I would like to ask about the specific annealing temperatures, such as A3, A1, Acm

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First question: As we all know, the temperatures for annealing, normalizing, and tempering refer to A3, A1, and Acm. I would like to ask what exactly these temperatures are Second question: According to the iron-carbon phase diagram, there are also AR1 and AC1, AR3 and AC3, as well as ACCM and ARCM. What are their exact temperatures? I’m not very clear about the iron-carbon phase diagram; I hope those who have relevant information or experience can provide some guidance... Here is what I’ve found: Annealing refers to a processing method in which steel is heated to a certain temperature, held at that temperature for a while, and then cooled slowly (either by cooling it in the furnace or in a medium with poor thermal conductivity) in order to obtain a balanced microstructure. Purpose: To reduce hardness to facilitate machining ； Increase plasticity to facilitate plastic processing and shaping ； Refine grains to improve mechanical properties ； Stress relief to prevent deformation and cracking. Normalizing refers to the heat treatment process in which steel is heated to 30–50 degrees above the A3 line (for hypoeutectoid steel) or the Acm line (for hyper-eutectoid steel), held at that temperature, and then cooled in still air. Quenching is a treatment process in which steel is heated to 30–50 degrees above its structure transformation temperature (A3 or A1), held at that temperature for a certain period, and then rapidly cooled. Its purpose is to obtain a martensitic structure, thereby endowing the steel with high hardness and high wear resistance. Quenching is an important method for strengthening steel. Tempering is a treatment process in which the steel that has been quenched is heated to a temperature below the A1 line, held at that temperature for a while, and then cooled to room temperature. This is a process that must be carried out on quenched workpieces; it determines the microstructure and properties of those workpieces in their operating condition, and can also be said to determine their performance and service life. The purpose of tempering is to eliminate the internal stresses resulting from rapid cooling during quenching, reduce the brittleness of the quenched workpiece, stabilize its dimensions, and endow it with properties suitable for operational conditions. This post was last edited by *QIU on 2009-4-8 13:45]