Information on SK-5 high carbon steel

[LarryAB1950@]

You can find a lot instead if you want i can share my experience with you

 

[Smiling]

You can find a lot instead if you want i can share my experience with you

Feel free to post, despite the fact this thread is really old.

Welcome to the forum.

 

[KenHash]

SK-5 stands for Steel Kogu (Tool Steel). The 5 indicates level of impurities so SK-4/SK-3 is actually higher quality. It is close to American W2 and 1084 in composition. But it is not a knockoff. It has been used in knives made in Japan in the 1960s and sold in the US since the mid 1980s. In Japan it is used on lower end kitchen knives because it's cheaper than the Hitachi Yasugi carbon steels White/Blue etc. As it was never export restricted many knives made in Taiwan and China use SK5.
However, SK-5 is hardly a "cheap" steel in terms of performance. Probably the first SK-5 knife to become well known in the US is the SOG S1int. More recently Cold Steel introduced an SK-5 version SRK which has received high reviews. Old thread but information on the net lasts forever.

 

[Smiling]

Actually, all SK steels have same ammount of impurities.

Hitachi makes a number of carbon steels. Here are the common ones found in knives.

SK Steels (sk5, sk4, sk3)- the least expensive of the carbon steels and the lowest carbon content (#5 has the least carbon, #3 the most). This steel has higher amounts of phosphorus and sulfur than the other steels i'm about to mention. This steel tends to be tough (due to the lower carbon content and thus lower hardness). It also tends to be more reactive.

Yellow Steel (yellow 3, yellow 2)- This steel is more pure (less phosphorus and sulfur than the SK Steels). It also has higher carbon content (#3 has less carbon than #2 in this case as well). This steel is commonly found in saws and wood working tools. It is also sometimes found in knives.

White Steel (White 3, white 2, white #1)- This steel is even more pure than yellow steel (which is relatively pure). Once again, the lower the number, the higher the carbon content, so white #1 has the most carbon and white #3 has the least. The higher carbon (and hardness) leads to white #1 having the best edge retention of the white steels and also the best ability to hold an acute angle. White #3 has the best toughness.