Heat treatment process of serpentine spring:
The heat treatment process of the serpentine spring: the first quenching, tempering-intermediate annealing-second quenching, tempering-final tempering are 4 steps. The detailed heat treatment process is as follows:
1. The first quenching and tempering: The purpose of the first tempering and tempering of the serpentine spring is to adjust the structure of the steel plate. The serpentine spring blank is 145.5mm×14.5mm×3mm, and each batch contains 3% The sample. Load the blank and sample into the spreader, heat it in a salt bath furnace, and cool it out of the furnace.
The tempered parts should be cleaned, degreasing, sandblasted, and coated with protective coatings on the surface of the parts and samples. The tempering temperature is 720℃±10℃, the temperature is kept for 60min, and the furnace is air cooled. The hardness is tested HRC26.
2. Intermediate annealing: the serpentine spring is initially formed and then subjected to intermediate annealing. Protective coating should be applied before the intermediate annealing, and lightly sandblasted to remove the residual wire coating after annealing, and then the final molding is carried out.
3. The second quenching and tempering: The purpose of the second quenching and tempering of the serpentine spring is to shape the final performance of the part. After the part is finally formed, the iron wire is tied, and heated in a fully deoxidized salt bath-after heat preservation After the oil is quenched, the oil is cooled thoroughly. After the oil is quenched, it is cleaned and degreasing with water at 60~80℃, and then tempered at 425℃±10℃. After tempering, the surface of the sample is ground off ≥0.2mm and the hardness should be HRC49~51.
4.Final tempering: After the hardness of the serpentine spring is qualified, the parts are sandblasted, and then pre-deformed, pressurized to 55mm±1mm at the actual measurement position, keep for 30-40h, and then perform final tempering.