TOOL STEELS

Tool steels are generally heat treated to give high hardness values, thereby producing steels with high wear resistance, toughness and impact strength.

D2

D2 is a high carbon high chromium steel, this gives it a very impressive wear resistance and toughness due to a large amount of carbide present in its structure. D2 shows minimal amounts of distortion in heat treating like other air hardening steels. It can also be machined when in an annealed condition. As a bonus polished D2, thanks to its chromium content shows a level of corrosion resistance.

D2 as its name would suggest is primarily used for the construction of tools such as dies in a forge, shear blades, thread rolling dies etc.

D3

D3 is similar to D2,  again it's high carbon high chromium steel. D3 contains approximately 0.5% - 1% more carbon than D2 as well as up to 0.5% more chromium. While the applications of D3 are broadly similar to that of D2 it does have a better wear resistance and is preferred for an application like shear blades as their longevity is significantly increased in this application. It still retains the corrosion resistance once polished. 

O1

O1 is an excellent tool steel for general use, it's relatively inexpensive and fairly easy to machine. O1 is an oil hardened tool steel supplied in the annealed condition. O1 others all characteristics synonymous with tool steels, a decent level of durability as well as wear resistance. It's a very viable substitute in place of more expensive tool steels were the extra utility would not be utilized. O1 forgoes the corrosion resistance of D series steels, as well as some level of wear resistance.

O2

O2 is very similar to O1 in that its; an excellent tool steel for general use, it's relatively inexpensive and fairly easy to machine. O2 is an oil hardened tool steel supplied in the annealed condition. O2 others all characteristics synonymous with tool steels, a decent level of durability as well as wear resistance. It's a very viable substitute in place of more expensive tool steels were the extra utility would not be utilized. O2 forgoes the corrosion resistance of D series steels, as well as some level of wear resistance. O2 has no tungsten when compared to O1 while its a fairly small amount it does aid the wear resistance. 

Technical Information