Aço inoxidável para rolamento JIS SUS440C: Propriedades, Usos & Comparação

Se você está lidando com umidade, corrosivo, 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: é um aço inoxidável martensítico que combina excepcional resistência à corrosão com a resistência ao desgaste necessária para rolamentos. Este guia detalha suas principais propriedades, usos no mundo real, processo de fabricação, e como ele se compara a outros materiais, 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 ruste handles wear. Let’s dive into its properties.

1.1 Composição Química

JIS SUS440C follows strict Japanese Industrial Standards (JIS G4303), garantindo um desempenho consistente. Abaixo está sua composição química típica:

1.2 Propriedades Físicas

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

• Densidade: 7.75 g/cm³ (slightly less than standard carbon bearing steels)
• Ponto de fusão: 1,450 – 1,480 °C (2,642 – 2,696 °F)
• Condutividade Térmica: 25.0 C/(m·K) no 20 °C (lower than carbon steels—common for stainless grades)
• Coeficiente de Expansão Térmica: 10.5 × 10⁻⁶/°C (de 20 – 100 °C)
• Propriedades Magnéticas: Ferromagnético (atrai ímãs)—unlike non-magnetic austenitic stainless steels (por exemplo, AISI 304).

1.3 Propriedades Mecânicas

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

1.4 Outras propriedades

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

• Resistência à corrosão: Excellent—resists water, spray de sal, and mild chemicals. Perfect for marine or food processing (outperforms standard steels like JIS SUJ2).
• Resistência ao desgaste: On par with carbon bearing steels (por exemplo, GCr15) thanks to high carbon content.
• Temperabilidade: Good—achieves uniform hardness across thick parts, so large bearings perform consistently.
• Estabilidade Dimensional: 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:

• Rolamentos: Corrosion-resistant bearings in food mixers, marine pumps, and chemical agitators—where water or chemicals would ruin standard steel.
• Elementos rolantes: Balls/rollers in wet bearings (por exemplo, washing machine bearings or boat engine bearings).
• Corridas: Inner/outer rings of bearings in sanitary equipment (por exemplo, pharmaceutical mixers) that need frequent cleaning.
• Componentes Automotivos: Bearings in car washes or undercarriages (exposed to salt, água, and dirt).
• Máquinas Industriais: Bearings in wastewater treatment pumps, humid factory equipment, and chemical processing gear.
• Componentes Aeroespaciais: Small bearings in aircraft fuel systems (resisting fuel and moisture).
• Dispositivos Médicos: 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 (por exemplo, FDA).
• Marine Applications: Bearings in boat engines, eixos de 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. Siderurgia:
   • JIS SUS440C is made using an Forno Elétrico a Arco (EAF) with argon oxygen decarburization (AOD). This controls carbon (for hardness) and ensures enough chromium (para resistência à corrosão).
2. Rolando:
   • Depois da siderurgia, o metal é Laminado a Quente (1,100 – 1,200 °C) em tarugos ou barras. Para peças de precisão, isso é Laminado a Frio (temperatura ambiente) to improve surface finish—important for sanitary uses.
3. Precision Forging:
   • Partes complexas (like custom bearing rings) are forged into near-final shapes. Forging refines the grain structure, boosting strength and corrosion resistance.
4. Tratamento térmico:
   • Critical for balancing hardness and corrosion resistance:
     • Têmpera: Aqueça até 950 – 1,000 °C, then cool quickly in oil to harden (forms a martensitic structure).
     • Temperamento: Reaquecer para 150 – 200 °C to reduce brittleness while keeping hardness and corrosion resistance.
5. Usinagem:
   • Tratamento pós-térmico, as peças são Ground (for ultra-smooth surfaces—reduces friction and bacterial buildup) e Turned (for cylindrical shapes like bearing races).
6. Tratamento de superfície:
   • Optional steps to boost performance:
     • Passivação: Treat with nitric acid to strengthen the chromium oxide layer (melhor resistência à corrosão).
     • Polimento: Creates a mirror finish for sanitary apps (easier to clean, no hidden spots for bacteria).
     • Revestimento: Thin PTFE coatings for extra chemical resistance (por exemplo, strong solvents).
7. Controle de qualidade:
   • Rigorous testing ensures compliance:
     • Análise química: Check chromium and carbon levels (via spectrometry) to confirm performance.
     • Corrosion testing: Salt spray tests (ASTM B117) to verify saltwater resistance.
     • Teste de dureza: Ensure HRC 58–62 for wear resistance.
     • Inspeção dimensional: Use CMMs (Máquinas de medição por coordenadas) to check bearing tolerances.

4. Estudos de caso: JIS SUS440C in Action

Real examples show how JIS SUS440C solves tough problems.

Estudo de caso 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 meses. This cut maintenance costs by 80% and stopped production downtime.

Estudo de caso 2: Marine Bearing Corrosion Resistance

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

5. JIS SUS440C vs. Outros materiais

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

Yigu Technology’s Perspective on JIS SUS440C

Na tecnologia Yigu, JIS SUS440C is our go-to for clients in food, marinho, 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. Para proteção extra, 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 (atrai ímãs). 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.