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CPM 20CV vs M390 Knife Steel Comparison

CPM-20CV vs. M390: Which Premium Knife Steel Reigns Supreme?

Introduction
Overview of CPM-20CV
Overview of M390
Typical Hardness (Rockwell C) Ranges and Practical Implications
Detailed Alloy Element Effects
Key Performance Characteristics
Heat-Treatment Nuances and Forging
Patina Formation and Protective Coatings
Side-by-Side Comparison Table
Real-World Performance and Ideal Uses
Cost, Availability, and Maintenance
Pros and Cons
Conclusion and Recommendations

1. Introduction

If you’re a knife enthusiast or collector, you’ve probably heard about CPM-20CV and M390. These stainless “super steels” are often lauded for their premium performance and are frequently compared because of their nearly identical compositions and properties. Both are produced using advanced powder metallurgy processes, which yield exceptionally fine grain structures and high concentrations of performance-enhancing carbides.

In this article, we’ll dive deep into the details—covering chemical composition, heat-treatment nuances, real-world applications, and more—so you can decide which steel might best suit your needs.

2. Overview of CPM-20CV

CPM-20CV is a high-end stainless steel made by Crucible Industries using the Crucible Particle Metallurgy (CPM) process. Its typical composition includes (approximately) 1.9% carbon, 20% chromium, 0.3% manganese, 1% molybdenum, 0.3% silicon, 1% tungsten, and 4% vanadium. The result is a premium steel that combines superior wear resistance (thanks to high vanadium carbides) with excellent corrosion resistance (due to the 20% chromium). CPM-20CV is also closely related to Carpenter CTS-204P, which has very similar chemical properties.

Manufacturer: Crucible Industries
Powdered: Yes (CPM process)
Primary Advantages: Excellent corrosion resistance, very good edge retention, reasonable toughness, and a manageable sharpening experience
Common Applications: Folding knives, high-end fixed blades, kitchen cutlery, and everyday carry (EDC) knives requiring top-tier edge holding and stain resistance

3. Overview of M390

M390 is produced by Böhler-Uddeholm in Austria through a specialized powder metallurgy process. Its composition closely matches CPM-20CV, typically with about 1.9% carbon, 20% chromium, 0.3% manganese, 1% molybdenum, 0.7% silicon, 0.6% tungsten, and 4% vanadium.

Manufacturer: Böhler-Uddeholm
Powdered: Yes (PM process)
Primary Advantages: Exceptional corrosion resistance, superb edge retention, fair toughness, and good ease of maintenance
Common Applications: High-performance folding knives, custom fixed blades, EDC, and cutlery where long-lasting sharpness and rust resistance are priorities

4. Typical Hardness (Rockwell C) Ranges and Practical Implications

Both CPM-20CV and M390 generally fall within the 59–62 HRC range when heat-treated optimally. Some makers push hardness to around 62–63 HRC to maximize edge retention, though this can decrease toughness. In general:

59–60 HRC: Slightly better toughness, easier to sharpen
61–62 HRC: Higher wear resistance, longer edge retention
Above 62 HRC: May become more prone to chipping under heavy use

Choosing the appropriate hardness depends on the blade’s intended purpose. Heavy-duty or impact-oriented tasks often benefit from a slightly lower HRC, whereas fine slicing or detailed cutting (e.g., food prep) can take advantage of higher hardness for more extended edge life.

5. Detailed Alloy Element Effects

Carbon (C ~1.9%): Increases hardness and wear resistance; forms carbides crucial for edge retention.
Chromium (Cr ~20%): Provides stainless properties and improves hardenability.
Vanadium (V 4%): Creates extremely hard vanadium carbides, boosting wear resistance and refining grain size.
Molybdenum (Mo 1%): Adds strength and hardness at higher temperatures; improves corrosion resistance.
Tungsten (W 0.6–1.0%): Helps form dense, fine carbides; enhances wear resistance and strength.
Manganese (Mn 0.3%): Aids in hardenability; can improve toughness.
Silicon (Si 0.3–0.7%): Improves strength; assists deoxidation in steelmaking.

6. Key Performance Characteristics

Both CPM-20CV and M390 excel in the following areas:

Excellent Corrosion Resistance: With ~20% chromium, these steels resist rust and staining well in moist environments.
Fair-To-Good Toughness: While not as tough as some dedicated tool steels (e.g., CPM 3V), they offer sufficient toughness for most EDC and outdoor tasks.
Outstanding Edge Retention: High carbon and vanadium levels form wear-resistant carbides, keeping edges sharp for longer.
Manageable Sharpening: Despite being very wear-resistant, they are still more forgiving to sharpen than ultra-high carbide steels like CPM S90V or Maxamet.

7. Heat-Treatment Nuances and Forging

Powder metallurgy steels require precise heat-treatment protocols to fully realize their potential:

Austenitizing: Typically around 2100°F (1150°C) to dissolve carbides.
Quenching: Rapid cooling for optimal hardness and microstructure.
Tempering: One or more temper cycles fine-tune the steel’s hardness and toughness levels.

