Advanced Heat Treatment & Hardening
To achieve the required mechanical durability, Srimukha operates an in-house heat treatment facility. By controlling the carbon diffusion and microstructural phase changes (Martensitic transformation) in-house, we guarantee tooth fatigue strength and surface hardness on our gears and shafts. Typical materials used for Heat Treatment: SCM415H/SCM420H/16MnCrS5H/42CrMo4/S45C/41Cr4/EN18D
Heat Treatment Equipment
Our heat treatment shop runs continuous sealed quench furnaces and specialised induction hardening lines:
- IPSEN Sealed Quench Furnaces (SQF): Multiple IPSEN furnace lines running controlled atmosphere (Endo gas) gas carburizing and hot oil quenching (120-140° C) with 24/7 SCADA control process monitoring & data logging features. 300kg (2 nos) & 1.5 MT (1 no)
- Vertical Induction Hardening Machines: 12+ CNC vertical scanner stations (high frequency) for shaft spline and journal hardening with shallow case-depth capability using polymer oil quenching and on-line tempering.
- Horizontal Induction Hardening: 4 horizontal induction hardening machines with auto-loading/unloading rotating fixtures & in-line tempering for armature shafts & shaft outputs with polymer oil quenching, leading to minimum distortion.
- Belt-type Annealing furnace: 2/4-ton slug annealing furnace with SCADA Control and nil/partial de-carburisation.
Process Workflow & Atmosphere Control
Parts are loaded into the IPSEN furnace and heated in an atmosphere enriched with carbon-carrying gases (Endothermic atmosphere). Carbon depth is precisely controlled by regulating carbon potential. After carburizing, parts are quenched in agitated quenching oil (hot oil – 120-140°C) to freeze the microstructure. Parts are washed and tempered to achieve the desired hardness.
“Gas carburizing followed by oil quenching produces a hard, wear-resistant surface case while preserving a tough, impact-resistant core.”
Hardness Testing & Metallurgy
Every batch is verified for quality parameters. We measure effective case depth (ECD) at 550 Hv, surface hardness (typically 58-62 HRC), and core hardness. Testing equipment includes MATSUZAWA Micro-Vickers hardness testers, Rockwell hardness testers, and non-destructive eddy current crack detectors.
Visual Technical Showcase
Sealed Quench Furnace: Atmospheric gas carburizing line showing oil quenching of automotive pinion shafts.
Induction Hardening: Horizontal scanner executing localized induction hardening on starter motor shafts.
