The raw material of the HSS cobalt drill bit is high-speed steel. It is complex alloy steel, containing carbide forming elements such as tungsten, molybdenum, chromium, and vanadium. The total amount of alloying elements is about 10-25%. It can maintain high hardness even when high heat is generated by high-speed cutting (about 500℃), and the HRC can be above 60. This is the main characteristic of high-speed steel-red hardness. After quenching and low-temperature tempering, carbon tool steel has high hardness at room temperature, but when the temperature is higher than 200℃, the hardness drops sharply, and the hardness at 500℃ has dropped to a level similar to the annealed state. , Completely lost the ability to cut metal, which limits the use of carbon tool steel to make cutting tools. High-speed steel, because of its good red hardness, makes up for the fatal shortcomings of carbon tool steel and can be used to make cutting tools.
The specifications are mainly round steel and square steel. The surface of the steel should be processed well, and there should be no visible cracks, folds, scars, and hairlines. The surface of the cold-drawn steel should be clean, smooth, free of inclusions and scale.
Inspection of the unevenness of high-speed steel carbides is related to the corrosion time of the sample. The relevant standards only suggest that the corrosion should be appropriate and not over-corrosive, which is often overlooked by people. The practice has proved that if the corrosion has occurred, the carbides will be blackened, showing a false appearance of improved unevenness, and it is particularly important to misjudge poor quality high-speed steel as high-quality steel.
In addition, the wood auger drill bit is the same as the high-speed steel drill bit. Like a drill bit, it is mainly used for woodworking.