Lembaran Logam Stainless Steel
Stainless steel sheets of metal are classified into different series based on microstructure and alloy composition, which determine their mechanical properties and performance in different environments.
The main stainless steel series include:
- Austenitik (300 seri)
- Feritik (400 seri)
- Martensit
- Rangkap
- Pengerasan curah hujan
- Keterangan
Stainless steel sheets of metal banyak digunakan dalam konstruksi, manufaktur, pengolahan makanan, dan teknik industri. They are available in different series and grades, and each series is designed based on specific chemical composition and performance requirements.
The classification of stainless steel sheets is mainly determined by microstructure, komposisi paduan, dan lingkungan aplikasi, which directly define the material’s corrosion resistance, kekuatan, dan tahan panas.
How Stainless Steel Series Are Defined
Stainless steel sheet metal is mainly categorized according to metallurgical structure, which is influenced by alloying elements such as chromium, nikel, molibdenum, and carbon.
The main factors that define a stainless steel series include:
- Kromium (Kr) content → corrosion resistance
- Nikel (Di dalam) content → toughness and stability
- molibdenum (Mo) content → pitting resistance
- Karbon (C) content → hardness and strength
- Heat treatment behavior → microstructure type
Based on these factors, stainless steel is divided into several major series.
1. Baja Tahan Karat Austenitik (300 Seri)
Austenitic stainless steel is the most widely used category.
Typical grades:
- 201
- 304
- 316
- 321
- 310S
Key characteristics:
- Non-magnetik
- Ketahanan korosi yang sangat baik
- Sifat mampu bentuk dan kemampuan las yang baik
- High ductility
Why it is defined:
- High chromium (16–25%)
- High nickel content stabilizes austenite structure
Aplikasi:
- Perlengkapan dapur
- Food processing
- Industri kimia
- Panel arsitektur
- Fabrikasi industri
2. Baja Tahan Karat Feritik (400 Seri)
Ferritic stainless steel is mainly chromium-based and has no or very low nickel content.
Typical grades:
- 409
- 410
- 430
Key characteristics:
- Magnetik
- Ketahanan korosi sedang
- Lower cost compared to 300 seri
- Ketahanan yang baik terhadap retak korosi tegangan
Why it is defined:
- High chromium (10.5–30%)
- Kandungan nikel rendah
- Ferrite microstructure at room temperature
Aplikasi:
- Sistem pembuangan otomotif
- Peralatan rumah tangga
- Peralatan industri
- Panel dekoratif
3. Baja Tahan Karat Martensit
Martensitic stainless steel is known for high hardness and strength.
Typical grades:
- 410
- 420
- 440C
Key characteristics:
- Magnetik
- Dapat diobati dengan panas
- High hardness after quenching
- Lower corrosion resistance than 304/316
Why it is defined:
- Kandungan karbon lebih tinggi
- Controlled heat treatment forms martensite structure
Aplikasi:
- Alat makan
- Surgical tools
- Bagian mekanis
- Komponen tahan aus
4. Baja Tahan Karat Dupleks (2000 Seri)
Duplex stainless steel combines austenitic and ferritic structures.
Typical grades:
- 2205
- 2507
Key characteristics:
- Kekuatan yang sangat tinggi
- Excellent chloride corrosion resistance
- Ketahanan retak korosi tegangan yang baik
Why it is defined:
- Balanced austenite + ferrite microstructure
- Higher chromium and molybdenum content
Aplikasi:
- Platform lepas pantai
- Tangki kimia
- Struktur laut
- Bejana tekan
5. Baja Tahan Karat Pengerasan Curah Hujan
This group is strengthened through heat treatment and precipitation hardening.
Typical grades:
- 17-4PH
- 15-5PH
Key characteristics:
- Kekuatan yang sangat tinggi
- Ketahanan korosi yang baik
- Heat treatable to different strength levels
Aplikasi:
- Aerospace parts
- Komponen mekanis berkekuatan tinggi
- Engineering structures
Stainless Steel Series Classification Summary
| Seri | Structure Type | Key Feature | Typical Grades |
|---|---|---|---|
| 200/300 Seri | Austenitik | Best corrosion resistance | 201, 304, 316 |
| 400 Seri | Ferritic/Martensitic | Magnetik, hemat biaya | 410, 430 |
| Rangkap | Mixed phase | Kekuatan tinggi + ketahanan terhadap korosi | 2205, 2507 |
| PH Series | Precipitation hardened | Kekuatan yang sangat tinggi | 17-4PH |
How Grade Numbers Are Assigned
Stainless steel grade numbers (seperti 304, 316, 430) are defined by international standards such as:
- ASTM (Masyarakat Amerika untuk Pengujian dan Material)
- AISI (Institut Besi dan Baja Amerika)
- DI DALAM / DIN standards (Eropa)
- JIS standards (Jepang)
The numbering system is not random; it reflects:
- Chemical composition range
- Sifat mekanik
- Intended application category
- Historical classification system
Misalnya:
- 304 = general-purpose austenitic stainless steel
- 316 = molybdenum-enhanced corrosion-resistant grade
- 430 = ferritic stainless steel for general use
