Heat Treating Sandvik 14C28N Knife Steel

Sandvik 14C28N is an advanced knife steel developed by the renowned Swedish company Sandvik. This steel offers exceptional performance due to its unique combination of excellent edge retention, high hardness, and good corrosion resistance.

In this comprehensive guide, we will delve into the intricacies of heat treating Sandvik 14C28N, exploring the recommended steps and temperature-hardness combinations for optimal results.

Understanding Sandvik 14C28N

Sandvik 14C28N is an upgraded version of the popular 12C27 steel and can be compared to other well-known steels like AEB-L/13C26 and Nitro-V.

What sets 14C28N apart is its use of nitrogen instead of carbon to enhance hardness without compromising corrosion resistance.

While most steels rely on carbon for higher hardness, the nitrogen content in 14C28N allows it to maintain excellent corrosion resistance while achieving desired hardness levels.

Sandvik 14C28N Knife Steel chemical compositions

The chemical composition of Sandvik 14C28N knife steel is as follows:

Carbon (C): 0.62%
Chromium (Cr): 14.0%
Manganese (Mn): 0.6%
Silicon (Si): 0.2%
Phosphorus (P): 0.025%
Sulfur (S): 0.010%
Nitrogen (N): 0.11%

Sandvik 14C28N Knife Steel Mechanical Properties

PropertyValue Range
Hardness (HRC)55 – 62
Tensile Strength1900 MPa – 2100 MPa
Yield Strength1600 MPa – 1800 MPa
Elongation10% – 14%
Impact ResistanceGood
Corrosion ResistanceGood

Sandvik 14C28N Knife Steel Equivalent Materials

Sandvik 14C28N knife steel is equivalent to other materials with similar composition and properties. While there may not be an exact equivalent, the following materials are often considered comparable to Sandvik 14C28N:

  1. AEB-L / 13C26: A stainless steel with similar composition and properties to Sandvik 14C28N. It is known for its excellent edge retention and corrosion resistance.
  2. Nitro-V: Another stainless steel that shares similarities with Sandvik 14C28N. Nitro-V offers good wear resistance, edge retention, and corrosion resistance.
  3. VG-10: A popular stainless steel used in knife making. VG-10 is known for its excellent corrosion resistance, toughness, and ability to hold a sharp edge.
  4. X50CrMoV15: This stainless steel is often used in European knife making. It offers good hardness, corrosion resistance, and edge retention.
  5. 154CM: A high-quality stainless steel that provides excellent edge retention, corrosion resistance, and toughness. It is commonly used in custom and production knives.
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Austenizing / Hardening

To start the heat treatment process for Sandvik 14C28N, follow these steps:

Preheating: Place the blade in a furnace and preheat it to a temperature between 1050°C and 1080°C (1922°F – 1975°F). The precise temperature will depend on the specific requirements of your application.

Soaking Time: The soaking time varies based on the thickness of the blade. For a 2.5mm blade, a soaking time of approximately 5 minutes is recommended, while a 5mm blade may require around 25 minutes for optimal results.

Home Heat Treating: If you are performing heat treatment at home, a temperature of 1060°C (1940°F) can be used, as it achieves high hardness without necessitating specialized equipment.

Quenching: After the austenitizing process, the blade must be immediately quenched to retain its hardened state. It is preferable to use quenching oil specifically designed for heat treatment to ensure effective and uniform cooling.

Quenching Media

The choice of quenching media plays a crucial role in the heat treatment process. Here are two recommended methods:

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Oil Quenching: If you opt for oil quenching, immerse the blade in the oil until it turns black. Subsequently, cool the blade in still air until it reaches room temperature (20°C or 70°F) within 30 minutes.

Alternative Methods: If you prefer using quench plates or compressed air, ensure that the blade reaches a temperature of 600°C (1112°F) within 1-2 minutes. Afterward, allow the blade to cool to room temperature within 30 minutes.

Sub-zero / Cryogenic Treatment

For enhanced hardness, corrosion resistance, and wear resistance, it is highly recommended to perform cryogenic treatment after quenching. Follow these steps:

Immediate Freezing: After the hardening process, freeze the blade using liquid nitrogen or place it in a household freezer capable of reaching a temperature of -20°C (-5°F).

Warming to Room Temperature: Allow the blade to gradually warm to room temperature in ambient air. This ensures the completion of the cryogenic treatment process.

Tempering

Tempering is a critical step in the heat treatment of Sandvik 14C28N. Here’s how to perform it effectively:

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Heating: Slowly heat the blade to the designated tempering temperature. The specific temperature will depend on the desired hardness and toughness for your application.

Tempering Time: The recommended tempering time is 2 hours (120 minutes). This duration allows for the necessary structural changes to occur within the steel.

Avoiding Excessive Temperatures: To prevent brittleness and the loss of corrosion resistance, it is crucial to avoid tempering above 450°C (840°F).

Temperature and Hardness Combinations

Here are some temperature and hardness combinations for Sandvik 14C28N that you can consider:

  • 62HRC: Austenitizing at 1080°C (1975°F), deep freeze to -70°C/-95°F, tempering at 175°C (345°F).
  • 60HRC: Austenitizing at 1060°C (1940°F), deep freeze to -20°C/-5°F, tempering at 175°C (345°F).
  • 59HRC: Austenitizing at 1050°C (1920°F), tempering at 175°C (345°F).
  • 57HRC: Austenitizing at 1050°C (1920°F), tempering at 225°C (435°F).
  • 59HRC: Austenitizing at 1050°C (1920°F), tempering at 350°C (660°F).

Conclusion

Proper heat treatment is vital for achieving the desired performance characteristics of Sandvik 14C28N knife steel. By following the guidelines outlined in this comprehensive guide, you can optimize hardness, edge retention, and corrosion resistance, ensuring that your knives perform at their best.

Remember to consider factors such as preheating, soaking time, quenching media, cryogenic treatment, and tempering to achieve the desired results.