Acier à roulement inoxydable JIS SUS440C: Propriétés, Utilisations & Comparaison

Si vous avez affaire à du mouillé, corrosif, or sanitary environments—like food processing or marine applications—standard bearing steel just won’t cut it.JIS SUS440C stainless bearing steel solves this problem: c'est un acier inoxydable martensitique qui combine une résistance exceptionnelle à la corrosion avec la résistance à l'usure nécessaire aux roulements. Ce guide détaille ses principales propriétés, utilisations réelles, processus de fabrication, et comment il se compare à d'autres matériaux, helping you pick the right steel for tough, wet conditions.

1. Material Properties of JIS SUS440C Stainless Bearing Steel

JIS SUS440C’s unique mix of high carbon and chromium makes it stand out: it resists rustet handles wear. Let’s dive into its properties.

1.1 Composition chimique

JIS SUS440C follows strict Japanese Industrial Standards (JIS G4303), garantir des performances constantes. Vous trouverez ci-dessous sa composition chimique typique:

1.2 Propriétés physiques

These properties describe how JIS SUS440C behaves under physical conditions like heat and magnetism:

• Densité: 7.75 g/cm³ (slightly less than standard carbon bearing steels)
• Point de fusion: 1,450 – 1,480 °C (2,642 – 2,696 °F)
• Conductivité thermique: 25.0 Avec(m·K) à 20 °C (lower than carbon steels—common for stainless grades)
• Coefficient de dilatation thermique: 10.5 × 10⁻⁶/°C (depuis 20 – 100 °C)
• Propriétés magnétiques: Ferromagnétique (attire les aimants)—unlike non-magnetic austenitic stainless steels (par ex., AISI 304).

1.3 Propriétés mécaniques

JIS SUS440C’s mechanical strength comes from heat treatment (trempe + trempe). Below are typical values:

1.4 Autres propriétés

JIS SUS440C’s key traits solve real-world problems:

• Résistance à la corrosion: Excellent—resists water, salt spray, and mild chemicals. Perfect for marine or food processing (outperforms standard steels like JIS SUJ2).
• Résistance à l'usure: On par with carbon bearing steels (par ex., GCr15) thanks to high carbon content.
• Trempabilité: Good—achieves uniform hardness across thick parts, so large bearings perform consistently.
• Stabilité dimensionnelle: Minimizes distortion during heat treatment, critical for precision parts like bearing races.
• Martensitic Structure: Yes—this structure (formed during quenching) gives it both hardness and magnetism, unlike austenitic stainless steels.

2. Applications of JIS SUS440C Stainless Bearing Steel

JIS SUS440C shines in environments where rust and wear are both concerns. Here are its top uses:

• Roulements: Corrosion-resistant bearings in food mixers, marine pumps, and chemical agitators—where water or chemicals would ruin standard steel.
• Éléments roulants: Balls/rollers in wet bearings (par ex., washing machine bearings or boat engine bearings).
• Courses: Inner/outer rings of bearings in sanitary equipment (par ex., pharmaceutical mixers) that need frequent cleaning.
• Composants automobiles: Bearings in car washes or undercarriages (exposed to salt, eau, and dirt).
• Machines industrielles: Bearings in wastewater treatment pumps, humid factory equipment, and chemical processing gear.
• Composants aérospatiaux: Small bearings in aircraft fuel systems (resisting fuel and moisture).
• Dispositifs médicaux: Bearings in surgical tools and sterilizable equipment (can handle autoclaving).
• Food Processing Equipment: Bearings in conveyors, dough mixers, and filling machines—meets food safety standards (par ex., FDA).
• Marine Applications: Bearings in boat engines, arbres d'hélice, and deck gear (fights saltwater corrosion).
• Chemical Processing Equipment: Bearings in acid tanks, solvent pumps, and chemical mixers.

