High-speed steel bit grade (HSS) is a tool steel with high hardness, high wear resistance, and high heat resistance, also known as wind steel or front steel, which means that it can be hardened even when cooled in the air during quenching, and is very sharp—also known as white steel.
The material of high-speed steel drill bit is a kind of alloy steel with complex composition, which contains carbide-forming elements such as tungsten, molybdenum, chromium, vanadium, and cobalt. The total amount of alloying elements is about 10~25%.
It can still maintain high hardness under high heat generated by high-speed cutting (about 500 ℃), and the HRC can be above 60. This is the most essential characteristic of high-speed steel – red hardness.
After quenching and low-temperature tempering, carbon tool steel has high hardness at room temperature. Still, when the temperature is higher than 200 °C, the hardness drops sharply, and the hardness at 500 °C has dropped to a similar level to the annealed state. , completely lost the ability to cut metal,
This limits the use of carbon tool steel to make cutting tools. High-speed steel makes up for the fatal shortcomings of carbon tool steel due to its good red hardness.
High-speed steel drills are mainly used to manufacture complex thin-edged and impact-resistant metal cutting tools, as well as high-temperature bearings and cold extrusion dies, such as turning tools, drills, hob, machine saw blades and high-demand dies.
Tungsten steel drill bit material (hard alloy) has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance, especially its high hardness and wear resistance, even at a temperature of 500 ° C It remains unchanged at 1000°C and still has a high hardness at 1000°C.
The main components of tungsten carbide drill bits are tungsten carbide and cobalt, which account for 99% of all components, and 1% are other metals, so they are called tungsten steel, also known as cemented carbide, and are considered to be the teeth of modern industry.
Tungsten steel is a sintered composite material composed of at least one metal carbide. Tungsten carbide, cobalt carbide, niobium carbide, titanium carbide, and tantalum carbide are common components of tungsten steel. The grain size of the carbide component (or phase) is typically between 0.2-10 microns, and the carbide grains are held together using a metallic binder. Binder metals are generally iron group metals, commonly used as cobalt and nickel. Therefore, there are tungsten-cobalt alloys, tungsten-nickel alloys, and tungsten-titanium-cobalt alloys.
The sintering molding of tungsten steel drill bit material is to press the powder into a billet, then heat it to a certain temperature (sintering temperature) in a sintering furnace, keep it for a certain time (holding time), and then cool it down, to obtain the tungsten steel with the required properties. Material.