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1.4418 is a martensitic stainless steel that is crafted using a double vacuum melting process. It is intended for use in applications requiring high strength and enhanced corrosion resistance. Compared to traditional steels such as AISI 410, 1.4418 outperforms them.
1.Core Advantages of 1.4418
High Strength
1.4418 boasts excellent tensile strength (≥900 MPa). It is ideal for heavy-duty applications such as shafts and valves. This effectively reduces the risk of material fatigue.
Superior Corrosion Resistance
With 15-17% chromium and 0.8-1.5% molybdenum, 1.4418 offers excellent corrosion resistance. It is highly resilient in harsh environments and can greatly extend the lifespan of your equipment.
Good Weldability
Its low carbon content (≤0.06%) prevents embrittlement during welding. This makes it an ideal material for stainless steel pipes and fittings.
Excellent Toughness
The optimised microstructure of 1.4418 improves impact toughness. It ensures reliable performance, even at low temperatures, for demanding applications.
2.Standards
- Europe (EN): X4CrNiMo16-5-1
- USA (UNS): S41500
- Japan (JIS): SUS F6NM
- China (GB): 0Cr16Ni5Mo
3.Chemical Composition of 1.4418
| Element | C | Cr | Ni | Mo | Mn | Si | P | S | N |
|---|---|---|---|---|---|---|---|---|---|
| Content (%) | ≤0.06 | 15.0-17.0 | 4.0-6.0 | 0.8-1.5 | ≤1.5 | ≤1.0 | ≤0.04 | ≤0.03 | ≤0.02 |
4.Physical Properties
| Physical Index | 20°C | 100°C | 200°C | 300°C | 400°C |
| Density | 7.7 | — | — | — | — |
| Modulus of elasticity (GPa) | 200 | 195 | 185 | 175 | 170 |
| Mean coefficient of thermal expansion (×10⁻⁶ K⁻¹) | — | 10.3 | 10.8 | 11.2 | 11.6 |
| Thermal Conductivity | 24.0 | 25.5 | 27.0 | 28.5 | 30.0 |
| Electrical Resistivity | 78 | 82 | 86 | 90 | 94 |
| Magnetic Permeability | Magnetic | Magnetic | Magnetic | Magnetic | Magnetic |
Comparison with other steels
1.4418 has a higher chromium and nickel content than AISI 410. This enhances its corrosion resistance, ensuring durability in harsh environments. Additionally, its low carbon content minimises the risk of embrittlement during welding. Consequently, it is ideal for use in stainless steel pipes and fittings, providing strength and weldability. Conversely, the low alloy content of AISI 410 limits its corrosion protection. Therefore, 1.4418 is a stronger and more reliable alternative.
5.Mechanical Properties (QT 900 Condition, Room Temperature)
| Property | Value | Notes |
| Tensile Strength (Rm) | 900–1050 MPa | Minimum guaranteed value |
| Yield Strength (Rp0.2) | ≥700 MPa | 0.2% offset yield strength |
| Elongation (A) | ≥12% | 50mm gauge length |
| Reduction of Area (Z) | ≥45% | Ductility indicator |
| Hardness | 28–34 HRC | Quenched & tempered condition |
| Impact Toughness (KV) | ≥40 J | Room‑temperature Charpy V‑notch |
6. Heat Treatment Specifications
- Solution Treatment: 950–980 °C, hold for 30–60 min, air cooling
- Quenching: Air‑quenched from solution temperature
- Tempering (QT 900): 580–620 °C, hold for 2–4 h, air cooling
- Stress Relief: Optional 200–250 °C post‑weld stress relief
7. Corrosion Resistance
- General Corrosion: Excellent resistance to fresh water, neutral atmosphere, weak acid and alkaline solutions
- Pitting & Crevice Corrosion: Better performance than common martensitic stainless steels in low‑chloride seawater and brackish water
- Stress Corrosion Cracking: Good resistance under mild chloride and tensile‑stress environments
- Oxidation Resistance: Stable below 550 °C in air atmosphere
8. Typical Applications
This grade is widely used in slightly‑corrosive and high‑strength‑required working scenarios:
- Marine Engineering: Offshore platform fittings, seawater pump shafts, marine valve components
- Petrochemical Industry: Pipeline connectors, pressure fittings, hydraulic valve bodies
- Water Treatment: High‑pressure pump parts, water supply system mechanical components
- Mechanical Manufacturing: High‑strength shafts, fasteners, heavy‑load structural parts
- Energy Industry: Hydraulic components, power equipment transmission parts
- Machinery Equipment: Precision machined parts requiring both strength and corrosion resistance
9. Available Product Forms
Seamless steel pipe, solid round bar, flat bar, steel plate, forgings, flanges, pipe fittings, custom‑machined precision components.
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