1.4418 Stainless Steel Bars / 1.4418 Steel Bars / 1.4418 Rods

Product Description

1.4418 (often referred to by the trade name M154 or Z8CND17-04) is a high-strength, martensitic-austenitic stainless steel. It is specifically engineered to overcome the common weaknesses of standard martensitic steels (like 410 or 431), such as poor weldability and low toughness.

By adding Nickel and Molybdenum to the Chromium base, 1.4418 provides a unique combination of high mechanical strength, excellent fatigue resistance, and superior corrosion resistance in mildly acidic and marine environments.

1. Technical Specifications

• Standard: EN 10088-3

• Material Number: 1.6587 (1.4418)

• Designation: X4CrNiMo16-5-1

• Common Equivalents: * AFNOR: Z8CND17-04

  • PWA: PWA 1213 (certain aerospace variants)

  • S15500: Closely related in performance to 15-5 PH, though 1.4418 is not technically a precipitation-hardening steel.

2. Chemical Composition (%)

The low Carbon content is key to its improved weldability and toughness compared to other 16% Chromium steels.

3. Mechanical Properties

1.4418 is typically supplied in a quenched and tempered condition (designated as QT 760 or QT 900).

• Tensile Strength ($R_m$): 760 “ 1150 MPa (depending on heat treatment).

• Yield Strength ($R_{eH}$): ‰ 550 “ 750 MPa.

• Impact Strength (KV): Excellent at sub-zero temperatures (down to -40C), which is rare for martensitic steels.

• Hardness: Generally ranges from 250 to 350 HB.

4. Key Advantages

• Corrosion Resistance: Much higher than standard 13% Cr steels. It performs exceptionally well in salt spray and marine atmospheres, approaching the resistance of 304 stainless in many conditions.

• Weldability: Unlike Grade 431, 1.4418 can be welded relatively easily due to its low carbon content and the presence of some austenite in the microstructure.

• Fatigue Resistance: Often used in components subject to high cyclic loading.

• Anti-Cavitational: Specifically resistant to cavitation, making it a favorite for water-handling equipment.

5. Applications of Bars and Rods

Because of its "tough-yet-hard" nature, 1.4418 bars are frequently machined into:

• Hydro-Power: Turbine shafts, propeller shafts, and valve components.

• Aerospace: Structural parts requiring high strength and corrosion resistance without the cost of high-nickel superalloys.

• Oil & Gas: Pump parts, separator components, and high-pressure valves.

• Marine: Propeller shafting and fasteners for offshore rigs.

6. Comparison: 1.4418 vs. 1.4462 (Duplex)

• 1.4418: Martensitic structure. Higher hardness and mechanical strength; better for wear-related applications and shafts requiring high torque.

• 1.4462 (2205): Duplex structure. Superior resistance to Stress Corrosion Cracking (SCC) and pitting in high-chloride environments, but lower surface hardness.