CPM 154 vs MagnaCut

In this post, “CPM 154 vs MagnaCut” I will compare the characteristics and performance of these two powder metallurgy steels to see how they stack up.

CPM 154 is a powder metallurgy version of 154CM conventional stainless steel, providing an improved, more uniform carbide distribution compared to 154CM. It offers a combination of good wear resistance, toughness, and corrosion resistance.

CPM 154 is an established stainless steel that has been popular in the knife industry and other applications for many years.

The new steel CPM MagnaCut was conceived by metallurgist Dr. Larrin Thomas and produced by Crucible Industries as an attempt to get superior edge retention, toughness, and corrosion resistance in one stainless steel.

By reducing chromium and adding vanadium, niobium, and nitrogen, MagnaCut achieves a very fine carbide structure for enhanced properties.

Both CPM 154 and MagnaCut are quality steels made using powder metallurgy for refined carbide distribution. But MagnaCut represents a newer approach to stainless steel metallurgy. 

MagnaCut vs CPM 154 Steel Differences At A Glance

Composition

Hardness

MagnaCut steel generally achieves a slightly higher hardness compared to CPM 154 steel, with typical values being around 1-3 HRC higher.

The recommended heat treatment for MagnaCut results in a Rockwell hardness range of 60-63 HRC, compared to the typical 55-62 HRC range for CPM 154. 

The higher hardness achieved by MagnaCut 60-63 HRC vs 55-62 for CPM 154 gives it better wear resistance and edge retention.

Edge Retention

Edge retention is the ability of a knife to maintain sharpness over an extended period of use. CPM MagnaCut demonstrates superior edge retention over CPM 154 due to its higher hardness and finer carbide structure. 

In standardized edge retention testing by CATRA (Cutlery & Allied Trades Research Association) performed by Crucible, CPM MagnaCut scored 135% better relative edge retention compared to a 440C baseline at 62.5 HRC. 

In comparison, CPM 154 rates at around 120% better edge retention than 440C based on its typical hardness of around 60 HRC. 

Additionally, MagnaCut contains extremely fine vanadium and niobium carbides compared to the larger chromium carbides in CPM 154 and other high alloy steels. This finer carbide distribution further enhances edge retention capability. 

Overall, the advanced powder metallurgy production of MagnaCut results in around 15% better relative edge retention over CPM 154, owing to the higher achievable hardness and finer carbide microstructure.

For applications demanding long-lasting sharp edges, CPM MagnaCut will hold an edge longer and is the better performer of these two blade steels. 

I have knives made of these two knife steels, but I always carry MagnaCut as my pocket knife as I find myself not needing to sharpen it as often.

Toughness

Toughness is an important measure that signifies the ability of a knife to resist chipped edges or breaking when dropped or put through abuse. 

The toughness difference is even more significant between these two steels, CPM MagnaCut demonstrates very high toughness, with Charpy C-notch impact values of 30-38 ft-lbs depending on hardness. 

This is a result of its fine vanadium and niobium carbides compared to the larger chromium carbides in other high alloy steels.

In comparison, CPM 154 is estimated to have moderate toughness around 26 ft-lbs at 60 HRC based on Crucible-provided data sheets. Thus, MagnaCut has substantially higher toughness, in the range of 10-15 ft-lbs greater than CPM 154.

Corrosion Resistance

Despite CPM 154 stainless steel having higher chromium content at 14% versus 10.7% for MagnaCut steel, MagnaCut steel still outperforms CPM 154 in corrosion resistance by about 25% according to a saltwater spray test.

This surprising result is attributed to MagnaCut’s lack of chromium carbides in its microstructure. The formation of chromium carbides in CPM 154 locally depletes the surrounding steel matrix of chromium, leading to weak spots vulnerable to corrosion.

In contrast, MagnaCut avoids this issue by reducing the chromium content to 10.7% and adding vanadium and niobium to form fine carbides instead.

The remaining chromium stays evenly distributed in the solution, enabling MagnaCut to exceed the corrosion resistance of CPM 154 despite having lower Cr content.

Testing by Spyderco knife company showed MagnaCut had corrosion resistance approaching that of top stainless steels like LC200N and Vanax, substantially better than CPM 154 and other stainless steels like S30V, S35VN, and S90V steel. 

While not quite exceeding the level of true marine-grade steels, MagnaCut knife steel demonstrated enough corrosion resistance to be included in Spyderco’s Salt Series knives.

Ease of Sharpening

CPM 154 is generally regarded as being slightly easier to sharpen compared to MagnaCut. CPM 154 contains only chromium carbides which are relatively soft, making the steel very responsive on sharpening stones. 

In contrast, MagnaCut contains very hard vanadium and niobium carbides that can make sharpening a bit more difficult. 

However, MagnaCut’s carbides are extremely fine due to the advanced powder metallurgy production process. This fine carbide size mitigates much of the difficulty and makes MagnaCut sharpen reasonably well.

According to Dr. Larrin Thomas, Multiple knifemakers have reported that MagnaCut sharpens easier than other carbide-strengthened steels like S35VN and S45VN.

MagnaCut provides good feedback on stones, establishes a burr easily, and deburrs well. The scratch pattern from standard aluminum oxide stones is sufficient for sharpening MagnaCut, unlike some steels that require diamond or CBN stones.

One knife maker noted MagnaCut was easier to sharpen than CPM-154 until about 240 grit where the vanadium carbides start to hinder sharpening. 

Overall, while CPM 154 remains a bit easier to put a razor edge on due to its lack of hard carbides, MagnaCut can achieve an extremely fine edge while sharpening with relative ease considering its high alloy content and hardness level.

For most sharpeners, the difference in ease between CPM 154 and MagnaCut will be moderate or negligible depending on your experience, I found it relatively similar or easier to sharpen MagnaCut.

Price

knives made from CPM 154 steel tend to be cheaper than those made from MagnaCut steel. As an older, established stainless steel, CPM 154 is more widely produced and available, keeping costs lower.

MagnaCut, on the other hand, is a newly developed proprietary steel made by Crucible Industries. The advanced powder metallurgy process required to achieve MagnaCut’s fine carbide structure also adds costs.

While pricing for steels varies, a knife in CPM 154 will generally be around USD 50 less expensive than a comparable model in MagnaCut with the same features.

Final Thoughts on CPM 154 vs MagnaCut

After reviewing the key characteristics, CPM MagnaCut stands out as having superior performance in hardness, edge retention, toughness, and even corrosion resistance compared to CPM 154.

The fine carbides in MagnaCut enable it to reach over 63 HRC hardness while maintaining toughness levels far greater than other high-alloy steels. MagnaCut also retains sharp edges for significantly longer periods of use.

While CPM 154 is easier to sharpen thanks to its simple chromium carbide structure, MagnaCut still sharpens reasonably well.

Additionally, MagnaCut is more corrosion resistant than CPM 154 by about 25% despite lower chromium content. The lack of chromium carbides in MagnaCut provides more uniform corrosion protection. 

From my personal experience with knives in both steels, I tend to prefer MagnaCut for its incredible combination of corrosion resistance, toughness, and edge retention. 

However, CPM 154 remains a very capable performer in its own right, providing a more economical option with easier sharpening. For those on a budget or who sharpen frequently, CPM 154 is a reliable choice.

But for maximizing hardness, edge retention, toughness, and wear resistance, I believe CPM MagnaCut represents the best balanced stainless steel overall for most folding or fixed blade knives.