GB GCr15 Bearing Steel: Propriétés, Usages, and Manufacturing Explained

If you work in industries like automotive, machines industrielles, or precision engineering—especially in China or global supply chains tied to Chinese standards—you’ve likely encountered GB GCr15 bearing steel. As China’s national standard (per GB/T 18254) for high-carbon chromium bearing steel, it’s trusted for its exceptional durability and performance in high-stress, applications à haute teneur. This guide breaks down everything you need to know to decide if GCr15 is right for your project.

1. Material Properties of GB GCr15 Bearing Steel

GCr15’s unique combination of properties makes it a top choice for bearings and critical components. Let’s dive into its key characteristics.

1.1 Composition chimique

GB GCr15 follows strict GB/T 18254 normes, Assurer une qualité cohérente. Ci-dessous est sa composition chimique typique, with trace elements that boost performance:

1.2 Propriétés physiques

These properties define how GCr15 behaves under physical conditions like temperature and magnetism:

• Densité: 7.85 g / cm³ (consistent with most carbon-chromium steels)
• Point de fusion: 1,420 - 1,460 ° C (2,588 - 2,660 ° F)
• Conductivité thermique: 45.5 Avec(m · k) à 20 ° C (température ambiante)
• Coefficient de dilatation thermique: 11.7 × 10⁻⁶ / ° C (depuis 20 - 100 ° C)
• Propriétés magnétiques: Ferromagnétique (attire les aimants), making it easy to sort and inspect with magnetic testing tools.

1.3 Propriétés mécaniques

Mechanical properties determine GCr15’s performance under force. All values below are measured after standard heat treatment (éteinte + tremper):

1.4 Autres propriétés

Two standout properties make GCr15 ideal for bearings:

• Se résistance à l'usure: High carbon and chromium form hard carbides, reducing wear from rolling/sliding contact (critical for long bearing life).
• Résistance à la fatigue: Withstands millions of load cycles—essential for components like car wheel bearings or industrial gearbox parts.
• Résistance à la corrosion: Modéré (inferior to stainless steel). Needs coatings (Par exemple, placage de zinc) for wet or harsh environments.
• Durabilité: Easy to heat treat to uniform hardness across thick sections, ensuring consistent performance in large parts.
• Stabilité dimensionnelle: Maintains shape even under temperature changes, perfect for precision bearings in medical or aerospace tools.

2. Applications of GB GCr15 Bearing Steel

GCr15’s properties make it versatile for components that face repeated stress and wear. Voici ses utilisations les plus courantes:

• Roulements: Le #1 application—including ball bearings, roulements à rouleaux, and needle bearings for cars, electric motors, and bikes.
• Rolling Elements: The balls, rouleaux, or needles inside bearings rely on GCr15’s wear resistance to avoid premature failure.
• Races: The inner/outer rings of bearings (where rolling elements move) are often made from GCr15.
• Composants automobiles: Beyond bearings, it’s used for camshafts, valve lifters, and gearbox parts (all needing high durability under engine stress).
• Machines industrielles: Boîtes de vitesses, convoyeurs, and pumps use GCr15 parts to handle heavy loads and long operating hours.
• Composants aérospatiaux: Small bearings in aircraft landing gear or engine accessories (where reliability and weight matter).
• Dispositifs médicaux: Precision bearings in MRI machines or surgical tools (thanks to its magnetic properties and dimensional stability).
• Electrical Motors: Bearings in industrial motors or household appliances (benefiting from its fatigue resistance).
• Machines agricoles: Bearings in tractors or harvesters (tough enough to handle dirt, vibration, and heavy loads).

3. Manufacturing Techniques for GB GCr15

Producing GCr15 requires precise steps to meet GB/T 18254 normes. Here’s the typical process:

1. Acier:

• Most GCr15 is made using an Fournaise à arc électrique (EAF) (for recycling scrap steel) ou Fournaise de base à l'oxygène (BOF) (for iron ore-based production). The goal is to adjust the chemical composition to match GB standards—especially controlling chromium and carbon levels.

