Product Overview
A heat-treated gear plate (also known as a hard-faced gear plate) refers to a precision gear that has undergone surface hardening treatment such as carburizing, nitriding, or induction hardening, achieving tooth surface hardness of HRC 58–62. Heat treatment is the key process for achieving high gear performance — surface hardening provides excellent wear resistance and anti-pitting capability while maintaining sufficient core toughness to withstand impact loads. The lifespan of a heat-treated gear can be 5–10× that of a soft-faced gear, making it a core component of modern high-end transmission systems.
Yubao Transmission Technology possesses a comprehensive heat treatment process system and post-heat-treatment gear finishing capabilities. Using controlled-atmosphere batch furnaces for carburizing, effective case depth (EHT) can be precisely controlled within 0.5–1.5mm. Nitriding treatment (gas nitriding/plasma nitriding) is also available with case depth 0.1–0.5mm and minimal distortion. Post-heat-treatment CNC worm wheel grinding or honing corrects heat treatment distortion to DIN Grades 5–6 accuracy with surface roughness Ra≤0.4μm, achieving the optimal combination of heat treatment strengthening and precision manufacturing.
Technical Parameters
Basic Gear Parameters
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Outer Diameter (Tip) |
da |
mm |
50–400 |
h11 |
Tip circle diameter |
| Module |
m |
mm |
0.5–5.0 |
— |
Straight or helical |
| Number of Teeth |
z |
— |
Customized |
— |
Determined by transmission ratio |
| Pressure Angle |
α |
° |
15°–30° |
— |
Typically 20° |
| Pitch Diameter |
d |
mm |
Customized |
— |
d = m×z |
| Face Width |
b |
mm |
5–200 |
±0.05 |
Working face width |
| Accuracy Grade |
— |
DIN/ISO |
Grade 5 |
— |
Post-heat-treatment machining achieves DIN 5 |
| Face Runout |
— |
mm |
0.02 |
≤ |
Relative to bore |
| Radial Runout |
— |
mm |
0.02 |
≤ |
Tip relative to bore |
Key Heat Treatment Parameters
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Pre-HT Accuracy |
— |
DIN/ISO |
Grade 7 |
— |
Typically 1–2 grades below finished accuracy |
| Heat Treatment Process |
— |
— |
Carburizing/Nitriding/Induction |
— |
Optimal process selected per application |
| Effective Case Depth |
EHT |
mm |
0.3–1.5 |
min. |
E.g., 0.5–0.8mm, 0.8–1.2mm |
| Surface Hardness |
HRC |
— |
58–62 |
Range |
Typical for carburized gears |
| Core Hardness |
HRC |
— |
30–45 |
min. |
E.g., 30–35, toughness assurance |
| Post-HT Finishing Process |
— |
— |
Grinding/Honing/Lapping |
— |
Corrects heat distortion, improves accuracy |
| Post-HT Accuracy Grade |
— |
DIN/ISO |
Grade 5 |
— |
Final finished accuracy |
| Tooth Surface Roughness (Post-HT) |
Ra |
μm |
0.4 |
≤ |
After grinding |
Process Flow
| Process Stage |
Process Content |
Quality/Accuracy Indicator |
| Blank Preparation |
Forging/Cutting + Rough Turning |
Leave machining allowance |
| Rough Hobbing |
CNC Hobbing Machine roughing |
DIN Grades 8–9 (leave 0.1–0.3mm grinding stock) |
| Heat Treatment |
Carburizing/Nitriding/Induction Hardening |
EHT达标, hardness HRC 58–62 |
| Post-HT Sizing |
Bore/Face Precision Grinding (distortion correction) |
Datum restoration |
| Finish Hobbing/Grinding |
Worm Wheel Grinder precision machining |
DIN Grades 4–6 |
| Honing (Optional) |
Honing to improve tooth surface quality |
Ra≤0.4μm |
| Final Inspection |
Gleason 300GMS full parameter inspection |
100% gear verification |
Heat Treatment Process Comparison
| Parameter |
Carburizing |
Gas Nitriding |
Plasma Nitriding |
Induction Hardening |
| Case Depth |
0.5–1.5mm |
0.1–0.3mm |
0.2–0.5mm |
0.5–3mm |
| Surface Hardness |
HRC 58–62 |
HV 900–1100 |
HV 900–1100 |
HRC 55–60 |
| Core Hardness |
Adjustable (HRC 30–45) |
Unchanged |
Unchanged |
Unchanged |
| Distortion Level |
Significant (requires post-HT machining) |
Minimal |
Very small |
Moderate |
| Material Requirement |
Carburizing steels (20CrMnTi etc.) |
Al-alloy steels (38CrMoAl etc.) |
Alloy steels |
Medium carbon/alloy steels |
| Suitable Module |
Medium (m≥1) |
Small module precision gears |
Small-medium |
Large module |
| Cost |
Moderate |
Higher |
Higher |
Lower |
| Wear Resistance |
Excellent |
Superior (white layer) |
Superior |
Good |
Product Features
- Extended Lifespan: Tooth hardness HRC 58–62 provides 5–10× wear resistance of soft-faced gears
- High Accuracy Maintained: Post-heat grinding corrects distortion to DIN Grades 4–6
- Strong Anti-Pitting Capability: Controllable case depth effectively resists contact fatigue
- Excellent Anti-Scuffing Performance: High hardness tooth surfaces resist adhesive wear, suitable for high-speed heavy-duty
- Mature Process: Complete carburizing-quenching-tempering-grinding process chain, stable quality
Typical Applications
| Application Sector |
Specific Use |
Recommended Heat Treatment |
| Precision Reducers |
High-precision gear plates |
Carburizing + Grinding |
| Automotive Transmissions |
Shift gears |
Carburizing (high volume) |
| Wind Energy |
Main gearbox gears |
Carburizing (large module) |
| Aerospace/Precision Instruments |
Small module precision gears |
Plasma Nitriding (minimal distortion) |
| Construction Machinery |
Heavy-duty gears |
Induction Hardening (localized hardening) |
