|
BLADE STEEL FACTS
We use specific blade steels to achieve a balance of properties based on the anticipated applications of the knife.
Steel is an alloy of iron, other metals and carbon. Stainless steel is a generic term for a family of corrosion-resistant alloy steels which contain 10.5% or more chromium. “Stainless” does not mean that these alloys will never stain or corrode, but that they “stain less” than steels which do not contain chromium. Each alloy imparts different properties to the stainless steel. The chart at the bottom of the page shows in detail what each alloy element contributes.
We use stainless steels from many international suppliers. The chart below shows within a reasonable range the equivalent qualities of comparable steels that we use. Note that the final hardness level achieved is not only a factor of composition, but depends greatly on proper heat treatment and quenching, to which we pay great attention.
In selecting the appropriate steel, we look at the performance requirements of the blade, the knife price range, and our manufacturing and finishing methods. There are trade-offs. While higher alloy levels and final hardness levels keep an edge longer, they also make it more difficult to field-sharpen a blade. Some premium alloys are low in nickel, and will stain if not kept clean and occasionally oiled after use. Consequently, we feature AUS 8 as our high-end alloy, which has compared very well to ATS 34 in performance tests conducted by international knife magazines.
Consider these examples: A mechanic who gives his work knife hard daily use, in contact with all types of solvents and moisture, will benefit from the durability, stain resistance and ease of sharpening found in 420J2 or AUS 4 steel. In contrast, the buyer of a CRKT Titanium M16® model expects an alloy steel such as AUS 8 steel, with its higher hardness and edge-holding ability.
Ductility, or toughness, has its place in knives that are subjected to hard useor even abuseas tactical and work knives must be, and so we have selected higher-toughness steels in many of these applications, as opposed to high-hardness steels. Based on our experience, we believe that the knife user benefits from having the strongest and toughest blade for the application.
The blade steel and hardness range of each CRKT knife are included with its catalog specifications to make the information easier to locate.
Stainless Steel Alloy Specifications
|
420J2
3Cr13
|
AUS 4
|
1.4116
5Cr15MoV
|
440A
|
AUS8
8Cr13MoV
|
9Cr18MoV
|
| Carbon % |
0.26 to 0.40
|
0.40 to 0.45
|
0.45 to 0.50
|
0.65 to 0.75
|
0.70 to 0.75
|
0.95 to 1.20
|
| Chromium % |
12.00 to 14.00
|
13.00 to 14.50
|
14.50 to 15.00
|
16.00 to 18.00
|
13.00 to 14.50
|
16.00 to 18.00
|
| Manganese % |
1.00
|
1.00
|
0.40
|
1.00
|
0.40 to 0.50
|
0.80
|
| Molybdenum % |
|
|
0.60
|
0.75
|
0.10 to 0.30
|
0.75
|
| Nickel % |
|
0.49
|
|
|
0.49
|
|
| Phosphorous % |
0.04
|
0.04
|
0.02
|
0.04
|
0.04
|
0.04
|
| Silicon % |
1.00
|
1.00
|
0.40 to 0.60
|
1.00
|
0.50 to 1.00
|
1.00
|
| Vanadium % |
|
|
0.10
|
|
0.10 to 0.25
|
|
| Hardness HRC |
52 to 55
|
55 to 57
|
55 to 57
|
55 to 57
|
58 to 59
|
58 to 60
|
Benefits of Elements of Stainless Steels
|
Increases
Edge
Retention
|
Increases
Hardness
|
Increases
Harden-
ability
|
Increases
Toughness
|
Increases
Tensile
Stength
|
Increases
Impact
Strength
|
Increases
Wear and
Abrasion
Resistance
|
Increases
Corrosion
Resistance
|
| Carbon |
x
|
x
|
|
|
x
|
|
x
|
|
| Chromium |
|
x
|
|
x
|
x
|
|
x
|
x
|
| Manganese |
|
|
x
|
|
x
|
|
x
|
|
| Molybdenum |
|
x
|
x
|
x
|
x
|
|
x
|
|
| Nickel |
|
x
|
|
|
|
|
|
x
|
| Silicon |
|
|
|
|
x
|
|
|
|
| Vanadium |
|
x
|
|
|
x
|
x
|
|
|
|