Steel and Carbide tools
The way tools are manufactured and the materials used in the manufacturing process have a great deal in determining the quality of the tool. Often times, in tools made of steel or carbide there are other materials added to increase the strength and wear of the tool. The process tools go through during manufacturing also affect the strength and wear of the tool. Some of these steel and carbide additives and processes are explained below.
Steel additives are sometimes added to the precision hand tools we sell. Here is a list of some of the additives that may have been added to our lines of precision hand tools and the benefits that these additives offer to the tools.
Chromium is sometimes added to the steel to improve wear resistance, hardness and corrosion resistance.
Cobalt is sometimes added to steel because it improves high temperature toughness so the steel will keep an edge at the high temperatures caused by drilling or cutting.
Copper makes steel tougher, improves yield strength and improves corrosion resistance
Manganese makes steel harden better for a tougher, stronger, more impact resistant material.
Molybdenum improves impact resistance to prevent breakage, tensile strength and elasticity to prevent tool breakage and snapping.
Nickel improves impact resistance, tensile strength, elasticity and corrosion resistance.
Vanadium improves impact resistance, tensile strength and elasticity as well as providing resistance to alternating mechanical stress. Vanadium also improves the grain structure for a tougher tool.
Tungsten produces a fine, dense matrix for a tougher, stronger tool and helps with hot hardness
Advanced, fine grain, spray dried, carbide with additives to control grain growth and provide corrosion resistance. This grade has the highest resistance to abrasion (flank wear) and the greatest strength.
Tantalum improves hardness and strength as the tool gets hot during cutting.
Tantalum Carbide (TaC) and Tantalum Niobium Carbide (TaNbC) are added to maintain edge strength at high temperatures. TaC is a grain growth inhibitor preventing the formation of large grains and increasing the hardness of the sintered part.
Titanium additives to carbide improve high red hardness and create very good wear qualities. They machine steel in the very high speed ranges, providing good surface finishes and size control. Titanium Carbide gives “lubricity” to the carbide so that the chip slides across the face of the cutter with less heat and friction. Titanium carbide additives permit the carbide to maintain high hardness at elevated temperatures. Where the material being machined tends to crater, bind, seize, or gall the workpiece, titanium carbide bearing grades should be used.
Tantalum (or Columbium) aids in resisting cratering, seizing, and galling. It improves resistance to deformation under heavy load where very high temperatures are created. Tantalum carbide maintains its hardness and strength at elevated temperatures better than titanium carbide or tungsten carbide.
Molybdenum is a very efficient catalyst to improve manufacturing quality and produce, better, tougher, more consistent parts.
Vanadium is chemically stable and has excellent high-temperature properties. It makes much finer carbide crystals and greatly improves the material.
HIP stands for Hot Isostatic Pressing. You bring the material, either steel or tungsten carbide, up to a point just below its melting temperature. You do this under tons of pressure. What happens is that all the voids and holes in the material are squeezed shut so you get a harder, stronger piece of material. It also rearranges the grain structure to make it a tighter, better packed, more consistent material. This also greatly improves strength and wear properties.
Casting versus forging
In casting you mix the material, heat it until it is molten and then poured it into a mold. In forging you get the material hot and you beat it into shape. Forging provides a much stronger, more consistent piece of material because the act of forging serves as a method to remove any air bubbles that may result from casting. In addition forging also improves the grain structure generally improving all desirable properties.
Hot rolling versus forging
Steel is often made in a continuous casting process where it is poured out into molds. These very large, very thick chunks of steel are then rolled and rerolled and rolled some more to make steel plate and steel sheet. This can cause problems in precision tools because the rolling introduces stress into the steel so that the steel wants to bend. The very best tools are stress relieved through heat treating or forging so that they stay straight and have no tendency to bend.
Machining versus casting
Cheap tools are cast because it is a cheap manufacturing process. High quality tools are forged, machined and polished or forged and polished. If you are making the body for a good router bit, you want a solid piece of steel with no voids or imperfections. Forging gives you this, casting does not. Machining adds a little more to the cost but a great deal more to the quality of the tool. With tools such as screwdrivers the best shafts are forged to shape rather than polished to bring them the final size and to create a smooth, safe, highly effective surface.
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