D2 Knife Steel Composition Analysis Graph
And Information Details

D2 - WWII era, semi-stainless tool steel. Very popular even today. Pretty much every steel manufacturer makes it and it's quite popular with knifemakers, custom and factory alike. Compotision-wise it's almost a stainless steel. Resists rust pretty well, good edge holding and ok toughness. Bob Dozier is perhaps the most acknowledged expert of D2 steel knives.
X12MF - Russian equivalent of the AISI D2 tool steel. Unlike standard D2, and most of the versions of it, contains trace amounts of Cu(Copper).
Amtek D2 - Yet another D2 variation, this time from Amtek Tool and Supply. Interesting part is the addition of the 1% Cobalt. Of all the D2 alloy compositions I have in the knife steel composition chart, there is only one - OCR12VM steel that has Cobalt in it, although compared to Amtek it's very low, just 0.3%. It is questionable whether the addition of such significant amount of alloying element still allows the steel to remain in the same standard designation. Anyway, Amtek lists it as AISI D2, so here we are.
KAD181 - Tool steel, used for cutting metals and other cutting instruments.

Alternate designations: D2(AISI), X155CrVMo121(DIN), X153CrMoV12(DIN), X165CrMoV12(DIN), 1.2379(W-Nr), X160CrMoV121(EN), SKD11(JIS), X160CrMoV12-28(AFNOR), 32CDV12-28(AFNOR), Z160CDV12(AFNOR), BD2(BS), X155CrVMo121KU(UNI), Cr12MoV(GB), Cr12Mo1V(GB), Cr12Mo1V1(GB), 19573(CSN), 19572(CSN), F520A(UNE), X12MF(GOST), T30402(UNS), A681(ASTM), J437(SAE), J438(SAE), Amtek D2(Amtek Tool), XW41(Assab), XW42(Assab), Sverker21(Bohler-Uddeholm), K110(Bohler-Uddeholm), K105(Bohler-Uddeholm), Z(Bonpertuis), No. 610(Carpenter), Airdi 150(Crucible), CPM D2(Crucible), DC53(Daido), DC11(Daido), CPPU(Dorrenberg Edelstahl), ZCD-M(Hitachi), SLD2(Hitachi), SLD(Hitachi), KAD181(Kobe Steel), LSS D2(Latrobe), LO-K 2379(Lohmann), OCR12VM(Metal Ravne), R31(Mitsubishi Steel), CDS11(Nachi Fujikoshi), KD11V(Nihon Koshuha), KD11(Nihon Koshuha), KD11S(Nihon Koshuha), RD11(Riken Seiko), QC11(Sanyo), QCD2(Sanyo), Thyrodur2379(Thyssen-Krupp), LC120S(Zapp).