Views:3101 Author:Changzhou Yinhua tools Co.,Ltd Publish Time: 2020-02-19 Origin:Original
In general, the color of the left-hand twist drill has nothing to do with its quality. It is not reliable to simply distinguish the quality of the left-hand twist drill from its color. The color has no direct and inevitable relationship with its quality, different color drill is mainly processing technology is different, of course, from the color can make a general judgment, but some factories will be poor quality of the left twist drill color processing into the appearance of high-quality drill style.
What is the difference between different colors of the left-hand twist drill the following only high-speed steel left-hand twist drill color and quality of the relationship. High-quality high-speed steel twist drill bits are often coated with titanium. This kind of drill bit is usually golden yellow. It is made of super-hard cobalt-containing high-speed steel. The reason why it is of high quality is that apart from the material itself, the quality control of the grinding process is also very strict, the surface of the tool will not appear burn. There are two kinds of black left-twist bits. One is all-black bit which is nitrided. The finished cutting tool is placed in a mixture of ammonia and steam. It is heated at 540 ~ 560 °C, objective a chemical method to improve the durability of cutting tools. At present, most of the black drill bits on the market are only black in color (to cover the burn or black skin on the tool surface) , but the actual use effect has not been effectively improved. The other is the drill outside diameter black, groove bright, this kind of left twist drill quality is very good, the surface wear-resisting, groove discharge chip is good.
The craft also has 3 kinds of craft than the all-black complex production drill, black for rolling, the worst. White for clear edge and grinding. Because, unlike rolling, high-temperature oxidation does not occur, the grain structure of the steel is not destroyed and is used to drill for work pieces of slightly higher hardness. Gold-colored drill, known in the industry as the high-cobalt left-hand drill, this is the drill industry's unspoken rules. Cobalt drill is originally white, grinding production, late titanium treatment, is the best in circulation is M42(Co 8%) there is a gold, industrial titanium plating quality is very good, hardness can reach HRC78, higher than cobalt drill hardness. There is also a kind of drill called titanium-plated drill is decorative plating. Decorative plating does not have a role, is good-looking, golden so that layman do not understand.