1. split into two Different materials, different equipment, different process parameters, and different microstructure and quality after heat treatment. Even if the material grade, equipment and process parameters are the same, the microstructure and quality after heat treatment will be different due to the upper and lower limits of the chemical composition, the upper and lower limits of the heat treatment temperature, and the upper and lower limits of the holding time. Even if the upper and lower limits of the chemical composition, the upper and lower limits of the heat treatment temperature, and the upper and lower limits of the holding time are the same, the structure and quality after heat treatment are also different due to the difference in the process, quality, and structure of the hot and cold processing in the early stage of the heat treatment. Therefore, after a problem arises, it is necessary to analyze the specific problem in detail, that is, to divide it into two. 2. Two figures Fe-C phase diagram and C curve. The Fe-C phase diagram is an essential knowledge for dealing with steel and is the basis for the development of heat treatment processes. The C curve is the tissue transition diagram of the steel after heating, and these two figures are the basis of the heat treatment. Only by grasping these two figures and understanding the two figures in depth, it is possible to dry heat treatment and heat treatment to get started. 3. Three processes That is, the three processes of heating, heat preservation and cooling . These three processes run through all the heat treatment processes, and the quality of these three processes determines the quality of the final heat treatment. The three processes are well understood, and the heat treatment is getting started. 4. Four fires That is, annealing, normalizing, quenching, and tempering . These four fires are the most conventional heat treatments. The quality of these four fires reflects the heat treatment level to some extent. If the four fires are well burned, it is a heat treatment technician. 5. Six organizations That is, austenite, cementite, ferrite, martensite, bainite, pearlite . A deep understanding of the characteristics, organization, precipitation (formation) conditions, performance, etc. of these six organizations, the level of heat treatment technology can be improved. 6. Six major defects The six major defects are oxidation, decarburization, overheating, overburning, deformation, and cracking . Among them, the most taboo in the work is the occurrence of overburning and cracking defects, because these two defects are irreparable defects, the other four should also be avoided as much as possible, although it can make up, but significantly increase the workload and production costs. The heat treatment can avoid or alleviate these six defects, which is a qualified heat treatment engineer. 7. Seven phase transitions (1) transformation of pearlite into austenite (P→A); (2) transformation of austenite into pearlite (A→P); (3) transformation of austenite to sorbite (A→S); (4) transformation of austenite into yttrium (A→T); (5) transformation of austenite to martensite (A→M); (6) transformation of austenite to bainite (A→B); (7) Martensite is transformed into tempered martensite (M→back M). Grasping these seven phase changes, heat treatment is a high level. 8. Eight major crafts Namely: annealing process, normalizing process, quenching process, tempering process, surface quenching process, chemical heat treatment process, vacuum heat treatment process, special heat treatment process (laser, ion nitriding, PVD, CVD, ion plating, etc.). Being able to accurately grasp these eight processes, heat treatment is an expert! ! ! milling cutter,Indexable Ball Nose End Mill,Corn Teeth End Mills.Diamond Coated Drill Bit JIANGYIN GOLD STAR INDUSTRY CO.,LTD , https://www.jygoldstarindustry.com