Presipitasi-hardening (Ph) stainless steels form a distinct class of high-performance materials combining the corrosion resistance of austenitic stainless steels with the strength of martensitic grades.
Di antara mereka, 15-5 baja tahan karat (DIN X4CrNiCuNb164) has emerged as a vital alloy in aerospace, medis, and industrial engineering sectors due to its superior strength, kekerasan, dan keandalan.
Originally developed as an improvement over the well-established 17-4 Ph (US S17400), 15-5 PH stainless steel (US S15500) was engineered to offer better transverse mechanical properties and greater compositional consistency.
Its name derives from its nominal composition—15% kromium dan 5% nikel—with copper added for precipitation strengthening.
1. Apa 15-5 Baja Tahan Karat?
15-5 baja tahan karat, also known by its Unified Numbering System (KITA) designation S15500, adalah a martensitic precipitation-hardening (Ph) baja tahan karat.
It is engineered to provide a combination of high strength, Ketangguhan yang sangat baik, dan resistensi korosi sedang.
The alloy is particularly valued for its consistent mechanical properties in both the longitudinal and transverse directions, which makes it ideal for high-reliability applications.
Karakteristik utama:
- Martensitic microstructure: Achieved through solution heat treatment followed by aging, resulting in high hardness and strength.
- Pengerasan presipitasi: Enhanced through the controlled addition of tembaga, which forms fine precipitates during aging to increase strength without compromising toughness.
- Improved over 17-4 Ph: Developed as a modification of 17-4 Ph (S17400) baja tahan karat,
15-5 offers better transverse toughness and more uniform mechanical properties across large cross-sections due to reduced delta ferrite and improved composition control.
Klasifikasi:
- Penunjukan AS: S15500
- Jenis material: Martensitic precipitation-hardening stainless steel
2. Komposisi Kimia dari 15-5 Baja Tahan Karat
The chemical composition of 15-5 baja tahan karat is carefully balanced to achieve its superior mechanical properties, resistensi korosi, and consistency across large cross-sections.
It is characterized by a combination of kromium, nikel, Dan tembaga, with tight control over carbon and other residual elements to minimize impurities and enhance performance.
Komposisi Kimia Khas (Weight%):
| Elemen | Isi (%) | Fungsi |
| Kromium (Cr) | 14.0 - - 15.5 | Provides corrosion resistance and contributes to hardenability |
| Nikel (Di dalam) | 3.5 - - 5.5 | Stabilizes the austenite phase, improves toughness and ductility |
| Tembaga (Cu) | 2.5 - - 4.5 | Forms precipitates during aging, significantly increases strength |
| Karbon (C) | ≤ 0.07 | Low content reduces risk of carbide precipitation, meningkatkan ketangguhan |
| Mangan (M N) | ≤ 1.0 | Enhances hot working and improves deoxidation during steelmaking |
| Silikon (Dan) | ≤ 1.0 | Deoxidizer during processing, minor effect on mechanical properties |
| Fosfor (P) | ≤ 0.04 (typical max) | Controlled to prevent embrittlement |
| Sulfur (S) | ≤ 0.03 (typical max) | Minimally present, aids machinability in small quantities |
| Niobium (NB) atau Columbium (Cb) | ≤ 0.45 | Bertindak sebagai penyuling biji -bijian, prevents grain growth during heat treatment |
| Besi (Fe) | Keseimbangan | Logam dasar |
Catatan: Actual composition may vary slightly by producer within the allowable specification ranges, especially to meet certain mechanical or corrosion resistance targets.
Role of Copper in Precipitation Strengthening
Salah satu fitur yang menentukan dari 15-5 stainless steel is its copper content, which plays a critical role in its precipitation-hardening mechanism.
Upon aging heat treatment (MISALNYA., H900 or H1025), finely dispersed copper-rich precipitates form within the martensitic matrix.
These particles impede dislocation motion, resulting in a significant increase in yield and tensile strength without severely compromising ductility.
3. Sifat mekanis dari 15-5 Baja Tahan Karat
15-5 baja tahan karat is highly regarded for its excellent kekuatan mekanis, kekerasan, Dan resistensi kelelahan.
These properties are primarily developed through Pengerasan presipitasi (Pengerasan Usia) following solution treatment.
