Details SK4 Steel Review

What is SK4 Steel?

The SK4 steel is a tool steel, which is an alloy of vanadium, chromium molybdenum and vanadium and is distinctive due to its hardenability and durability. Sk4 steel comes in the form of a tool that is water hardening steel that is similar to AISI W1 steel. It belongs to the Sk family of steel that includes the SK3, SK4, SK5, Sk6…

Steel SK4 is not stainless steel due to the fact that it has extremely low levels of the element chromium (0.30 percent) which makes it extremely susceptible to rust and corrosion. SK4 has also been known to have significant impurities, including sulfur and phosphorus which adversely affects its performance.

Many knife users avoid knives made of this steel due to its weak resistance to corrosion. It is however, a leader in other qualities such as cutting edge retention and wear resistance and durability, so it could be a suitable option if you do not plan to use it in environments that are corrosive.

The SK4 blade steel is utilized in the making of knives and other tools such as drills, drawing tools, reaming equipment handsaw, blade cutter, as well as many other instruments that demand moderate strength and high edge retention.

SK4 Steel Composition (SK4 Steel Chart)

  • Carbon C 0.9-1.0 percent: Improves strength, edge retention, and the tensile strength. It also increases steel resistance against wear, scratching, and corrosion.
  • Chromium Cr 0.30 percent: Chromium increases hardness, tensile strength as well as the resistance to corrosion of blades.
  • Manganese Mn 0.50 percent: increases the hardness and strength of steel. When steel is heated and hardenability is increased due to an increase in manganese.
  • Nickel Ni 0.25 percent increases strength and toughness. It improves hardenability, but not nearly as much as the alloying elements found in steel. It may improve corrosion resistance in substantial quantities
  • Silicon Si 0.350 percent Strengthens and improves resistance to heat.
  • Cu Cu 0.25 percent: helps prevent the blade from oxidation
  • Sulfur S 0.03%: Improves machinability
  • Phosphorous P 0.03 percent forms hard carbide when in conjunction with other elements

Steel properties of SK4

SK4 Steel Hardness

Steel SK4 has a hardness of 62HRC according to the Rockwell hardness scale, which makes it a hard steel. The high degree of hardness comes from the abundance of carbon that are present in its composition , giving the steel exceptional edge retention and wear resistance properties.

However, the degree of hardness differs based on the heat treatment process used by the manufacturer so that some blades made from SK4 have a lower hardness of 55HRC.

SK4 Steel Toughness

The durability of SK4 steel isn’t among the most durable however it is acceptable and is superior to most steel. Knife steel SK4 doesn’t break, chip or crack when exposed to extreme conditions.

The above average level of toughness on this steel is due to the high carbon content as well as the absence of a significant quantity of chromium-carbide which tend to form tough but bristly carbides.

The durability of SK4 is affected due to the significant quantity of impurities such as sulfur and phosphorous within the alloy composition.

The SK4 Steel Edge retention

With a high degree of hardness that is 62 HRC SK4 has excellent properties for edge retention. Knives made of this material don’t lose their edge or dull quicker when used regularly. So, you’ll use the knife rather than sharpening it which is the aim for all knife owners.

Steel Corrosion Resistance SK4

The SK4 steel is not stainless steel since it has a 0-3% content of the chromium. This implies that the steel has issues in terms of corrosion and rust. If you’re looking to purchase a knife to be used in locations with high humidity or salty water, steer clear of SK4 knives.

It is crucial to note that some companies coat SK4 blades in anticorrosion coats such as DLC to improve the corrosion resistance of their blades. Consider these alternatives if you are awed by all the other characteristics of the coating.

The ease of sharpening SK4 Steel

Another drawback for SK4 steel’s disadvantage is it’s difficult to sharpen. This is to be expected since it is hard steel. Sharpening your razor-sharp edges with blades made from this type of steel will require longer and require more time than with soft steel.

Furthermore, sharpening it can be more difficult in the event that you don’t have the proper sharpening techniques and tools. Positively it’s not going to lose its sharpness faster, meaning that you don’t have to perform the process of sharpening each day.

SK4 Steel Comparison

SK4 Steel Equivalent

AISI W1 is regarded as an equivalent to SK4 steel, W1 is hardening water tool steel that has a identical alloy composition to the SK4 tool steel. It is much more sought-after than SK4 in the majority of knife makers because of the ease with which it can forge, and also its superior hardenability providing good edge retention.

SK4 steel vs SK5 steel

SK4 has higher levels of carbon than SK5 and is therefore more durable. Thus, SK4 steel is more effective in durability and edge retention over SK5. However, SK5 provides better toughness and is much easier to sharpen. SK5 is considered to be a superior steel over SK4 because of its more balanced characteristics in terms of strength edge retention, strength and easy sharpening.

The SK5 steel is commonly found in all knife blades, survival tools, and kitchen knives because of its strength as well as edge retention. The Sk5 as well as the Sk4 steels are inexpensive steels, and knives made of these blade steels are inexpensive.

SK4 steel vs. VG10 steel

VG10 steel is superior to steel from SK4 in all-around performance. It has more carbon, making it stronger and has improved edge retention and wear resistance properties. It also has more levels of chromium, which makes it stainless steel, which is why it’s better in fighting corrosion and rust.

VG10 steel is considered to be premium Japanese steel, and it is also more expensive. It’s also user-friendly and requires minimal maintenance because of its outstanding resistance to corrosion. SK4 knives are however easier to sharpen, and also affordable.

Is SK4 steel good knife steel?

The SK4 steel isn’t an excellent all-around knife steel, however it’s dependent on your needs for knives and the maker you select. The best manufacturers employ the correct heating process to create SK4 knives with superior durability, wear-resistant edges and decent toughness.

Because of its weak alloy composition The alloy composition of SK4 is relatively inexpensive and knives made of this steel are purchased at a low cost from many dealers. Sometimes , you’ll be fortunate enough to find an inexpensive SK4 Japanese knives for kitchen use.

About the author

Hi, my name is Jaba Ray. I'm a knife expert and researcher. I am the creator of, your one-stop site for everything related to knives. I love people who need suitable steel or knife for their cook because I'm also a food lover. I work with a team of people who've always had a passion for knives and blades on this site.

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