JIS SUJ2 Bearing Steel: Comprehensive Guide to Properties, Usos

If you’re involved in manufacturing, automotor, or precision engineering, you know how crucial high-quality bearing steel is.JIS SUJ2 bearing steel—a Japanese industrial standard alloy—stands out for its exceptional durability and performance in high-stress applications. This guide covers everything from its core properties to real-world uses, helping you decide if it’s the right choice for your project.

1. Material Properties of JIS SUJ2 Bearing Steel

JIS SUJ2’s unique properties make it a top pick for bearings and high-wear components. Let’s break down its key characteristics.

1.1 Composición química

JIS SUJ2 follows strict Japanese Industrial Standards (JIS G4805), Garantizar un rendimiento constante. A continuación se muestra su composición química típica:

1.2 Propiedades físicas

These properties define how JIS SUJ2 behaves under physical conditions like temperature and magnetism:

• Densidad: 7.85 g/cm³ (consistent with most carbon-chromium steels)
• Punto de fusión: 1,420 - 1,460 ° C (2,588 - 2,660 ° F)
• Conductividad térmica: 46.0 W/(m · k) en 20 ° C (temperatura ambiente)
• Coeficiente de expansión térmica: 11.6 × 10⁻⁶/° C (de 20 - 100 ° C)
• Propiedades magnéticas: Ferromagnético (Atrae imanes), useful for sorting and non-destructive testing.

1.3 Propiedades mecánicas

Mechanical properties determine JIS SUJ2’s performance under force. All values below are measured after standard heat treatment (apagado y templado):

1.4 Otras propiedades

Two key properties make JIS SUJ2 ideal for bearings:

• Resistencia al desgaste: High carbon and chromium form hard carbides, reducing wear from rolling/sliding contact.
• Resistencia a la fatiga: Withstands millions of load cycles, critical for long-lasting bearings in motors or machinery.
• Resistencia a la corrosión: Moderate—needs coatings (P.EJ., enchapado de zinc) for wet/harsh environments (inferior to stainless steel).
• Endurecimiento: Easy to heat treat to uniform hardness across thick sections, ensuring consistent performance in large parts.

2. Applications of JIS SUJ2 Bearing Steel

JIS SUJ2’s properties make it perfect for components facing repeated stress and wear. Aquí están sus usos más comunes:

• Aspectos: The primary application—including ball bearings, rodamiento de rodillos, and needle bearings for cars, bicicleta, and industrial equipment.
• Rolling Elements: Balls, rodillos, or needles inside bearings rely on JIS SUJ2’s wear resistance to stay functional.
• Races: Inner/outer rings of bearings (where rolling elements move) are often made from JIS SUJ2.
• Componentes automotrices: Árbol de levas, valve lifters, and gearbox parts—all requiring high durability under engine stress.
• Maquinaria industrial: Cajas de cambios, transportadores, and pumps use JIS SUJ2 parts to handle heavy loads and long operating hours.
• Componentes aeroespaciales: Small bearings in aircraft landing gear or engine accessories (where reliability and weight matter).
• Dispositivos médicos: Precision bearings in MRI machines or surgical tools (thanks to its magnetic properties and strength).
• Electrical Motors: Bearings in electric motors (P.EJ., for appliances or industrial motors) benefit from its fatigue resistance.

3. Manufacturing Techniques for JIS SUJ2

Producing JIS SUJ2 requires precise steps to meet JIS standards. Here’s the typical process:

1. Creación de acero:
   • Most JIS SUJ2 is made via Horno de arco eléctrico (EAF) (for scrap steel recycling) o Horno de oxígeno básico (Bof) (for iron ore-based production). The goal is to adjust chemical composition to match JIS G4805 requirements.
2. Laminación:
   • Después de la creación de acero, the metal is Rollado caliente (1,100 - 1,200 ° C) into billets or bars to shape it. For precision parts, it’s then Enrollado (temperatura ambiente) to improve surface finish and dimensional accuracy.
3. Tratamiento térmico:
   • Critical for JIS SUJ2’s performance:
     • Temple: Calentarse 820 - 860 ° C, then rapid cooling in oil/water to harden the steel.
     • Templado: Reheat to 150 - 200 °C to reduce brittleness while maintaining high hardness.
     • Carburador: Sometimes used for parts needing a hard outer layer (P.EJ., dientes de engranaje)—heat in a carbon-rich atmosphere to add surface carbon.
4. Mecanizado:
   • Tratamiento posterior al calor, parts are machined to final shapes using Torneado (for cylindrical parts like bearing races) o Molienda (for ultra-smooth surfaces, essential for bearing performance).
5. Tratamiento superficial:
   • Pasos opcionales para mejorar el rendimiento:
     • Nitrurro: Adds a hard surface layer to boost wear resistance.
     • Blackening: Creates a protective oxide layer to prevent minor rust.
6. Control de calidad:
   • Inspections include:
     • Análisis químico (to verify element content).
     • Hardness testing (Rockwell/Vickers machines).
     • Pruebas no destructivas (ultrasonic testing for internal cracks).
     • Dimensional checks (calipers/CNC tools to ensure fit).

4. Estudios de caso: JIS SUJ2 in Action

Real-world examples show how JIS SUJ2 solves industry problems.

Estudio de caso 1: Electric Motor Bearing Durability

A manufacturer of industrial electric motors faced frequent bearing failures (después 8,000 horas de uso). They switched from a low-grade steel to JIS SUJ2 bearings. Post-switch, bearing life extended to 20,000 horas, reducir los costos de mantenimiento por 40%.

Estudio de caso 2: Automotive Bearing Failure Analysis

A Japanese carmaker noticed bearing failures in their compact car engines (después 60,000 km). Testing revealed the original bearings used a non-standard steel. Switching to JIS SUJ2 bearings cut failure rates by 75%, with bearings lasting 150,000 km.

5. JIS SUJ2 vs. Other Bearing Materials

How does JIS SUJ2 compare to other common bearing materials? La mesa a continuación lo desglose:

Yigu Technology’s Perspective on JIS SUJ2

En la tecnología yigu, JIS SUJ2 is a go-to for clients in automotive and electrical motor industries. Its balance of wear resistance, fatiga, and cost-effectiveness is unmatched for most bearing needs. We pair JIS SUJ2 with precision machining to make parts that last 15-20% longer than standard steel options. For harsh environments, we offer custom nitriding or zinc plating to boost its corrosion resistance, meeting strict client requirements.

FAQ About JIS SUJ2 Bearing Steel

1. Can JIS SUJ2 be used in wet or corrosive environments?
   JIS SUJ2 has moderate corrosion resistance. For wet/harsh environments (P.EJ., marine or food processing), apply a protective coating like zinc plating or nitriding to prevent rust.
2. What surface treatments work best for JIS SUJ2?
   Nitrurro Mejora la resistencia al desgaste, mientras enchapado de zinc aumenta la resistencia a la corrosión. Blackening is a low-cost option for minor rust protection in dry environments.
3. How does JIS SUJ2 compare to 100Cr6?
   Son casi idénticos! JIS SUJ2 is the Japanese standard, and 100Cr6 is the European (EN) estándar. Both have the same carbon (0.95–1.05%) y cromo (1.30–1.65%) contenido, so they’re interchangeable in most applications.