Compared with foreign tools, domestic cutting tools have a large gap in cutting life. Some people suspect that tool materials are not strong, and they are not as good as foreign countries. Therefore, high-performance high-speed steel and even high-speed steel such as M42 and M35 are imported from abroad, but the quality of the tools is still not as good as others. . Experts believe that heat treatment is not as good as people. Here are some tips on how to improve tool life.
1. Pay attention to the core role of carbide
High-speed steel heat treatment is doing the transformation and transformation of carbides. Carbide is a double-edged sword for high-speed steel tools. It is well treated. It can ensure high-speed steel with high hardness, wear resistance and hot hardness. If it is not handled well, it will lead to overheating and over-burning, thus affecting the tool. life. In order to prolong the life of high-speed steel tools, it is necessary to have a deep understanding of the carbides in steel, and to deeply understand the formation and variation of carbides, so as to develop in a direction that is conducive to improving tool life.
The most intuitive one is to check the unevenness of the carbides, and to improve the morphology and distribution of the carbides by pressure processing. The quenching heating pays attention to the solubility of the carbides and checks the changes of the tempered carbides.
2. Check the grain size must look at the carbide solubility
The inspection of high-speed steel grain size has always been used as an important means to test the quenching quality of high-speed steel, and some even serve as the only means to detect hardness. How much influence does grain size have on the life of high speed steel tools? Domestic and foreign counterparts have different opinions and even have major differences.
In the former Soviet Union, tests on the f8mmP6M5 (M2) steel straight drill showed that the knives had the best service life (460 drilled holes) when the grain size was 9.5, and the grain size was too thin or too thick, and the bit life was reduced. We share the same feelings in the activities of “Chuangyou†and “Creating a National Brand Drill Bitâ€, but we should add two points: the carbide dissolution should be sufficient; the hardness after heat treatment is >65HRC.
The requirements of different cutters for quenching austenite grain size and carbide solubility are different. For example, the gear hob grain size is 9 grade, the turning tool is 8 grades, the carbide dissolution is sufficient, and the machine tap is 10.5. The crystal grains and carbides are generally dissolved.
The grain size is at best a reflection of the quenching heating temperature. For tools requiring high thermohardness, the carbide solubility is more important than the grain size. Therefore, when looking at the metallurgical phase before the furnace, it is necessary to take both into consideration.
3. Hardness problem
In many papers, the author repeatedly emphasized the basic viewpoint that "hardness is a superficial phenomenon and metallographic organization is the essence". For high-speed steel tools, it is a good idea to get a high hardness of 64HRC or more, but it is not an easy task to achieve an ideal metallurgical organization. For example, super hard high speed steel such as M42 is not as high as possible, but has a suitable range. The hardness is too high, not only will not have a long life, but will lead to life. High-speed steel tools have never been a hero in terms of hardness. For a specific steel grade, the tool has a practical hardness value under specific working conditions. If it is high or low, it will not have a high life. According to my experience, HSS steel cutter hardness is 65~66HRC; HSS-E steel cutter 66~67HRC; HSS-L steel cutter can not reduce hardness because it is low alloy, it should reach 65~66HRC. In practice, it has been found that high-life tools generally have high hardness, but high hardness does not necessarily have a high life. Therefore, it is necessary to strive for high hardness under the premise of using the toughness of the foot.
4. Surface strengthening
Some people say that the space for improving the heat treatment potential of high-speed steel tools is very small, and it should be a "surface article". This is true, but not comprehensive.
The surface strengthening technology of high-speed steel tools is developing very fast. At present, steam treatment, oxynitridation, TiN coating, TiA1N coating and multi-layer composite coating are all helpful to improve tool life.
There are two problems that must be noted for surface strengthening: pre-treatment must be too hard, low hardness or overheated tool, no matter how hardened it will not have a high life. Surface strengthening must be targeted to ultimately improve tool life.
5. Strive to stabilize tool life
Feedback from domestic and foreign markets shows that a high-quality tool product not only has a high average life, but also has stable quality and good tool life repeatability. A considerable number of tool factories in China have low tool life, not the life of each product is low, but the life span is very different, and the dispersion is too large, resulting in a significant decline in the average life of the tool. Many domestic tool factories have done such tests: compared to single pieces, domestic tools are not worse than foreign ones, but if you take 10 pieces of PK, there will always be 1 or 2 pieces of domestic tools.
The stability of product quality and tool life is a comprehensive reflection of the technical level and management level of a factory. It is not an easy task to make the tool life high. It is a systematic project. From the inspection of raw materials, machining, heat treatment, to the final packaging of the product, there must be a strict set of rules and regulations. The craft documents, as well as the complete testing methods and the good quality of the staff.
The successful application of advanced heating equipment such as precision temperature control and vacuum on the heat treatment furnace of the computer has made positive contributions to the stability and improvement of the quality of the tool products. In addition, the German Zeiss metallurgical microscope also adds weight to the stability of product quality.
In summary, to improve China's tool life requires "positive energy", steel mills must give strength, mechanical processing should give strength, but the most important thing is to heat treatment colleagues to compete. As long as we are serious about doing every step, we will be able to create high-life knives and do our part for China to become a world machinery manufacturing power.
Air purification Activated Carbon pore developed for chemical raw materials chemical synthesis gas, the pharmaceutical industry gas drinks with carbon dioxide and hydrogen, nitrogen, the inert gas such as hydrogen chloride purification and atomic facilities purification, also used to drop off the air pollutants and the classification of mixed gas purification.
Activated Carbon For Air Purification
Activated Carbon For Air Purification,Pellet Activated Carbon For Air Purification,Coconut Shell Activated Carbon,Decolorizing Activated Carbon
NINGXIA SINOTOPSKY INTERNATIONAL TRADING CO.,LTD. , http://www.nxsinotopsky.com