What is the hardness of C55 steel material in HRC?

The hardness of C55 steel material in HRC (Rockwell Hardness C scale) varies depending on its heat treatment condition. Since C55 steel is a medium-carbon steel (0.52-0.60% carbon), it can be heat-treated to achieve different hardness levels.  

Hardness in Different Conditions:  
1. Annealed Condition:  
- Softest state with improved machinability  
- Hardness: HRC 15-20 (Brinell Hardness: ~140-180 HB)  

2. Normalized Condition:  
- Refining grain structure for better toughness  
- Hardness: HRC 20-30 (Brinell Hardness: ~180-250 HB)  

3. Quenched Condition (Oil or Water Quenching):  
- Achieves maximum hardness before tempering  
- Hardness: HRC 50-55 (Brinell Hardness: ~500-550 HB)  

4. Tempered Condition (After Quenching):  
- Balances hardness with improved toughness  
- Hardness: HRC 40-50 depending on tempering temperature  
- Lower tempering temperature (~200°C) retains higher hardness (~HRC 50)  
- Higher tempering temperature (~500°C) reduces hardness (~HRC 35-40) while improving ductility  

C55 steel factors Affecting Hardness:  
- Quenching Medium: Water quenching gives higher hardness than oil quenching.  
- Tempering Temperature: Higher temperatures reduce hardness but improve toughness.  
- Section Thickness: Thicker sections may not fully harden due to slower cooling rates.  

Typical Applications of Hardened C55 steel:  
- High-strength machine parts  
- Gears, shafts, and axles  
- Springs and clutch plates  
- Cutting tools requiring moderate wear resistance  

If you need specific hardness values based on your application or processing method, let me know! We will supply more C55 steel informations and details.