Bearing steel Comparison Guide: 52100 steel vs. GCr15 steel

If you are sourcing or designing bearings and precision shafts, you will inevitably encounter these two grades: AISI/SAE 52100 (US) and GB GCr15 (China). People often ask which is better and whether 52100 is a higher grade. This guide covers their differences in composition, performance applications, and purchasing advice.

What is the Relationship Between 52100 and GCr15?

52100 and GCr15 are not two different types of steel. They are two different names for the same type of steel under two different standard systems.

GCr15 is the grade in the Chinese standard GB/T 18254 for high-carbon chromium bearing steel. The G stands for rolling bearing steel, Cr for chromium, and 15 for an average chromium content of about 1.5%. 52100 is the SAE/AISI designation, covered in the US by ASTM A295.

These grades are in the same category as 100Cr6 in Europe and SUJ2 in Japan, and have corresponding grades in all major standard systems.

Standard system	Grade	Note
China GB/T 18254	GCr15	National standard; the main grade for domestic sourcing
US SAE/AISI (ASTM A295)	52100	US system; common for export and international projects
Europe EN ISO 683-17	100Cr6 (1.3505)	Widely used in Europe, often written directly on drawings
Japan JIS G4805	SUJ2	Japanese bearing steel grade

Chemical Composition Comparison

Both types of steel follow the same alloying principles: approximately 1% carbon content is used to improve hardness and wear resistance, approximately 1.4%–1.6% chromium content is used to improve hardenability and contact fatigue performance, while manganese and silicon are used to adjust hardenability and assist in deoxidation. Comparing the elemental limit standards of China and the United States side-by-side, you’ll find they are essentially the same table.

Composition (%)	GCr15 (China)	52100 (USA)
Carbon (C)	0.95–1.05	0.93–1.05
Chromium (Cr)	1.40–1.65	1.35–1.60
Manganese (Mn)	0.25–0.45	0.25–0.45
Silicon (Si)	0.15–0.35	0.15–0.35
Sulfur (S)	≤0.025	≤0.025
Phosphorus (P)	≤0.02	≤0.015

The chemical composition ranges of 52100 and GCr15 almost overlap, with only a few minute differences that are virtually imperceptible in engineering applications.What actually decides bearing fatigue life is steel cleanliness and inclusion control,both of which have strict regulations.

Heat Treatment Comparison

GCr15:

Quenching temperature: 830–850℃
Tempering temperature: 150–180℃

52100:

Quenching temperature: 845–860℃
Tempering temperature: 150–200℃

The two steel grades follow the same processing route.

First, spheroidizing annealing is performed: carbides are spheroidized, softening the microstructure for easier machining. The annealing hardness is typically 179–207 HRC.

Then, austenitizing is performed at approximately 830–860°C, followed by oil quenching to obtain a martensitic microstructure. Finally, low-temperature tempering at 150–190°C is carried out to relieve stress and maintain hardness.

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	Slightly better
Wear resistance	Excellent	Very excellent

Applications:52100 vs GCr15

he classic application is bearing rings and rolling elements (balls and rollers). Beyond that, they appear in precision shafts, ball screws, gauge blocks, and cold-work tooling where high hardness and wear resistance are required.

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).

Their limitations are also similar. Neither of these steels is stainless steel, so rust prevention treatment is required in humid environments. Due to their carbon content of approximately 1%, their weldability is poor. Welding requires preheating and post-weld heat treatment, and welding is generally avoided entirely for critical load-bearing components.

How to Choose Between 52100 and GCr15 steel?

If ASTM/AISI certification standards are required, for high-load/high-speed bearings, large-section parts, and applications demanding ultimate performance, choose 52100 steel.

For domestic procurement, with limited budgets and for small to medium-sized parts, GCr15 steel is sufficient.

The truly important factor isn’t the steel grade, but rather the requirements for non-metallic inclusions, decarburization, spheroidization, and ultrasonic testing standards. Even with the same steel grade, different mills and quality levels can result in significant differences in fatigue life.

Therefore, the next time someone compares 52100 and GCr15 steel, don’t ask which is better. Instead, confirm three things: which standard the product follows, what grade is indicated on the certificate, and what quality grade is required by the acceptance specifications.