Why are the drill bits black, white and gold？ What is the difference？ Which one is good quality？

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Drilling is a very extensive processing method in the manufacturing industry. I believe that the little partners who are often in the front line of drilling will not be unfamiliar with the understanding of drills. When purchasing drills, the drills will have drills of different materials and colors, so different colors. How can you help the drill bit? Is the color related to the quality of the bit? Which color bit is better??

First of all: It is impossible to distinguish the quality of drills from the color alone. There is no direct and inevitable relationship between color and quality. Drills of different colors are mainly processed by different processes. Of course, you can make a rough judgment from the color, but the current quality of the drills is also poor. Will process their own colors to achieve the appearance of high-quality drills.


High-quality, fully ground high-speed steel drill bits are often usedwhiteAppeared, of course, the rolled drill can also be white by fine grinding of the outer circle. The reason for this is high quality. In addition to the material itself, the quality control during the grinding process is also quite strict, and there will be no burns on the surface of the tool..blackIt is a drill bit that has been nitrided. It is a chemical method that puts the finished tool in a mixture of ammonia and water vapor and passes 540-560C
heat preservation treatment to improve the durability of the tool..At present, most of the black drill bits on the market only achieve the color black (in order to cover the burn or black skin on the surface of the tool), but the actual use effect has not been effectively improved..


There are 3 processes for producing rock drill bits, Black is rolled, the worst.The white ones are trimmed and polished.Because it does not produce high-temperature oxidation, unlike rolling, the grain structure of the steel is not damaged. It is used to drill workpieces with slightly higher hardness..tanThe drill bit is called cobalt-containing drill in the industry. This is the unspoken rule of the drill bit industry.Cobalt-containing diamonds are originally white and are produced by grinding. When they are atomized in the later period, they become yellowish brown (generally called amber), which is currently the best in circulation..M35 (Co 5%) and another is Golden Yes, this kind of drill is called titanium-plated drill, divided into decorative plating and industrial plating.The decorative plating has no effect at all, it's just beautiful and golden.Industrial plating is very good, the hardness can reach HRC78, which is higher than the hardness of cobalt-containing diamonds


Judging from experience, in general, the white ones are generally all-ground high-speed steel drill bits, and the quality should be the best.The golden ones are titanium nitride-plated, and are generally either the best or the worst to fool people.The quality of black is also uneven. Some are made of very poor carbon tool steel, which is easy to anneal and rust at the same time, so it needs to be blackened..

Generally, when buying a drill bit, you can see the trademark on the drill bit shank and the mark of the diameter tolerance. The mark is clear, and the quality of laser or electric corrosion is not too bad..If it is a typeface embossed, if the edge of the word bulges, the quality of the drill is poor, because the bulged outline of the word will cause the drill bit to be less accurate, and the edge of the word is clear, which is very good with the cylindrical surface of the drill shank The bordered ones are of good quality.In addition, it depends on the cutting edge of the tip of the drill. The cutting edge of the fully ground drill is well opened, the spiral surface meets the requirements, and the quality is poor at the rear corner surface..


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