The heat treatment plan for screws mainly consists of the following points


1. Normalizing
The heat treatment process of heating medium carbon steel or high carbon steel parts such as screws to an appropriate temperature above the critical point AC3 or ACM for a certain period of time and then cooling in air to obtain pearlite structure is also the most common heat treatment method.



2. Solution heat treatment
The alloy is heated to a high temperature single-phase region and maintained at a constant temperature, so that the excess phase is fully dissolved into the solid solution, and then rapidly cooled to obtain a supersaturated solid solution.








3. Annealing
The screw hypoeutectoid steel workpiece is heated to 20-40 degrees above AC3, and after holding for a period of time, it is slowly cooled with the furnace (or buried in sand or cooled in lime) to a heat treatment process of below 500 degrees and cooled in air.



4. Time limit
The phenomenon that the properties of alloys change with time when they are placed at room temperature or kept slightly higher than room temperature after solution heat treatment or cold plastic deformation.



5. Solution treatment
The screw fully dissolves various phases in the alloy, strengthens the solid solution and improves the toughness and corrosion resistance, eliminates stress and softening, so that it can continue to be processed and formed. The most common processing scheme for stainless steel screw demagnetization, but the hardness will become soft, which should be noted.