Cold cutting tool steel, such as 01, d2 and w1, is used to make shears and shear blades. It is also used to make knives and other tools that require edge-holding ability but will not be exposed to excessive heat or shock. Sheet metal shears, needle-nose pliers, wire cutters and bolt cutters are all cold-cutting tools.
Impact resistant steels, such as s5, s7 and 4130, are superior for things like jackhammer bits, impact driver bits, cold chisels and crowbars. Impact resistant steels will take a lot of repeated work stress without shattering or cracking. While it makes durable jackhammer bits, impact resistant steel is not used to make items that need to hold a sharp edge as well as cold cutting steel does.
Hot cutting steels are designed to cut and form metals at excessively high temperatures. They are mainly used in steel mills for rollers, slitting wheels and shears to cut red-hot steel. Hot cutting steel is rarely used outside of steel and bronze foundries or drop forge plants.
High-speed steel is used to make tools where friction may bring the cutting surface up to 1000 degrees Fahrenheit. The tools used in the process still require a keen edge. High-speed steel includes metal lathe tool bits, milling cutters, drill bits, router bits and steel-cutting saw blades.
When selecting your tool steel, consider what function the tool will serve, and the required properties the steel needs to accomplish the task. You need to know how much shock will be involved in using this tool, how hot you expect it to get and how keen of an edge it needs to hold. Just because a piece of steel makes a great knife doesn't mean it will make a good pry bar.