What is K720 Steel?

Joker K720 Steel Knife

What is K720 Steel?

K720 steel is a high carbon tool steel manufactured by Bohler Industries, its alloying composition is highly comparable to AISI O2 tool steel. It is popularly used as knife steel to make survival knives, fixed blades, and bushcraft knives. 

K720 tool steel is a good steel choice for outdoor knives because offers all-round balanced performance in terms of edge retention, toughness, and ease of sharpening. Its well-rounded performance is enhanced by the balance of Carbon and Manganese in its composition.

K720 tool steel is also used for making industrial machine knives, punches, gauges, measuring tools, and jigs. The biggest downside of K720 blade steel is that it does not contain enough chromium to qualify as stainless steel. 

K720 Steel Composition

  • Carbon C 0.90%: Increases edge retention, hardness, and tensile strength. It also improves steel resistance to wear, abrasion, and corrosion.
  • Chromium Cr 0.35%: The formation of Chromium carbide Increases the hardness, tensile strength, and corrosion resistance of the blade.
  • Vanadium V 0.10%: Increase wear resistance and toughness, it also improves corrosion resistance. 
  • Manganese Mn 2.00%: Increases the hardenability of the steel alloy.
  • Silicon Si 0.25%: Increases strength and heat resistance.

Properties of K720 steel

K720 Steel Hardness

The hardness of K720 steel ranges from 62-65HRC as per the Rockwell hardness scale, depending on the heat treatment used. K720 steel can make high-end knife blades when used by manufacturers who employ superior heat treatment. 

With this hardness level, expect K720 knives to offer excellent wear resistance and keep a sharp edge for a very long time.

K720 Steel Toughness

As a rule of thumb, hard steel offers low toughness. However, K720 steel goes against this steel rule. Although it is hard steel, it offers decent toughness to keep breaking, chipping, and cracking away.

The great balance of hardness and toughness of K720 knife steel qualifies it as the ideal steel for the manufacturer of camping and survival knives. It is hard and tough enough to easily cut through hard and thick materials without chipping.

K720 Steel Wear resistance

Wear resistance is the ability of steel to resist abrasion, and it is directly related to hardness. Hard steel offers great resistance to wear and abrasion resistance. Being hard steel, K720 shines in this department.

K720 knives will last long without deforming or losing shape, even with frequent use. The excellent wear resistance is attributed to the blend of carbon, manganese, and vanadium in its composition.

K720 Steel Edge retention

Edge retention is a major consideration for many knife makers, and K720 steel offers superb edge retention thanks to its high hardness. You will not have to sharpen K720 blades after every use, and that is why it is great for outdoor knives.

K720 Steel Corrosion resistance

The major drawback of K720 knife steel is its low corrosion resistance. Without proper care and maintenance, you can quickly lose your K720 steel knives to rust and stains. The steel is not good in corrosion resistance because it contains very low amounts of chromium.

With that in mind, you should wipe dry K720 knives after every use and keep them lubricated by applying a coat of oil on dry blades before storage.

Ease of sharpening

Unlike most hard steel, K720 tool steel is easy to sharpen. K720 knives come with a very sharp edge and hold it for a long time. It takes a razor edge with simple sharpening tools and minimum sharpening skills when it becomes dull.

The edge retention and ease of sharpening balance of k720 knives make them a favorite of many outdoor knife users.

K720 steel comparison

K720 Steel Equivalent

K720 equivalent is AISI O2 steel, they both contain same alloying elements and can take similar heat treatment techniques. K720 is also similar to Daido YK30 steel and JIS SKS93 steel.

K720 vs 14C28N Steel

14C28N stainless steel is better knife steel than K720 steel in two major aspects, firstly 14C28N stainless steel offers incredibly high toughness, and secondly, 14C28N offers higher corrosion resistance.

K720 and 14C28N both offer an almost similar level of edge retention, however, it is easier to sharpen 14C28N stainless steel due to the production process that results in finer grain structure.

K720 steel vs. O1 steel

K720 is an equivalent of O2, which makes it an upgrade of O1. Generally, the performance of both steel is very similar, but O1 contains tungsten which gives it increased hardness at higher temperatures, while K720 has more manganese than O1 for hardenability.

K720 steel vs. D2 steel

K720 steel offers higher toughness than D2 steel. On the other hand, D2 is generally better than K720 because it offers better edge retention, wear resistance, and corrosion resistance.

K720 vs. A2 steel

K720 is easier to sharpen than A2 steel. On the other hand, A2 outshines its counterpart in hardness, wear resistance, edge retention, toughness, and corrosion resistance.

Is K720 good knife steel?

K720 is good knife steel for knife users and makers who are not keen on corrosion resistance. It offers great knife steel properties like excellent wear resistance, great edge retention, decent toughness, and is fairly easy to sharpen.

On the downside, it has low corrosion resistance and may not be the best choice for knives to be used in highly corrosive environments.

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