Alleima® (previously Sandvik) 14C28N is a martensitic stainless chromium steel with a chemistry optimized for high-quality professional knife applications. The optimized chemistry provides a knife steel with a unique combination of excellent edge performance, high hardness and good corrosion resistance.
Dr Larin Thomas of KnifeSteelNerds.com has referred to 14C28N as the “best budget knife steel” [2] available. While it does exhibit excellent corrosion resistance and very high toughness, users may want better edge holding/retention.
14C28N® is an upgrade of 12C27 and is readily comparable to Bohler’s AEB-L/13C26 and Nitro-V and as such is recommended for pocket knives, chef knives, hunting knives and fishing knives.
14C28N® is martensitic stainless chromium steel with a unique combination of properties:
- Excellent edge performance (fine carbide distribution)
- Polishes well (Mirror polish)
- Good hardness (62HRC max)
- Good corrosion resistance
14C28N® Chemical composition (nominal %)
| Grade | C | Mn | Cr | N | P | S | Si |
| 14C28N | 0.62 | 0.60 | 14 | 0.11 | <0.025 | <0.010 | 0.2 |
Here is a composition comparison graph of the steel (visit zKnives.com).
14C28N has better corrosion resistance than AEB-L as it was designed to have much more Cr in solution. In most steels, carbon is used to increase hardness but 14C28N uses nitrogen [3]. This allows for higher hardness without compromising corrosion resistance.
14C28N Heat Treatment:
Austinizing / Hardening
When the blade has been soaked in the furnace for the time specified above, it is removed and immediately quenched, preferably in oil intended for quenching (Genheat 22, other medium-speed oils) not canola no used motor oil.
Rehardening is generally not recommended as it will not give optimal product properties.
Austenitizing Temperature: 1050°C – 1080°C (1922°F – 1975°F) see summary table below for additional options
- No Cold Treatment Used / Available: 1050°C / 1922°F
- Cold Treatment (-20°C): 1060°C / 1940°F
- Cryogenic Deep Freeze (< -95°C): Ramp 850°C / 1560°F hold 30 minutes, Ramp 1075°C / 1965°F
Recommendation: For most home heat treating, 1060°C (1940°F) is recommended as no extra equipment is needed (ie: Cryo) and high hardness (59-60 HRC) can still be achieved.
Recommended Soak Times (depending on thickness):
- 2.5mm (0.098 in.) – 5 minutes
- 3.75mm (0.147 in.) – 10 minutes
- 4mm (0.157 in.) – 12 minutes
- 5mm (0.196 in.) – 25 minutes
* The danger of an insufficient soak is much worse, leading to poor hardness, toughness, and corrosion resistance. While the chances of an overly long soak time are low. The changes to the steel in terms of transformation and carbides dissolving will “level off” after a certain amount of time and then changes are slow after that. So it is recommended that the soak is “long enough”, ie: 15min or longer, rather than trying to make it as short as possible.
Quenching Media
Please note that Sandvik steels are shipped in large strip coils and thus retain a certain amount of that “memory” when heat treated resulting in warping issues. Therefore quench plates are recommended to alleviate that issue.
- Quenching in oil (Recommended by Alleima): Quench until black, and then cool in still air to 20°C (70°F) within 30 minutes or less. ATP41 /
- If using Quench plates with or without compressed air, 600°C (1112°F) should be reached within 1–2 minutes and room temperature 20°C (70°F) within 30 minutes or less.
Sub-zero / Cryogenic Treatment
The maximum hardness of 14C28N is obtained at a retained austenite content of 15%, therefore deep freezing is recommended to reach the higher hardness range as well as high corrosion and wear resistance (in combination with higher austenitizing temperatures (1080°C-1975°F).
Note: Any cryo treatment (whether between tempers or after the quench, should always be followed by a tempering cycle.
- Quench, cool to room temperature and then freeze immediately after hardening and before tempering.
- Remove from cryo and allow the blade to warm to room temperature in ambient air.
- Once the blade is at room temperature, proceed with tempering.
Tempering
Slow heating to tempering temperature and then hold.
- Tempering Temperature Range: The range is between 100°C / 212 °F (minimum) – 400°C / 752 °F)
- Recommended: Balanced 180 °C ( 350 °F )
- Times: 1 (one) Times
- Duration: 2 hours (120 minutes).
It is not recommended to temper above 400°C / 750°F. Generally for knifemaking, secondary hardening / high-temperature tempers aren’t recommended and can insight embrittlement, leading to a reduction of toughness and corrosion resistance (should not be used for food handling applications).
*If using a small toaster oven or household kitchen oven for tempering, using a blade holding rack made from kiln furniture, a roasting tray lined with fine sand, or a similar large object will help retain thermal mass to reduce wide swinging temperatures as the device fluctuates trying to maintain temperature.
Summary / Results
| Hardening Temperature | Cold Treatment | Tempering temperature | Tempering time | Expected Hardness |
|---|---|---|---|---|
| 1095°C (2000°F) | -71°C / -95°F | 150°C (300°F) | 1 x 2 h | 63 HRC |
| 1075°C (1975°F) | -71°C / -95°F | 175°C (345°F) | 1 x 2 h | 62 HRC |
| 1060°C (1940°F) | -20°C / -5°F | 175°C (345°F) | 1 x 2 h | 60 HRC |
| 1050°C (1920°F) | 175°C (345°F) | 1 x 2 h | 59 HRC | |
| 1060°C (1940°F) | -20°C / -5°F | 225°C (435°F) | 1 x 2 h | 58 HRC |
| 1050°C (1920°F) | 225°C (435°F) | 1 x 2 h | 57 HRC |
References / Links:
- Alleima (Sandvick) 14C28N Data Sheet (pdf)
- What is the Best Budget Knife Steel?
- Nitrogen-Alloyed Knife Steels
- Why Nitrogen Knife Steels are Soft
- Knife Steels Rated by a Metallurgist – Toughness, Edge Retention, and Corrosion Resistance
- Purchase: 14C28N Knife Steel
- Purchase: Knu-foil / Stainless steel tool wrap
Disclaimer:
All the information above is from my readings of research papers, forum posts, and discussions with people. I am not a metallurgist; the above is presented here for the benefit of all knifemakers. You do not have to follow them and I’ll not be held responsible for any loss or damage you may experience.
Please comment below if you have to add anything to the above.
