Dewaxing operation guide for investment casting

Operation procedure:

Equipment preparation:

1) The pressure of steam generator for dewaxing shall be 0.8-1.0mpa, and the minimum pressure shall not be less than 0.6MPa

2) Carefully check whether the steam dewaxing filter screen needs to be cleaned or replaced to prevent wax running in the process of dewaxing. ]

3) Before the start of dewaxing, the pressure test shall be carried out on the dewaxing kettle, and it shall be preheated 1-2 times (i.e. hot pot), and the redundant shell materials at the gate cup edge shall be removed.

Shell preparation: remove the modules that have reached the standard drying time, remove the hook, cover plate, etc., and remove the redundant shell materials at the gate cup edge.

Put the module upside down on the dewaxing steam kettle trolley, quickly send it into the dewaxing kettle, and immediately close and close the door.

Open the steam valve, the pressure shall reach 0.6MPa within 14s, and the dewaxing shall be completed within 6-10min.

Close the steam valve, open the exhaust valve, release the steam, and release the pressure slowly for more than one minute.

When the indicated pressure of the pressure gauge of the dewaxing kettle is zero, open the wax discharge valve, discharge the wax completely, open the door of the dewaxing kettle, and pull out the basket of the shell.

Check the dewaxing quality and shell quality, send the qualified shell to the designated place, place it on the rack in order according to the casting alloy material, wait for baking and pouring, the shell with cracks or holes shall be repaired, and the shell with cracks more than 0.5mm shall be scrapped by the quality inspector.

Shell repair

(1) When the surface of the shell is only slightly cracked, it can be repaired by coating.

(2) When there is a hole in the shell due to missing parts, a clean shell can be placed at the hole, and then sealed with paint slurry (or refractory mud) for drying.

Pour the discharged wax liquid into the 290 ℃ static barrel in time, keep it warm and static. If the water content of the wax liquid is too high, the wax liquid can be directly poured into the dewatering bucket, the temperature is raised to remove the water, the water is stirred to evaporate fully, and then recycled to the stationary bucket for heat preservation.

After the work is completed, shut down the boiler, thoroughly clean the equipment and site used, and pay attention to thoroughly remove the overflow residual wax on the dewaxing axe and wax storage tank, so as to prevent more and more accumulation.


Regularly check whether the pressure gauge, water level gauge and safety valve of steam dewaxing kettle are normal.

Do not damage or scratch the plastic sealing ring on the door of the dewaxing kettle, and replace it immediately if there is any damage and air leakage.

When the module is transported from the shell making workshop to the dewaxing place, it should be transported to the dewaxing axe at the same time. If the delay time is delayed, the shell will be heated in advance, and the shell will crack due to the wax expansion.

The wax pipe shall be inspected at any time to ensure that the pipe is unblocked between 70-85 ℃. After use every day, the wax pipeline shall be cleaned with steam to ensure that the pipeline is unblocked during re dewaxing, and the wax liquid shall not be stored in the wax storage tank.

If the wax pipeline is blocked, it is strictly prohibited to barbecue with open fire to prevent accidents, and the vent pipe can be used to heat the pipeline to make it smooth.

Strictly follow the operation procedures to avoid accidents.