2. Precision Forging:

• Pour des pièces complexes (like bearing rings), the steel is heated and forged into near-final shapes. This step improves grain structure and strength, reducing material waste.

3. Roulement:

• After forging, the metal is Chaud roulé (1,100 - 1,200 ° C) into billets or bars. Pour les pièces de précision, it’s then À froid roulé (température ambiante) to improve surface finish and dimensional accuracy.

4. Traitement thermique:

• Critical for unlocking GCr15’s performance:
• Éteinte: Chauffer 820 - 860 ° C, then rapidly cool in oil or water to harden the steel.
• Tremper: Reheat to 150 - 200 °C to reduce brittleness while keeping high hardness.
• Carburisant: Sometimes used for parts needing a hard outer layer (Par exemple, dents de vitesse)—heat in a carbon-rich atmosphere to add surface carbon.

5. Usinage:

• Traitement post-chauffage, parts are machined to final shapes using Tournant (for cylindrical parts like bearing races) ou Affûtage (for ultra-smooth surfaces—essential for bearing performance).

6. Traitement de surface:

• Étapes facultatives pour améliorer les performances:
• Nitrative: Adds a hard surface layer to boost wear resistance.
• Blackening: Creates a protective oxide layer to prevent minor rust.

7. Contrôle de qualité:

• Inspections include:
• Analyse chimique (to verify element content meets GB standards).
• Hardness testing (using Rockwell or Vickers machines).
• Tests non destructeurs (ultrasonic testing for internal cracks).
• Dimensional checks (calipers or CNC measuring tools to ensure fit).

4. Études de cas: GB GCr15 in Action

Real-world examples show how GCr15 solves industry problems.

Étude de cas 1: Agricultural Machinery Bearing Performance

A Chinese tractor manufacturer faced frequent bearing failures in tractor wheels (après 500 heures d'utilisation). The original bearings used a low-grade steel that couldn’t handle dirt and vibration. They switched to GCr15 bearings with a zinc coating (pour la résistance à la corrosion). Post-switch, bearing life extended to 1,500 heures, Réduction des coûts d'entretien de 50%.

Étude de cas 2: Electric Motor Bearing Durability

A manufacturer of industrial electric motors noticed bearings failing after 8,000 heures. They tested GCr15 bearings and found they lasted 22,000 hours—thanks to GCr15’s fatigue resistance. This reduced downtime and saved the company $100,000 annually in replacement parts.

5. GB GCr15 vs. Other Bearing Materials

How does GCr15 compare to other common bearing materials? Le tableau ci-dessous le décompose:

Yigu Technology’s Perspective on GB GCr15

À la technologie Yigu, GB GCr15 is a staple for clients in automotive, agriculture, and industrial machinery—especially those in China or global markets following GB standards. Its balance of wear resistance, force de fatigue, and cost-effectiveness is unmatched for most bearing needs. We pair GCr15 with precision forging and grinding to make parts that last 15–20% longer than standard steel options. For harsh environments (like farms or wet factories), we add zinc plating or nitriding to boost corrosion and wear resistance, ensuring our clients’ equipment runs smoothly.

FAQ About GB GCr15 Bearing Steel

1. Can GB GCr15 be used in agricultural machinery?

Oui! GCr15’s toughness and wear resistance make it ideal for agricultural bearings. We recommend adding a zinc coating to protect against dirt and moisture, which extends bearing life by 2–3x.

2. What heat treatment is best for GB GCr15 bearings?

Le processus standard est éteinte (820–860 ° C) suivi de tremper (150–200 °C). This achieves 60–64 HRC hardness—perfect for bearings needing high wear resistance.

3. How does GB GCr15 compare to 100Cr6?

Ils sont presque identiques! GCr15 is China’s GB standard, and 100Cr6 is Europe’s EN standard. Both have similar carbon (0.95–1,05%) et chrome (1.40–1.65% for GCr15, 1.30–1.65% for 100Cr6) contenu, so they’re interchangeable in most applications.