ASTM A743 CA6NM is a martensitic stainless steel cast alloy standardized under ASTM A743, widely used in industrial components requiring high strength, excellent corrosion resistance, and superior toughness.

The designation CA6NM indicates:

• C: Chromium content (~13%)
• A6: Nominal carbon content (~0.06–0.08%)
• NM: “Nickel Modified” – addition of nickel (~4%) to improve toughness

This alloy is engineered for cast components, offering good machinability after heat treatment.

It is commonly heat treated to martensitic condition to achieve a combination of high hardness, tensile strength, and impact resistance.

Key Standards:

• ASTM A743 (Standard Specification for Cast Stainless Steel
• Also often referenced in ASTM A351 for certain cast grades)

Features of CA6NM Stainless Steel

1. Martensitic Microstructure – Achieved via solution annealing and quenching, giving high hardness and strength.
2. Corrosion Resistance – Chromium content (~13%) protects against oxidation and mild corrosion environments.
3. Nickel Modification – Enhances toughness, especially at lower temperatures.
4. Good Machinability – Suitable for complex castings, valves, pumps, and similar components.
5. Heat Treatable – Properties can be tailored with tempering to achieve desired hardness and toughness balance.

Advantages of CA6NM Stainless Steel

• High Strength – Tensile strength typically 620–750 MPa after heat treatment.
• Excellent Toughness – Suitable for components under high stress and impact.
• Wear and Erosion Resistance – Works well in fluid-handling applications with moderate abrasive conditions.
• Corrosion Resistance – Withstands mildly corrosive media like water, steam, and certain chemicals.
• Dimensional Stability – Maintains shape and structural integrity after casting and heat treatment.

Applications of CA6NM Stainless Steel

ASTM A743 CA6NM Stainless Steel is widely used in industries such as power generation, chemical processing, oil & gas, and marine engineering.

Typical applications include:

• Pump Components – Impellers, pump casings, and wear rings.
• Valve Components – Valve bodies, stems, and disc assemblies.
• Turbine Parts – Steam turbine blades and rotors.
• Industrial Machinery – Gears, couplings, and other load-bearing components.
• Marine Applications – Components exposed to seawater where moderate corrosion resistance is required.

Summary: CA6NM provides a balance of high strength, toughness, wear resistance, and moderate corrosion resistance, making it ideal for cast components in demanding industrial environments.