Quenching process for multi blade saw spindle

The spindle of a multi blade saw is an important component of a multi blade saw. The main spindle of a multi blade saw mainly plays a role in transmitting power, and bears various loads such as bending, torsion, and impact when cutting wood. It is required to have sufficient stiffness, strength, fatigue resistance, wear resistance, and stable accuracy.

(1) The heat treatment technology requires local quenching of the 160mm section of the main shaft, with a hardness of 48~53HRC.

(2) Manufacturing process route: forging → normalizing → mechanical processing → quenching → tempering → mechanical processing → finished product.

(3) The heat treatment process analysis shows that the length and diameter of the spindle are relatively large (about 9:1), and although it is prone to deformation, the difficulty of preventing and straightening deformation is reduced due to the requirement for local quenching. It is worth mentioning that the threaded holes and pin holes in the quenching area have small and numerous apertures, and it is difficult to clean them after heating and cooling medium immersion during the quenching process. Therefore, appropriate measures need to be taken to prevent them. In addition, during quenching and cooling of the inner cone hole, effective measures should be taken to strengthen the cooling of the cone hole due to the difficulty in discharging the medium after vaporization, which affects the uniformity of hardening.

(4) Heat treatment process design

1) Normalizing: Using forging waste heat (i.e. controlling the final forging temperature of the blank forging, about 850 ℃), dispersing and blowing for cooling.

2) Quenching: Before heating, all screw and pin holes in the 160mm quenching section of the main shaft are blocked with screws and pins (or asbestos or refractory mud). Then, the main shaft is suspended and the head (160+20mm) section is immersed in a completely deoxygenated RYD-100-8A salt bath furnace. The furnace is heated at 820-840 ℃ for 20-22 minutes. After being discharged from the furnace, it is suspended and placed on a specialized nozzle for quenching the conical hole inside the main shaft. The nozzle is completely immersed in a 5% -10% (mass fraction) NaCl aqueous solution for cooling, Transfer to the oil tank for further cooling after 9-11 seconds.

3) Tempering: Hang the quenched part and immerse it in a nitrate bath furnace at 380~400 ℃, hold it for 20~25 minutes, and then air cool it.

4) Auxiliary treatment: cleaning, sandblasting, rust prevention, etc.

(5) The surface hardness of the quenching section is 48~52HRC as a result of the treatment.