Our readers always ask me about the knife steel. For example, which steel is best for a knife; what steel can make the sharpest knife; What is knife steel; what is the hardest knife steel and etc. At this part, I will do my best to try to let you guys know which steel is best for a knife.
Steel is an alloy of iron with typically a few percent of carbon to improve its strength and fracture resistance compared to iron. Many other additional elements may be present or added according to the requirements of properties. Many tpyes of steel can be used to make a knife. And the common types are tool steel, carbon steel, stainless steel, spring steel, bearing steel, Damascus steel.
Tool steel has good hardness, wear resistance, toughness as hard alloy steel, so it usually is used to make all kinds of cutting tools. The popular grades of it are D2, O1, M4 and more. But they are not the same. Some tool steels have higher carbon element, its stability is pretty good, so is the good choices for the small and straight knife. On the other hand, tool steels with a lower carbon element, the toughness is higher, always be used to make medium and big size chopping knife.
It is the most common type of steel. The grades are 1045, 1040, 1060, 1095 and etc. Its internal structure is simple, after good and right processing, its strength, hardness, machinability, impact toughness will be better. Combat knife, survival knife, and household chopper always be made of carbon steel. It is easy to polish to grows sharper. If it becomes blunt, you can polish on the marble, then it will get sharp as begin.
At the knife group, people always say: carbon steel is the king. That means hardness and sharpness of it are the best, no steel material can beat it. But there is a defect that it get rust easily due to Cr element is quite low. So many people ignore its value to choose stainless steel.
At the base of carbon steel to add Cr to improve the corrosion resistance and fineness of material. But the consequence is that the toughness and strength will be lower. The chemical composition of Cr is bigger than 13%. Common grades are 440C, A36, 420, 154CM and etc. Most people know the 440C stainless steel, it is a good material for surgical knife. Not because of how sharpness it is, but its beautiful fineness makes people think that it is more healthy and easy to sterilize. This type of steel is hard to get rust if you maintain it in the right way. But weakness is that it has bad machinability in any hardness. Even at the high hardness, it is very delicate. And it is hard to polish to make it sharp.
Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. It has great toughness is the biggest advantage. And the ability of straightening is bigger than carbon steel. It is widely to make the big size outdoor knife.
It is one of the strictest steel grades for steel production. It has high and uniform hardness, good wear resistance and toughness and better corrosion resistance.
Because of the beautiful pattern, it always is used to manufacture high-end knives. Its advantage is good hardness and toughness compared with other steel grade material. The production processing, temperature control and welding of this type of steel are very difficult. That means the cost will be very high.
Those steel types are good material for the knife. But we can not get the answer of which steel is best for knife. We also need to consider several points. What will you do with a knife is the most important thing. That will determine which steel grade is best. If you need a kitchen knife, stainless steel is the best choice. Including 420, 440, 316 steel. And if you have high requirements for strength, sharpness, carbon steel is suitable for you. But if your budget is enough, you best to choose Damascus steel, it can satisfy all you imagine for knife, including sharpness, strength, surface and etc.