness: 58–62 HRC
Core hardness: 35–45 HRC
Effective case depth: 0.8–1.2 mm
Minimal distortion and post-processing

Technical Challenge

Uniform deep case depth with precise carbon control
Zero oxidation and IGO-free surfaces
Low distortion without oil quenching
Compliance with EU safety and environmental norms

Solution Delivered

Lakshmi Vacuum delivered a custom LPCF furnace system with 15-bar High Pressure Gas Quenching (HPGQ), SCADA automation, and full process flexibility for medium alloy steels like 16MnCr5 and 20MnCr5.

Key Features of the Furnace

Chamber: Horizontal, cold-wall, double-shell SS
Heating: Graphite elements with multizone control
Vacuum Level: Base vacuum up to 10⁻⁵ mbar
Carburizing: Acetylene/Propane pulse at ~10–13 mbar
Quenching: 15 bar N₂/He via internal blower
Cooling: Internal exchanger + centrifugal fan
Control: PLC-SCADA with recipe management
Case Depth: Up to 1.5 mm programmable

Metallurgical Results

Joint validation trials on 20MnCr5 gear blanks (120 mm dia × 30 mm):

Surface Hardness: 60 ± 1 HRC
Core Hardness: 38–42 HRC
Effective Case Depth: 1.0 mm (550 HV1)
Distortion: <0.1 mm ovality
Surface: Bright, oxide-free, polishing-ready

“We were impressed by the consistency of hardness and the absence of oxidation – even in blind bores. The gas quenching delivered distortion control far superior to oil. It has transformed our approach to gear hardening.”
— Production Head, Gear Facility, Bulgaria

Customer Impact

<±0.05 mm case depth variation across batches
No need for shot blasting or cleaning post-process
Energy savings with electric heating + N₂ quenching
CE compliant and EU certified furnace system
Remote diagnostics + SCADA logging built-in

Long-Term Benefits

Clean Process: No oil, no smoke, eco-friendly

Flexibility: Treats various steel grades

Cost Savings: Lower rework, scrap, energy

Autonomy: Client runs 3 LPC recipes independently

Reliability: >97% uptime over 3 years

Why Lakshmi Vacuum?

One of India’s few 15-bar HPGQ furnace OEMs
Integrated LPC + HPGQ with full SCADA
In-house process metallurgy and hands-on training
CE-certified for global deployment

Conclusion

Lakshmi Vacuum’s advanced LPCF platform empowered the client to transition from conventional oil quenching to modern gas quenching with complete process control. The result: cleaner, safer, and more precise gear heat treatment for European OEM standards.