By adjusting the aging temperature and time, the alloy can be tailored to meet specific application requirements.
| Milik | H900 | H1025 | H1075 | H1100 | H1150 | H1150m |
| Kekuatan tarik (MPa) | ~1310 | ~1170 | ~ 1100 | ~1060 | ~1030 | ~1030 |
| Kekuatan luluh 0.2% Mengimbangi (MPa) | ~1170 | ~ 1070 | ~ 1000 | ~950 | ~ 900 | ~ 930 |
| Pemanjangan (%) | ~ 10 | ~ 14 | ~ 15 | ~ 16 | ~ 17 | ~16–18 |
| Kekerasan (HRC) | 40–45 | 33–38 | 30–34 | 28–32 | 25–30 | 26–31 |
| KETEREBITAN Patahai K_IC (MPa√m)* | ~ 55 | ~65 | ~ 70 | ~72 | ~75 | ~75+ |
| Batas kelelahan (MPa)** | ~ 620 | ~540 | ~ 510 | ~490 | ~470 | ~ 460 |
4. Sifat fisik 15-5 Baja Tahan Karat
15-5 stainless steel exhibits a well-balanced set of sifat fisik that complement its high mechanical performance.
| Milik | Nilai | Catatan |
| Kepadatan | 7.78 g/cm³ | Slightly higher than austenitic grades due to martensitic structure |
| Rentang leleh | 1390 - - 1440 ° C. | Narrow melting range typical of stainless steels |
| Modulus elastisitas | ~ 200 IPK | Kekakuan tinggi; stable across common temperature ranges |
| Konduktivitas termal | ~ 18 w/m · k at 100 ° C. | Lebih rendah dari baja karbon; affects heat transfer in thermal cycling parts |
| Kapasitas panas spesifik | ~ 460 j/kg · k | Sedang; relevant for thermal fatigue and energy absorption |
| Resistivitas listrik | ~0.90 μΩ·m | Lebih tinggi dari baja karbon; useful in electrical isolation applications |
| Koefisien ekspansi | ~10.8 × 10⁻⁶ /°C (20–100 ° C.) | Lower than austenitic stainless (MISALNYA., 304), important for dimensional stability |
| Daya tarik | Magnetic in all conditions | Karena struktur martensitnya, remains magnetic even after aging |
5. Perlakuan panas dan penuaan 15-5 PH stainless steel
15 5 PH stainless steel derives its exceptional mechanical properties through a two-step Proses Perawatan Panas: solusi anil diikuti oleh Pengerasan presipitasi (penuaan).
This controlled sequence develops a fine dispersion of strengthening precipitates, particularly copper-rich phases, dalam matriks martensit.
Solusi anil (Kondisi a)
Solusi anil is the initial and essential heat treatment step for 15-5 baja tahan karat, biasanya disebut sebagai Kondisi a.
This process prepares the alloy for subsequent aging by dissolving existing precipitates and homogenizing its microstructure.
Parameter proses
- Suhu: Sekitar 1038° C. (1900° f)
- Soaking Time: Khas 30 ke 60 menit, depending on material thickness
- Metode pendinginan: Biasanya Pendinginan udara atau oil quenching untuk bagian yang lebih tebal
Purpose and Effects
- Dissolution of Precipitates: Any copper- or carbide-based precipitates formed during prior processing are fully dissolved, resulting in a uniform solid solution.
- Austenitizing: The steel is heated into the austenite phase field where the microstructure transforms to face-centered cubic (FCC) Austenite.
- Martensitic Transformation on Cooling: Upon rapid cooling, a diffusionless transformation occurs, converting austenite into body-centered tetragonal (Bct) martensit.
This martensitic matrix is the foundation for further precipitation hardening. - Homogenisasi: Eliminates segregation and microstructural inconsistencies, ensuring consistent mechanical properties throughout the material.
- Prepares for Aging: Sets the stage for controlled precipitation of strengthening phases during subsequent aging treatments.
