GCr15 (Chinese standard GCr15) and 52100 (American standard SAE 52100) are both high-carbon chromium bearing steels, widely used in bearings, precision machinery parts and other fields. The following is a comparative analysis from multiple dimensions:
1. Chemical Composition Comparison
| Composition (%) | GCr15 (China) | 52100 (USA) |
| Carbon (C) | 0.95–1.05 | 0.98–1.10 |
| Chromium (Cr) | 1.30–1.65 | 1.30–1.60 |
| Manganese (Mn) | ≤0.25 | 0.25–0.45 |
| Silicon (Si) | 0.15–0.35 | 0.15–0.35 |
| Sulfur (S) | ≤0.020 | ≤0.025 |
| Phosphorus (P) | ≤0.027 | ≤0.025 |
What are the main differences in the chemical composition of 52100 and GCr15 steel?
- Manganese content: 52100 has a higher manganese content (0.25–0.45% vs. ≤0.25%), which helps improve hardenability and strength.
- Chromium range: GCr15 has a slightly wider chromium range, which may affect corrosion resistance stability.
2. Physical & Mechanical Properties Comparison
| Performance index | GCr15 Steel | 52100 Steel |
| Hardness (after quenching)(HRC) | 62-65 | 62-65 |
| Tensile strength (MPa) | 2000 | 2100 |
| Yield strength (MPa) | 1800 | 1900 |
| Impact toughness | Medium (better than ordinary high carbon steel) | Slightly better (due to high Mn content) |
| Wear resistance | Excellent | Very excellent |
What is the difference in mechanical properties between 52100 and GCr15 steel?
52100 has a higher manganese content and slightly better hardenability, which is suitable for uniform hardening of thicker cross-section parts; its wear resistance and fatigue strength are slightly better than GCr15.
3. Comparison of Quenching & Tempering Processes
GCr15:
- Quenching temperature: 830–850℃ (oil cooling)
- Tempering temperature: 150–180℃ (low temperature tempering, maintaining high hardness)
52100:
- Quenching temperature: 845–860℃ (oil or salt bath cooling)
- Tempering temperature: 150–200℃
What are the core differences in quenching and tempering between 52100 and GCr15 steel?
52100 has a wider quenching temperature range to adapt to complex working conditions; and some of its processes use salt bath cooling to reduce deformation.
4. Differences In Application Fields
- Common applications: rolling bearings, precision gears, cutting tools, measuring tools, etc.
- GCr15 tends to: Chinese manufacturing (lower cost), small and medium-sized bearings.
- 52100 tends to: European and American high-end bearings, aviation/racing car parts (high fatigue life requirements).
5. Comparison of Advantages & Disadvantages
| GCr15 Steel | 52100 Steel | |
| Advantages | Low cost, easy to obtain (Chinese market) | High fatigue life, good hardenability |
| Disadvantages | Slightly poor hardenability in large sections | Higher price (import-dependent regions) |
Summary: How to Choose Between 52100 & GCr15 steel?
- Prioritize GCr15: limited budget, small and medium-sized parts, and local Chinese supply chain.
- Prioritize 52100: high-load/high-speed bearings, large-section parts, and pursuit of extreme performance.
GCr15 and 52100 are essentially the same type of high-carbon chromium steel, but they differ slightly in composition and performance due to differences in standards. 52100 has a slightly higher manganese content, which makes it better in hardenability and fatigue life and suitable for high-end applications; GCr15 has a more cost-effectiveness and is suitable for conventional needs. The selection should be based on performance requirements, budget, and supply chain convenience.
