If you're shopping for a new knife, there are a lot of different options. There is also a wide range of opinions about which material produces the best knives. This article will focus on 440 steel, one of the most popular choices for custom knifemakers and others looking for a tough, durable blade.
440 steel is a martensitic stainless that has moderate corrosion resistance. Its strength and hardness make it a good choice for sharpened knives and other cutting tools like medical scalpels. Unlike grade 304, 440 has a higher carbon content and is able to attain a high Rockwell hardness rating without sacrificing toughness. This is due to the chromium and molybdenum content that promotes steel toughness and depth hardening.
While 440 is not as malleable as some other grades of stainless, it can be worked into various shapes and dimensions with heat treatment. 440 is typically offered in long forms such as bars, wires, billets and coils.
When annealed, 440 has a Brinell hardness of 269 (Rc29). For most purposes, it is cold drawn and rolled to produce finished products with a lower Brinell hardness, such as bar stock or strip.
440 steel is capable of welding, but it should be preheated and fully annealed following welding to prevent cracking. Using grade 420 filler rods will help achieve a weld with similar properties to the base metal.
