Heat treatment of claws by quenching equipment

　A chuck is a mechanical device used to clamp workpieces on machine tools. According to the number of chuck claws, it can be divided into: two-claw chuck, four-claw chuck, six-claw chuck and special chuck. Today we will take a three-jaw chuck as an example to introduce the heat treatment of the jaws using high-frequency induction quenching equipment.

　　The three-claw chuck uses a large wrench to rotate the bevel gear. The bevel gear drives the plane to thread, and then drives the three claws to move centripetally. Since the pitch of the plane rectangular thread is equal, the three claws move at the same distance and have an automatic centering effect. The three-claw chuck is composed of a large bevel gear and three claws. The three claws are equally installed on the flat thread, and the small bevel gear rotates when a wrench is used. The flat thread on the back allows the three claws to move toward or withdraw from the center.

　　The material of the claw is 45 steel, the overall dimensions are 70.3*56*20.5mm, and the tooth width is 12mm. The hardness is ≥52HRC, the sides and base are 30-40HRC, and the remaining parts are 53-58HRC. The introduction of quenched heat treatment workpieces is as follows:

　　①Normalize the fire. The process is: 850℃X1.5-2h, the hardness after normalizing is ≤187HBW.

　　②Quenching, the process is: 820-830℃x10min water and oil double liquid quenching, the claws are cooled in water for 5-6S and immediately transferred to oil for cooling. The hardness after quenching is 54-58HRC.

　　③Tempering. The process is: 200-210℃x2h nitrate salt tempering. The hardness after tempering is 53-57HRC.

　　④High frequency induction hardening and tempering. Special induction coil, the quenching part is 12mm wide. Affected by high-frequency induction heating, the tooth root undergoes tempering transformation, and the hardness just reaches the technical requirement of 30-40HRC. After high-frequency induction quenching, nitrate salt tempering at 180-200℃*2h.