M390 vs S90V – Knife Steel Shootout (My Opinion…)

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At A Glance
Bohler-Uddeholm’s M390 and Crucible Industries’ S90V are two high-performing blade steels. M390, often referred to as “super steel,” is recognized for its hardness, wear resistance, and corrosion resistance. S90V stands out for its edge retention and wear resistance, albeit being harder to sharpen. Though both are premium options, M390 is typically more expensive due to superior performance. The choice between M390 and S90V depends on personal preferences and the knife’s intended use, but selecting a knife from a reputable manufacturer will ensure optimal performance.

Top Rated Knives

The quality of blade steel can make or break your experience with a knife. Two such steels that frequently arise in conversations about blade materials are M390 and CPM S90V. Each of these steels has its unique strengths and characteristics. In this article, we will dissect M390 and S90V, analyzing their composition, hardness, toughness, corrosion resistance, edge retention, and ease of sharpening to pinpoint which one excels for knife making.

Understanding blade materials is no simple feat, and even experienced knife enthusiasts can find themselves in a maze of steel types and attributes.

This article aims to untangle this web by offering a deep dive into the specifics of two of the most well-regarded knife steels: Bohler-Uddeholm’s M390 and Crucible Industries’ S90V.

By closely examining their composition, hardness, toughness, corrosion resistance, edge retention, and ease of sharpening, we aim to provide a clear picture of what each steel brings to the table and how they compare as materials for knife blades.

Steel Background

Understanding the basics of each steel type is essential before delving into the finer details of the comparison.

M390

Bohler-Uddeholm’s M390 is often referred to as a “super steel” due to its excellent performance characteristics. It is a powder metallurgy stainless steel, appreciated for its outstanding hardness, wear resistance, and corrosion resistance. Often, it is used in premium knife models due to its superior quality and cost.

S90V

Crucible’s S90V is another high-end stainless steel. It features high vanadium content, leading to exceptional edge retention and wear resistance. Though it can be challenging to work with and sharpen, many high-quality knives utilize S90V because of its impressive long-term performance.

Steel Composition

Exploring the chemical compositions of each steel provides insight into their unique properties.

M390

• Carbon: 1.9%
• Chromium: 20%
• Molybdenum: 1%
• Vanadium: 4%
• Tungsten: 0.6%
• Manganese: 0.3%
• Silicon: 0.7%

S90V

• Carbon: 2.3%
• Chromium: 14%
• Molybdenum: 1%
• Vanadium: 9%
• Manganese: 0.5%
• Silicon: 0.6%
• Niobium: 0.5%

From their compositions, it’s clear that S90V contains more Carbon and Vanadium, contributing to its high hardness and wear resistance. Meanwhile, M390’s high Chromium content aids its superior corrosion resistance.

M390 vs S90V – Complete Comparison

Hardness

The hardness of a blade steel directly impacts its wear resistance and edge retention.

M390 exhibits a Rockwell hardness (HRC) of 60-62, striking a balance between hardness and toughness, with an excellent wear resistance.

S90V, with its high carbon and vanadium content, reaches a Rockwell hardness (HRC) of 59-61. This hardness level gives it exceptional edge retention but also makes it more brittle, meaning it may chip under intense usage.

Toughness

Toughness pertains to a steel’s ability to resist damage like chipping and breaking under use.

M390, thanks to its powder metallurgy production process, boasts a high degree of toughness, performing admirably under heavy-duty use.

On the other hand, S90V, while tough, is slightly more prone to chipping due to its high hardness.

Corrosion Resistance

The corrosion resistance of a steel determines how well it can resist degradation from exposure to harsh elements.

M390 excels in this regard, thanks to its high Chromium content. This high resistance to corrosion makes it an excellent choice for knives that will be exposed to harsh environments or water.

S90V, although not quite matching M390, provides decent corrosion resistance that will suffice in most regular conditions.

Ease of Sharpening

Sharpening ease directly impacts user experience, and is usually inversely proportional to edge retention and hardness.

M390, while not as easy to sharpen as some lower-end steels, can still be worked with standard sharpening methods, providing a sharp, long-lasting edge.

S90V, in contrast, is known to be challenging to sharpen due to its high hardness. Specialized tools and techniques are often required to sharpen an S90V blade effectively.

Edge Retention

Edge retention refers to how well a blade maintains its sharpness during use.

Both M390 and S90V offer exceptional edge retention due to their high hardness and wear resistance. Of the two, S90V, with its high Vanadium content, generally provides slightly better edge retention.

Price

Both M390 and S90V are considered premium steels and are typically found in higher-end knives. However, M390 is usually more expensive due to its all-around superior performance and slightly better market availability.

Conclusion

Both M390 and S90V are high-performing blade steels, each with its unique strengths. M390 stands out for its impressive toughness, corrosion resistance, and wear resistance, making it a robust and versatile option for a range of knife uses. S90V, on the other hand, impresses with its exceptional edge retention and wear resistance, although it can be more challenging to sharpen.

Your choice between M390 and S90V will largely depend on the intended use of the knife and your personal preferences. Each of these steels is a solid choice for knife making, and both are favored by reputable knife manufacturers. As always, selecting a knife from a trustworthy brand will ensure that you truly experience the benefits these steels offer.