Heat Treatment & Metallurgy Solutions
Heat Treatment and Surface Hardening for Enhanced Material Performance
Heat treatment is a metallurgical process that improves the mechanical properties of metal parts—such as hardness, wear resistance, toughness, and fatigue strength—by controllably altering the microstructure. At Akce Engineering, we perform thermochemical and neutral (volumetric) heat treatments in accordance with international standards for the automotive, defence, machinery, energy, and tooling sectors. All processes are reported with full traceability through hardness measurement, microstructural analysis, and case-depth inspection.
Thermochemical (Diffusion) Heat Treatments
A high-hardness surface layer is formed by diffusing elements such as carbon, nitrogen, or boron into the part surface, while core toughness is preserved.
- Case Hardening (Carburizing): Carbon diffusion into the surface of low-carbon steels for high surface hardness and a ductile core.
- Nitriding: Nitrogen diffusion at low temperature for high wear and corrosion resistance with minimal distortion.
- Carbonitriding: Simultaneous diffusion of carbon and nitrogen; hard surface even on steels with low hardenability.
- Boriding: Boron diffusion creating an extremely hard (1500–2000 HV) surface layer with high wear resistance.
- Oxidation (Steam Oxidation / Black Oxide): Corrosion resistance and aesthetic black surface finish; friction reduction.
Neutral and Volumetric Heat Treatments
Desired mechanical properties are achieved by controlling microstructure and internal stresses throughout the entire cross-section of the part.
- Quench & Temper: Hardening followed by tempering to achieve a balanced hardness–toughness combination.
- Vacuum Hardening: Oxide-free, bright surface finish; low distortion and high repeatability.
- Induction Hardening: Surface and localized hardening; ideal for shafts, gears, and journal bearings.
- Normalizing: Grain refinement and homogenization for balanced mechanical properties.
- Stress Relieving (Annealing): Reduction of internal stresses caused by welding and machining.
- Solution Annealing: Dissolution of carbides in stainless and alloy steels to restore corrosion resistance.
- Martempering & Austempering: Controlled cooling for low distortion and high toughness.
- Cryogenic Treatment (Deep Freezing): Conversion of retained austenite to martensite for improved dimensional stability and wear resistance.
Quality and standards: All heat treatments are reported with hardness (HRC/HV), microstructure, case depth, and distortion inspections; process control in compliance with AMS 2750, CQI-9, and relevant customer specifications is ensured.
For your manufacturing needs before and after heat treatment, we offer end-to-end solutions including pressure vessels, stainless spool manufacturing, and overhaul services.
Which Process for Which Part
The same furnace gives a different result on a different part. Below are the part types we work with most often and the processes we apply to them.
Gears and Transmission Parts
Case hardening and carbonitriding give a hard surface over a ductile core; fatigue strength at the tooth root rises.
Shafts, Axles and Pins
Induction surface hardening or quench and temper; the wear zone hardens while the toughness of the part is kept.
Dies and Tool Steels
Vacuum hardening gives a scale-free, bright surface and low distortion, for dies where dimensional consistency is critical.
Defence Industry Parts
Heat treatment traceable through batch-level process records with hardness and case depth reporting.
Hydraulic and Pneumatic Components
Nitriding gives low distortion with high wear and corrosion resistance, for cylinder and piston surfaces.
Pump and Valve Bodies
Stress relieving and solution annealing remove post-weld internal stresses and carbide precipitation.
Parts Exposed to Wear
Boriding gives a case in the 1500–2000 HV range, for applications where abrasive wear dominates.
Parts Needing Dimensional Stability
Cryogenic treatment converts retained austenite to martensite; dimensional stability and wear resistance improve.
Welded Structures
Post-weld stress relief annealing reduces the risk of distortion and cracking.
Process and Control Framework
Hardness, microstructure and case depth are measured on every batch and the results go into the report. In heat treatment, traceability matters as much as the result itself.
What Buyers Ask Before a Quote
The questions purchasing and technical teams ask most often about the equipment on this page.
How do you determine which process suits my part?
Material, part geometry, the expected surface hardness against core toughness, and the service condition (wear, fatigue, corrosion) are weighed together. Send those four and we settle the process and the control plan with you.
What is the difference between case hardening and nitriding?
Case hardening diffuses carbon at high temperature to form a thick, very hard case, then needs quenching, which carries a distortion risk. Nitriding works at a lower temperature through nitrogen diffusion; the case is thinner but distortion is minimal and corrosion resistance also improves. Where dimensional accuracy is critical, nitriding comes forward.
Does distortion occur after heat treatment?
Some dimensional change is unavoidable in processes that involve quenching. Controlled-cooling processes such as vacuum hardening, nitriding and martempering reduce distortion markedly. On critical parts we recommend leaving a grinding allowance before treatment.
Do you issue hardness and case depth reports?
Yes. Every batch gets hardness testing (Rockwell, Vickers or Brinell), microstructure analysis and case depth control; results go into the report together with the batch-level process record.
When is boriding preferred?
Boriding forms a very hard case in the 1500–2000 HV range. It is preferred on parts where abrasive wear dominates and case hardening or nitriding falls short. The case is hard but brittle, so it needs weighing on parts under high impact load.
Not sure which process suits your part?
Send us the material, the part geometry and the hardness and service conditions you expect; we will settle the process and the control plan together.