While both CPM-20CV and M390 can be forged, their high alloy content demands careful temperature control, extended soak times, and thorough normalizing cycles. Compared to some other high-alloy steels, these aren’t the most notorious for warping, but attention to detail is crucial to avoid brittleness or uneven hardness.

8. Patina Formation and Protective Coatings

Because of their high chromium content (~20%), CPM-20CV and M390 generally do not form a patina in normal use. Unlike lower-chromium or carbon steels (e.g., 1095 or 52100), you’ll have a difficult time forcing a patina:

Minimal to No Patina: Any patina will be superficial and slow to form, if at all.
Protective Coatings Unnecessary: Their natural rust resistance makes coatings optional, though some may prefer a coating for tactical or aesthetic reasons.

9. Side-by-Side Comparison Table

Below is a quick-reference chart highlighting the key similarities and small differences between CPM-20CV and M390:

	CPM-20CV	M390
Manufacturer/Process	Crucible (CPM Powdered Steel)	Böhler-Uddeholm (PM Process)
Typical Composition	~1.9% C, 20% Cr, 0.3% Mn,	~1.9% C, 20% Cr, 0.3% Mn,
	1% Mo, 0.3% Si, 1% W, 4% V	1% Mo, 0.7% Si, 0.6% W, 4% V
Corrosion Resistance	Excellent	Excellent
Toughness	Fair to Good	Fair to Good
Edge Retention	Very Good	Very Good
Ease of Sharpening	Good	Good
Typical HRC Range	59–62	59–62

10. Real-World Performance and Ideal Uses

Bushcraft & Survival: Both steels handle moderate chopping, slicing, and carving. If extreme impact is anticipated, a steel like CPM 3V offers better toughness.
Everyday Carry (EDC): Exceptional edge retention and corrosion resistance make 20CV and M390 excellent for daily cutting tasks in varied environments.
Kitchen Use: Ideal for long-term sharpness in wet conditions. A hardness around 60–61 HRC is often preferred for a balance of edge retention and easier maintenance.
Tactical & Self-Defense: Holds an edge exceptionally well, resists corrosion under harsh conditions, and is “tough enough” if you avoid extreme prying.
Outdoor Knives: The stainless quality ensures minimal maintenance during fishing, hunting, or camping, where moisture is a concern.

Why choose these steels over others? They offer a rare combination of high-edge retention, stainless properties, and relative ease of sharpening. If you prize longevity of sharpness and low maintenance, CPM-20CV or M390 will serve you well.

11. Cost, Availability, and Maintenance

Cost: Both CPM-20CV and M390 command premium prices due to complex manufacturing and brand prestige. Expect to pay more than for mid-tier steels like VG-10 or 154CM.
Availability: Widely found in mid-to-high-end production knives. M390 is popular across European brands, while 20CV is a mainstay for many American makers.
Maintenance: Basic cleaning and occasional oiling or waxing suffice, thanks to excellent corrosion resistance. Regular stropping helps extend intervals between full sharpenings.

12. Pros and Cons

CPM-20CV

Pros:
- Outstanding corrosion resistance
- Excellent edge retention and wear resistance
- Relatively friendly to sharpen (versus ultra-hard steels)
- Versatile in a wide range of applications
Cons:
- Only “fair” toughness for heavy-impact tasks
- Premium pricing reflects its proprietary nature

M390

Pros:
- Top-tier corrosion resistance
- Very high edge retention
- Good sharpenability compared to other “super steels”
- Widely recognized and used by many major knife brands
Cons:
- Toughness is decent but not suited for extreme abuse
- Premium cost may deter budget shoppers

13. Conclusion and Recommendations

CPM-20CV and M390 are nearly equivalent in most real-world scenarios. Both are powder metallurgy “super steels” that balance excellent corrosion resistance, outstanding edge retention, fair toughness, and manageable sharpening difficulty. Their sweet spot is typically around 59–62 HRC, adjustable based on whether you prioritize toughness or extreme edge life.

Durability Concerns: For brutal prying or batoning, consider a tougher steel like CPM 3V.
EDC and Kitchen Stars: Their corrosion resistance and edge retention shine in everyday carry, culinary prep, and general-use blades.
Final Choice: Often comes down to brand preference, specific knife design, or heat-treatment quality. In real-world cutting tasks, you’ll rarely notice major differences between the two.

In short, whether you opt for CPM-20CV or M390, you’re investing in a top-tier steel that delivers long-lasting sharpness, premium rust resistance, and a reliable cutting edge. For knife enthusiasts and professionals seeking a best-in-class material, you can’t go wrong with either.

Last updated: [Month Year]
(Always check the latest datasheets from Crucible and Böhler-Uddeholm for the most accurate and up-to-date composition and heat-treat information.)