Surface hardening process comparison and selection guide
All called "surface hardening", different processes have very different applications. Choosing wrong means at best failing service life targets and at worst deforming and scrapping parts. Below we set out the key differences among commonly used processes.
| Process | Hardness | Deformation | Applications |
|---|---|---|---|
| Carburizing and quenching | HRC58-62 | Relatively large, post-heat finishing required | Gears and shafts requiring high hardness plus a tough core |
| Nitriding | HV900-1100 | Very small | Precision parts and long shafts with no machining after heat treatment |
| Medium-frequency induction hardening | HRC50-58 | Medium | Roll surfaces and large journals, local hardening |
| Hard chrome plating | Above HV800 | Almost none | Guide rollers and piston rods, wear plus corrosion resistance |
| Tungsten carbide coating | Above HRC65 | Small | High-speed wire rod step cone pulleys, high-temperature wear conditions |
| PVD coating | HV2000-4000 | None (≤500℃) | Molds and cutting tools, reducing friction |
Basic logic for selection
First look at the failure mode: abrasive wear, adhesive wear or corrosion? Then look at part accuracy requirements: can it still be ground after heat treatment? Finally look at batch size and cost. After these three steps, usually only one or two processes remain.
Several common misconceptions
It is a misconception that higher hardness is always better; increased brittleness instead makes edge chipping likely; nitriding layers are thin and cannot bear large contact stress; chrome plating solves wear but does not resist high temperatures. For specific selection, send us the working conditions, drawings and failure samples together for evaluation.