Pengerasan presipitasi (Penuaan)
After solution treatment, aging is performed at various temperatures to tailor the final mechanical properties. The most common aging tempers are:
| Aging Condition | Suhu (° C.) | Suhu (° f) | Lamanya | Key Effects |
| H900 | 482 | 900 | 1 jam | Maximum strength, berkurangnya keuletan |
| H1025 | 552 | 1025 | 4 jam | Kekuatan dan keuletan yang seimbang |
| H1075 | 579 | 1075 | 4 jam | Slightly reduced strength, Ketangguhan yang lebih baik |
| H1100 | 593 | 1100 | 4 jam | Increased ductility, better fracture toughness |
| H1150 | 621 | 1150 | 4 jam | Overaged for optimal toughness and stress relief |
| H1150m (Double Age) | 621 × 2 | 1150 × 2 | 4 + 4 jam | Highest toughness, stabilitas dimensi |
Catatan: All aging is done in air; no quench is needed after aging.
6. Resistensi korosi
15 - - 5 stainless steel offers good corrosion resistance in atmospheric, laut, dan lingkungan kimia ringan.
Dalam kondisi atmosfer normal, it can resist corrosion for long periods without significant degradation.
In marine environments, it can withstand the corrosive effects of saltwater spray and humidity better than many other martensitic stainless steels.
Compared to martensitic grades like 410 Dan 420, 15 - - 5 stainless steel has better pitting and crevice corrosion resistance.
This is due to its chemical composition, which promotes the formation of a more stable and continuous passive film on the surface.
Namun, 15 - - 5 stainless steel is not ideal for chloride-rich or highly acidic environments.
In such conditions, austenitic stainless steels like 316L or duplex stainless steels like 2205 are more suitable, as they offer superior corrosion resistance.
7. Manufacturing Processes and Fabrication of 15-5 Baja Tahan Karat
Pengecoran
15-5 stainless steel can be cast through various methods, termasuk casting investasi Dan casting pasir, each suited to different component requirements.
- Pengecoran Investasi is often favored for producing complex-shaped components with high dimensional accuracy and superior surface finish.
This process involves creating a wax pattern of the desired part, melapisinya dengan cangkang keramik, then melting out the wax to form a cavity.
Molten 15-5 PH stainless steel is poured into this cavity to form precise, bagian yang rumit. - Casting pasir, sebaliknya, is better suited for larger, less complex components.
It is generally more cost-effective for producing sizable parts where tight tolerances and fine surface finishes are less critical.
Pekerjaan panas dan dingin
In its kondisi anil, 15 5 stainless steel exhibits good formability, allowing for a wide range of hot and cold working processes:
- Bekerja panas: Techniques such as forging and rolling are performed at elevated temperatures (typically above 900°C).
This enables shaping the steel into various forms—bars, piring, and tubes—while refining the grain structure and enhancing mechanical properties. - Bekerja dingin: Processes like cold rolling, menggambar, and stamping enable precise dimensional control and improved surface finishes.
Namun, cold working induces work hardening, which may necessitate subsequent annealing or stress-relief treatments to restore ductility and reduce internal stresses.
Pemesinan
Kemampuan mesin 15 5 stainless steel is generally good in the dianil (Solusi yang diperlakukan) kondisi, but decreases significantly as the material is hardened through precipitation aging.
- To machine 15-5 secara efektif, the use of carbide-tipped cutting tools is recommended due to their hardness and heat resistance.
- Employing pemesinan berkecepatan tinggi techniques helps minimize cutting forces and heat buildup.
- Adequate use of coolants and lubricants is essential to reduce tool wear and achieve superior surface finishes on machined parts.
Pengelasan
Pengelasan 15 5 stainless steel requires meticulous control to prevent issues such as cracking and degradation of mechanical properties.
- Pemanasan awal the base metal to around 150–200 ° C. prior to welding helps minimize thermal stresses and reduce the risk of cracking.
- Depending on the welding method and application, A Perlakuan panas pasca-keluhan may be necessary to restore mechanical strength and relieve residual stresses.
- Selection of logam pengisi that closely match the chemical composition of stainless steel is critical for ensuring weld integrity and maintaining the desired mechanical properties in the joint.
