Why is CPM 3V powder steel so strong?


Composition CPM-3V Chemical %(Carbon 0.80; Chromium 7.50; Vanadium 2.75; Molybdenum 1.30)


CPM 3V (Crucible Industries in Syracuse, New York) - Introduced in 1997.

CPM 3V is a tool steel made of metal powders with a unique chemical composition that provides the tool with a unique combination of properties, including high impact strength and good wear resistance. Toughness is enhanced due to the fine grain size, small carbides and excellent purity of the powder metallurgy (PM) microstructure.

3V, although very hard, provides better ductility than most tool steel grades. It has very good abrasion resistance, approximately 50% better than D-2 and can be hardened to RC 56-60. It holds the cutting edge very well and at the same time is quite easy to process and sharpen due to the relatively low content of added ingredients.

CPM 3V is one of the hardest tool steels available, particularly interesting for its high wear resistance. In other words, there are other harder tool steels, such as AISI S1 steel, but none have comparable wear resistance. CPM 3V is also 7.5% which definitely helps with corrosion resistance although it is not stainless steel. Initially, when the steel was new, the Knife Steel FAQ stated that there would be pitting instead of surface rust. More recent tests show the opposite, even after prolonged exposure to the elements, the CPM 3V did not develop pitting, only surface rust. I suppose if left outside in a aggressive environment, the CPM 3V would eventually develop pitting, but not before or in place of surface rust. When maximum toughness combined with very good wear resistance is required, 3V is an excellent choice.

The CPM 3V also works very well for small fixed blades and folders with a high hardness of 62-64HRC. The edge stability is very high even at 63 HRC due to its high ductility and will not show edge blunting due to micro spalling which happens with many alloys of this hardness.

Durability - This steel has exceptional strength so you can expect it to survive heavy use in the field and in survival scenarios. This is the main reason why you should choose the CPM 3V for knife making. The blade of the knife is resistant to chipping and complete breakage under the influence of impact or twisting, which is why it is ideal for camping and outdoor use, e.g. in the forest.

Edge retention/wear resistance - CPM 3V steel does not hold edges as well as some other steels such as S35VN or S30V. This means that the combination of alloys in the steel makes it more susceptible to blunting with repeated use. According to Crucible tests, CPM 3V holds an edge better than D2 (which is a comparable tool steel used in the manufacture of knives) with a hardness of 60 RC. Comparing CPM 3V steel with A2 steel, 3V has better cutting edge retention.

Corrosion resistance - CPM 3V steel is not stainless, it will oxidize if not cared for properly. Even with proper care, discoloration or oxidation can be expected over time.

Heat Treatment - Heat treatment affects edge retention and strength and is determined by the knife manufacturer. According to Crucible, 3V steel is to be heat treated in the range of 58-60 RC (Rockwell hardness measurement) for knife blades. Less hardness in heat treatment will mean more strength but less edge retention; this is a compromise in quality.

                                                                                                              Author: Adam Kornalski AK KNIVES