1, divided into two: different materials, different equipment, different process parameters, heat treatment after the organization and quality are also different. Even if the material grade, equipment, process parameters are the same, due to the chemical composition content of the upper and lower limits, heat treatment temperature upper and lower limits, holding time upper and lower limits are different, the organization and quality after heat treatment will be different. Even if the upper and lower limits of chemical composition content, the upper and lower limits of heat treatment temperature and the upper and lower limits of holding time are the same, the organization and quality after heat treatment will also be different due to the different processes, quality and organization of cold and hot processing in the early stage of heat treatment. Therefore, after the problem to specific problems specific analysis, that is, to be divided into two.

2. Two diagrams: Fe-C phase diagram and C curve. The Fe-C phase diagram is a necessary knowledge to deal with steel, and the C curve is the organizational transformation diagram of steel after heating and cooling. These two diagrams are the basis of heat treatment. Only by grasping these two diagrams and understanding these two diagrams in depth can dry heat treatment be possible and heat treatment can be started.

Three processes: heating, heat preservation and cooling. These three processes run through all heat treatment processes, and the quality of these three processes determines the quality of the final heat treatment. These three processes are thoroughly understood, and heat treatment is even the beginning.

4. Four fires: annealing, normalizing, quenching and tempering. These four fires are the most regular heat treatment, and the quality of these four fires reflects the level of heat treatment to a certain extent. If these four fires burn well, they are a heat treatment technician.

5, five tissues: Austenite, carburizing, martensite, bethosome, pearlite. A deep understanding of the characteristics of these five organizations, organizational morphology, precipitation (formation) conditions, performance, etc., the level of heat treatment technology can be improved.

6. Six major defects: oxidation, decarburization, overheating, over-burning, deformation and cracking. Among them, over-burning and cracking defects are the most taboo in work, because these two defects are irreparable defects, and the other four should also be avoided as far as possible. Although they can be made up, they significantly increase the workload and production cost. Engage in heat treatment can avoid or reduce these six defects is a qualified heat treatment engineer.

7. Seven phase transitions: pearlite transforms into austenite (P→A), austenite transforms into pearlite (A→P), austenite transforms into sorbite (A→S), austenite transforms into flexor (Torr) (A→T) austenite transforms into martensite (A→M), austenite transforms into bainite (A→B), martensite transforms into tempered martensite (M→M) to grasp this seven phase change heat treatment is a high level.

8, eight processes: 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, PCD, CVD, ion plating, etc.) can grasp the eight processes, heat treatment is an expert!