8. Keunggulan dan keterbatasan 15-5 Baja Tahan Karat
Keuntungan
- Rasio kekuatan terhadap berat yang tinggi:
15-5 PH stainless steel offers excellent tensile and yield strength while maintaining relatively low density, making it ideal for weight-sensitive applications such as aerospace and high-performance engineering. - Excellent Toughness and Mechanical Stability:
The alloy demonstrates outstanding toughness, including across thick cross-sections and transverse directions, reducing the risk of brittle failure in critical components. - Resistensi korosi yang baik:
It resists atmospheric, laut, and mild chemical environments better than conventional martensitic stainless steels (MISALNYA., 410/420), enhancing durability in many industrial and marine settings. - Heat Treatability for Tailored Performance:
Its precipitation-hardening response allows engineers to customize mechanical properties (kekuatan, kekerasan, kekerasan) through controlled aging cycles. - Good Machinability in Hardened Conditions:
Compared to many other stainless steels, 15-5 maintains relatively good machinability after aging, facilitating efficient manufacturing of precision parts.
Batasan
- Susceptibility to Chloride and Acidic Environments:
Despite improved corrosion resistance over some martensitic grades,
15-5 is not recommended for prolonged exposure to highly chloride-rich or strongly acidic environments; alternatives such as 316L or duplex stainless steels are preferred. - Requirement for Precise Heat Treatment:
Achieving optimal mechanical and corrosion properties depends on strict control of solution annealing and aging parameters, adding complexity to manufacturing and quality assurance. - Higher Cost Compared to Austenitic Stainless Steels:
Due to alloying elements and specialized processing, 15-5 typically costs more than common grades like 304 atau 316, potentially limiting its use to performance-critical applications. - Limited Cold-Forming Flexibility:
The alloy is less ductile and more prone to work hardening than austenitic stainless steels, restricting its formability and necessitating intermediate annealing during cold working.
9. Aplikasi
15-5 stainless steel’s unique combination of high strength, kekerasan, resistensi korosi, and heat-treatability makes it a preferred material across a broad spectrum of demanding industries.
Luar angkasa
- Komponen struktural: Used in airframe parts, kurung, and supports where the strength-to-weight ratio is critical.
- Shafts and Fasteners: Ideal for landing gear, aktuator, and high-strength fasteners due to their toughness and dimensional stability.
- Turbine and Engine Parts: Suitable for components requiring good fatigue resistance and thermal stability.
Medis
- Orthopedic Instruments: Surgical tools and implants benefit from 15-5’s biocompatibility, resistensi korosi, dan keandalan mekanis.
- Surgical Tools: Scalpel handles, klem, and other precision instruments use 15-5 stainless steel for durability and ease of sterilization.
Industri
- Gear Parts and Valve Stems: High-strength gears, poros, and valve components in chemical and petrochemical plants.
- Pump Shafts and Fittings: Resistant to wear and corrosion in moderately aggressive environments.
- High-Strength Fittings: Used where weight savings and mechanical performance are essential.
Pembuatan aditif
- Metal Powder for 3D Printing: 15-5 PH stainless steel powder is increasingly used in Melting laser selektif (Slm) Dan Sintering laser logam langsung (DMLS) processes to produce complex, high-performance components with excellent mechanical properties.
10. Comparison with Similar Stainless Steels
15 5 PH stainless steel is part of the family of martensitic precipitation-hardening (Ph) Baja tahan karat, and it shares many characteristics with alloys such as 17-4 Ph, 13-8 Mo, Dan 17-7 Ph.
Understanding its differences and advantages compared to these steels helps in selecting the most suitable material for specific applications.
| Milik / Paduan | 15-5 Baja Tahan Karat | 17-4 Ph Baja Tahan Karat | 13-8 Mo Stainless Steel | 17-7 PH stainless steel |
| Penunjukan AS | S15500 | S17400 | S13800 | S17700 |
| Sorotan Komposisi | ~15% Cr, 5% Di dalam, Cu, NB | ~ 17% cr, 4% Di dalam, Cu, NB | ~13% Cr, 8% Di dalam, Mo, Cu | ~ 17% cr, 7% Di dalam, Cu, NB |
| Perlakuan panas | Solusi Anneal + penuaan (H900–H1150M) | Solusi Anneal + penuaan (H900–H1150M) | Solusi Anneal + penuaan | Solusi Anneal + penuaan |
| Kekuatan mekanis | Tinggi, up to ~1310 MPa tensile (H900) | Sangat tinggi, up to ~1380 MPa tensile (H900) | Kekuatan yang lebih tinggi, ketangguhan yang baik | Kekuatan sedang, keuletan yang sangat baik |
| Kekerasan | Superior toughness and transverse properties | Good toughness but lower than 15-5 | Ketangguhan tinggi, improved over 17-4 Ph | Excellent toughness and formability |
| Resistensi korosi | Better than 17-4 Ph, good marine resistance | Resistensi korosi umum yang baik | Resistensi korosi yang baik | Resistensi korosi sedang |
| Kemampuan mesin | Bagus, especially in annealed and overaged states | Bagus, widely used in machining | Kemampuan mesin sedang | Kemampuan mesin yang baik |
| Aplikasi | Bagian Struktural Aerospace, alat kesehatan | Luar angkasa, industri, general-purpose PH | High-strength aerospace and chemical parts | Aerospace springs, bagian presisi |
| Biaya | Sedang hingga tinggi | Sedang | Higher due to Mo content | Sedang |
Application Scope:
Ketika 17-4 PH stainless steel is often the go-to for general-purpose applications due to its cost-effectiveness and wide availability, 15-5 PH stainless steel is preferred where higher toughness and dimensional stability are required.
