S30V vs 12C27 Steel

12C27 is a Swedish martensitic stainless steel originally produced by Sandvik Steel using conventional melt processes.

12C27 served as a precursor to steels like Sandvik 14C28N and Uddeholm’s AEB-L steel which are renowned for their toughness and stainlessness. 

S30V is a US-made powder metallurgy steel produced by Crucible Industries. The use of powder metallurgy allows S30V to achieve high hardness and vanadium carbide content for extreme wear resistance.

While 12C27 has origins as a historic razor blade steel, S30V is a more modern knife steel alloyed for hardness and edge retention.

Both steels can attain high hardness levels above 60 HRC when heat treated properly, but S30V is capable of achieving greater hardness due to its higher carbon and alloy content.

This gives CPM S30V steel better edge holding but at the expense of reduced toughness compared to Sandvik 12C27. 

In applications where hardness and durability are critical like high-end cutlery, S30V demonstrates clear advantages over 12C27 but with trade-offs in sharpenability, and costs.

S30V vs 12C27 Steel At A Glance

Toughness

12C27 steel has an advantage over S30V steel in toughness. The lower carbon content and lower achievable hardness of 12C27 give it better toughness compared to S30V. 

As a precursor to AEB-L steel, 12C27 retains some of the excellent toughness qualities of AEB-L while still reaching hardness levels exceeding 60 HRC.

In contrast, the higher carbon and alloy content of S30V steel, along with its greater hardness capacity, make it more prone to brittleness and reduced toughness.

Transverse toughness values indicate that Sandvik 12C27 can absorb significantly more impact energy before fracturing compared to S30V. 

In knife application, this higher toughness reduces the risk of chipping, cracking, or breaking, especially for larger blades that undergo high impacts and leverage forces. 

12C27 would provide a tougher and more resilient blade, while S30V offers better edge holding but is more susceptible to chipping or fracturing under impacts. 

Hardness

When optimally heat treated, S30V steel has a clear hardness advantage over 12C27 steel.

According to the Sandvik data sheets, 12C27 can reach peak hardness levels of around 61 HRC (Rockwell C hardness).

Meanwhile, S30V can attain hardness values between 58-64 HRC depending on exact heat treatment parameters.

The higher carbon and vanadium content in S30V enables it to achieve 3-4 points higher hardness on the Rockwell C scale compared to 12C27 steel which maxes out at around 61 HRC. 

S30V’s greater hardness gives it superior abrasion resistance and edge-holding ability over 12C27. However, S30V is also more expensive to produce than 12C27.

While both steels can reach high hardness levels exceeding 60 HRC through proper heat treating, S30V’s greater hardness capacity allows it to better resist wear and retain a sharp cutting edge over prolonged use.

Overall, the higher achievable hardness of S30V gives it a measurable performance advantage over 12C27 steel for cutlery applications where hardness and edge retention are critical.

Edge Retention

S30V steel has significantly better edge retention and wear resistance compared to 12C27 steel for knife applications.

S30V can attain peak Rockwell hardness levels 3-4 points higher on the Rockwell scale than 12C27 through optimal heat treatment. 

This increased hardness gives S30V outstanding wear resistance and the ability to retain a sharp cutting edge through prolonged use. 

Testing shows S30V has 45% better relative wear resistance over 440C steel, while 12C27 would perform even lower than 440C steel. 

The high vanadium carbide content in S30V provides enhanced edge retention and durability against scratches.

For knives, the greater hardness and wear resistance of S30V translates to longer-lasting sharpness through repeated cutting tasks, reducing the need for frequent resharpening. 

Corrosion Resistance

S30V  and 12C27 steel are both stainless steels with good corrosion resistance, however, S30V knife steel has better corrosion resistance compared to 12C27 stainless steel.

S30V steel contains 14% chromium along with 2% molybdenum which enables it to resist corrosion in various environments.

Testing indicates S30V steel has a 150mV higher pitting potential than 12C27 steel when exposed to saltwater. 

The higher chromium and molybdenum content provides S30V with enhanced protection against rust, pitting and staining when exposed to moisture, acids, or other corrosive substances.

S30V knives will show fewer signs of corrosion such as spotting, pitting, or red rust when subjected to humid, salty or acidic conditions.

12C27 stainless steel still provides decent corrosion resistance with its 13.5% chromium but lags behind S30V stainless steel. 

Over prolonged use, a knife made from S30V would better retain its appearance and performance even in damp or wet environments compared to 12C27 which is more prone to corrosion effects. 

Ease of Sharpening

According to the data, both 12C27 and S30V are readily sharpenable with most stones, owing to their lack of large carbides.

However, S30V steel higher hardness and vanadium carbide content make it more difficult to put an extremely fine edge compared to 12C27 steel. 

The high grindability and machinability of 12C27 also make it easier to manufacture at lower costs compared to S30V.

For knife makers, 12C27 offers easier sharpening to a polished edge along with more economical grindability during manufacturing.

In contrast, S30V’s hardness and wear resistance advantages come at the cost of increased difficulty in sharpening and grinding.

While S30V can be sharpened effectively with the right equipment, more skill and effort are required to attain a fine edge compared to softer 12C27 steel.

Overall, 12C27 provides easier and more cost-effective sharpening and grinding, while S30V offers superior edge holding that requires more work to maintain through repeated sharpenings.

The choice depends on which is more important – easy maintenance or maximum cutting performance.

Final thoughts on S30V vs 12C27 Steel

Having experience with both 12C27 and S30V steels, I would recommend 12C27 for kitchen knives that require frequent sharpening and maintenance.

The combination of good toughness and easy sharpenability make 12C27 an excellent choice for kitchen cutlery that sees repeated cutting tasks.

For EDC knives, I would suggest S30V for its outstanding hardness, edge retention, and corrosion resistance.

S30V steel exceptional wear resistance means pocket knives stay sharper for far longer between sharpenings.

In summary, S30V steel compensates for its reduced toughness with much greater hardness, edge retention, and wear resistance.

12C27 cannot match S30V cutting performance but provides decent edge holding paired with excellent toughness and easy sharpening.