AISI 317LMN / 1.4439 Stainless Steel

Stainless Steel AISI 317 LMN / EN 1.4439: Properties, Applications, and Features

✅ General Technical Characteristics

Stainless steel AISI 317 LMN (EN 1.4439) is a high-alloy austenitic stainless steel with enhanced corrosion resistance due to its high molybdenum and nitrogen content. This steel offers exceptional resistance to pitting and crevice corrosion, particularly in chloride and acidic environments. It surpasses AISI 316 and AISI 317L in terms of strength and durability.

Main Characteristics:

• High corrosion resistance, especially in aggressive environments.
• Increased strength due to the addition of nitrogen.
• Excellent weldability and machinability.
• High resistance to pitting and crevice corrosion.
• Suitable for use in marine, chemical, and pharmaceutical industries.

🔬 Chemical Composition AISI 317 LMN / EN 1.4439 (%):

• Carbon (C): ≤ 0.03
• Silicon (Si): ≤ 1.0
• Manganese (Mn): ≤ 2.0
• Phosphorus (P): ≤ 0.045
• Sulfur (S): ≤ 0.015
• Chromium (Cr): 17.5 – 20.0
• Nickel (Ni): 12.0 – 14.0
• Molybdenum (Mo): 4.0 – 5.0
• Nitrogen (N): 0.10 – 0.22

💡 The addition of nitrogen and high molybdenum levels significantly improve strength and corrosion resistance in acidic and marine environments.

🏭 Applications

Steel AISI 317 LMN (EN 1.4439) is widely used in environments where high corrosion resistance and strength are required.

Main Application Areas:

• Chemical and petrochemical industry (reactors, pipelines, heat exchangers).
• Marine industry (ship components, desalination plants, offshore platforms).
• Pharmaceutical industry (sterile equipment, production lines).
• Pulp and paper industry (equipment for handling aggressive substances).
• Food industry (storage tanks and transport systems for aggressive liquids).

📊 Mechanical Properties

• Tensile Strength (Rm): 650 – 850 MPa
• Yield Strength (Rp0.2): ≥ 300 MPa
• Hardness (HB): ≤ 230 HB
• Elongation (A5): ≥ 40 %

⭐ Features

• High corrosion resistance – an ideal choice for aggressive environments.
• Heat resistance – maintains structural stability at elevated temperatures.
• Excellent weldability – easy to weld without the risk of cracking.
• Increased strength – due to the addition of nitrogen.
• Wide range of applications – used in industrial, marine, and pharmaceutical sectors.

AISI 317 LMN / EN 1.4439 steel delivery forms