3. Manufacturing Techniques for JIS SUS440C

Making JIS SUS440C requires care to keep both corrosion and wear resistance intact. Here’s the process:

1. Sidérurgie:
   • JIS SUS440C is made using an Four à arc électrique (AEP) with argon oxygen decarburization (AOD). This controls carbon (for hardness) and ensures enough chromium (pour la résistance à la corrosion).
2. Roulement:
   • Après la sidérurgie, le métal est Laminé à chaud (1,100 – 1,200 °C) en billettes ou en barres. Pour pièces de précision, c'est Laminé à froid (température ambiante) to improve surface finish—important for sanitary uses.
3. Precision Forging:
   • Pièces complexes (like custom bearing rings) are forged into near-final shapes. Forging refines the grain structure, boosting strength and corrosion resistance.
4. Traitement thermique:
   • Critical for balancing hardness and corrosion resistance:
     • Trempe: Chauffer à 950 – 1,000 °C, then cool quickly in oil to harden (forms a martensitic structure).
     • Trempe: Réchauffer à 150 – 200 °C to reduce brittleness while keeping hardness and corrosion resistance.
5. Usinage:
   • Traitement post-thermique, les pièces sont Ground (for ultra-smooth surfaces—reduces friction and bacterial buildup) et Turned (for cylindrical shapes like bearing races).
6. Traitement de surface:
   • Optional steps to boost performance:
     • Passivation: Treat with nitric acid to strengthen the chromium oxide layer (better corrosion resistance).
     • Polissage: Creates a mirror finish for sanitary apps (easier to clean, no hidden spots for bacteria).
     • Revêtement: Thin PTFE coatings for extra chemical resistance (par ex., strong solvents).
7. Contrôle de qualité:
   • Rigorous testing ensures compliance:
     • Analyse chimique: Check chromium and carbon levels (via spectrometry) to confirm performance.
     • Corrosion testing: Salt spray tests (ASTM B117) to verify saltwater resistance.
     • Test de dureté: Ensure HRC 58–62 for wear resistance.
     • Dimensional inspection: Use CMMs (Machines à mesurer tridimensionnelles) to check bearing tolerances.

4. Études de cas: JIS SUS440C in Action

Real examples show how JIS SUS440C solves tough problems.

Étude de cas 1: Food Processing Bearing Durability

A bakery had monthly bearing failures in their dough mixers. The original bearings used JIS SUJ2, which rusted after daily water cleaning. Switching to JIS SUS440C bearings (with passivation) made them last 12 mois. This cut maintenance costs by 80% and stopped production downtime.

Étude de cas 2: Marine Bearing Corrosion Resistance

A boat builder struggled with propeller shaft bearing failures every 6 mois (saltwater rust). They switched to JIS SUS440C bearings. Now the bearings last 3 années, économie $20,000 per boat in replacements.

5. JIS SUS440C vs. Autres matériaux

How does JIS SUS440C compare to other bearing materials? The table below shows key differences:

Yigu Technology’s Perspective on JIS SUS440C

Chez Yigu Technologie, JIS SUS440C is our go-to for clients in food, marin, and chemical industries. Its mix of corrosion and wear resistance fixes the biggest issue we see: rusted bearings in wet environments. We pair it with passivation and precision grinding to meet sanitary standards and tight tolerances. Pour une protection supplémentaire, we add PTFE coatings—making JIS SUS440C parts last 5–10x longer than standard steel in wet conditions. It’s a cost-effective choice for long-term reliability.

FAQ About JIS SUS440C Stainless Bearing Steel

1. Is JIS SUS440C magnetic?
   Yes—it’s martensitic stainless steel, so it’s ferromagnetic (attire les aimants). This is different from non-magnetic austenitic stainless steels like AISI 304.
2. Can JIS SUS440C handle saltwater?
   Yes—its high chromium content (16–18%) resists saltwater corrosion, making it perfect for marine parts like boat engine bearings. Passivation can boost this resistance even more.
3. How does JIS SUS440C compare to EN 1.4125?
   They’re almost identical! Both are martensitic stainless bearing steels with similar corrosion and wear resistance. JIS SUS440C follows Japanese standards, while EN 1.4125 follows European standards—they’re usually interchangeable.