Case Hardening vs. Through Hardening in Roller Chains
In the manufacturing process of roller chains, heat treatment is not only a process step, it directly determines the life limit, transmission efficiency, and failure resistance of the chain in harsh working environments. Among them, case hardening (Case Hardening) and overall quenching (Through Hardening) are two dominant technical routes, each forming unique performance advantages and applicable scenarios. The correct choice of hardening technology can increase the service life of roller chains.
What is Case Hardening?
Case hardening (also known as carburizing and quenching) is essentially a carbon diffusion process whose core goal is to build a high-carbon hardened layer on the surface of mild steel while maintaining the original toughness of the core.
Table: Comparison of main surface hardening process methods
| Process Type | Medium | Temperature Range | Hardened Layer Depth | Features |
| Gas Carburizing | Methane/propane gas | 900 - 950 ℃ | 0.5 - 2.0 mm | Precise control, suitable for mass production |
| Liquid Carburizing (cyanidation) | Sodium cyanide salt bath | 870 - 950 ℃ | 0.25 - 0.75 mm | Fast, but cyanide is highly toxic |
| solid Carburizing | Charcoal + barium carbonate | 900 - 930 ℃ | 1.0 - 1.5 mm | Simple equipment, suitable for small batches of special-shaped parts |
Nitro-Carburizing | Ammonia gas + hydrocarbon gas | 750 - 880 ℃ | 0.1 - 0.8 mm | Higher surface hardness and less deformation |
What is Through Hardening?
Overall quenching (also known as through quenching) is a traditional process for processing medium and high carbon steel (carbon content >0.3%). It achieves an increase in the overall hardness of the material through complete phase change. This technology is particularly suitable for components that require overall wear resistance and no impact load.
The core advantage of solidly quenched steel lies in its cross-sectional uniformity - it maintains consistent hardness and metallographic structure from the surface to the core. It is especially suitable for roller chain applications that require full-section wear resistance, such as conveyor chains that are in long-term contact with abrasive materials.
Table: Typical materials and properties of overall quenching
| Material | Carbon Content(%) | Medium | HRC | Applicable Chain Type |
| AISI 52100 | 1.0 | Oil | 60 - 64 | Precision Roller Chain |
| 1060 | 0.6 | Water | 55 - 60 | Agricultural Machinery Chain |
| 440C Stainless Steel | 1.2 | Air Cooling | 58 - 60 | Corrosion-resistant Chain |
Case Hardening VS. Through Hardening
| Aspects | Case Hardening | Through Hardening |
| Hardness Profile | Hard surface, soft core | Uniform hardness thoughout |
| Wear Resistance | High on the surface | Moderate |
| Thoughness | High due to ductile core | Lower, more brittle |
Fatigue Strength | Enhanced due to compressive surface stresses | Good, but less than case hardened |
Application | Components facing surface wear | Components under high tensile loads |
Choosing the Right Hardening Method
Loading characteristics
If there are impact loads or variable loads. Choose case-hardening roller chains
Wear mechanism
Deep abrasion or surface wear? The former chooses overall quenching
Environmental factors
Presence of corrosive media or high temperatures? Stainless steel overall quenching is better.
Accuracy requirements
High-precision transmission chains should be surface-hardened with small deformation.
Cost constraints
Overall quenching is more cost-effective when the budget is limited.
For applications requiring high surface wear resistance with impact loads, such as in conveyor systems, case-hardened roller chains are preferred.
For applications demanding uniform strength and less concern for surface wear, such as in lifting mechanisms, through-hardened roller chains are suitable.
CTS® | Professional Chain Manufacturer
CTS®-ChinaTransmissionS is a professional roller chain supplier with over 15 years in the power transmission industry. Our roller chains are manufactured from high-performance material, undergo nitro-carburizing compound heat treatment, enhancing their quality, durability & reliability.
High-performance Material
Chain Plate: 45Mn
Chain Pin: 20CrMnMo
Chain Bushing: 20Mn
Superior roller chain materials ensure a longer service life.
Nitro-Carburizing Compound Heat Treating
CTS uses automatic heat treatment, which is more efficient and accurate. During the carbonitriding heat treatment process, the addition of ammonia significantly enhances the roller chains' durability and resistance.
Wide-waist Link Plates
Increasing in width of the waist, wider-than-standard waist link plates greatly increase chain fatigue resistance and shock-load resistance.
As a professional roller chain supplier, our experienced technical team always learns the latest manufacturing technology. We offer various industrial chain options: roller chains, conveyor chains, stainless steel chains, heavy-duty roller chains, double-pitch roller chains, roller chain attachments, etc.
If you have any questions about roller chains, please contact us.