13-8 Mo stainless steel offers higher strength but at increased cost, sedangkan 17-7 PH stainless steel is valued for excellent ductility and spring properties.
11. Forms and Specifications of 15-5 Baja Tahan Karat
Available Forms
- Batang, rod, mengupas, piring
- Forgings and extrusions
- Powder for AM (pembuatan aditif)
Standar dan Spesifikasi
- ASTM A564/A564M – Bars and shapes
- AMS 5659 – Aerospace components
- ASTM F899 – Surgical applications
- Iso 16061, DI DALAM 10088-3 – International equivalents
12. Kesimpulan
15-5 baja tahan karat stands out as a premium engineering alloy that blends kekuatan tinggi, resistensi korosi, Dan stabilitas dimensi with excellent kemampuan mesin.
Its widespread use in aerospace, medis, and industrial sectors underscores its value where performance cannot be compromised.
With the increasing adoption of pembuatan aditif, 15-5 PH also opens new frontiers in design flexibility and lightweighting without sacrificing strength.
While it demands precise processing and heat treatment, its benefits in critical applications continue to make it a material of choice for demanding engineering environments.
Langhe: Pengecoran baja tahan karat presisi & Layanan Fabrikasi
Langhe adalah penyedia tepercaya Casting stainless steel berkualitas tinggi dan layanan fabrikasi logam presisi, melayani industri di mana kinerja, daya tahan, dan resistensi korosi sangat penting.
Dengan kemampuan produksi canggih dan komitmen untuk keunggulan teknik, Langhe memberikan dapat diandalkan, Solusi stainless steel yang disesuaikan untuk memenuhi persyaratan aplikasi yang paling menuntut.
Kemampuan stainless steel kami termasuk:
- Pengecoran Investasi & Casting lilin yang hilang
Casting presisi tinggi untuk geometri kompleks, memastikan toleransi yang ketat dan lapisan permukaan yang unggul. - Casting pasir & Cetakan cangkang
Ideal untuk komponen yang lebih besar dan produksi yang hemat biaya, terutama untuk bagian industri dan struktural. - Pemesinan CNC & Pasca-pemrosesan
Layanan pemesinan lengkap termasuk berbelok, penggilingan, pengeboran, pemolesan, dan perawatan permukaan.
Apakah Anda membutuhkan komponen presisi tinggi, Rakitan stainless yang kompleks, atau bagian yang direkayasa khusus, Langhe adalah mitra Anda yang dapat diandalkan dalam pembuatan stainless steel.
Hubungi kami Hari ini untuk mempelajari caranya Langhe dapat memberikan solusi stainless steel dengan kinerja, keandalan, dan presisi tuntutan industri Anda.
FAQ
Adalah 15-5 steel magnetic?
Ya, 15-5 ph stainless steel is magnetic in all conditions due to its martensitic crystal structure.
Bisa 15-5 baja tahan karat dilas?
Ya, Tapi pengelasan membutuhkan pemanasan awal (typically 150–200°C), proper filler metals, and often post-weld heat treatment to avoid cracking and maintain mechanical properties.
Adalah 15-5 stainless steel suitable for additive manufacturing?
Ya, 15-5 stainless steel powder is widely used in selective laser melting (Slm) and direct metal laser sintering (DMLS) to produce complex, komponen berkinerja tinggi.
